Hiatal Hernia

Typical Signalment

Sharpei dogs are predisposed to this disorder.

Description

A hiatal hernia is a diaphragmatic abnormality that allows part of the stomach and the abdominal oesophagus to prolapse into the thoracic cavity. Two types of hiatal hernia have been recognized in the dog and cat:

Sliding hiatal hernia - Cranial displacement of the distal oesophagus and stomach into mediastinum through the oesophageal hiatus.

Para-oesophageal hiatal hernia - Cranial displacement of part of the stomach into mediastinum through a defect adjacent to the oesophageal hiatus

An oesophageal stricture is an abnormal circumferential narrowing of the lumen secondary to severe oesophagitis. A deep wall injury results followed by healing by fibrosis. The most important causes are:

Chemical injury from swallowed substances
Gastro-oesophageal reflux
Foreign bodies
Oesophageal surgery
Neoplasia
Oesophageal abscesses

Diagnosis

Clinical Signs

Depend on the severity and extent of the stricture but include:

Regurgitation shortly after feeding (may then attempt to re-ingest the regurgitant)
Anorexia
Weight loss
Malnutrition
Ptyalism
Aspiration pneumonia (with associated pulmonary signs such as wheezing and crackling on lung auscultation)
Liquid food better tolerated than solid food.

Diagnostic Imaging

Fibrosing strictures must be differentiated from vascular ring anomalies, oesophagitis, intraluminal and extraluminal masses. This can be done with survey and contrast radiography, endoscopy and ultrasonography.

Survey radiographs are usually unremarkable in animals with benign oesophageal strictures. Barium contrast radiography is normally diagnostic of the disorder and may demonstrate:

Segmental or diffuse narrowing of the oesophagus
Oesphageal dilatation proximal to the site of the stricture

Ultrasonography is not usually useful in diagnosing small benign strictures but may visualise those caused by mass compression.

Oesophagoscopy is used for a definitive diagnosis. It should be used to confirm the site and severity of the stricture and also to exclude the presence of an intraluminal mass.

Treatment

The suspected cause (ie.Oesphagitis)should be corrected first. Oral feedings should be withdrawn in patients with severe stricture or oesophagitis. An oesophagostomy tube may be placed in these cases to provide nutritional support.

Medical therapies:

Oral sucralfate
Gastric acid secretory inhibitors (cimetidine, ranitidine, omeprazole)
Anti-inflammatory doses of corticosteroids (prednisolone) to prevent fibrosis and re-stricture.

Surgical therapies:

Dilation/widening of the stricture by ballooning or bougienage.
Surgical resection is not recommended because iatrogenic strictures at the anastomotic site are possible.

Prognosis

The shorter the length of oesophagus involved and the quicker the corrective procedure is performed the better the prognosis. Animals with large, mature strictures and those with continued oesophagitis have a guarded prognosis. Long term gastrostomy tubes may be required in some cases.

References

Hall, E.J, Simpson, J.W. and Williams, D.A. (2005) BSAVA Manual of Canine and Feline Gastroenterology (2nd Edition) BSAVA

Merck & Co (2008) The Merck Veterinary Manual

Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier.