UKZN General Surgery Lecture Notes PDF

LECTURE NOTES IN GENERAL SURGERY – A STUDENTS GUIDE PRODUCED BY THE DEPARTMENT OF GENERAL SURGERY NELSON MANDELA SCHOOL OF MEDICINE 1ST EDITION EDITED APRIL 2012 - PROF B SINGH...

LECTURE NOTES IN GENERAL SURGERY – A STUDENTS GUIDE PRODUCED BY THE DEPARTMENT OF GENERAL SURGERY NELSON MANDELA SCHOOL OF MEDICINE 1ST EDITION EDITED APRIL 2012 - PROF B SINGH AND MR S MOODLEY CONTENT PAGE NO 1. Foreword 3 2. Fluids and Electrolytes – Mr D Skinner 4 3. Nutrition in the surgical patient - Mr VM Nair 14 4. Burns - Mr D Hollander 19 5. Thyroid – Mr J Reddy 25 6. Breast - Benign breast disease - Mr S Cheddie 33 - Breast Cancer – Mr S Cheddie 37 7. Skin Disorders and Melanoma - Ms R Naidu 40 8. Soft Tissue Tumors - Mr CG Bhula 43 9. Approach to dysphagia and oesophageal Cancer - Ms R Naidu 48 10. Approach to abdominal masses - Dr K Maharaj 53 11. Approach to acute abdominal pain – Mr S Mewa-Kinoo 56 12. Acute pancreatitis - Mr S Cheddie 60 13. Upper gastro-intestinal bleeding - Mr SO Rambarran 64 14. Lower gastrointestinal bleeding - Mr SO Rambarran 69 15. Colorectal Cancer - Mr M Naidoo 71 16. Perianal pathology - Mr A Singh 80 17. Obstructive jaundice - Mr CG Bhula 87 18. Intestinal obstruction - Mr S Moodley 95 19. Vascular Surgery – Mr B Pillay - Peripheral vascular disease 99 - Trauma 102 - Aneurysms 105 - Venous disorders 107 20. Approach to the Polytrauma Patient - Mr T Hardcastle 111 -2-  FOREWORD Lectures Notes in Surgery is a compilation of topics that form the core of undergraduate teaching in General Surgery. This booklet is a guide that should help in directing the reading of the undergraduate student. This document is by no means a comprehensive overview of the topics and supplementation of these notes will be necessary as the student progresses through the clinical years. -3-  FLUIDS AND ELECTROLYTES Mr DL Skinner Introduction Understanding fluid and electrolyte derangements requires an understanding of fundamental principles of physiology. A good working knowledge on the topic is crucial in the proper assessment and treatment of all patients, not just those with surgical problems. The topic is even more relevant in the management of trauma, surgical emergencies and critically ill patients. Fluid distribution In a 70kg man the total body water comprises about 60% of body mass. This body water is divided into two main compartments: 1. Intracellular fluid (40% body mass) 2. Extracellular fluid (20% body mass) a. Interstitial fluid (16% body mass) b. Intravascular fluid (4% body mass) Intravascular fluid makes up a very small component of fluids in the body. The fluid compartments are separated by semi-permeable membrane that freely allows water molecules to flow through to and fro under the influence of osmotic forces. This means that intravenous fluids are distributed throughout the body equally if isotonic. Fluid Therapy Fluid therapy seeks to replace fluid loss with fluid similar in composition with the lost fluid. It is important to know the likely composition of the fluid being lost and the composition of the fluid for therapeutic administration. Plasma electrolyte composition: Sodium 135-145mmol/l Chloride 95-105mmol/l Potassium 3.5-5.5mmol/l HCO3- 22-26mmol/l Therapeutic fluid administration can be divided into enteral and parenteral. Generally, in significant derangements, parenteral fluids are used. Parenteral solutions are divided into two groups: colloid and crystalloid, based on their size and ability to cross semipermeable membrane. Crystalloids are made up of a solution of salts which readily pass through a semipermeable membrane, thus increasing both the intravascular and interstitial spaces. Colloids exert a high osmotic pressure in the blood and theoretically tend to remain within the intravascular space. This assumes an intact vascular membrane, which is rarely the case in patients with critical illness. Fluids are further divided into resuscitation, rehydration, maintenance and special type fluids. Resuscitation fluids Colloids Colloids are solutions made up, on the whole, by particles of varying molecular size. Some are monodisperse (all molecules in the solution are the same size) e.g. albumin while all the others are polydisperse (molecules in the solution show a large variation in size) e.g. gelatins, starches and dextrans. At present the following colloid fluids, with their mean molecular weights are easily accessible to most practitioners: Albumin (66 – 69 000 D) Dextrans (40 – 70 000 D) Gelatins (30 – 35 000 D) Succinylated (Gelofusine®) -4-  Urea linked (Haemaccel®) Hydroxyethyl starches (40 – 450 000 D) Tetrastarch (Voluven®, Venofundin®) Pentastarch (Haesteril®) The use of colloids even in low concentrations substantially reduces the fluid volumes required for correction of hypovolaemia because colloids last longer in the intravascular space and are more efficient plasma expanders. The five issues that have featured in the literature most prominently regarding the use of colloids are those of: Bleeding and clotting disorders Acute kidney injury Damage to donor organs Colloid metabolism and residue accumulation Colloid induced allergic and anaphylactoid reactions The use of artificial colloids such as the hydroxyethyl starches is controversial and recent studies are showing conflicting results. Crystalloids 1. Isotonic Saline (0.9% “ normal” NaCl) a. Prototype crystalloid b. Has higher concentration of sodium and chloride than plasma Disadvantage c. Hyperchloraemic acidosis is a potential risk with large volume isotonic saline resuscitation in a euvolaemic patient 2. Hypertonic saline a. 5-7.5% saline b. Highly hyperosmolar c. Infused intravenously in small volume of about 250ml in hypovolaemic shock as a powerful plasma expander. Its use is still experimental. d. Small volumes therefore easily transportable e. Potential immunomodulation f. Improves blood rheology g. Disadvantages: Hypernatraemia Difficulty in assessing extent of blood loss 3. Ringer’s Lactate a. A balanced salt solution b. Adding other electrolytes to the salt solution to approximate the composition of the plasma minimizes dilution of normal plasma components and dilutional hyperchloraemic metabolic acidosis. c. Contains potassium and calcium in concentrations that approximate the free concentration in plasma. d. Lactate added (28 mmol/l) in chloride concentration. Disadvantages e. The calcium binds to certain drugs and reduces their bio availability and efficacy. Of note is calcium binding to citrate anticoagulant in blood products, which inactivate the anticoagulant and promote formation of clots in donor blood. 4. Plasmalyte a. pH is equivalent to that of plasma b. Has magnesium which may provide some benefit in patient with magnesium depletion. 5. Dextrose solutions -5-  a. Not an effective volume expander – used to supplement non-protein calories b. Hypertonic solution which when the dextrose is metabolised generates pure water so becomes hypotonic once intravascular. c. Enhanced CO2 production which is a burden in ventilator – dependent patients. d. Enhanced lactate production and aggravation of head injury Colloids vs crystalloids controversy The crystalloid vs colloid debate continues and for reasons discussed below, is unlikely to be resolved. As an increasing number of colloids become available, the controversy may evolve into which colloid vs crystalloid. There are some areas of agreement between the opposing views. Most agree that colloids are more efficient in that equivalent intravascular volume expansion is achieved with less colloid. Colloids are more expensive than crystalloids. There is no risk of anaphylaxis with crystalloids. Colloid oncotic pressure is better maintained with colloid. Fluid overload is bad for the patient regardless of the type of fluid used. The amount of interstitial oedema is dependent on the volume of fluid given and there is a negative correlation between a positive fluid balance and survival in critically ill patients. As it takes 2 – 6 times the volume of crystalloid compared with colloid to maintain the same haemodynamic state in critically ill patients, it is not surprising that crystalloid fluid resuscitation cause greater interstitial oedema. In theory, interstitial oedema has several adverse effects:  Cerebral -obtunded conscious level  Pulmonary - impaired gas exchange  Myocardial - reduced compliance  Tissue - impaired wound healing  Gut - reduced absorption and enhanced bacterial translocation. Increased leak rates from anastomoses  Increased risk of abdominal compartment syndrome. Despite these reservations, no prospective randomized studies have demonstrated clearly the superiority of colloids over crystalloids for trauma resuscitation. In the Advanced Trauma Life Support guidelines currently, Ringer’s lactate is recommended as part of the emergency resuscitation of the trauma patient, proceeding to blood products as required. The American College of Surgeons Classes of Acute Haemorrhages specify four classes of acute haemorrhage using a blood loss ranging from up to 750 ml to >2000ml. The American College of Surgeons Classes of Acute Haemorrhages Parameter Class I Class II Class III Class IV blood loss in mL = 2,000 mL mL mL blood loss as % total = 40% blood volume pulse > 100 > 100 > 120 >= 140 blood pressure normal normal decreased decreased pulse pressure normal or decreased decreased decreased increased capillary refill normal delayed delayed delayed respirations 14 – 20 20 – 30 30 – 40 > 35 urine output >= 30 mL/h 20 – 30 mL/h 5 – 10 mL/h minimal mental status slightly anxious mildly anxious anxious and confused and confused lethargic Recommendations for fluid choice: (1) Crystalloid: sufficient for Classes I and II (2) Crystalloid and blood (in ratio of 3:1): for Classes III and IV -6- Despite the above recommendations, crystalloidsare not the ideal resuscitation fluid although they are still widely used. Early use of blood and blood products is advocated in more recent advances in understanding of coagulation disturbances in trauma and knowledge of the complications of large volumes of crystalloid and artificial colloids. Maintenance Normal daily requirements of water and major electrolytes per kg/day: Water 36 mL Sodium & potassium 1 mmol Chloride 1-2 mmol Calcium & Magnesium 0.1 mmol Phosphate 0.1 mmol These fluids are used to replace fluids lost through the basal metabolic reactions. Fluids used for maintenance include  Electrolyte No. 2 with 10% dextrose  Maintelyte  Post Surgisol  Paediatric: PMS  Neonates: Neonatalyte. These fluids should NOT be used for resuscitation. Replacement Fluid replacement should be appropriate to the fluid deficit (e.g. pure dehydration, lack of salt and water, or intravascular hypovolaemia). Replacement is also needed in salt losing renal or endocrine disease. Increased evaporation, for example from hyperventilation, non-humidified face masks, open wounds or excessive sweating, results in proportionately greater need for free water replacement. Gastrointestinal fluid composition: Composition and Volume of Intestinal Secretions Source Volume (ml/day) [Na+] [K+] [Cl-] [HCO3-] Saliva 1500 10 26 15 50 Gastric 1500 100 10 100 0 Duodenum 2000 130 5 90 10 Ileum 3000 140 5 100 30 Pancreas 800 140 5 75 115 Biliary 800 150 5 100 35 Excessive losses from gastric aspiration/vomiting should be treated preoperatively with an appropriate crystalloid solution which includes an appropriate potassium supplement. Hypochloraemia is an indication for the use of 0.9% saline, with appropriate additions of potassium and care not to produce sodium overload. Losses from diarrhoea/ileostomy/small bowel fistula/ileus/obstruction should be replaced volume for volume with Hartmann’s or Ringer’s Lactate (balanced salt solution) type fluids. -7- Electrolyte Disturbances Hyponatraemia Defined as serum sodium of less than 135mmol/l. This is best thought of as a disorder of water rather than a sodium disorder. Symptoms include fatigue, muscle weakness, apprehension, diarrhoea, abdominal cramps, oliguria and convulsions. Hyponatraemia can be divided into 3 types  Normotonic hyponatraemia (Pseudohyponatraemia) This is caused by hyperlipidaemia or hyperproteinaemia. Older tests used flame emission spectrophotometry. This however measured the sodium concentration in the entire plasma volume and not just in the pure water component. The lipid and protein contain no sodium and is normally about 6% of total plasma. When this percentage increases, sodium concentrations may be falsely low. Currently ion specific electrodes are used which measure the activity of sodium directly and this problem is not common now. Hypertonic hyponatraemia Osmotically active non electrolyte particles that are in the extracellular fluid, and do not cross the cell membrane cause a shift of fluid from the interstitial space and the intracellular compartment into the extracellular fluid, thereby causing a dilution of the fluid in the intravascular compartment. Examples are mannitol, glycerol. Treatment is rarely needed for the hyponatraemia but the underlying cause of the hyperosmolar state should be corrected. Hypotonic hyponatraemia All cases of hypotonic hyponatraemia result from excess total body water. Depending on the circulating plasma volume, it is divided into hypovolaemic, euvolaemic or hypervolaemic hyponatraemia based on history or clinical assessment. Clinically increase of 12 litres or more in total body water is required to develop oedema. In a healthy individual such high volumes of water need to be ingested to cause dilution of sodium in plasma. In individuals with high circulating antidiuretic hormone levels due to existing illnesses, hypovolaemia or pain water retention occurs at lower volumes of water ingested. 1. Hypervolaemic hypotonic hyponatraemia a. Excess water retention e.g. - psychogenic polydipsia (> 15-20 litres of ingestion before water retention and hyponatraemia develops) b. TURP syndrome - retention of water from irrigation fluid c. Water retention in conditions with altered ADH response e.g. cardiac, liver, thyroid, adrenal and kidney failure 2. Normovolaemic hypotonic hyponatraemia a. SIADH 3. Hypovolaemic hypotonic hyponatraemia a. Water retention occurs at lower volumes where there is high ADH levels e.g. hypovolaemia, diarrhoea, diuretic abuse. Syndrome of inappropriate ADH secretion (SIADH) This is characterized by an inappropriately concentrated urine of low volume (>100 mosmol/kg) in the setting of hypotonicity and hyponatraemia. High urinary sodium levels are required for diagnosis (>40mmol/l) Causes of SIADH:  Tumours (paraneoplasia) secrete ectopic ADH: Bronchogenic carcinoma, pancreatic adenocarcinoma, lymphomas, prostate carcinoma, and mesothelioma.  CNS disorders: head trauma, brain tumour, meningitis, CVA.  Pulmonary diseases : TB, pneumonia, bronchiectasis  Drugs: opiates, carbamazepine, phenothiazine, tricyclic antidepressants.  Miscellaneous : postoperative state, pain, nausea, psychosis -8- Management of SIADH The only definitive treatment of SIADH is elimination of its underlying cause. Most cases caused by malignant disease resolve with successful treatment and most of those due to medications resolve promptly when the offending agent is discontinued. Treatment of hyponatraemia Treatment of hyponatraemia depends on the severity of the deficit, the duration of the deficit, the underlying illness or factors predisposing or causing it and the symptoms that the patient is experiencing.  Low ECF o Infuse with isotonic or hypertonic saline depending of the severity of the deficit. o The sodium deficit is calculated by multiplying the sodium deficit by the approximate extracellular volume which is about 15% of the body weight. (Desired sodium concentration – current sodium concentration) * (total body weight * 15/100).  Normal ECF o Isotonic saline in asymptomatic patients o Hypertonic saline in symptomatic patients  High ECF o Furosemide diuresis In general, correct the serum sodium concentration at an hourly rate of no more than 0.5 mmol/L. If symptoms are severe, more rapid correction is necessary in the first few hours, since the patient is at risk of cerebral oedema. With intravenous therapy, correct the serum sodium concentration by no more than 12 mmol/L in the first 12–16 hours, or 0.5–1.0 mmol/L per hour. Choose an intravenous solution according to the symptoms. Reserve hypertonic saline for patients with severe symptoms. The final plasma concentration should not increase to greater than 130mmol/L. The aim is to take over 48 hours to achieve normal sodium levels. Hypernatraemia This is a sodium concentration of 145mmol/L.The symptoms include: dry mucous membranes, decreased lacrimation, elevated body temperature, irritability, drowsiness, confusion and coma. There will also be signs of decrease in the intravascular and interstitial fluid compartments. Causes: 1. Iatrogenic: hypertonic saline infusion, sodium bicarbonate. 2. Increased losses with normal/decreased intake - pyrexia, high output states i.e. thyrotoxicosis, hot dry environment 3. Decreased intake with normal/increased losses - thirst centre dysfunction, unconscious patients, insufficient intravenous fluid therapy, and restricted access to fluids. 4. Increased water loss 5. Diabetes insipidus (nephrogenic or neurogenic) Consequences of hypernatraemia  Fluid shift- water moves from the intracellular compartment to the extracellular fluid compartment, causing cellular dehydration. In the brain this can lead to tearing of blood vessels causing intracranial haemorrhage.  Hyperkalaemia- ECF hypertonicity causes potassium to move out of the cells in an attempt to maintain the gradient between the ICF and the ECF.  Hyperglycaemia Treatment  Pure water loss: Replace fluids with hypotonic fluids over a period of 1-3 days. Replacement has to be gradual to ensure that ECF tonicity is not lowered rapidly as this will result in large shifts of water into the intracellular compartment resulting in cerebral oedema. Fluids that can be used include: -9-  1. Tap water, taken orally or via NGT 2. 5% dextrose water 3. 0.45% normal saline  Water and salt loss: The ECF compartment has to be expanded in order to improve renal function. This is best done with normal saline. This is done fairly rapidly. After renal function and blood pressure have improved, the pure water deficit can be corrected over 1-3 days. This is done by replacing with isotonic fluids.  Pure salt gain: Treatment is aimed at removing excess sodium and correcting the hypertonicity. Salt removal is done by using a loop diuretic while infusing with 5% dextrose. If the hypernatraemia is refractory to these measures, dialysis may be necessary. Potassium disorders Potassium is the major intracellular cation. It concentration within the cell is maintained by the Na+-K+ pump. Maintenance of normal potassium concentrations depend on 1. Adequate intake 2. Acid base status a. Alkalosis causes hypokalaemia b. Acidosis causes hyperkalaemia 3. Insulin: promotes cellular uptake. Hyperkalaemia also stimulates insulin secretion. 4. Catecholamines: Stimulation decreases serum potassium while antagonists increase serum potassium. 5. Aldosterone: Increased aldosterone production causes increased urinary excretion of potassium. Hypokalaemia This is serum potassium of less than 3.5mmol/L. Symptoms include: weakness, depression constipation, ventilatory failure, ventricular tachyarrhythmias and coma with severe and prolonged deficiency there may be rhabdomyolysis, thirst and polyuria. The characteristics ECG changes are: flattening of the T waves, depression of the S-T segment, a prominent U wave and low voltage. Causes 1. Inadequate intake 2. Abnormal body losses a. GIT losses – vomiting, diarrhoea, nasogastric suction 3. Renal Loss 4. Drugs, e.g. Diuretics, corticosteroids; insulin 5. Renal tubular acidosis 6. Conn’s syndrome 7. Compartment shift 8. Hypokalaemic periodic paralysis Treatment Any underlying illness that predisposes to trans cellular potassium shifts. If the hypokalaemia is due solely to a potassium deficit, a deficit of 10% of total potassium stores is expected for every 1mmol/L decrease in the serum potassium. Check K+ and other electrolytes (1- 4 hourly) and monitor ECG Serum K+< 2.5 mmol/l is life threatening  20 mmol KCl(1 amp of 10 ml 15% solution) diluted in 200 ml 0.9% saline infused IV over 1 hour. Check serum K+ before repeating.  Oral K+ may be given for serum K+ value > 3.0 mmol/l  Investigate and treat the cause - 10 - *If the potassium is refractory to supplementation, the serum magnesium should be checked as magnesium deficiency promotes urinary excretion of potassium. Hyperkalaemia This is serum potassium greater than 5.5mmol/l. Symptoms include: tingling, paraesthesia, muscle weakness and flaccid paralysis, hypotension, diminished AV conduction time, ventricular arrest or fibrillation. ECG changes consist of S-T segment elevation and peaked T waves. Causes  Factitious o Improper collection of specimens, haemolysed specimens o Haematological - marked leucocytosis, thrombocytosis.  Increased input o Endogenous - burns, trauma, rhabdomyolysis o Exogenous  IV or oral Cl  Massive blood transfusion  Altered distribution o Acidosis o Insulin deficiency, succinylcholine o Hyperkalaemic periodic paralysis  Reduced excretion o Renal failure o Mineralocorticoid deficiency o Renal tubular transport defect  Drugs o Spirinolactone o Triameterene o Amiloride o Prostaglandin inhibitors Treatment Potassium concentrations > 7mmol/l and symptomatic patients, or patients with ECG changes is a medical emergency. Treatment involves membrane antagonism, transcellular shift and enhanced clearance. Check K+ and other electrolytes (1- 4 hourly) and monitor ECG Stop K+ supplements/ K+ sparing diuretics o K+> 6.0 – 100 ml 50% glucose solution with 10 u rapid acting insulin given rapidly as a bolus o K+> 6.5 – as for (a), but infuse calcium chloride (10ml) over 10-15 minutes first (stabilizes cardiac cell membranes). Correct acidosis o K+> 7.0 – as for (a) and (b) above, and infuse 50- 100ml 8.5 % sodium bicarbonate over 30 minutes (unless patient in respiratory failure). Repeat glucose and insulin hourly if necessary o If response to above is inadequate, consider furosemide and haemodialysis o Consider using β stimulants (nebulisation) o Prophylaxis for recurrent hyperkalaemia – Kayexalate exchange resin – 30 – 60 g orally or as a retention enema, 6 hourly o Treat the cause!! NB: Calcium should be infused separately from sodium bicarbonate to prevent precipitation - 11 - Calcium 99% of calcium is found in the skeleton. The other 1% is found in the extracellular and intracellular system. The calcium that is found in plasma exists in 3 forms: o Protein bound (40%) o Ionised, unbound (50%); o Complex, non-protein bound, non-ionised It is the ionised form that is the active form. Factors that are involved in calcium homeostasis include:  Parathyroid hormone o Osteoclastic activity; Increases renal absorption of calcium; Stimulates renal production of Vit D  Calcitriol o Increases calcium absorption in the gut; Increases renal calcium absorption; Promotes mineralization of the organic bone matrix  Calcitonin o Opposes the action of PTH; Decreases osteoclastic activity; Increases renal excretion of calcium  Phosphate  Acid-base status  Magnesium: hypomagnesaemia decreases PTH secretion and impairs PTH responsiveness. Hypocalcaemia Causes  Decreased intake  Inadequate intake - Vitamin D deficiency (Lack of sunlight, renal disease, malabsorption)  Anticonvulsant therapy  Decreased plasma albumin – malnutrition, liver cirrhosis, nephritic and nephritic syndrome, protein losing enteropathy, burn and severe crush injuries  Decreased release from bone  PTH deficiency – congenital, idiopathic, surgical removal of parathyroid gland, surgical removal of adenomas, infarction of adenomas  Resistance to PTH action – uraemia, Mg deficiency, pseudohypoparathyroidism  Drugs – Bisphosphonates, calcitonin, glucocorticoids  Increased flux into bone  Post parathyroidectomy  Extraskeletal sequestration - acute pancreatitis, soft tissue deposition  Increased renal loss Symptoms include: neuromuscular and cardiac muscle excitation, reduced contractile force in cardiac muscle, hyperactive deep tendon reflexes, carpopedal spasm, abdominal cramps and convulsions, decreased cardiac output and ventricular ectopics, coma. The ECG shows a prolonged Q-T interval. Treatment is aimed at supportive care and elevating serum calcium levels as well as correcting any underlying cause. Treatment therefore may involve airway support and ECG monitoring.  CaCl is used to supplement calcium in acute hypocalcaemia as well as when there is myocardial dysfunction  MgSO4 is also given if there is associated magnesium deficiency  Calcitonin is given to correct any Vit D deficiency.  Hyperphosphataemia may be corrected with aluminium hydroxide which will bind phosphate in the intestine  Mg and K deficiency should also be corrected  In non-acute settings calcium and vitamin D supplementation taken orally may be used. - 12 - Hypercalcaemia Causes The commonest causes are malignancies, primary hyperparathyroidism and vitamin D intoxication.  Increased intake or absorption o Milk alkali syndrome o Hyperalimentation o Granulomatous disease - sarcoidosis, TB  Increased plasma albumin o Dehydration o Prolonged application of tourniquet during venepuncture  Increased bone resorption o Malignancy o Hyperparathyroidism o Renal failure o Thyrotoxicosis o Immobilisation  increased renal reabsorption o Thiazide diuretics o Familial hypocalciuric hypercalcaemia o Addison’s disease Symptoms include: fatigability, anorexia, nausea, polydipsia, polyuria, deep bony pain, decreased muscle tone, renal stones, depression and coma. (Bones, stones, groans,psychic moans) Treatment is aimed at enhancing renal excretion of calcium, decreasing calcium influx from bone and decreasing absorption of calcium from the bone and to decrease the serum concentration of calcium. Treatment involves using  0.9% NaCl solution to correct dehydration and correct electrolyte abnormalities.  Furosemide then produces a forced diuresis and reduces renal tubular reabsorption of calcium.  Phosphate supplementation also enhances the movement of calcium from plasma into bone.  Calcitonin is used in patients with renal and cardiovascular impairment.  Mithramycin is useful for patients with hypercalcaemia as a result of metastatic cancer.  Bisphosphonates inhibits bone resorption.  Corticosteroids are useful for hypercalcaemia associated with Addison’s disease and sarcoidosis.  If there is renal failure or the hypercalcaemia is refractory to these methods, then dialysis may be required. - 13 -  Nutrition in the Surgical Patient Mr. V. M. Nair Key Concepts  Human body is an engine designed to burn fuel in order to perform work  The fuels we utilize are called nutrients which are carbohydrates, lipids and proteins  Oxidation releases energy stored in the chemical bonds of nutrients – which is harnessed in the form of ATP which is the energy currency of the body  Feeding stimulates anabolic reactions – synthesis and storage  Physiologic stressors like disease or starvation stimulate catabolism - mobilise energy stores – in preparation of “fight or flight” response Impact on Outcome  Nutrition has an underappreciated role in the recovery of patients from surgery  30-50% of hospitalized patients are malnourished  Poor nutrition has deleterious effects on wound healing and immune function.  Perioperative nutritional support has reduced complications by about 10% Who will need it?  Well nourished and mildly malnourished patients who cannot take oral food for more than one week post operatively to avoid prolonged starvation  Severely malnourished patients undergoing general surgery procedures.  All critically ill patients – Severe Sepsis, Polytrauma, Burns patients  Patients whom you predict cannot use their gut for prolonged period of time (Short bowel syndrome, EC fistula, etc) Assessment of Nutritional Status – History  History of weight loss is a significant indicator o More than 10% unintentional loss in 6 months o 5% loss in 1 month  History of anorexia, persistent nausea, vomiting, diarrhoea, malaise. Assessment of Nutritional Status – Examination  Signs of specific nutritional deficiencies. o Skin rash o Pallor o Cheilosis, glossitis, gingival lesions, o Hepatomegaly, o Neuropathy, dementia.  Loss of subcutaneous fat, muscle wasting, oedema, ascites. Assessment of Nutritional Status – Adjuncts to Examination  Anthropometric measurements o Triceps skin fold thickness o Midarm muscle circumference o Body mass index = weight(kg)/height(cm)2  Creatinine-height index Assessment of Nutritional Status – Laboratory Markers  Serum proteins – nonspecific indicators of the degree of illness rather than strict marker of nutrition o Albumin 10% TBSA and infants with burns of > 7.5% TBSA require intravenous fluid resuscitation. Patients with lesser burns will usually be able to take in the required fluid replacement by mouth. If oral intake is not feasible (due to concurrent disease, or mental retardation) an IV line should be set up. If no IV access can be obtained, and the person receiving the burns patient cannot put up an intra-osseous line (e.g. a clinic nurse), a nasogastric tube may be passed and the calculated amount of fluid given orally as oral rehydration fluid. Airway and Breathing 1. Carefully assess the airway in all patients with flame or scald burns of the face and neck. Signs of inhalational injury are presence of pharyngeal burns, air hunger, stridor, carbonaceous sputum and hoarseness. Intubate patients who are unconscious, hypoxic due to severe smoke inhalation or with signs of airway compromise. All intubated burn patients must be discussed with the Provincial Burn Center at IALCH. 2. All patients with moderate to major burns must receive oxygen per face mask. 3. The following symptoms should raise suspicion of carbon monoxide poisoning: restlessness, headache, nausea, poor co-ordination, memory impairment, disorientation. The diagnosis can be confirmed if you have a blood gas analyzer which gives you a carboxyhemoglobin level. Manage by administering 100% oxygen via a non- rebreathing face mask. If the patient is still in respiratory distress, intubate and ventilate the patient with 100% oxygen. 4. If the patient’s ventilation is compromised by a tight eschar around the trunk, perform an urgent escharotomy (see section on escharotomies). - 20 - Causes of Respiratory embarrassment in the acute burns patient:  Inhalation of toxic gases such as cyanide or carbon monoxide is the most common cause of death on the scene. If the patient survives to hospital high-dose oxygen and the administration of an antidote in case of cyanide poisoning (sodium nitrite, dimethylaminopherol, hydroxycobalamine) are essential. The patient may need intubation and ventilation. Fire-fighters who in their line of duty may be exposed to cyanide, should carry an antidote for use in case of accidental exposure.  Oedema of the airway as a result of direct thermal damage. Note that this may occur in any type of burn, including the inhalation of steam in connection of a hot water burn. Airway obstruction in burns usually occurs within the first 2-12 hours, and is characterized by the occurrence of stridor as well as respiratory distress (tachycardia, use of accessory respiratory muscle, intercostal and substernal retractions). Early intubation is essential, by the most experienced intubator available. If intubation failed, a cricothyroidotomy should be performed in an adult, or a needle tracheotomy in a child.  Inhalational burn is due to the inhalation of the toxic byproducts of combustion, inhaled with the smoke. Smoke particles are not in itself toxic, so although seeing them in the mouth or throat of a patient is indicator that the patient is at risk of developing inhalational injury, this will not always happen. Smoke inhalational injury takes anything between 12 and 38 hours to develop, and patients at risk for this complication should be transferred to a Burns Center with facilities to ventilate these patients during this period.  A tight eschar around the chest might restrict respiratory movements to such an extent that respiratory distress results. An escharotomy must be done immediately. Two lateral incisions, one in each anterior axillary line are joined by two incisions, one below the clavicles, the other following the costal margin. Circulation 1. Establish large-bore intravenous access (1 in moderate, 2 in major burns) and resuscitate the patient, using urine output as the end point of resuscitation (aim for a urine output of between 0.5 – 1.0 ml/kg/hr in both adults and children) 2. Fluids are calculated according to the patient’s weight and TBSA burnt tissue, and half of this amount is given during the first 8 hours, with the remainder during the following 18 hours. Give 3 ml/kg/% TBSA initially over 24 hours, and adjust on the basis of urine output. 3. During the first period of 8 hours give Ringer’s lactate. You should aim to give this fluid from the time of admission up to 8 hours after the injury. 4. During the second period of 16 hours, give 0.75 ml/kg/% TBSA as a colloid such as Voluven or FFP. In children with major burns FFP is preferable because it replenishes immunoglobulins that are lost through the burn wound. 5. If the patient is in shock give a colloid such as Voluven until blood pressure, heart rate and urine output have been normalized. 6. In children, add their daily maintenance fluids to the replacement regime. 7. Insert a Foley’s catheter in all patients with burns over 15% TBSA 8. Observe the color of the urine, particularly in patients with electrical burns. ‘Burgundy-colored’ urine suggest myoglobinuria which should be managed by increasing the administration of fluids aiming for a urine output of 2 ml/kg/hr. 9. In major burns (> 25-30%) do regular blood gases (arterial if there is a suspicion of inhalational injury) and aim to normalize base excess (< - 3) and lactate level (< 2 mmol/l). If base excess or lactate levels are high, add additional Voluven. Rationale Burn patients lose fluid rapidly and therefore patients with a major burn who present late may already be in a shock or pre-shock state. For instance, a patient with a 25% burn who presented after 6 hours has already lost 24 mls of fluid/kg or an amount equivalent to a third of their circulating blood volume. Providing venous access is therefore a priority. The following options are available:  Ante-cubital vein  Femoral vein (if groins not affected by burn)  Central venous line (this can be through burnt tissue. Suture the line in place) - 21 -   Intra-osseous line. Aim to have established venous access within 10 minutes of arrival in an adult and within 5 minutes in a child. Do not waste time with repeated attempts to establish a peripheral line, but try an alternative after 2-3 failed tries. Patients with major burns develop a capillary leak throughout the body. Many burn surgeons feel that if during this period colloids are administered they will leak into the interstitium and cause prolongation of tissue oedema. Recent research has suggested that this capillary leak is largely reversed by 6-8 hour post-burn, and at this stage resuscitation with colloids is safe and preferable. Resuscitation with colloids reduces tissue oedema, which benefits the precarious zone of stasis of the burn wound, and prevents the development of compartment syndromes. The loss of immunoglobulins through the burn wound has been mentioned as a possible contributor of toxic shock syndromes that have been described in burns patients, and particularly in children. Do not give dextrose-containing fluids (except for maintenance in children) as they may cause an osmotic diuresis and confuse the adequacy of fluid resuscitation assessment. Ideally use Ringer’s lactate or Plasmalyte B for ongoing fluid losses. The burn patient who has achieved the target urine output is well resuscitated and further fluid administration will only serve to increase tissue oedema with all its untoward consequences, a phenomenon described in the burns literature as fluid creep. FURTHER ACUTE MANAGEMENT 1. Insert a nasogastric tube in any adult patient with a burn of > 20% TBSA, child with > 15% TBSA, or any patient who is unresponsive or shocked. 2. Assess all extremities and the trunk for circumferential burns. If these are present, assess the circulation of the peripheral tissues and perform escharotomies if this is in any way compromised. Escharotomies will usually be necessary in circumferential deep partial or full thickness burns. The performance of escharotomies is the responsibility of the referring hospital, as the tissues will as a rule not be viable by the time the patient arrives in the referral hospital! They can be done at the bedside with a sterile blade and do not require anesthesia. Cut through the constricting eschar until bleeding tissue is bulging through the wound. Ensure that the entire length of the eschar is opened from top to bottom. Avoid leaving a constricting ring at the proximal end of the eschar! 3. Give tetanus immunization 4. Provide pain management by drawing up the patient’s maximum dose of morphine in a syringe, and administer small doses of morphine IV until the patient is pain free. Do not administer IM opiates. 5. All patients with burns need early nutritional support. This includes that oral feeds are started as soon as the patient is resuscitated. All patients with moderate to major burns have a nasogastric tube inserted so that additional nutrition can be given on continuously. The aim is to hyperaliment the patient, as the burns patient is in catabolic state and will lose structural and functional proteins if insufficient nutrition is given. You simply cannot overfeed a burn patient! Vitamins and trace elements are prescribed for all patients. (The protocol in use at the burns Unit at IALCH is given in the flow-chart the end of the chapter ). 6. Sufficient painkillers are given to deal with background and procedural pain. For background pain we use a combination of paracetamol (perfalgan in patients with an IV line), Non-steroidal anti-inflammatory drugs, moderately strong opiates (tramadol), and gabapentin (an anti-epileptic drug with mood-elevatory, opiate- sparing and anti-pruritic qualities in the burn patient) 7. Antibiotics are not given routinely in burns patients. All burn wounds become contaminated with pathogens rapidly, but this is treated with topical antibiotics, preferably silver (Acticoat, Silverlon), chlorhexidine (Bactigras) or povidone-iodine (Betadine). Only if there are local (redness, progression of the burn depth) or systemic signs of invasive infection (fever, reluctance to feed in a child, general toxicity) are antibiotics started. Our policy is to start first with a combination of Piperacillin/Tazocin with either Ciprofloxacin or Amikacin (to cover the common Gram-negatives, including Pseudomonas) and Vancomycin if there is suspicion that a multidrug resistant Staphylococcus aureus (MRSA) is involved. Second line drugs are Meropenem plus Vancomycin plus an antifungal agent. - 22 - ADMISSION CRITERIA  BSA > 15% in adults or 8 - 10% in children  Extremes of age : Infants and neonates + elderly  Special burns ie electrical or chemical  Special areas : Face , perineum , ventral aspect of hand or foot , flexure aspect of joints , circumferential burns  Suspected non-accidental injury ( NAI ) in children  Inhalational burns REFERRAL CRITERIA This referral policy for burns patients throughout the Province aims to regionalize burns care. Regionalization means that each burn patient reaches the level of care that is most suited to his/her injury. Regionalization stratifies patients into:  Minor burns : Burns that generally do not meet admission criteria noted above. These can be managed at the District General Hospital, either on an outpatient basis, or non-operatively as an inpatient.  Moderate burns: these should be managed by a general surgeon in a regional or urban hospital  Major burns, which should be managed at the Regional Burn Center. Generally includes patients with > 35% BSA , those requiring ICU , and those requiring extensive grafting or reconstructive surgery. 3. Burn Wound Management Remove Any Sources of Heat 1. Remove any clothing that may be burned, covered with chemicals or that is constricting. Remove constricting rings. 2. Cool any burns less than 3 hours old with cold tap water for at least 30 minutes and then dry the patient 3. Estimate the percentage TBSA burned (see above) 4. Cover the patient with a clean sheet or blanket to prevent hypothermia. First dressing Dress the burn wounds with Flamazine ointment. In the resuscitation phase it is unnecessary to clean the wounds, unless they are grossly contaminated. Apply ample amounts of Flamazine to the dressings and put these onto the burn wounds. Burnshield, if available, is an acceptable alternative, and is a very effective means of cooling and dressing during the first 24 hours. Subsequent Dressings 1. Dressing changes in burns patients are painful, and should therefore preferably be done under conscious sedation and analgesia. We use Ketamine for our children and a combination of Fentanyl and Midazolam for the adult patients. Guidelines of the South African Society of Anaesthesiologists should be followed 2. Eschar (burned skin) contains many toxins and inflammatory mediators and all obviously dead and loose skin should be removed as soon as possible by a combination of rubbing with a dry sterile swab and cutting with a tissue scissors. In superficial or moderate partial thickness burns this can usually be done under conscious sedation. In deeper burns this is done by tangential excision in theatre. 3. Superficial or moderate partial thickness can be dressed with Bactigras (chlorhexidine-impregnated tule-grass). Although Flamazine is still widely used in the Province, its effectiveness has come under critique recently, as it performs worse than any dressing against which it is tested. 4. Deeper burns are best dressed initially using a nanocrystalline-silver dressing. After excision the wound is either grafted immediately, or dressed with a dermal substitute such as Biobrane. 5. Cereum-nitrate in silver sulfadiazine (Flammacereum) has recently been proposed as a dressing which ‘traps’ burn toxins in the eschar, thus preventing or ameliorating the local edema and the systemic inflammatory response that normally occurs after severe burns. It enables one to delay early excision until the patient is stable. - 23 -  4. Rehabilitation and Long-term treatment Burns are a long-term and often life-long problem, and prolonged follow-up and rehabilitation is essential. The following are essential in the burn patient regaining and maintaining a good functional recovery:  Splinting – joints must be splinted in the position of function, i.e. where the ligaments and capsule of the joint are maximally stretched. A painful joint will assume the position of comfort, which is the position where the capsule and ligaments are relaxed, and which is thus the opposite of the position of function. In the hand the position of rest is referred to as the intrinsic minus position. In this position the wrist is plantar flexed, the metacarpal-phalangeal (MCP) joints hyper-extended and the interphalangeal (IP) joints flexed. The hand is virtually useless in this position. To prevent the hand from becoming fixed in this position, splinting it in the intrinsic plus position is essential in all patients with burns deeper than superficial partial thickness. In this position the wrist is in 30o dorsiflexion, the MCP joints of the fingers in 90o flexion and the fingers in extension. In addition, to avoid contraction of the first webspace, the thumb must be kept in 60 o abduction. Splints should be worn continuously until all wounds have healed, and during the night until the scars have matured.  Physiotherapy: passive (the therapist moves the joint) and active (the patient moves the joint) exercises should be performed at least twice a day, and should be supervised by a qualified physiotherapists at least three times a week until full range of joint movement is fully recovered.  Pressure garments: all burn wounds which have taken more than 2 weeks to heal, or which required a skin graft should be covered with a pressure garment fitted by the occupational therapist. Pressure garments should be worn a minimum of 23 hours a day, i.e. they should only be taken off for the patient to take a bath. Pressure garments may be supplemented by silicone sheets and by rubbing the scar with virgin coconut oil.  Ideally all patients should be seen by a social worker before discharge. Issues that should be discussed are: o The circumstances of the burn, in particular if the burn was non-accidental (child abuse, assault, intimate partner violence, attempted suicide), the social worker should evaluate whether it is safe for the patient to return home o The social worker should evaluate if the patient needs a grant, whether permanent or temporary. A patient who was involved in a house fire may have lost everything. Burt even where this was not so the hospital stay may have exhausted the patient’s or family’s resources and they may have no funds to present for follow-up o Epileptic fits are a common cause of burns, and some of these patients may be non-compliant with their therapy for a variety of reasons. This has to be rectified if the burn is not to recur. This may require for instance, mobilization of a support system, or bringing the patient into contact with a patient support group.  Hypertrophic scars, which commonly form after burns, are first managed by pressure garments, and silicone sheets. Steroid injections (triamcinolone, celestone) may be used to soften the scar.  The following are indications for reconstructive surgery : o Any restriction of motion over a joint due to a tight scar: these patients must be referred as a matter of urgently, as delay may lead to secondary shortening of tendons, nerves and ligaments. A variety of operative techniques may be employed to rectify such situations (tendon transfers or plasty operations). o The problems presented by facial burns range from cosmetic problems to those threatening the function of vital organs (such as ectropions threatening eye function). Never tell a patient to learn to live with his or her deformities without consulting a burn surgeon or a plastic surgeon with a special interest in the management of burns. o Burn scars over the head may result in bald patches. These are usually managed using tissue expanders, followed by local transfers of hair-bearing tissue. o A tight scar over the chest in a pubertal girl may interfere with the normal development of the breasts, and require release. o A tight abdominal scar may make expansion of the pregnant uterus impossible. A woman with an tight abdominal burn scar who wishes to fall pregnant needs to be referred to the burns unit or a plastic surgeon for evaluation of the scar before falling pregnant. - 24 -  THYROID Mr J Reddy It is important to differentiate a thyroid mass (goitre) from other masses that might occur in the anterior triangle of the neck. Midline neck lumps Upper midline  Skin & subcutaneous lesions  Lymph nodes  Thyroglossal duct cysts Lower midline  Thyroid masses – solitary nodules , multinodular goitres and diffuse thyroid masses Lateral neck lumps  Skin and subcutaneous lesions – Epidermoid, dermoid cysts, lipomas  Developmental masses – Lymphangiomas, cystic hygromas  Branchial cysts  Lymph nodes – Infectious, Inflammatory, neoplastic  Neurogenic tumours – Neurofibromas, Schwannomas  Vascular tumours – Carotid body tumour  Salivary glands Patients with a goitre may present to the surgeon in either of the following ways:  Nontoxic goitre  Hyperthyroidism – Grave’s disease, Toxic MNG, Solitary toxic nodule, Thyroid cancer or Thyroiditis  Thyroid nodule  Thyroid carcinoma Benign Thyroid Pathology Goitre  Any enlargement of the thyroid gland is referred to as goitre.  In your clinical evaluation it is helpful to classify patient according to the WHO’s classification of goitres (size) & growth pattern. Size Class 0 No visible or palpable goiter Class 1 in the normal posture of head, it cannot be seen, it can only be found on palpation & moves up with swallowing Class 2 the goiter is palpable and can be easily seen Class 3 the goiter is very large and is retrosternal, pressure results in compression marks Growth pattern Uninodular can be inactive or toxic Multinodular can be inactive or toxic Diffuse the whole thyroid appears to be enlarged  Aetiology of goitres - Endemic to regions – iodine deficiency in salt ,fertilizer or animal feed , dietary goitrogens - Medications – iodine, amiodarone, lithium - 25 -  - Thyroiditis – subacute, chronic - Familial – hormonal dysgenesis from enzyme defects - Resistance to thyroid hormone - Neoplasm  Most non-toxic goiters result from TSH stimulation secondary to inadequate thyroid hormone synthesis and other paracrine growth factors. The gland enlarges in size in order to maintain a euthyroid state. Familial goiters can be complete or partial. Elevated TSH causes diffuse thyroid hyperplasia or focal hyperlasia that result in nodules that may or may not concentrate iodine. The TSH dependant nodules concentrate iodine and become autonomous.  The clinical evaluation includes : - Assessment of toxic vs nontoxic symptoms - Local symptoms of compression such as dyspnoea, dysphagia, hoarseness of voice, pain, and cosmetic concern - co-mordities and comprehrensive anaesthetic history that will affect the overall surgical management of this patient - Examine for the presence of hoarseness, stridor dysphonia, dyspnoea. The presence of positive Pemberton’s sign, ie assess for a substernal component (facial plethora and distended neck veins when elevating arms above head, the implication is thoracic outlet obstruction from goiter). - Evaluate the size, consistency, growth pattern, presence of adjacent lymph nodes. - Remember a goiter moves up with swallowing and a thyroglossal cyst moves up in the midline when the tongue is protruded.  Investigations - A thyroid function test would confirm toxic vs nontoxic symptoms - Ultrasonography is used to assess the gland size, nature of gland and nodules (solid or cystic). - X-ray of the thoracic inlet is used to evaluate the degree of tracheal compression; if significant compression is found a CT scan of the neck and chest is indicated to further evaluate the degree of tracheal compression. - The thoracic inlet x-ray will also confirm clinical suspicion of a substernal component of thyroid gland. A CT scan will greater detail of the extent of retrosternal extension. - Radioactive uptake scans can demonstrates areas of patchy uptake with hot or cold nodules. - Sampling of the gland is achieved with fine needle aspiration biopsy either percutaneously or under ultrasound guidance. Any suspicious lesion, dominant nodule, painful or enlarging nodule should be biopsied. Remember surgery is also regarded as a form of biopsy i.e. excision biopsy when fine needle aspiration biopsies fail to yield answers.  The treatment of non-toxic goiters - Thyroid hormone suppression is used by some to reduce TSH stimulation and thereby decrease gland growth and stabilize goiter size. Endemic goiters can be treated with iodine administration. This therapy is used for small diffuse goiters and for those who do not wish to have surgery. The risk of thyroxine use includes osteoporosis and cardiac arrthymias which the clinician need to monitor. - Radio-iodine ablative therapy is effective in reducing the size of large goiters and 2/3 of patients respond with a 60% size reduction. About a fifth of patients become hypothyroid and need thyroxine replacement. - The surgical options include: - subtotal thyroidectomy, leaving 5g of tissue behind in a MNG - total/near total thyroidectomy in other forms of goiters a may be required to rule out tumours. - lobectomy and isthmustectomy is acceptableIf unilateral enlargement is encountered - 26 - Hyperthyroidism  The clinical manifestation of a toxic state results from the excess amount of circulating thyroid hormone  Of the numerous disorders of hyperthyroidism, Graves’s disease, toxic multinodular goiter and solitary toxic nodule and thyroiditis are most relevant to the surgeon.  It is important to distinguish disorders such as Graves’s disease and toxic nodular goiters from those disorders that lead to release of stored hormone from injury to thyroid gland (thyroiditis) or other non- thyroid gland-related conditions. Graves disease  Common cause of hyperthyroidism, accounting for 60-80% of cases  Autoimmune disease of unknown cause  Strong familial predisposition and female prevalence of ( 5:1)  Peak incidence between 35 to 60 years  Characterized by thyrotoxicosis, diffuse goiter & extrathyroidal conditions, including opthalmopathy, dermopathy, gynaecomastia and other manifestations. Eye signs are an important feature of this condition.  Biochemical features include an elevated fT4 or T3 level and a suppressed TSH. 123  Iodine uptake scan would demonstrate elevated uptake with a diffusely enlarged gland.  Thyroid antibodies are elevated in up to 75-90% of patients  The treatment usually includes 3 treatment modalities: antithyroid drugs, thyroid ablation with radioactive iodine (Iodine123) and thyroidectomy  Antithyroid medications are generally administered in preparation for radioactive iodine ablation or surgery. Propylthiouracil (PTU), methimazole & carbimazole are used for reducing the thyroid hormone production by inhibiting the binding of iodine and coupling of iodotyrosines. PTU also inhibits the peripheral conversion of T4 to T3. Propanolol also decreases the peripheral conversion of T4 to T3 and lowers the catecholamine response of thyrotoxicosis. 123  Radioactive iodine therapy (Iodine ): this is the mainstay of treatment in the West. It has the advantage of avoiding the surgical procedure and risks, reducing treatment costs. Antithyroid drugs are given until patient is euthyroid and then discontinued to maximize the isotope uptake. It is associated with development of hypothyroidism requiring thyroxine replacement. Effect is usually seen in 2 months and 50% are euthyroid in 6 months.. Absolute contraindications includes female that are pregnant or breastfeeding. Relative contraindications includes young patients (children & adolescents), patients with thyroid nodules and ophthalmopathy. Women of child bearing age are advised to wait one year before attempting to conceive.  Surgical treatment:The patients are rendered euthyroid before operation with antithyroid drugs continued up to day of surgery. Lugol’s iodine or supersaturated potassium iodide administered preoperatively to reduce vascularity of gland and decrease risk of thyroid storm (main action is to inhibit release of thyroid hormone).Goal of surgery is to promptly control disease with minimum morbidity (i.e. recurrent laryngeal nerve injury or hypoparathyroidism).The options of surgery include a near or total thyroidectomy for patients with coexistent thyroid cancer, those who refuse RAI therapy, patients with severe ophthalmopathy or having severe reactions to antithyroid medications. Eye signs have been shown to stabilize or improve in most patients after a total thyroidectomy (presumably from removal of antigenic stimulus).A subtotal thyroidectomy can be used in all remaining patients. Toxic adenoma  Single, benign autonomous nodule  Ultrasound of thyroid will define nodule and a radio-iodine uptake will demonstrate a hot nodule with suppression of the rest of the gland.  The principle again is to control the hyperthyroidism prior to surgery and render patient euthyroid.  Treatment is surgical – lobectomy & isthmustectomy of the involved side. Toxic Multinodular Goiter  Patients often have a history of a nontoxic goiter  Nodules become autonomous to cause features of hyperthyroidism with no extrathyroidal manifestations - 27 -   Hyperthyroidism can also be caused by iodinated contrast media and drugs like amiodarone which expand iodine pool (Jodbasedow phenomenon)  Confirm biochemically with TFT (raised T3ot T4 and suppressed TSH) and morphologically with an ultrasound. RAIU scan show multiple nodules with increased uptake and suppression of the rest of gland.  Treatment is surgical (subtotal or near total thyroidectomy) after hyperthyroidism is controlled.  RAI ablation is problematic to treat MNG because the non-functioning nodules donot take up iodine; thus large doses are requiredto achieve an effect, resulting in side effect of RAI. Malignant Thyroid Pathology Risk factors for thyroid cancer include : - Exposure to high levels of radiation i.e. radiation therapy for tumours, fallout from nuclear power plant or weapons. - Family history of goitre - Inherited genetic syndromes such as familial medullary thyroid cancer, multiple endocrine neoplasia, familial adenomatous polyposis - Age >60 - Rapid growth and pain Clinical features : Thyroid cancer typically does not cause any signs or symptoms early in the disease. As it grows it may cause: - Lump or nodule that can be felt - Changes to voice including hoarseness from obstruction or infiltration - Dysphagia - Pain in the neck - Swollen lymph nodes in the neck Investigations : All patients are assessed with thyroid function test (biochemical), ultrasound (morphological) and fine needle aspiration biopsy either percutaneously or under ultrasound guidance. Classification and incidence of thyroid malignancies Tumours of follicular cell origin Differentiated  Papillary 75%  Follicular 10%  Hurthle cell 5% Undifferentiated  Anaplastic 5% Tumours of Parafollicular or c-cell origin  Medullary 5% Other  Lymphoma & others 4cm Age, Metastasis, Extent, Size (AMES criteria)  Papillary carcinoma may be multifocal tumour with up to 80% micro-metastasis to lymph nodes  Surgical therapy includes total thyroidectomy (because of the multifocal nature of tumour) + selective lymph node dissection if lymph nodes palpable or noted on ultrasound. Because of the indolent course of metastasis prophylactic cervical lymph node dissection not warranted.  Adjuvant (post op) radioactive iodine ablative therapy is to control residual tumour in the thyroid bed and to address metastatic disease elsewhere. Follicular thyroid cancer  Accounts for 10% of thyroid cancers, female to male ratio of 3:1  Mean age at presentation 50 years  It can present as a painless solitary nodule or as a rapidly growing nodule within a multinodular goitre  Spread haematongenous with predilection for lungs and bone  Multicentricity and LN metastases are less common than papillary carcinoma  FNAB (assesses cellular features) cannot distinguish between benign (follicular adenoma) vs. malignant follicular carcinoma, a tissue sample for histological examination will have to demonstrate capsular or vascular invasion to demonstrate a carcinoma.  If the lesion is demonstrated in one lobe, a lobectomy and isthmustectomy is advocated & if carcinoma is demonstrated a completion thyroidectomy is performed. Lymph node dissection is only done for gross metastatic disease.  Adjuvant (post op) radioactive iodine is performed for detection and treatment of metastatic disease. Hurthle cell cancer  5% of thyroid cancers, many features similar to follicular cancers including differentiating Hurthle cell adenoma from carcinoma on a FNAB. Malignancy is determined by capsular or vascular invasion on tissue sample.  Propensity for vascular invasion, female to male ratio 2-10 :1 ,multicentric disease  Surgical therapy is a total thyroidectomy for malignant disease; if a solitary nodule is present a lobectomy and isthmustectomy is performed first and if this demonstrates malignancy a completion thyroidectomy is indicated. Lymph node dissection is indicated only for clinically or sonographic evident disease. Poorly differentiated tumours – Anaplastic thyroid carcinoma (ATC)  Rare but aggressive tumour occurs in patients > 60-70 years of age and usually present with a rapidly growing thyroid mass. 5 year survival rate of 3.6%  Extensive invasion of adjacent structures is common hence obstructive symptoms and neck pain common. - 29 -   Lymph node involvement and enlargement occurs in 84 % of cases and systemic metastasis in 75% of cases to lung, bone, brain, and adrenal glands.  FNAB is suitable for diagnosis. The diagnosis must be differentiated from lymphoma and poorly differentiated medullary carcinoma by immune-histochemical staining and other markers.  Surgery, radiotherapy & chemotherapy in combination have improved results for local control of tumour. Because of the aggressive nature of tumour for local infiltration and systemic metastasis combined Chemoradiotherapy in the neoadjuvant setting followed by surgery and further chemotherapy and radiation after surgery yielded best results.  The current treatments of ATC have a limited role because the majority of patients die within months of their diagnosis from local or distant metastasis. Factors favouring longer survival age 10cm, mediastinal involvement, and dysphagia.  5 year survival rate ranges from 50-70% - 30 -  APPENDIX 1 Approach to Thyroid Nodule Clinical examination and History + TFT + thyroid Ab + serum thyroglobulin + ultrasound Nodule > 1cm or suspicious on U/S for U/S guided FNAC Benign Non diagnostic Malignant Toxic Hypofunctional Suspicious nodule, noduleon RAI has irregular Borders, increased vascular flow andmicrocalcificati ons Yearly follow Repeat FNAB Lobectomy & Lobectomy & Lobectomy & up, U/S + TG and if isthmusectomy isthmusectomy isthmusectomy and TG inadequate ablevels then open biopsy > 3cm, multicentric, family history < 3cm & radiation exposure Total Lobectomy or Thyroidectomy & Total post op RAI if Thyroidectomy indicated 6-12 month follow Yearly follow up up with U/S and with U/S and TG tumour markers and Ab - 31 - APPENDIX 2 Technique of Fine Needle Aspiration (FNAC ) Fine needle aspiration is a percutaneous procedure that uses a fine gauge needle (22 or 25 G) and a syringe to sample fluid or remove clusters of cells from a mass lesion. The procedure is performed using a sterile aseptic technique. Once consent has been obtained, the skin area to be punctured is cleaned with aqueous Chlorhexidine. The surgeon then palpates the lesion and stabilizes it between his/her fingers. The needle is then attached to the syringe (preferably 10ml syringe) and inserted into the lesion. Suction is then applied on the syringe, and the needle is then redirected in different directions within the target. The negative pressure created from the suction is then released before withdrawal of the needle. The needle is then detached from the syringe and the syringe filled with air, bearing in mind that the sample for cytology is contained within the hub and needle lumen itself. After filling the syringe with air, the needle is then reconnected and the sample is then sprayedonto a microscope slide which is then fixed with an alcoholic spray and allowed to air dry. The cytological specimen is then analyzed by an experienced cytopathologist. 32  BENIGN BREAST DISEASE Mr S Cheddie Benign breast conditions are more common than breast cancer and cause much anxiety to female patients. A diagnostic approach is necessary to actively exclude malignancy and effect appropriate management. Classification of benign breast disease Aberrations of Normal Development and Involution (ANDI) The ANDI classification is widely used to classify benign breast disease according to pathogenesis and clinical presentation. Stage Normal Process Aberration Extreme form Early Reproductive Lobular development Fibroadenoma Giant fibroadenoma (15-25yrs) Stromal development Hypertrophy Gigantomastia Nipple eversion Nipple inversion Subareolar abscess Mature Reproductive Cyclic menstrual Cyclical mastalgia Incapacitating (25-40 yrs) changes mastalgia Epithelial hyperplasia Nipple discharge of pregnancy Involution Lobular involution Microcysts Macrocysts* (35-55 yrs) Duct involution Sclerosing lesions* Periductal mastitis Duct ectasia Radial scar/complex sclerosing lesions Epithelial turnover Epithelial hyperplasia Epithelial hyperplasia with atypia* *increased risk of malignancy Other benign breast conditions are classified as Non- ANDI: Fat necrosis Gynaecomastia Infected lesions Fibrocystic changes Papillomas Diabetic mastopathy Phylloides tumour Hamartoma Breast conditions during pregnancy Approach to a breast lump The approach to a breast lump is based on the principles of Triple Assessment: namely clinical examination, imaging and needle biopsy in order to exclude malignancy. 1. Fibroadenoma Are aberrations of normal development of the breast lobule and occur due to an exaggerated response to hormonal stimuli. They are common in adolescence and the mid-twenties. They usually present as a firm, rubbery, mobile breast lump. Diagnosis is made by clinical examination, imaging and needle biopsy ( fine-needle aspirate or core-needle biopsy). Ultrasound is done in 35 years due to the lower density of the breast tissue that allows for adequate assessment of the lump and to assess for calcification. Management The natural history of fibroadenoma is to grow to 1-3cm; get smaller or resolve (one third to one half). Patients < 25 years may be observed and re-examined annually if the diagnosis is confirmed. Surgical excision is indicated for patients > 25 years; giant fibroadenoma > 5cm or symptomatic/ upon patient request. 33 2.Breast Cyst Breast cysts arise from involution of breast lobules with excessive secretion of fluid from the epithelium. They usually occur in the > 40 year age group. They can be further classified into simple cysts or complex cysts (thick walled, septations) on ultrasound imaging. The risk of malignancy for complex cysts is very low (0.3%). Management Triple assessment Bloody/residual mass Aspirate to dryness Non-bloody/ no mass Send for cytology Follow up in 3 and Biopsy mass months Approach to a nipple discharge Only 5% of patients who present with nipple discharge have serious underlying pathology. A nipple discharge is regarded as pathological if it arises from a single duct orifice, spontaneous, unilateral, bloody/clear or sero-sanguinous effluent or associated with a mass. Classification Galactorrhoea Non-galactorrhoea Physiological Benign Pregnancy/lactation Intraductal papilloma Stress Duct ectasia Excessive mechanical stimulation Fibrocystic breast changes Non-physiological Malignant Tumours – prolactinoma/ectopic PRL secretion Ductal carcinoma in situ Hypothyroidism Infiltrating ductal carcinoma Renal and hepatic disorders Drugs – H2 receptor antagonists, antipsychotics, antihypertensives, anti-emetics 34 Types of nipple discharge 1. Galactorrhoea – milky discharge  physiological/pathological 2. Multi-coloured  infection/duct ectasia 3. Purulent  infection/ duct ectasia 4. Bloody/sero-sanguinous  intraductal papilloma/ malignancy 5. Watery  intraductal papilloma /duct ectasia Management Triple assessment Non-galactorrhoea Benign cytology/no mass Galactorrhoea Ductal Normal TSH PRL Single duct Multiple No Rx High High Microdochectomy Major duct excision Treat CT/MRI pituitary Antibiotics/reassure –duct ectasia Mastalgia Breast pain is a common presenting symptom and does not exclude the diagnosis of breast cancer which may occur in up to 6% of cases. Classification 1.Cyclical mastalgia – worsens with the luteal phase of the menstrual cycle and improves at the onset of menses. Is associated with nodularity and swelling 2. Non-cyclical mastalgia – unrelated to the menstrual cycle Treatment 1. Reassurance – this may help to alleviate anxiety and should only be done once malignancy is excluded using triple assessment. A thorough chest examination should be done to exclude chest wall pain (costochondritis) and pleurisy. Patient should be advised to wear a well-fitting brassiere. 2. Advise to stop smoking and decrease caffeine intake 3. Topical anti-inflammatory gel 4. Evening primrose oil – contains essential fatty acids  has anti-inflammatory properties 5. Endocrine therapy ( severe mastalgia) - Danazol – a synthetic testosterone  inhibits pituitary gonadotrophins and has anti-oestrogenic and anti-progestogenic properties - Bromocriptine – dopaminergic agonist - Tamoxifen – anti-oestrogen effect  high response rate. Side effects include DVT and endometrial cancer 35 Breast Infection Lactational mastitis/breast abscess Occurs within the first six weeks of breastfeeding. The infection route is usually via a cracked nipple. The most common infecting organisms is Staphylococcus aureus. Mastitis may progress to form an abscess collection. Management 1. Early antibiotic therapy – flucloxacillin 2. Incision and drainage of abscess Non-lactational abscess May be caused by peri-ductal mastitis or malignant duct obstruction. Occurs in older women with variable organisms. Management Incision and drainage of the abscess with mandatory biopsy of the abscess wall. Gynaecomastia Defined as benign enlargement of the male breast. May be physiological occurring during the neonatal period, at puberty or in the senile age group. Aetiology 1. Pathological – chronic liver disease, hypothyroidism, Klinefelter’s syndrome (hyper-oestrogenic states) 2. Pharmacological – H2 receptor blockers, digoxin, spironolcatone, HAART (efavirenz, didanosine) 3. Idiopathic – most common – occurs in up to 25% of cases Investigations Triple assessment should also include a scrotal examination to exclude a testicular tumour and breast ultrasound or mammography. Core needle biopsy or FNAC should be done for masses, clustered microcalcifications and skin thickening to exclude malignancy. Endocrine workup should include TFT, prolactin, FSH,LH, oestradiol, testosterone, liver function tests. Management 1. Reassurance – it is a benign condition without increased risk of male breast cancer 2. Pharmacotherapy – danazol and tamoxifen have been used. 3. Surgery – subcutaneous mastectomy indicated  large ptotic breast tissue and fibrotic glands ; intolerance to medical therapy 36  BREAST CANCER S Cheddie Definitions Breast cancer is divided clinically into early, locally advanced and metastatic breast cancer. This distinction is critical to the understanding of the disease and impacts on the management approach.  Early breast cancer is limited to stage I and stage II disease ( T2/N1 or T3N0) and is defined as breast cancer that is amenable to operative intervention, since these tumours are considered curable.  Locally advanced breast cancer refers to tumours that are characterised clinically by size(>5cm), features suggesting infiltration of the skin and chest wall and/or nodal status. These patients do not have metastatic disease. They include N2 and N3 disease and inflammatory breast cancer.  Metastatic breast cancer refers to disease beyond the loco-regional site with spread to bone, lung, soft tissue , liver and brain. They include any T/N and M1 disease. Risk factors Hormonal Non-Hormonal Increased oestrogen exposure Female sex - Early menarche(50yrs) menopause(>55yrs) Personal history of breast cancer - Nulliparity/ obesity Obesity - Exogenous oestrogen Alcohol - Older age at first live birth(>30yrs) Radiation exposure Combined hormonal replacement therapy Family history of breast cancer – immediate first degree relatives Oral contraceptives Hereditary breast cancer BRCA 1 mutation(90% lifetime risk) BRCA 2 mutation(85% lifetime risk) Proliferative lesion with atypia - Atypical lobular hyperplasia - Atypical ductal hyperplasia Screening Due to limited resources, screening mammography for breast cancer must be individualized according to the risk profile of the patient. In the South African context, women over age 50 years should have a screening mammogram and then every 2 to 3 years. Patients who have a high risk profile, should be screened annually after age 50yrs until the age of 75. Histological classification of Breast Malignancy Invasive epithelial cancer Non-Invasive epithelial cancer Paget’s disease of the nipple Ductal Carcinoma in situ(DCIS) Infiltrating lobular carcinoma Lobular carcinoma in situ(LCIS) Infiltrating ductal carcinoma Mixed connective and epithelial tumours - Medullary - Sarcoma - Mucinous - Carcinosarcoma - Tubular - Angiosarcoma - Papillary - Malignant phylloides 37 Clinical presentation History Clinical examination Elucidate risk factors for breast cancer Describe the site, size, consistency, tenderness, Painless breast lump / back pain temperature , shape, borders, skin changes – satellite nodules, ulceration, peau d’ orange, skin tethering Duration / How was it first noticed? Fixity to underlying muscle Nipple discharge – bloody? Palpate axillary & supraclavicular lymph nodes Pregnancy/lactation/ history of trauma Examine for metastatic disease – pleural effusion, hepatomegaly/ascites / spinal tenderness / neurological deficit Staging TNM(Tumour/node/metastases) staging system is used to stage , direct therapy and prognosticate patients. Tumour Nodes Metastases T1 - 5cm nodules,peau d orange N3 – supraclavicular M1 – distant T4 – any size T4c – T4a and T4b nodes metastases T4d – inflammatory breast Ca Diagnosis Triple assessment forms the cornerstone of the diagnostic workup for breast cancer and entails a detailed history and clinical examination; imaging and biopsy. Diagnostic Imaging Investigation Comment Ultrasound Women < 35 yrs; dense breasts; differentiate solid and cystic lesion Mammogram Women > 35yrs; assess for muticentric lesions ; multifocal lesion (> 2 tumors in separate quadrants of the breast) ; features of malignancy – increased density, irregularity, microcalcification, spiculation MRI Not routine – may be used to screen patients with BRCA mutations, silicone implants, detect lobular carcinoma PET scan Not routine – may be used to detect recurrence in scarred breasts Tissue diagnosis A fine-needle aspiration cytology of the lump(FNAC) is usually the 1st line biopsy technique and is cheap and non-invasive. It has up to a 10% false negative rate. A core-needle biopsy (Trucut) is the biopsy technique of choice. Sensitivity is high (85-96%) and specificity 100%. It gives accurate information regarding the histology, differentiation and hormone receptor status of the tumour. Incisional and excisional biopsy can be done if histology is still not attained. Image guided biopsy can also be done under mammogram (stereotactic), ultrasound or MRI guidance. 38 Staging investigations Investigation Comment Ultrasound liver Exclude liver metastases Chest xray Exclude lung and bony metastases Bone scan Exclude bone metastases Ancillary Investigations : MUGA Scan : Assess ejection fraction prior to chemotherapy(anthracycline -cardiotoxic agent used) Management 1. Early breast cancer (EBC) Management ofEBC entails breast conserving surgery which comprises wide local excision of the tumor with a 1cm macroscopic margin of clearance and 1mm microscopic margin. This is followed by adjuvant radiotherapy to the chest wall to prevent local recurrence. If the axillary lymph nodes are clinically palpable, then a level II(up to the upper border of pec minor muscle) axillary lymph node dissection is done. If the axillary lymph nodes are not clinically palpable, then a sentinel lymph node biopsy is done. If the sentinel lymph node is positive for metastatic tumour, a level II axillary lymph node dissection is performed. A mastectomy may be done if wide local excision is contra-indicated: 1. Mutlicentric/multifocal tumours 2. Increased tumour to breast ratio 3.Pregnancy 4. Previous radiation to the chest wall Adjuvant chemotherapy(cyclophosphamide, adriamycin and 5 flouro-uracil[5FU]) is given for: 1. Hormone receptor negative tumours 2. Node positive disease 3. Tumour size > 1cm Adjuvant hormonal therapy( Tamoxifen – selective oestrogen receptor modulator) is given if the tumours are oestrogen or progesterone receptor positive. Aromatase inhibitors(raloxifene) which block the peripheral conversion of androgens to oestrogen may be used in post-menopausal women. The duration of therapy is 5 years. Adjuvant monoclonal antibodies(Herceptin) may be given for a period of 1 year for tumours that express the Her2 receptor. 2. Locally advanced breast cancer(LABC) The management of LABC involves the administration of neoadjuvant chemotherapy(CAF) for up to 6 cycles. Chemotherapy is given prior to surgery to decrease the size of the tumor so that a mastectomy is achievable. Chemotherapy also allows an in vivo assessment of the tumour response to chemotherapy. Adjuvant radiotherapy is given following a mastectomy and level II axillary lymph node clearance. Adjuvant hormonal therapy and monoclonal antibodies are given if the receptor status is positive. 3. Metastatic disease Patients undergo systemic chemotherapy only. A toilet mastectomy may be done for a fungating /ulcerating lesion for local control. 39  SKIN DISORDERS Miss R Naidu INFECTIONS Cellulitis is a superficial spreading infection of the skin and subcutaneous tissue. Clinical features :Swelling,erythema,tenderness,warmth Common organism : Streptococcus / Staphyloccus Treatment : Antibiotics – Penicillin for simple community acquired cellulitis/ Co -amoxiclav for immunocompromised patients / add cloxacillin if not responding Folliculitis, Furuncles, and Carbuncles - Folliculitis is infection and inflammation of a hair follicle. The causative organism is usually Staphylococcus. - Furuncle (boil) begins as folliculitis but progresses to form a nodule that eventually becomes fluctuant. - Deep-seated infections that result in multiple draining cutaneous sinuses are called carbuncles. Folliculitis usually resolves with time and adequate hygiene. Warm soaks to a furuncle may hasten liquefaction, speed drainage, and encourage healing. Carbuncles are more difficult to treat and require wide excision of the infected tissue and sinuses. An abscess is a localized accumulation of pus with an associated superficial cellulitis. The body's response is to isolate this accumulation, necessitating drainage. Necrotizing Fasciitis Infection of the soft tissue rapidly spreading along fascial planes. Maybe skin sparing. The most common organisms isolated from patients presenting with necrotizing soft-tissue infections include the gram-positive organisms: Group A Streptococci, Enterococci, coagulase- negative Staphylococci, S. aureus, S. epidermidis, and Clostridium species; the gram-negative organisms: Escherichiacoli, Enterobacter, Pseudomonas species, Proteus species, Serratia species, and bacteroides. 57 Clinical features: Pain not in keeping with clinical presentation, possible crepitis of soft tissue, swelling Treatment includes resuscitation, broad spectrum antibiotics and urgent, aggressive surgical debridement most importantly. Pilonidal Disease Infected pilonidal cysts of the sacrococcygeal region occur primarily in young males. The infection likely begins in a pilo-sebaceous unit in the natal cleft. Recurrent trauma causes obstruction of a hair follicle and leads to infection. The localized folliculitis spreads into the surrounding soft tissue and produces an abscess. This eventually drains to the surface and produces a sinus that is usually located lateral to the midline. The sinus is lined with granulation tissue but over time can epithelialize. Pilonidal abscesses should be incised and drained. Without further therapy, many will recur. There are many different ways of treating the chronic sinus tract, including tract curettage, local excision and closure, wide excision and Marsupialization, and wide excision and flap closure. 40 SKIN LESIONS Differential diagnosis: - Benign pigmented naevus - Melanoma - Basal cell carcinoma - Squamous carcinoma When to be suspicious of a skin lesion: i. Asymmetry ii. Border irregularity iii. Colour variation iv. Diameter > 6mm v. Evolving lesion MELANOMA Risk factors for melanoma Include positive family history of melanoma prior melanoma (10% risk developing another melanoma) multiple clinically atypical moles or dysplastic nevi inherited genetic mutations sun exposure exposure to carcinogens (coal tar, creosote, arsenic compounds) Impaired immunity Xeroderma pigmentosum Fair skin/ ethnicity Full thickness biopsy of suspicious lesion. Excisional or incisional biopsy. Confirm melanoma Stage the disease – CXR and CT scan chest / abdomen /pelvis Staging systems include: Clarks / Breslows / AJCC TNM staging TYPES  Superficial spreading  Nodular  Lentigna maligna melanoma  Acral lentigionous Mainstay of therapy is surgery Address the primary lesion by wide local excision. Clearance margin  2mm thickness – 2cm clearance margin Lymph nodes (lower limb melanomas) may addressed by sentinel lymph node biopsy ( >1mm thickness, clinically node negative) 41 Superficial lymph node dissection (positive sentinel node biopsy) Deep inguinal dissection :  Clinically palpable nodes  Positive pelvic nodes on CT Scan  Cloquets node positive  More than 3 nodes positive on superficial dissection ADJUVANT THERAPY Chemotherapy used mainly in metastatic disease. Poor response rate. Radiotherapy is of limited value. 42  SOFT TISSUE TUMOURS Mr CG Bhula Soft tissue tumours (STS) arise from embryonic mesodermal tissue and are diverse in their genetic and histological make-up. Most of these tumour cells arise from undifferentiated precursor cells and then acquire some phenotypic identity with a spectrum of behaviour ranging from benign activity through to malignant infiltration. The median age of diagnosis is 56 years with a predilection for males than females( 3.7 vs 2.6 per 100 000). About 10% are diagnosed in the under 20 age group, whereas 52% are diagnosed in the over 55 year age group. Although these tumors may develop in any anatomic site, 43% occur in the extremities, with two thirds of extremity lesions occurring in the lower limb, followed in order of frequency by visceral (19%), retroperitoneal (15%), trunk/thoracic (10%), and other locations (13%). Hence the focus of this lecture will focus on the approach to extremity soft tissue tumours The ‘tissue of origin’ classification scheme is the most commonly used scheme and is the basis for the recent World Health Organization (WHO) classification system for soft tissue tumours BENIGN AGGRESSIVE MALIGNANT Fibroma Fibromatosis Fibrosarcoma Fibrous Desmoid tumour Dermatofibroma Dermatofibrosarcoma protuberans Malignant fibrous Fibrohistiocytic Histiocytoma Lipoma Atypical lipoma Liposarcoma Adipose Angiolipoma Smooth muscle Leiomyoma Leiomyosarcoma Striated muscle Rhabdomyosarcoma Haemangioma Haemangioendothelioma Angiosarcoma Blood vessels Kaposi’s sarcoma Lymphangioma Lymphangiosarcoma Lymph vessels Cystic hygroma Giant cell tumour Synovial sarcoma Synovium of tendon sheath Localized fibrous Mesothelioma Mesothelial mesothelioma Neurilemmoma Malignant schwannoma Neural Neurofibroma Myxoma Epithelioid sarcoma Uncertain Alveolar soft part sarcoma Table 1: HISTOLOGICAL CLASSIFICATION SOFT TISSUE TUMOURS 43 Aetiology There are various environmental and genetic factors that predispose to STT but in most patients, a clear aetiological agent is not found. Environmental risk factors: Factor Agent Patient Profile Comment Radiotherapy Orthovoltage and megavoltage Therapeutic Most commonly radiation radiation osteosarcoma; dose-response patients relationship Chemotherapy Alkylating agents: Pediatric cancer Relative risk of bone sarcoma cyclophosphamide, melphalan, patients increased with cumulative procarbazine, nitrosourea, and drug exposure chlorambucil Chemical Thorotrast Diagnostic x-ray Hepatic angiosarcoma exposure patients