RCSI Acute Appendicitis Pathology Lecture 2024 PDF

RCSI Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Acute Appendicitis Course Pathology Lecturer Dr. Clive Kilgallen Date 30th September 2024 LEARNING OUTCOMES List the differential diagnosis for RIF pain Describe the histological...

RCSI Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Acute Appendicitis Course Pathology Lecturer Dr. Clive Kilgallen Date 30th September 2024 LEARNING OUTCOMES List the differential diagnosis for RIF pain Describe the histological features of acute appendicitis Summarise the complications of acute appendicitis based on the consequences of inflammation Distinguish granulation tissue from granulomatous inflammation List the causes of granulomatous inflammation HISTORY 25 year old female P.C. - Pain RIF x 36 hours Pain was initially periumbilical and then moved to RIF  Nausea  Vomited x 1 PMH - Nil of note S/R - Nil of note LMP - 10/7 ago EXAMINATION Pyrexia HR 90/min R/R Normal BP 120/75 Hydration ? CVS, RS, CNS - NAD FOCUSED EXAMINATION Abdomen  Rebound tenderness RIF  Guarding RIF  No rigidity  Bowel sounds present  PR – NAD What is guarding? What is rigidity?  What organs could lead to pain in the RIF? 1. Appendix 2. ovary/adnexa 3. kidney 4. small bowel 5. all of the above DIFFERENTIAL DX OF PAIN RIF What organs are located in the RIF? DIFFERENTIAL DIAGNOSIS Acute appendicitis Terminal Ileitis Meckel’s Diverticulum Urinary tract infection/pyelonephritis Renal / Ureteric colic Ectopic pregnancy Salpingitis Ovarian mass What investigations will you perform? INVESTIGATIONS FBC - especially WCC and differential – why WCC? MSU - C/S and microscopy  Why?  For what? Pregnancy Test + Pl. Abdomen X-ray – why? + Ultrasound abdomen – why? FBC Hb - 12.5g (Norm) MCV 90fL (Norm) MCHC 29pg (Norm) WCC – 14,500 ↑ – 95% polymorphs What is the significance of ↑ polymorphs compared to ↑ lymphocytes? CRP elevated. What is CRP? URINE Microscopy - < 5 pus cells Culture - mixed growth E-coli and Staphylococcus Colony count - < 100,000 organisms/ml What is the significance of these urine findings? Why is it not a UTI?  What is your diagnosis? 1. Appendicitis 2. Pyelonephritis 3. Salpingitis 4. Ectopic pregnancy 5. Crohn's disease DX: ACUTE APPENDICITIS Normal Appendicitis The point of maximal tenderness may be elicited at the McBurney’s point. GROSS PATHOLOGY Normal Appendiciti s  What is the predominant inflammatory cell in acute appendicitis? 1. Plasma cells 2. Eosinophils 3. Neutrophils 4. Lymphocytes 5. Macrophages NORMAL APPENDIX APPENDICITIS WHAT IS THE ROLE OF THE POLYMORPH IN THE INFLAMMATORY PROCESS? Phagocytosis Killing  Superoxide radicals  Hydrogen peroxide What other cells in the body are phagocytic? What is the outcome of acute inflammation? OUTCOME - ACUTE INFLAMMATION Complete resolution  Rare in acute appendicitis Chronic inflammation Abscess Fibrosis How should this patient be managed? MANAGEMENT OF THIS PATIENT Prepare for Surgery Appendicectomy by open surgery or laparoscopy Role of prophylactic antibiotics What are the causes of acute appendicitis?  98% due to inflammation of the wall of the appendix by organisms native to bowel. What precipitates the infection? IMPORTANT PRINCIPLE Obstruction to the lumen by a faecolith causes  Stasis  Bacterial proliferation  Inflammation  Oedema  Reduced blood supply and sometimes gangrene Sometimes obstruction may be due to stenosis of the appendix lumen due to other causes examples. Faecolith Any other causes of appendicitis?  Other causes of acute appendicitis:  Crohn’s disease  Yersinia  TB  Measles What are the complications of acute appendicitis? COMPLICATIONS OF ACUTE APPENDICITIS Gangrenous transformation Perforation - peritonitis Abscess Septicaemia What is an abscess? ABSCESS Localised collection of pus  Dead and degenerate leucocytes  Dead and degenerate host tissue cells  Oedema fluid  Dead microorganisms What does perforation of the appendix mean? PERFORATION A “hole” in the appendix allowing contents of appendix into peritoneum What is the clinical significance of perforation? Peritonitis V Perforation. What is the difference?  Appendicitis can cause a localised or a generalised peritonitis. How? What are the clinical signs of intra-abdominal organ perforation?  Radiology of Abdominal Perforation Air under the diaphragm on an erect x-ray film of the abdomen perforated viscus e.g. perforated duodenal ulcer post laparoscopy, post surgery , peritonitis with gas forming organisms What are the systemic effects of inflammation? SYSTEMIC EFFECTS OF INFLAMMATION Acute phase response  Inflammatory mediators produced in response to infection / injury  Pyrexia  Acute phase proteins (e.g. CRP, ESR)  Leukocytosis  Increased BP and pulse, sweating and rigors, sleep, anorexia, malaise  Severe sepsis  DIC, hypotension and shock  Treatment of perforated appendicitis.  Surgery  IV antibiotics Why does the pain of acute appendicitis classically migrate from the peri-umbilical area to the RIF? 1. Visceral pain – umbilicus and appendix innervated by same segment autonomic nervous system 2. Somatic pain – serosal and parietal peritoneum irritated, pain localises to RIF In the case of retro-caecal or pelvic appendix, presentation may not be typical Chronic Inflammation What type of cells are found in chronic inflammation? CHRONIC INFLAMMATION Inflammation with chronic inflammatory cells e.g. lymphocytes, plasma cells, histiocytes.  Progress from acute inflammation  Ab initio  Autoimmune diseases Granulation tissue Vs Granuloma??  Define Granulation tissue GRANULATION TISSUE A NON SPECIFIC RESPONSE TO INJURY Specialised type of tissue characteristic of healing Characterised by proliferation of fibroblasts and new thin- walled capillaries in a loose extracellular matrix with chronic inflammatory cells Progressively accumulates connective tissue matrix, eventually resulting in dense fibrosis DEFINE A GRANULOMA  What are the causes of granulomatous inflammation? 1. Infection 2. Foreign material 3. Malignancy 4. Idiopathic 5. All of the above GRANULOMATOUS INFLAMMATION A specific immune response or a foreign body response Infection (specific types) Foreign body (e.g. splinter, suture, keratin, hair…) Metal/dust  Berylliosis  Silicosis Response to tumours Unknown aetiology  Sarcoidosis  Crohn’s disease GRANULOMATOUS INFLAMMATION INFECTIOUS CAUSES Bacteria  TB, Leprosy, Cat scratch disease Fungi  Histoplasmosis, Blastomycosis Parasites  Schistosomiasis, Toxoplasmosis, Leishmaniasis Spirochetes  Syphilis AETIOLOGY OF GRANULOMAS Foreign body response Type IV immune reaction  THANK YOU