Esophageal obstruction (choke) occurs when the
esophagus is obstructed by food or foreign objects. It is the most
common esophageal disease in large animals. Horses most commonly
obstruct on grain, beet pulp, or hay. Esophageal obstruction can also
occur after recovery from standing chemical restraint or general
anesthesia. Cattle tend to obstruct on a single solid object, eg,
apples, beets, potatoes, turnips, corn stalks, or ears of corn.
Clinical Findings
In horses,
clinical signs associated with
esophageal obstruction include nasal discharge of feed material or
saliva, dysphagia, coughing, or ptyalism. The horse may appear anxious
and/or appear to “retch” by stretching and arching the neck. Affected
horses may continue to eat or drink, worsening the clinical signs.
In cattle,
clinical signs include free-gas
bloat, ptyalism, or nasal discharge of food and water. Ruminants may be
bloated and in distress or recumbent, or there may be protrusion of the
tongue, extension of the head, bruxism, and ptyalism. Acute and complete
esophageal obstruction is an emergency because it prohibits eructation
of ruminal gases, and free-gas bloat develops. Severe free-gas bloat may
result in asphyxia as the expanding rumen puts pressure on the
diaphragm and reduces venous return of blood to the heart.
Diagnosis
The clinical signs of esophageal obstruction are
usually diagnostic. Physical examination findings compatible with
esophageal obstruction include nasal discharge of feed material and
water, bruxism, ptyalism, and palpable enlargement of the esophagus; in
some instances, foreign objects lodged in the cervical esophagus may be
located via palpation. Subcutaneous emphysema, cervical cellulitis, and
fever may be associated with esophageal rupture. The inability to pass a
stomach (ruminants) or nasogastric tube (horses) can also confirm the
diagnosis.
Endoscopic examination is useful in localizing the
site of esophageal obstruction, type of obstructing material, and extent
of esophageal ulceration. Because of the risk of aspiration pneumonia,
the respiratory tract should be evaluated carefully, including
auscultation of the heart and lungs and thoracic radiography. In
complicated or chronic cases, a CBC and serum biochemistry profile
should be performed. CBC abnormalities include leukocytosis, left shift,
toxic neutrophils, and hyperfibrinogenemia. Biochemical abnormalities
include hyponatremia, hypochloremia, and hypokalemia secondary to
excessive loss of saliva.