Colic Flashcards
What % of horses develop colic annually?
10%
What % of horses that develop colic require surgery?
10%
Colic risk factors
- recent change in diet
- recent change in stabling
- recent change in activity level
- previous colic or abdominal surgery
- inadequate deworming or dental care, weather?
What are the most critical parts of a history for a horse with colic?
- treatments already given
- any known medication reactions
- duration of colic
- severity of colic
How much nasogastric reflux may be considered normal?
up to 2L
How long is “skin tent” in a normal horse?
2-3 seconds
What are some gut sounds that may be heard?
- opening of ileocecal orifice (sounds like drain emptying)
- sand in ventral colon
- short, sharp tinkling sounds
What factors are used in assessing dehydration status?
- skin tent
- degree of enophthalmos
What are normal parameters for abdominal fluid?
TNCC<10,000 cells/ul
TP<2.5g/dl
When should you consider referral?
- refractory/unrelenting pain
- lack of response to therapy (think about referral on second visit to patient
- evidence of endotoxemia (consistently elevated HR, congested gums, prolonged CRT)
- findings inconsistent with a simple colic (excessive reflux, distended viscous tight band, extensive impaction on rectal, serosanguinous abdominocentesis)
Causes of nasogastric reflux
- pyloric obstruction
- SI obstruction or strangulation
- nephrosplenic entrapment
- occasionally large colon volvulus
- anterior enteritis
Causes of tight bands
- large colon displacement or volvulus
- grossly distended cecum
- mesentery under tension
- uterine torsion
Causes of abnormal abdominal taps
- small intestinal compromise
- enteritis
- large intestinal compromise
- splenic tap
Normal pulse in a horse?
48 bpm or less
What two equine analgesia drugs are often combined due to synergism?
xylazine, butorphanol
Typical clinical signs of large intestinal simple obstruction
- consistent mild pain
- normal gums usually
- elevated pulse
- distended or impacted colon
- normal abdominal tap
Where are enteroliths usually located?
- right dorsal colon
- transverse colon
- small colon
Surgical approach to enteroliths
pelvic flexure enterotomy +/- incision in the right dorsal colon or where enterolith is located
Risk factors for enteroliths
- high calcium diet
- ingestion of foreign body
What are the causes of secondary cecal impaction?
- associated with ortho or ophtho pain
Treatment for secondary cecal impactions
cecal evacuation & aggressive pain management
Treatment options for NS entrapment
- phenylephrine, walk/trot
- roll horse +/- phenylephrine
- straight to surgery for horses not suspected to respond to phenylephrine or don’t want to give phenylephrine
What are causes of simple obstruction of small colon?
- meconium impaction in foals
- fecal impaction in miniature horses
Typical clinical signs with small intestinal strangulating obstruction
- consistent moderate pain
- congested gums
- elevated pulse
- reflux
- multiple distended SI loops
- serosanguinous tap
Typical clinical signs seen with anterior enteritis
- depression/mild pain
- congested gums
- elevated pulse
- copious reflux
- several mildly distended SI loops
- serosanguinous tap with slight elevation in TP; no elevation in TNCC
Predisposing factors for mesenteric lipoma
- horses over 15 years
- geldings
What structures border the epiploic foramen?
- portal vein
- vena cava
- caudate process of liver
What is the most common form of intussusception?
ileocecal
What age of horses is at risk for intussusception?
young horses
What are typical clinical signs for large intestinal strangulating obstructions?
- consistent severe pain
- pale gums
- normal or elevated pulse
- markedly distended colon
- inconsistent tap results
Maintenance fluid requirements for horse
50 ml/kg/day (~1L/hour)
What are the three major types of intestinal lesions?
- simple obstruction
- strangulating obstructin
- non-strangulating infarction
Prognosis for simple obstructions
- good for large colon simple obstruction
- fair for SI, cecum, small colon
- lower for foals
Cause of ascarid impactions
foals on poor de-worming program that are suddenly de-wormed with a very effective dewormer; ascarids all die at once creating an obstructing mass
Treatment of ileal hypertrophy
bypass the lesion with a jejuno-cecostomy
What is the most common type of large colon obstruction?
pelvic flexure impactions
Where does sand accumulate?
right dorsal & transverse colon
In what region are enteroliths most common?
west coast
What is an indication that there may be more enteroliths?
an enterolith with a flat side
Prognosis for strangulating lesions
guarded; poor if horses present in shock
How much small intestine can be resected without affecting horse’s ability to maintain condition?
up to 50%
How much large colon can be resected? special considerations?
up to 95%; feed special diets
Examples of strangulating obstruction of small intestine
- inguinal hernias
- strangulating umbilical hernias
- epiploic foramen entrapment
- strangulation by mesenteric lipomas
- small intestinal volvulus
- intussusceptions
What is the cause of thromboembolic colic?
Strongylus vulgaris-induced thrombus formation in cranial mesenteric artery
What antibiotics are common post-surgery
K-pen, gentamicin
What are some postoperative complications that may be encountered?
- recovery stall complications (fractures, airway obstruction, myositis)
- ileus
- incisional infections/dehiscence
- adhesions
- peritonitis
- laminitis
What is the difference between hemorrhagic strangulating obstruction and ischemic strangulating obstruction?
hemorrhagic: occlusion of arterial blood supply
ischemic: occlusion of arteries & veins simultaneously
Breeds predisposed to inguinal hernias
Standardbreds, Saddlebreds, Tennessee Walking Horses
