ESOPHAGITIS
Inflammation of the esophagus is accompanied initially by clinical findings
of spasm and obstruction, pain on swallowing and palpation, and regurgitation of bloodstained, slimy material.
ETIOLOGY
Primary esophagitis caused by the ingestion of chemical or physical irritants
is usually accompanied by stomatitis and pharyngitis. Laceration of the mucosa
by a foreign body or complications of nasogastric intubation may occur.
large- diameter nasogastric tubes is associated with a higher risk of pharyngeal
and esophageal injury when performed in horses examined for colic.
The administration of sustained. Release anthelmintic boluses to young
calves that are not large enough for the size of the bolus used may cause
esophageal injury and perforation. Death of Hypoderma lineatum larvae in the
submucosa of the esophagus of cattle may cause acute local inflammation and
subsequent gangrene. Inflammation of the esophagus occurs commonly in many
specific diseases, particularly those that cause stomatitis, but the other clinical
signs of these diseases dominate those of esophagitis.
PATHOGENESIS
Inflammation of the esophagus combined with local edema and swelling
results in a functional obstruction and difficulty in swallowing. Traumatic injury
to the esophagus results in edema, hemorrhage, laceration of the mucosa and
possible perforation of the esophagus, resulting in periesophageal cellulitis,
which spreads proximally and distally along the esophagus in fascial planes
from the site of perforation. Perforation of the thoracic esophagus can result in
severe and fatal pleuritis. There is extensive edema and accumulation of
swallowed or regurgitated ingesta along with gas. The extensive cellulitis and
the presence of ingesta results in severe toxemia, and dysphagia may cause
aspiration pneumonia.
CLINICAL FINDINGS
In the acute injury of the esophagus, there is salivation and attempts to
swallow, which cause severe pain, particularly in horses. In some cases,
attempts at swallowing are followed by regurgitation and coughing, pain,
retching activities and vigorous contractions of the cervical and abdominal
muscles. Marked drooling of saliva, grinding of the teeth, coughing and profuse
nasal discharge are common in the horse with esophageal trauma with
complications following nasogastric intubation. Regurgitation may occur and
the regurgitus contains mucus and some fresh blood. If the esophagitis is in the
cervical region, palpation in the jugular furrow causes pain and edematous
tissues around the esophagus may be palpable. If perforation has occurred, there
is local pain and swelling and often crepitus. Local cervical cellulitis may cause
rupture to the exterior and development of an esophageal fistula, or infiltration
along fascial planes with resulting compression obstruction of the esophagus,
and toxemia. Perforation of the thoracic esophagus may lead to fatal pleurisy.
Animals that recover from esophageal traumatic injury are commonly affected
by chronic esophageal stenosis with distension above the stenosis. Fistulae are
usually persistent but spontaneous healing may occur. In 'specific diseases such
as mucosal disease and bovine malignant catarrh.
CLINICAL PATHOLOGY
In severe esophagitis of traumatic origin a marked neutrophilia may occur,
suggesting active inflammation.
NECROPSY FINDINGS
Pathological findings are restricted to those pertaining to the various specific
diseases in which esophagitis occurs. In traumatic lesions or those caused by
irritant substances, there is gross edema, inflammation and, in some cases,
perforation.
TREATMENT
Feed should be withheld for 2-3 days and fluid and electrolyte therapy may be
necessary for several days. Parenteral antimicrobials are indicated, especially
if laceration or perforation has occurred. Reintroduction to feed should be
monitored carefully and all feed should be moistened to avoid the possible
accumulation of dry feed in the esophagus, which may not be fully functional.
ESOPHAGEAL OBSTRUCTION
Esophageal obstruction may be acute or chronic and is characterized clinically
by inability to swallow, regurgitation of feed and water, continuous drooling of
saliva, and bloat in ruminants. Acute cases are accompanied by distress. Horses
with choke commonly regurgitate feed and water and drool saliva through the
nostrils because of the anatomical characteristics of the equine soft palate.
ETIOLOGY
Obstruction may be intraluminal by swallowed material or extraluminal due
to pressure on the esophagus by surrounding organs or tissues. Esophageal
paralysis may also result in obstruction.
- Intraluminal obstructions
These are usually due to ingestion of materials that are of inappropriate size
and that then become lodged in the esophagus:
- Solid obstructions, especially in cattle,
- The most common type of esophageal obstruction in horses is simple
obstruction due to impaction of ingesta after a race or workout.
-Foreign bodies in horses include pieces of wood, antimicrobial boluses
and fragments of nasogastric tubes.
Extraluminal obstructions
- Tubercles or neoplastic lymph nodes in the mediastinum or at the
base of lung.
- Cervical or mediastinal abscess
-Esophageal paralysis, diverticulum or megaesophagus has been recorded in
horses and in cattle.
-Esophageal strictures These arise as a result of cicatricial or granulation tissue
deposition, usually as result of previous laceration of the esophagus.
Other causes of obstruction
- Carcinoma of stomach causing obstruction of cardia
- Squamous cell carcinoma of the esophagus of a horse.
-Esophageal hiatus hernia in cattle
- Para esophageal cyst in a horse.
-Cranial esophageal pulsion (pushing outward) diverticulum in a horse.
- Esophageal mucosal granuloma.
-Traumatic rupture of the esophagus.
PATHOGENESIS
An esophageal obstruction results in a physical inability to swallow and, in
cattle, inability to eructate, with resulting bloat. In acute obstruction, there is
initial spasm at the site of obstruction and forceful, painful peristalsis and
swallowing movements. Complications of esophageal obstruction include
laceration and rupture of the esophagus, esophagitis, stricture and
stenosis, and the development of a diverticulum .
Acquired esophageal diverticula may occur in the horse. A traction diverticulum occurs following periesophageal scarring and is of little consequence.
An esophageal pulsion diverticulum is a circumscribed sac of mucosa protruding
through a defect in the muscular layer of the esophagus. Causes that have been
proposed to explain pulsion diverticula include excessive intraluminal pressure
from impacted feed, fluctuations in esophageal pressure and external trauma.
CLINICAL FINDINGS
-Acute obstruction or choke
The animal suddenly stops eating and shows anxiety and restlessness. There
are forceful attempts to swallow and regurgitate, salivation, coughing and
continuous chewing movements. If obstruction is complete, bloating occurs
rapidly and adds to the animal's discomfort. Ruminal movements are
continuous and forceful. However, rarely is the bloat severe enough to seriously
affect the cardiovascular system of the animal, as occurs in primary leguminous
bloat. The acute signs, other than bloat, usually disappear within a few hours.
Many obstructions pass on spontaneously but others may persist for
several days and up to a week. In these cases there is inability to swallow,
salivation and continued bloat.
Chronic obstruction
in cattle the earliest sign is chronic bloat, which is usually of moderate
severity and may persist for several days without the appearance of other signs.
Rumen contractions may be within the normal range. In horses and in cattle in
which the obstruction is sufficiently severe to interfere with swallowing, a
characteristic syndrome develops. Swallowing movements are usually normal
until the bolus reaches the obstruction, when they are replaced by more forceful
movements. Dilatation of the esophagus may cause a pronounced swelling at the
base of the neck. The swallowed material either passes slowly through the
stenotic area or accumulates and is then regurgitated.
Complications following esophageal obstruction .
Complications following an esophageal obstruction are most common in the
horse and include esophagitis, mucosal ulceration in long-standing cases,
esophageal perforation and aspiration pneumonia. Mild cases of esophagitis heal
spontaneously.
CLINICAL PATHOLOGY:
Radiographic examination is helpful to outline the site of stenosis,
diverticulum or dilatation, even in animals as large as the horse. Radiological
examination after a barium swallow is a practicable procedure if the obstruction
is in the cervical esophagus. Viewing of the internal lumen of the esophagus
with a fiberoptic endoscope has completely revolutionized the diagnosis of
esophageal malfunction. Biopsy samples of lesions and tumor masses can be
taken using the endoscope.
TREATMENT
Conservative approach: Many obstructions will resolve spontaneously and a
careful conservative approach is recommended. If there is a history of prolonged
choke with considerable nasal reflux having occurred, the animal should be
examined carefully for evidence of foreign material in the upper
respiratory tract and the risk of aspiration pneumonia. During this time, the
animal should not have access to feed and water.
Sedation:
In acute obstruction, if there is marked anxiety and distress, the animal should
be sedated before proceeding with specific treatment. Administration of a
sedative may also help to relax the esophageal spasm and allow passage of the
impacted material. For sedation and esophageal relaxation in the horse, one of
the following is recommended:
- Acepromazine 0.05 mg/kg BW intravenously. Xylazine 0.5-1.0 mg/kg BW
Intravenously.
- Detomidine 0. 01-0.02 mg/kg BW intravenously For esophageal relaxation,
analgesia and anti-inflammatory effect hyoscine: dipyrone 0.5:0.22 mg/kg BW
intravenously can be used and for analgesia and anti-inflammatory effect.
Pass a stomach tube and allow object to move into stomach The passage of the
nasogastric tube is always necessary to locate the obstruction. Gentle attempts
may be made to push the obstruction caudal but care must be taken to avoid
damage to the esophageal mucosa. A fiberoptic endoscope can be used to
determine the presence of an obstruction, its nature and the extent of any injury
to the esophageal mucosa.
-Removal by endoscope
If a specific foreign body. such as a piece of wood, is the cause of the
obstruction, it may be removed by endoscopy.
Manual removal through oral cavity
in cattle Solid obstructions in the upper esophagus of cattle may be reached by
passing the hand into the pharynx with the aid of a speculum and having an
assistant press the foreign body up towards the mouth.