Perineal Hernia in Cats

While vets and researchers aren’t sure what causes this condition to develop, they do believe that several causes may work together to cause the diaphragm to break or weaken. Perineal hernias are most often seen, diagnosed and treated in older cats, between seven and nine years of age. These cats are also more likely to not to have been altered. Male and female cats can develop perineal hernias.

A perineal hernia is the failure of the cat’s pelvic diaphragm. This hernia can result if the diaphragm simply weakens. This muscle helps to support the structure of the rectum, preventing abdominal organs, including the small intestine, prostate, bladder, rectum, and even fat from crowding into this area. This health issue is easily visible, with an obvious swelling close to the cat’s rectum. The feline will also have other symptoms that show it is obviously ill.

The cat will be unable to hide signs of illness, especially as the hernia begins to allow abdominal organs to slip into the perineum (the area around the cat’s anus)

• Inability to urinate, retaining urine
• Acute illness because cat is unable to empty bladder completely
• Constipation
• Straining to defecate and urinate
• Urinary incontinence (has “accidents” before reaching its litter box)
• Lethargy
• Depression
• Abdominal pain
• Not interested in food, doesn’t eat
• Changes how it positions its tail
• An obvious lumpy swelling on one or both sides of the cat’s anus
• Bruising in the perineum
• Pain or discomfort
• Vomiting (this happens most often if the blood supply to the bowel is affected)

While the causes of perineal hernia aren’t well understood or known, vets suspect that, if the cat hasn’t been neutered or spayed, it may be more vulnerable to developing a hernia. Other causes may include:

• Age (most cats affected are either middle-aged or senior/geriatric
• Prostate enlargement (related to being unaltered)
• Hormone imbalances (disease may affect the cat’s hormone levels)
• Anatomic issues
• Straining to defecate due to disease in this part of the cat’s body
• Straining to urinate because of prostate enlargement
• Damaged nerves in the cat’s pelvic diaphragm
• Testicular disease in male cats
• Disease of the prostate (tumors, abscesses or cysts)
• Increased abdominal pressure resulting from pregnancy

Cats with swelling in their perineums should be seen immediately. They will undergo a full physical exam, with the vet’s focus on the cat’s rectum and perineum. The cat will undergo a digital rectal exam, which allows the vet to look for any masses, signs of prostate disease, whether the problem is unilateral (on one side of the cat’s body) or bilateral. The vet also tries to find out the contents of the hernia, or what abdominal organs are intruding into the perineum.

After diagnosing a perineal hernia, the vet orders blood work, including a biochemical profile and a urinalysis, which allows them to determine if the cat has developed a urinary tract infection. An ultrasound and abdominal X-ray help the vet to determine where the cat’s organs are now sitting since the hernia has displaced them. These tests also help the vet to diagnose any other illnesses the cat may have, such as tumors, cancer, and prostate disease. The vet will also be able to see whether any organs have become trapped in the hernia. If so, immediate treatment is needed. If organ entrapment isn’t corrected, this threatens the cat’s life.

While the vet is examining the cat, they will examine the cat’s prostate and testicles (for a male cat) and take a small portion of the prostate for a biopsy. The cat may also undergo a chest X-ray.

Before the cat undergoes surgery, the vet orders medical treatments that include stool softeners, enema, dietary changes or management, painkillers and IV fluid therapy. All of these help to stabilize the cat’s condition if its hernia isn’t life-threatening. These treatments won’t correct or control the hernia.

Surgical intervention is required to correct the hernia and repair the cat’s pelvic diaphragm. While the cat is under anesthesia, the surgeon may also suture or tack the cat’s bladder and colon to the abdominal wall so they won’t protrude into the perineum in the future. The cat’s ductus deferens will also be tacked to the abdominal wall so the prostate won’t herniate in the future. (The ductus deferens is a narrow cord that leads to one of the cat’s testicles.)

The surgeon also places an internal obturator muscle flap, which strengthens the repair work done. This muscle is moved from the floor of the pelvis to the area where the diaphragm failed. If the hernia was severe, the vet may incorporate surgical mesh. If the cat has already been through a hernia repair that failed, the vet may take a flap of muscle from one of the animal’s rear legs to close off the area of the defect/failure to make a second repair. If the cat is an unaltered male, he will be castrated during the hernia repair surgery so the hernia is less likely to return. After castration, the cat’s prostate begins to shrink.

Once a perineal hernia in a cat has been diagnosed, with the appropriate treatments given, the cat can recover and return to full health. Post-surgery, the cat will take pain medications and broad-spectrum antibiotics (antibiotics that are suitable for a broad range of infections) to reduce the chance of infection. Cold compresses placed on the area where surgery took place help reduce perineal irritation and swelling. 

Once the cat has recovered from surgery, its diet will change. Its new diet will be a high-fiber diet which, along with stool softeners, to allow it to defecate without straining. This high-fiber food also lessens the risk of a post-surgery breakdown of the repaired diaphragmatic tissue. 

The cat should be kept quiet for about two weeks after surgery. Cage rest will help with this. It will also be necessary for the cat to wear an E-collar (Elizabethan collar) so it can’t lick at or bite its stitches.

The cat’s prognosis post-surgery is good as long as it receives all treatments the vet ordered. Hernias may re-develop in about ten to fifteen percent of animals. The vet may prescribe stool softeners long-term to reduce the need for the cat to strain during defecation.