Perineal hernia
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Perineal hernia is a condition seen in dogs characterized by herniation of abdominal contents through the pelvic diaphragm and causing swelling on one side of the anus. The perineum is the area between the anus and the genitals. The pelvic diaphragm is made up of the levator ani muscle, the external anal sphincter, and the internal obturator muscles. The hernial sac may contain fat, intestines, or the bladder. Perineal hernias may be bilateral, but are usually unilateral and found on the right side.[1] Most cases are in older intact (not neutered) male dogs (93 percent in one study).[2] Breeds that may be at risk include Welsh Corgis, Boxers, Australian Kelpies, Boston Terriers, Collies, Dachshunds, Old English Sheepdogs, and Pekingese.[3] Perineal hernias are rare in female dogs and uncommon in cats.
Perineal hernias can be caused by excessive straining to defecate (tenesmus). Causes include prostate or urinary disease, constipation, anal sac disease, and diarrhea. Atrophy of the levator ani muscle and disease of the pudendal nerve may also be related to perineal hernias. Dogs with benign prostatic hyperplasia have been found to have increased relaxin levels and suspected subsequent weakening of the pelvic diaphragm.[4] In cats, perineal hernias are seen most commonly following perineal urethrostomy surgery or secondary to megacolon.[5] Medical treatment consists of treatment of the underlying disease, enemas, and stool softeners. Because only about 20 percent of cases treated medically are free of symptoms, surgery is often necessary.[5] Recurrence is common.
[edit] References
- ^ Head L, Francis D (2002). "Mineralized paraprostatic cyst as a potential contributing factor in the development of perineal hernias in a dog". J Am Vet Med Assoc 221 (4): 533-5, 500. PMID 12184704.
- ^ Seim, Howard B., III (2004). Perineal Hernia Repair. Proceedings of the 29th World Congress of the World Small Animal Veterinary Association. Retrieved on 2007-03-25.
- ^ Perineal Hernia. The Merck Veterinary Manual (2006). Retrieved on 2007-03-25.
- ^ Niebauer G, Shibly S, Seltenhammer M, Pirker A, Brandt S (2005). "Relaxin of prostatic origin might be linked to perineal hernia formation in dogs". Ann N Y Acad Sci 1041: 415-22. PMID 15956739.
- ^ a b Hoskins, Johnny D. (Sept. 2006). "Anorectal Disease". DVM: 8S-10S.
