Differential diagnosis of the foal with abdominal pain
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Abdominal pain in the foal can be a frustrating diagnostic challenge as the differential diagnosis are extensive (See Table
1). Abdominal pain can progress rapidly leading to septicemia or even death. The approach to the neonate with a painful or
distended abdomen includes history, type and dose of analgesics, administered and whether there are any animals affected with
diarrhea. Surgical versus medical treatment may be determined with a proper history and physical exam. Mild signs of colic
( Example: Meconium Impactions or Rotavirus) may include restlessness, attempts to defecate, swishing the tail, straining
to urinate/urinating frequently, walking around the stall and not nursing. Severe colic signs should not be ignored and may
include bloating, lying down and rolling, abdominal distention, and full body sweat. Immediate placement of a stomach tube
should be performed in any foal that had chronic mild signs or colic or violently colicky. The age of the animal is also important
in the determination of risks of certain conditions.
During the first 6 to 24 hours of age, congenital atresia of the colon, rectum, anus or meconium impactions are the most
frequent causes of colic. In paint foals that are primarily white and whose dam and sire are overo are at risk for ileocolonic
aganglionosis. Meconium is composed of glandular secretions from the gastrointestinal tract, amnionic fluid and cellular debris,
which should be passed by 24-36 hours of age. In utero sepsis with associated hypoglycemia and sympathomimetic release can
have bowel hypomotility and be at high risk for meconium impactions. Meconium impactions are more common in colts because
of their narrow pelvic canal. The diagnosis of meconium impactions can be achieved by contrast radiographs, abdominal ultrasonography
and/or proctoscopy. If routine warm water enemas do not relieve the impaction then hyperosmolar solutions (Hypertonic saline
3-4ml/kg per rectum) or acetylcysteine retention enemas may be used. The animal is usually first sedated with either xylazine
or valium. I prefer valium at a dose of 0.1 mg/kg IV , because this medications causes minimal hemodynamic changes in the
patient. The use of Buscopan (N-butylscopalammonium bromide 20mg/ml- Boehringer Ingelheim) at a dose of 0.1-0.2 mg/kg IV
can also be used to help decrease the gastrointestnal "spasms" that may be occuring at the junction of the meconium impaction.
These hypermotile segments will relax allowing the enema to flow around the impaction resulting in its resolution. The acetycysteine
enemas consists of mixing 200ml water, 8 grams of acetylcysteine powder, and 20 g of sodium bicarbonate OR 40 ml of 20% acetylcysteine
with 160 ml of water. A well lubricated 12 or 14 Fr, cuffed Foley urinary catheter is introduced into the rectum and the
cuff inflated. 200 ml of the retention enema solution is then slowly infused and the end of the catheter plugged. The catheter
is then taped to the foal's tail and left in place for 15 minutes. These enemas can be repeated several times a day. If using
the hypertonic solutions for more than 2 treatments in a 24-hour period the sodium status of the patient should be re-evaluated
to prevent hypernatremia. Additional therapy includes fluids and laxatives (120 ml of mineral oil SID to BID and/or milk
of magnesia 30ml PO QID). Analgesics , such as flunixin meglumine 1.1mg/kg IV SID and butorphanol tartrate 1-2mg IV/IM Q 4-12
hours, may also be necessary to help control the foal's discomfort.
Older foals 2-5 days of age are more likely to be suffering from intussusceptions, ruptured bladders, enteritis, gastroduodenal
ulceration, inguinal hernias and small intestinal volvulus. Ultrasonography can be used to help diagnosis conditions that
may be causing colic. Dynamically distended small intestine > 2.5cm in diameter with no motility and absence of gastric distention
could be suggestive of a small intestinal volvulus. A large amount of peritoneal fluid with a history of infrequent urinations
is suggestive of a ruptured bladder. Unfortunately severe abdominal pain is not pathognomonic for a surgical lesion. Tachycardia
of excess of 120 beats per minute that is non-responsive to pain medication and in the absence of fever is suggestive of a
surgical lesion.
