Oesophageal obstruction or Choke

Oesophageal obstruction or Choke is condition where there is obstruction of oesophagus. It could be complete or partial with food mass, foreign bodies, inanimate object.

Depending upon obstruction, various signs are manifested, like inability to swallow, regurgitation of food and water, continuous drooling of saliva, severe distress, and in ruminants, a bloat called a secondary bloat or dependent bloat (cause is away from rumen).

Etiology of Choke

Etiology of oesophageal obstruction or choke in various animals is listed below:

• Cattle: whole potatoes, cabbage, beat root, turnips, apples, onions, feed pellets, feed boluses, mineral supplement boluses, anthelmitic boluses (sustained-releasing boluses) etc.
• Horse: gelatin capsule, pieces of wood, dry food etc.
• Canines: bones, vertebrae, soft toys, stones, pieces of wood, balls etc.
• Cat: toys, food mass etc.

Pathogenesis of Choke

Ingestion of object leads to physical obstruction hence peristalsis gets struck at the site leading to inability to swallow. Followed by regurgitation through mouth or nostrils (but in pharyngeal obstruction it is only through nostrils).

In horse both type of obstruction leads to regurgitation through nostrils (because of large soft palate). If there is partial obstruction then liquid food is easily swallowed. Solid food gets regurgitated. Local inflammation causes pain and animal will be in lot of distress.

Sequele of choke

If the case is not attended in time it may cause laceration and rupture of oesophagus, stricture or stenosis.

Oesophageal diverticulum: later on lumen enlarges which is called as mega oesophagus.

Extra luminal obstruction

Obstruction of mediastinal region due to thymoma, cervical region due to enlargement of retro-pharyngeal lymph node is possible.

Congenital defect: persistent aortic arch can also cause extra luminal blockage.

Clinical signs of choke

In cattle: Usually the obstruction is in cervical part and rarely at thoracic inlet. Animal suddenly stops eating, shows anxiety and restlessness. Initially there is forceful attempt to swallow followed by regurgitation. Continuous drooling of saliva, repeated chewing movement without actually chewing feed. If obstruction is complete then bloat develops rapidly and adds to the animals discomfort. Because of distension of abdomen, the respiratory distress and even systolic murmur can be heard on auscultation on cardiac region.

In horse: Signs of restlessness are much more prominent and most of the times horses are unmanageable. Horse makes forceful attempt to swallow followed by retching type of movements. If the pain is severe at the site of obstruction the profuse sweating, stamping, tachycardia and sometimes even rolling is seen. This is confused for colic for most of the times and therefore immediate differentiation is required which can be done by passing of naso-gastric tube.

In dogs: Here also dog is restless, constantly shakes head in order to expel obstructing mass. Dog tries to swallow things followed by retching to regurgitate profuse salivation. Dog is excited and is many a time nonresponsive to owner that is confused with rabies.

Diagnosis of choke

• History: animal has tendency to ingest hard object or solid (potatoes, apple), habit of eating inanimate objects due to pica.
• Symptoms: forceful attempt to swallow, salivation, signs of distress, bloat in ruminants.
• Palpation: palpation on the course of oesophagus is many times helpful for diagnosing obstructing mass.
• Passage of stomach tube / probe: done under sedation with xylazine or chloral hydrate. Radiographic examination: barium meal x-ray.
• Endoscopy: in animals gastro scope is used. It is a fibre-gastric endoscopy which reflexes in any direction with light and magnified lens.

Differential diagnosis

• Oesophagitis: here is also there is pain and difficulty in swallowing but pharyngitis and stomatitis will be accompanying.
• Primary ruminal tympany: can be differentiated by passing stomach tube.

Treatment of choke

• Sedation: animal is excited and in distress it may cause laceration. Examples are chloral hydrate 10% solution, 0.5-1 ml/kg. It has muscle relaxation effect, results in oesophageal dilation retrieval of obstruction becomes easy.
• Relieving of bloat: by abdominocentesis
• Location of obstruction: if near to the pharynx, then pressure is applied from downwards, then by chital forceps foreign body is taken out. If it is in thoracic inlet, attempts are made to push the obstruction using stomach tube.
• Surgical intervention: Obstruction in cervical part is relieved by oesophagotomy whereas thoracic obstruction requires rumenotomy through oesophageal opening forceps is passed and obstruction is taken out.
• Antibiotics and analgesics for 3-5 days is given.
• Animal is maintained on soft palatable diet.

If a foreign body is reachable by hand, then it is good to grasp it by hand. Removal should be made. In this case, xylazine and a mouth gag are required, as xylazine works as a muscle relaxant and a mouth gag prevents hands from being bit by cattle. Hands should be entered into the oesophagus, and FB can be removed. Another person needed to hold the Facebook from outside so it couldn’t go further away.