Equine Colic Management Quiz

Approach to Colic

• Colic is a clinical syndrome in horses associated with abdominal pain, predominantly involving the gastrointestinal tract (GIT) but potentially affecting other body systems
• Colic is a common and significant problem
• US general population experienced 4.2 colic episodes /100 horses per year with a 11% fatality rate.
• UK thoroughbred population experienced 7.19 colic episodes/100 horses per year with a 6.2% fatality rate.
• Spontaneous recovery 28.7%
• Medical recovery 63.1%
• Surgical recovery 2.0%

Signs of Colic

• Signs vary depending on the source and degree of pain, breed, and individual horse
• Mild signs include restlessness, pawing, flank watching, gas build-up, or smooth muscle spasms
• Moderate signs involve lying down flat, groaning, or impaction
• Severe signs include very fractious behaviour, violent rolling, acute strangulation, and dullness
• End-stage colic shows severe illness and potential rupture

Aetiology of Colic

• Smooth muscle spasm, inflammation (colitis/ulceration), impaction, gas accumulation, obstruction, tension on the mesentery, displacement, tissue congestion/infarction/necrosis, torsion/volvulus and strangulation
• Endotoxaemia is a common feature of strangulating intestinal lesions, but also possible with non-strangulating obstructions.
• Endotoxins (LPS) are abundantly present in the horse's GIT, but are normally prevented from absorption by the mucosa.
• Mucosal injury increases LPS absorption, making horses extremely sensitive to even small amounts in the blood

Approach to Colic: Priorities

• Provide analgesia and triage
• Assess severity of the case
• Construct a treatment plan

Colic Aetiologies (Gastro-intestinal)

• Gastric Diseases: ulceration, impaction, rupture
• Small intestinal diseases: inflammatory disease, anterior enteritis, simple obstruction, ileal impaction, ascarid impaction, functional obstruction (equine grass sickness, strangulating obstruction, etc)
• Caecal diseases: impaction, caecocolic intussusception, caecal perforation
• Large (ascending) colon diseases: inflammatory disease, colitis, right dorsal colitis, simple obstruction, impaction
• Small (descending) colon diseases: impaction, mesenteric rent, meconium retention, neoplasia

Causes of Colic

• Many cases are not able to be definitively diagnosed
• About 50% of cases have a non-specific diagnosis.
• Other factors include poor management, and/or other diseases which may show as colic

Differentials for Colic

• Any non-gastrointestinal source of abdominal pain
• Liver disease, hepatomegaly, urinary disease (renal pain or urolithiasis)
• Peritonitis, intra-abdominal abscess, intra-abdominal neoplasia
• Peritonitis
• Intra-abdominal abscess
• Intra-abdominal neoplasia
• Reproductive disorders (e.g., uterine torsion, dystocia)
• Broad ligament haemorrhage
• Retained placenta

History

• Accurate history to formulate differential diagnosis

• Signalment (animal's characteristics)

• Recent management (feeding, stabling, pasture access, exercise, dental history, parasitic control, geographical area, vices)

• Nature of colic (onset, duration etc)

• Results from clinical examination

• Assess severity and duration (signs)

• Food and water intake since colic started

• Faecal output

• Has any treatment been administered?

• Previous history of colic

Clinical Examination

• Assess severity of the horse's condition

• Establish appropriate "level" of treatment

• Conservative treatment

• Refer for more intensive medical therapy

• Referral for surgery

• Establish prognosis for cases not suitable for treatment

  • Observing the horse from a distance:
    • Current status of colic
    • Pain level/signs of depression
    • Respiratory rate & depth
    • Abdominal distension
    • Presence of faeces
    • Evidence of duration / severity
    • Injuries or signs of stress e.g. traumatic/ bedding injuries or soil/shavings on back

• Rapid assessment of cardiovascular status (heart rate, pulse quality, jugular refill, mucous membrane colour, CRT)

• Assessment of hydration status (moisture content of oral MM, HR, CRT)

• Auscultation of GI tract: listen to the abdomen area for normal/ abnormal bowel sounds

• Rectal temperature using a thermometer

• Digital pulses asses circulation for presence of laminitis (not suitable for assessing circulation)

Clinical Examination - Impact of pain on the clinical exam

• Mild-moderate increase in HR (40-60 bpm) Is common
• Marked-severe tachycardia (>60 bpm) is a sign of hypovolemic shock
• Tachypnoea
• Can make it very difficult to examine the horse

Clinical Examination - Treatment to provide pain relief

• Use alpha-2 agonists (Xylazine, Detomidine, Romifidine) and opioids (butorphanol) for pain relief
• NSAIDs (Flunixin meglumine, Phenylbutazone, Ketoprofen, Meloxicam) for more prolonged pain relief
• Consider the potential anti-inflammatory effects of medications like flunixin, which may mask early signs of endotoxaemia, and use Phenylbutazone if unsure.
• Should take care to NOT TOP-UP NSAIDs, to avoid overdose, and associated renal compromise or right dorsal colitis

Clinical Examination - Spasmolytics

• N-Butylscopolamine (Buscopan) is a smooth muscle relaxant with a rapid onset and short duration of activity.
• Use it to treat hypermotile/spasm type colic)
  • "Gas" colic

Clinical Examination - Fluid Therapy

• Use enteral fluids in most colic cases.

• Contraindicated if NG reflux are present or suspect small intestinal lesion

• Possible to leave a nasogastric tube in-dwelling and bolus of isotonic fluids (tap water, nacl, or KCl) can be administered

• 5-8L can be given q2-4hrs to a 500 kg horse

• 10-20mL/kg over 30 minute-1 hr (5-10L/500kg horse)

• Use hypertonic saline, 3-5mL/kg in a bolus, to rehydrate (2L per 500kg horse)). followed up with isotonic fluids, to resuscitate or in rapid volume expansion

Clinical Examination - Purgatives

• Magnesium Sulphate (Epsom Salts) 1g/kg by NG tube once daily.
• The osmotic effect softens gut content
• Systemic effects, or possible electrolyte derangements may be seen with repeated administration
• Liquid Paraffin/Mineral Oil is a lubricant and may help to loosen impactions

Donkeys: Hyperlipaemia Treatment

• Reverse the negative energy balance.

Prognosis

• When to refer a colic case for surgery and/or hospitalisation:
  • Non-response to analgesia
  • Significant compromise (e.g., heart rate > 60)
  • Rapid deterioration despite therapy
  • Complex abnormalities (e.g., large distended loops of small intestine [DSIs])
  • Presence of ≥2 L NG reflux
  • Recurrent/chronic cases with unclear diagnosis

Client Advice

• If you haven't referred the horse:
  • Establish if referral is necessary
  • Leave the owner with a plan.
  • Withhold food
  • Monitor signs
  • What, when, and how much to feed.
  • Re-check or follow up (phone calls/appointments etc)

Further Diagnostics

• Nasogastric Intubation:
  • Check for reflux
  • Fluid/ingesta reflux: indicative of small/large intestinal obstruction

  • 2 litres fluid = abnormal

  • Pressure on the duodenum may occur due to large colon displacement
  • Reflect time and/or location of lesion
  • To relieve the reflux and prevent rupture
• Abdominocentesis
  • Assess presence of changes in peritoneal fluid (appearance, colour, clarity)
  • Perform laboratory analysis for cell count and other factors suggestive of ischaemia (e.g., total protein, lactate)
• Abdominal Ultrasound
  • Detect abnormalities by assessing the abdomen area
• Imaging: to visualise the entire abdomen (for foals)