Short Bowel Syndrome

Description

Short bowel syndrome occurs when greater than 75-90% of small intestine is absent. It is most commonly caused by iatrogenic surgical resection, although congenital anomaly can occur in rare cases. The remaining small intestine cannot adequately absorb nutrients and electrolytes, resulting in diarrhoea. If the ileocolic valve has been removed, large number of bacteria is more likely to reach the small intestine. Changes in gastrointestinal hormone regulation such as hypergastrinaemia and increased acid secretion may occur.

This syndrome may only be transient until the remaining intestine can undergo adaptive hyperplasia. However, it does not necessary occur in all cases of massive intestinal resection. Large resection of intestine should ideally be avoided in the first instance. If needed, it may be better to perform a second surgery 24-48 hours after the first surgery.

Diagnosis

Clinical Signs

• Small intestinal diarrhoea, often with undigested food particles in the faeces
• Severe weight loss

In cases which occur after surgical bowel resection, the presenting clinical signs are sufficient to make a diagnosis. In cases of congenital origin, a plain or contrast radiography is required.

Treatment

Nutritional support

• Total or partial parenteral nutrition may be required to provide adequate nutrition until adaptive hyperplasia takes place.
• At the same time, it is important to continue oral feeding to stimulate mucosal hypertrophy.

Dietary modification

• Small, frequent meals of highly digestible, low fat diet is recommended.
• Vitamin supplementation may be required.

Antimicrobials

• A secondary antibiotic responsive diarrhoea may result if the ileocaecal valve is removed.
• Metronidazole or tylosin can be given in these cases.

Antisecretory agents & antacids

• These may be needed in cases which are poorly responsive diet and antimicrobials alone. Its aim is to lessen diarrhoea and gastric hypersecretion.
• Antisecretory agents such as loperamide, diphenoxylate.
• Antacids such as ranitidine, famotidine.

Prognosis

This is dependent on the length of the small intestine left and response to therapy. If adequate adaption occurs, the patient may respond well and eventually be able to consume a near-normal diet. However, there will always be a limitation in the absorptive capacity of these animals. Some cases may respond poorly and can never be fed on a normal diet and others may die. Malnourished animals have a poorer prognosis.

References

• Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company.
• Hall, E.J, Simpson, J.W. and Williams, D.A. (2005) BSAVA Manual of Canine and Feline Gastroenterology (2nd Edition) BSAVA
• Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier.