Approach to Colic - A. Prutton - PDF

APPROACH TO COLIC ALISON PRUTTON BVSC SFHEA MRCVS LEARNING OBJECTIVES To define the term colic as it relates to horses, and understand the clinical importance, incidence and mortality rates associated with colic. To outline the first-line approach to a colic case, detailing the pe...

APPROACH TO COLIC ALISON PRUTTON BVSC SFHEA MRCVS LEARNING OBJECTIVES To define the term colic as it relates to horses, and understand the clinical importance, incidence and mortality rates associated with colic. To outline the first-line approach to a colic case, detailing the pertinent aspects of the history, clinical examination and diagnostic investigations. Apply the principles of analgesia to the treatment of colic. Understand the indications for referral of a colic case. 2 COLIC INCIDENCE Clinical syndrome associated with abdominal pain Predominantly associated with GIT May involve other body systems Common and significant problem USA General population (Traub-Dargatz et al. 2001) 4.2 colic episodes /100 horses per year 11% fatality rate UK Thoroughbred population (Hillyer et al 2001) 7.19 colic episodes/100 horses per year Spontaneous recovery 28.7 % 6.2% fatality rate Medical recovery 63.1 % Surgical Recovery 2.0 % 3 SIGNS OF COLIC Degree of pain may vary with individual horse, breed, and source of pain Reduced faecal Mild signs: Restless, Pawing, Flank watching Inappetance output Vocalisation Gas build up / inflammation of GIT / Smooth muscle spasms Agitation Pawing at the ground Lip curling Moderate signs: Lying down flat out, groaning Impaction or other simple obstruction Severe signs: Very fractious, violent rolling Flank watching Lying down – long periods, or Stetching/posturing to urinate repeatedly Acute, severe strangulation Dull, unresponsive Rolling/thrashing Sweating excessively Straining End-stage: Severe illness due to colic, possible rupture Take breed into account Are they typically stoic? Or dramatic?! 4 COLIC AETIOLOGY What causes colic pain? » Smooth muscle spasm » Inflammation o Colitis / Ulceration » Distension o Impaction o Gas accumulation » Obstruction o Impaction » Tension on the mesentery o Displacement » Tissue congestion/infarction/necrosis o Torsion/volvulus ENDOTOXAEMIA o Strangulation 5 ENDOTOXAEMIA Common feature with strangulating intestinal lesions May be observed with non-strangulating obstructions LPS (endotoxin) is found in abundance in horse GIT Normal mucosal function prevents absorption from the lumen Mucosal injury results in an increase in LPS absorption Horses are extremely sensitive to even small amounts in the blood Inflammatory mediators +++ (SIRS) Signs = hyperaemic mm and hypotensive shock 6 APPROACH TO COLIC: PRIORITIES 1. Provide analgesia and triage 2. Assess severity of the case 3. Construct a treatment plan 7  COLIC AETIOLOGIES (GASTRO-INTESTINAL) Gastric Diseases Small intestinal diseases Caecal diseases Large (ascending) colon diseases Small (descending) Gastric ulceration colon diseases Inflammatory disease Caecal impaction Inflammatory disease Gastric impaction - Anterior enteritis (duodenitis-proximal - Colitis Impaction jejunitis) Caecocolic intussusception - Right dorsal colitis Gastric rupture Mesenteric Rent Simple obstruction Simple obstruction - Ileal impaction Caecal perforation - Impaction - Ascarid impaction - Sand enteropathy Meconium retention - Enterolithiasis Functional obstruction - Nephrosplenic ligament entrapment - Equine grass sickness (EGS) (Left dorsal displacement) Strangulating obstruction - Right dorsal displacement - Strangulating pedunculated lipoma Strangulating obstruction - Epiploic foramen entrapment (EFE) - Large colon volvulus - Gastrosplenic ligament entrapment - Jejunal volvulus - Meckel’s diverticulum - Mesodiverticular band - Jejunal intussusception - Ileocaecal intussusception - Idiopathic focal eosinophilic enteritis (IFEE) Neoplasia 8  CAUSES OF COLIC 30 27.8 BEVA Colic EBM Project (2005) 25.6 25 Prevalence (%) 20 Curtis et al 2015 15 12.7 10 8.6 7.1 7.4 5 4.4 4 2.4 >50% cases return non-specific diagnoses (or spasmodic) 0 *Making a diagnosis is not as important as making an accurate assessment of the severity of the condition* Diagnosis 9 DIFFERENTIALS FOR COLIC “False” colic https://www.google.co.uk/search?q=down+horse&rlz=1C1GGRV_enGB781GB7 82&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiPkdyB1I_eAhWtyYUKHbAjCI Any non-gastrointestinal source of abdominal pain AQ_AUIDigB&biw=1536&bih=675#imgrc=T-8nPNbHeRfGAM: Liver disease / hepatomegaly Urinary disease Renal pain Urolithiasis Peritonitis Intra-abdominal abscess Intra-abdominal neoplasia Reproductive disorders Non-abdominal pain which may be mistaken for colic: Uterine torsion Oesophageal obstruction Dystocia Rhabdomyolosis (tying-up) or atypical myopathy Broad ligament haemorrhage Retained placenta Laminitis Pleuroneumonia/pleuritis 10  HISTORY Accurate history will lead to formulation of differential diagnosis list Signalment Recent management Nature of colic Results of clinical examination then used to refine differential list 11 HISTORY Assess severity and duration Identify risk factors “When was the horse last seen normal?” (Signalment) Current management & any recent Changes Acute or chronic onset? Feeding What signs are being displayed? Stabling Persistent, intermittent, progressive? Pasture access Food and water intake since colic started? Exercise Dental history Faecal output? Parasite control programme Has any treatment been administered? Geographical area, soil type? Previous history of colic? Vices Windsucking/crib-biting Drugs 12 MORE ON RISK FACTORS… Increased/change in hours of stabling Crib-biting, windsucking – EFE Large colon volvulus, EFE, impaction Drugs: Opioids, alpha-2 agonists, atropine: Ileus (+ consider Geographical area (between and within countries) concurrent hospitalization/box rest… > impaction) EGS more common in certain areas in UK (And horses Antimicrobials: antibiotic induced colitis aged 2-7, spring months, and those who have recently NSAIDs: Right dorsal colitis moved premises) Parasites: IFEE more common the North West UK? (And in younger Tapeworm: ileal impaction. Has also been associated with horses) spasmotic colic Regional differences in soil sand content - Sand Cyathastomins – can cause damage to gut wall when they re- enteropathy emerge Management and dietary differences across the world Ascarids: impaction (foals) Strongyles: can disrupt blood supply to the intestine Time of year (verminous arteritis) (now very rare) EGS – more common in spring months Extreme temperatures (hot or cold) – horses may not drink enough and become dehydrated, leading to impaction Feed Alfalfa (60 >100 Pulse quality Strong Moderate Weak Jugular refill Rapid Slow Sluggish MM Colour Pink Dark pink → Red Red → Purple CRT ≤ 2s 2-3s >3s Moisture content of oral MM is an assessment of hydration status; Moist – Normal Tacky or Dry - Dehydration 16 C L I N I C A L E X A M I N AT I O N Assessment of hydration status Compromised CV status is an important indicator for referral; Deteriorating CV status associated with poorer prognosis PCV% / TP g/L Serum % Dehydration MM moisture HR CRT (s) (Normal PCV = ~32-46, Lactate Normal TP = ~55-75) mmol/L 6% Tacky 40-60 2 ~40/70 100 >4 >50/>80 >6.0 17 C L I N I C A L E X A M I N AT I O N 3. Auscultation of Gastrointestinal Tract GIT borborygmi of the ascending colon (caecum & LC) - Absent + Hypomotile ++ Normomotile +++ Hypermotile Hypermotility: Increased smooth muscle activity - spasmodic colic Local hypomotility: Localised stasis of GIT General absence: GIT ileus – common finding in most colic cases (except spasmodic) Useful for monitoring – e.g. progressive loss of motility 18 C L I N I C A L E X A M I N AT I O N Rectal Temperature Most uncomplicated colic cases will have normal rectal temperature Very low core temp – usually associated with severe/end stage shock Pyrexia (>38.5oC)– Can indicate alternate diagnosis, e.g. peritonitis, colitis Endotoxaemia can cause a mild pyrexia Digital pulses Not appropriate to assess circulation: only useful to assess for presence of laminitis (Eg secondary to colitis) Respiration Tachypnoea: usually due to pain, but could be associated with endotoxaemia Detailed auscultation of lungs rarely necessary 19 C L I N I C A L E X A M I N AT I O N Impact of pain on the clinical exam Mild-moderate increase in HR (40-60bpm) common Marked-severe tachycardia (>60bpm) is a sign of hypovolaemia Tachypnoea Can make it very difficult to examine the horse (CARE!) May need to administer a quick-acting, potent analgesic 2-agonist Xylazine Detomidine Romifidine  opioid Butorphanol Try to assess CV status before giving 2-agonist (HR, MM) 20 DONKEYS “Beware the dull Donkey” *Treat as an emergency* Good at masking signs of pain and disease: take signs of pain seriously Low head position, less interested in env, not eating (or ‘sham’ eating), more time spent recumbent Slight variation in CE parameters compared to horses (T 36-37.8, HR 36-52, RR 12-28) Rectal examination usually can be done (unless miniature) Pharmacology: Phenylbutazone & Flunixin safe BID Impaction colic most common type of colic seen Hyperlipaemia a secondary risk Negative energy balance > lipolysis > hyperlipaemia Take blood early (triglycerides) Treatment = reverse the negative energy balance Treatment intensity depends on case Acknowledgement: Dr Karen Otherwise, mostly similar to horses… Moore & The Donkey Sanctuary 21  FURTHER DIAGNOSTICS: T R A N S - R E C TA L E X A M I N AT I O N Ideally done for all colic cases at first presentation Abnormalities: Impaction Distended small intestine (‘DSIs’) - fluid filled thin-walled loops Distension of large colon (gas accumulation) Displacement Masses Tension on mesentery (taut taenial bands) 22 T R A N S - R E C TA L E X A M I N AT I O N - S P E C I F I C E X A M P L E S Condition Likely rectal findings Spasmotic colic Usually normal or mildly gas distended Pelvic flexure impaction Palpable ingesta filled area (can be small/doughy initially, becoming larger and more firm with increased duration / severity) in left ventral abdomen Small intestinal strangulating obstruction (eg Distended loops of small intestine (DSIs) strangulating pedunculated lipoma) or functional small intestinal obstruction (eg Grass sickness) Right dorsal displacement Large intestinal gas distension, taut tenial band running horizontally across abdomen Neprosplenic entrapment (left dorsal Large intestinal gas distension, spleen may be pushed displacement) axially by large intestine Caecal impaction Firm ingesta filled structure in right mid abdomen Small colon or rectal impaction Firm ingesta filled small colon or rectum 23 FURTHER DIAGNOSTICS: N A S O G A S T R I C I N T U B AT I O N Should perform in most, if not all colic cases on first presentation Done before or after rectal examination, depending on severity of case Check for nasogastric reflux Fluid/ingesta reflux from the stomach >2 Litres of fluid = abnormal Usually indicative of small intestinal obstruction (physical or functional) Can occur due to large colon displacement (pressure on duodenum) Presence of gastric reflux has significant diagnostic value Majority of cases with reflux require referral Quantity can reflect time and/or location of lesion Relieving reflux (if present) is also therapeutic >8L will stretch stomach and be a significant source of pain Prevention of rupture 24  FURTHER DIAGNOSTICS Abdominocentesis Not indicated in every case. Useful prognostic indicator Assess for presence of changes in peritoneal fluid Appearance Laboratory analysis Colour and clarity (normal = pale yellow & WBC count transparent) Cytology Serosanguinous = more likely to be strangulating Predominantly neutrophils lesion (serosal compromise, leakage of blood Total protein concentration components) Lactate concentration Increased turbidity usually = increased cell Marker for ischaemia numbers & protein Shouldn’t be higher than blood lactate Presence of ingesta Increased peritoneal fluid:blood lactate ratio Rupture? = more likely to be strangulating Enterocentesis? 25 ABDOMINOCENTESIS 26 FURTHER DIAGNOSTICS Blood: PCV/TP Blood Lactate ( overdose > renal compromise or right dorsal colitis 31 T R E AT M E N T: S PA S M O LY T I C S Spasmolytics (Anticholinergics) N-Butylscopolamine (Buscopan Injectable ) Smooth muscle relaxant Rapid onset and short duration of activity Good for: Treating hypermotile/spasm type colic ‘Gas’ colic Relaxing rectum prior to rectal examination 32  T R E AT M E N T: F LU I D T H E R A P Y A N D P U R G AT I V E S Enteral fluids Indicated in the majority of colic cases (Most cases will have at least slight dehydration) Contraindicated if NG reflux is present, or suspect small intestinal lesion (DSIs) Possible to leave tube in-dwelling Excellent way to rehydrate the colonic content (impactions) Bolus(es) of isotonic fluids (tap water + NaCl + KCl or rehydration sachets) 5-8L can be given q2-4hrs to 500kg horse IV fluid bolus? 10-20mL/kg over 30min – 1h (5-10L/500kg horse) If rapid resuscitation and volume expansion required: Hypertonic saline: 3-5mL/kg bolus (2L per 500kg horse) followed up with isotonic fluids 33 T R E AT M E N T: P U R G AT I V E S Indicated if impaction colic Magnesium Sulphate (Epsom Salts) 1g/kg by nasogastric tube once daily Osmotic effect > softens gut content Systemic effects may be seen with repeated administration (electrolyte derangements) Or: Liquid Paraffin/Mineral oil Via nasogastric tube Lubricant effect within lumen of gut Efficacy as a laxative debated Good marker of GI transit 34 D O N K E Y S : H Y P E R L I PA E M I A T R E AT M E N T Reverse the negative energy balance Acknowledgement: Dr Karen Moore & The Donkey Sanctuary 35 PROGNOSIS When to refer a colic case for surgery and/or hospitalisation? Essentially, any indicators that the case won’t resolve with simple conservative therapy (ie analgesics & enteral fluids) Non-response to analgesia Significant CV compromise (eg HR >60) Rapid deterioration despite therapy Complex abnormalities on rectal exam (eg DSIs) Presence of >2L NG reflux Recurrent/chronic cases with unclear Dx 36 CLIENT ADVICE If you haven’t referred the horse: Usually a good idea to establish if referral is an option should the horse get worse Always leave the owner with a plan; for example: Withhold food +/- handwalking What to expect if things go well What to monitor for (signs of pain, faecal output etc) What, when and how much to start feeding (may not be until after recheck) Arrange a time to recheck the horse later (or follow up conversation on the phone, for milder cases). 37  QUIZ What features of the signalment, history and clinical exam stand out for you in the following case? Ta l k t h ro u g h yo u r c l i n i ca l re a s o n i n g , co n s i d e r i n g how each feature could be relevant, and why. What is your top differential diagnosis at this stage, based on the information you have? S I G N A L M E N T, H I S T O R Y A N D C L I N I C A L E X A M 23 old year-old shire gelding, in light work as a hacking/leisure horse. Insured. Last seen normal 8am this morning, it is now 6pm Quieter than usual, inappetant. Was lying down when owner arrived but got up and now standing with head in corner. Hasn’t passed as many dropping as usual today. Normal diet is grass, hay ad lib when stabled overnight and a little bit of mix On box rest for the past few days due to a foot abscess, also on 1.5 sachets of bute twice daily Faecal egg counts and tapeworm serology are carried out regularly; worming hasn’t been required this year based on the results. Normally he is turned out with a pony companion Body Condition Score 3.5/5 Last dental examination was 3 months ago, there were some mild sharp points and 2 narrow diastemata were noted – chaff removed from feed to help manage those Clinical exam: QAR, HR 44, mm pink, slightly tacky, CRT