Anal Sac Disease in Cats

Orange tabby halfway in covered litterbox with hind legs and tail sticking out.

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Anal sacs aren't something obvious in a cat but all cats have them. In most cats, these tiny body parts are typically problem-free but some cats can develop issues that cause problems with normal bodily functions and pain. Because of this, it is important for cat owners to be aware of the potential diseases that anal sacs can have and what signs they should look for in their cat.

What Are Anal Sacs in Cats?

Anal sacs are also known as anal glands and are two small balloon-like body parts located on either side of your cat's rectal opening. The anal sacs are related to scent glands in skunks and the sacs produce a smelly fluid that is expressed when they defecate. They are just under the skin's surface, at the anal sphincter muscles, and have a tiny duct that connects the sac to the rectum.

Within the anal sacs, the smelly fluid can also thicken into a paste. If not expressed normally during defecation or manually by your veterinarian, the anal sacs can become engorged and uncomfortable to your cat.

Types of Anal Sac Diseases in Cats

While anal sacs are normally out of sight and out of mind, they can occasionally develop problems requiring veterinary care. Anal glands can become impacted, inflamed, and infected which prevents the secretions from exiting the sac. If the secretions continue to build up and are unable to exit, the sac can then burst or rupture creating a new opening in the skin and sac next to the rectal opening. This is of course very painful for your cat.

Anal sacs can also develop masses or tumors in them. Like an infection and impaction, these masses can prevent the secretions from exiting the sac and may also cause issues with defecation.

Signs of Anal Sac Diseases in Cats

  • Crying when defecating
  • Blood in stool
  • Blood on surfaces after sitting or lying down
  • Sticky anal sac secretions on surfaces after sitting or lying down
  • Foul odor from hind end
  • An additional hole in the skin near the rectal area
  • Scooting or dragging the hind end on the floor
  • Incessant licking at the rectal opening
  • Biting at the rectal opening or the hind end

Anal sac diseases will at first cause minor discomfort along with noticeable anal gland fluid on surfaces and a foul odor. As the problem grows, your cat may cry in pain when defecating and blood may be seen in the feces and on surfaces where your cat sits or lies down. Excessive licking or even biting at the rectal opening or general hind end area is a sign that things are getting very uncomfortable or painful as well. Scooting or dragging the hind end in an effort to relieve the pressure or pain in the anal sacs may be seen before a ruptured anal gland finally occurs. A rupture is very painful so a cat will typically cry out and an additional hole will be noted next to the rectal opening along with a large amount of blood and anal sac secretions.

Causes of Anal Sac Diseases in Cats

If anal sacs are not allowed to naturally express as a cat defecates, problems will occur due to bacteria and inflammation that builds up in the sacs. Various things can prevent anal glands from being expressed and therefore contribute to this unhealthy build up.

  • Diarrhea - Soft stools and diarrhea do not put enough pressure on a cat's anal sacs and therefore do not encourage them to be expressed during defecation. This can be seen with a variety of diseases including inflammatory bowel disease (IBD).
  • Obesity - If a cat is obese, the ducts from the anal sacs to the rectal opening may be compressed by fatty tissue and won't allow secretions to be expressed during defecation.
  • Mass/Tumor - A mass or tumor can serve as a space occupying lesion which blocks the drainage of the anal sacs. As a result, the anal sac fluid is not released and fluid will accumulate in the anal sacs.
  • Constipation - If a cat has difficulty defecating or is unable to defecate due to various diseases or other issues such as megacolon, the anal sacs will not naturally express and are prone to developing issues.

Treatment of Anal Sac Diseases in Cats

If the anal sacs are impacted they will need to be drained. This may be able to be done by physically squeezing the sacs or may require a surgical incision to allow the sac to drain. A veterinarian will perform a physical examination to determine what is necessary to get your cat relief. Antibiotics, pain medications, and occasionally special diets will be prescribed to help in your cat's recovery.

How to Prevent Anal Sac Diseases in Cats

The best things you can do to help prevent anal sac disease in your cat is to keep it from getting overweight and monitor its stool consistency. Obesity contributes to a variety of issues including anal sac disease so by increasing physical activity and decreasing calorie intake, you can help keep your cat trim and hopefully free of anal sac problems. In addition to your cat's weight, stool consistency is also important to monitor so that the feces regularly expresses the anal sacs. Probiotics, prebiotics, fiber, and other ingredients can help keep feces firm and therefore decrease the likelihood that your cat will have anal sac issues.

Article Sources
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  1. Joudrey, Scott D et al. Perianal neuroendocrine tumor with suspected lymph node metastasis causing colonic compression and subsequent megacolonThe Canadian veterinary journal = La revue veterinaire canadienne vol. 56,3, 240-4, 2015.

  2. Disorders of the Rectum and Anus in Cats. Merck Veterinary Manual.