Rectal Prolapse - Cat and Dog

Signalment

• No breed predisposition but may occur more often in Manx cats due to anal laxity
• No sex predilection

Description

Rectal prolapse is defined as the protrusion of the rectal mucosa from the anus. It is classified as complete or incomplete. A complete prolapse involves all layers of the rectal wall whereas an incomplete prolapse only involves the mucosal layer.

Any conditions which cause tenesmus will cause rectal prolapse, this includes:

• Gastrointtestinal disese
  • Parasites
  • Tumours
  • Foreign bodies
  • Colitis
  • Megacolon
• Urogenital disease
  • Cystitis
  • Prostatic disease
• Perineal hernia
• Dystocia

Endoparasite and enteritis are more common in young animals whereas tumours or perineal hernias are more common in milddle-aged to older animals.

The everted tissue becomes oedematous, which prevents retraction back into the pelvic canal. The exposed tissue is vulnerable, which leads to inflammation, ulceration and congestion.

Diagnosis

Clinical Signs

Protrusion of an elongated, cylindrical mass from the anus. It is vital to differentiate a rectal prolapse from an ileocolic intussusception. This can be done by passing a probe adjacent to the anus. With rectal prolapse, the probe cannot be passed.

Laboratory Tests

There are no specific tests.

Diagnostic Imaging

This may be used to identify the cause of the prolapse.

Treatment

Medical

This may be suitable for acute prolapse where it is ameanable to manual reduction, under general anaesthesia. A loose purse-string suture should be placed around the anus for a period of 5-7 days. Prior to manual reduction, the protruded mass should be treated with warm saline lavages, massages and lubrication or hypertonic saline sugar solution to relieve oedema. Tenesmus can be reduced by enema, faecal softener, and a moist diet. Complications such as tenesmus, dyschezia, haematochezia and recurrence can occur with manual reduction.

Surgery

Rectal resection and anastomosis may be needed in cases where manual reduction is not possible or if the tissue is severely traumatised. Colopexy can be considered in recurrence cases. Complications such as haemorrhage, leakage, anal struicture, infection, dehiscence and faecal incontinence can occur following surger.

Prognosis

Prognosis is poor in untreated cases of chronic rectal prolapse. The prognosis for surgical patients is good provided the underlying cause is appropriately addressed.

References

• Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier