Impaction of the Oesophagus

Upper Block	Lower Block
Acute vomiting	Gradual intestinal distention
Dehydration	Mucosal destruction
Alkalosis	Toxaemia
Pre-renal azotaemia	Peritonitis

• Commonly in cattle, horses and dogs.
• The most common sites of obstruction are the thoracic inlet, the base of the heart, and the hiatus oesophagus of the diaphragm, i.e.: the narrowest points.

Horse

• With foods that expand in oesophagus such as haylage etc.
• Also seen with whole apples.

Cattle

Impaction of a bovine oesophagus (Courtesy of Alun Williams (RVC))

• May eat a spherical object that obstructs the oesophagus mostly in anterior 1/3rd of oesophagus and can often be palpated in live animal.
• Potatoes can be a cheap source of feed and if fed whole can become stuck in oesophagus.
• If obstruction occurs further down can be difficult to diagnose and remove.
• Cattle develop bloat when oesophagus obstructed.
• Apples fairly easily to dislodge.

Dog

• Usually with small bones
• Animals that feel protective of feed may gulp food down quickly, particularly if given small chops / knuckle bones.
• Knobbly shape may make bone lodge in oesophagus, particularly just anterior to heart.
• Very difficult to dislodge (because of shape).
• Pressure necrosis occurs very quickly around it and can erode through oesophagus within about 24 hours.
• Small bone may also lodge in duodenum if they pass through the stomach.