Anal Gland Disease in Cats

Most dog owners are aware of anal gland disease and the need to bring their pets into a veterinarian to have ‘their glands squeezed’. Unfortunately, this problem often goes unrecognized in cats because the cats rarely show the classic signs of licking and scooting. The cat habit of hiding their health problems means they all to often suffer in silence.

The anal glands are actually two sacs that lie under the skin on either side of the anus, usually at the 4 and 8 o’clock positions. Small openings are seen on the anal opening. The lining of the sac secrets a smelly material that is unique to each cat. When the cat contracts to pass stool, the material is excreted.  Stool is one of the ways cats mark their territory. This is why dominant cats do not cover their feces.

Anal gland disease is broken down into two separate categories based on cause:

  1. Impaction – When the glands are not emptied, the material builds up causing pressure and pain. I see this develop in cats with constipation, diarrhea, obesity and anal dysfunction because the cat does not evacuate the sacs on a regular basis. The secretion dries out forming a thick black paste that requires a good deal of pressure to express. The thickened secretion is often seen protruding through the gland opening like a plug.  It can appear like two black dots.
  2. Sacculitis – Sacculitis means inflammation of the anal gland usually caused by a bacterial infection. These cats act sick and often have a fever. The secretion is usually a mix of blood and pus. If the cat is not treated at this stage, the gland will rupture through the skin.

Treatment varies depending upon the cause and severity of the anal gland disease. The first step is expressing both glands through digital pressure. Additional treatments may include infusing medication into the sacs, antibiotics, compresses and anti-inflammatory medications. Once the glands have been distended, regular expression may be needed to keep the glands empty. High fiber diets that bulk up the stool and weight loss are used to prevent further impactions.  Below is a video clip of me expressing a cat’s anal glands.

Cat AG expression

Source:

-Rothrock, Kari. ‘Anal Sac Impaction and Infection’ Associate Database, VIN, last updated 4/6/2011.

You Make The Diagnosis: Dental Fracture In Dogs

Pictured below is the right side of a dog’s mouth. During her annual exam, I noticed an abnormality on her upper fourth premolar called a slab fracture. Part of the enamel had fractured away from the rest of the tooth exposing the pulp cavity. The gingival tissue is still attached which holds it in place. With the  nerves exposed, the tooth was painful. It was also infected. The tooth was removed and now this dog is pain free. Please study the picture then answer the following questions: What is this fracture called?  What causes this type of injury to occur?

slab fracture

Diagnosis: Slab Fracture

Chewing on hard objects is the cause of these fractures. Here is a list of the most common objects that I have seen cause slab fractures in my canine patients:

  1. Cow hooves
  2. Ice cubes
  3. Bones
  4. Hard toys such as Nylabones. The gumabones from the same company are softer.
  5. Deer antlers

When deciding what to let your dog chew on, remember the advice given by the veterinary dentist, Dr. Steve Holmstrom. He discourages people from giving their dogs anything that doesn’t bend or break easily, anything that makes you grimace at the thought of chewing it yourself and anything that would hurt if it hit your kneecap.

Injection-Site Sarcomas in Cats

“Cats are not small dogs,” is a saying used in veterinary medicine to capture the uniqueness of the feline species. It helps us remember that treatments used for dogs may not be suitable for cats. One unique feature of cats is how they react to anything placed under their skin. When medications, nonabsorbable suture and microchips are placed into the subcutaneous tissue of cats, an inflammatory reaction occurs. In some cats, “It is hypothesized that post-injection inflammatory reactions, with the release of cytokines and growth factors, result in uncontrolled fibroblast and myofibroblast proliferation, leading to malignant transformation.” (Axiak, S) This means chronic inflammation may lead to cancer.

In my experience, fibrosarcomas are the most common type of tumor to occur after an injection in cats although osteosarcomas, chondrosarcomas, malignant fibrous histiocytomas, rhabdomyosarcomas and undifferentiated sarcomas have been documented. They usually occur after vaccines although they can also occur after injection of long-acting medications like the steroid triamcinolone. The malignant transformation may occur within weeks to years of the injection. I have seen two cats over my career who developed cancer from a rabies injection. Historically, fibrosarcomas are more likely to occur after rabies and FELV vaccination in products that are made from ‘killed’ virus or contain adjuvants (aluminum).

To decrease the occurrence of fibrosarcomas after vaccination, the Feline Injection Site Sarcoma Guidelines recommend:

  1. Vaccinate as infrequently as possible to prevent adverse reactions.
  2. Give vaccines subcutaneously, not intramuscular.
  3. Bring vaccines to room temperature prior to injection.

A fourth recommendation, that I offer and adhere to in my own practice, is to use non-adjuvant vaccines containing as few antigens as possible. Adjuvants are added to vaccines to amplify the immune response.  A study by Dr. Day found that vaccines that did not contain adjuvants created less inflammation at the injection site. Since chronic inflammation increases the chances of malignant changes in fibroblasts, I try to avoid adjuvants in cats. So far, there are no well-designed scientific studies which document a lower rate of sarcoma between vaccines with adjuvants versus those without.  However, it seems commonsense to me to use those without adjuvants as they may be superior – so in case it is true, I believe we should give our cats every effort we can to prevent sarcomas.

Once an injection-induced sarcoma has developed, the prognosis is poor. Even with aggressive surgical removal, recurrence is common because these tumors have indistinct boundaries. Advanced imaging with CT often demonstrates the tumor extends far beyond the lump at the injection site. Radiation and chemotherapy have been tried with varying degrees of success. In my experience, it is rare for a cat to live more than 2 years without recurrence even with radiation. The tumor invades surrounding tissues including bone causing pain. Most cats are humanely euthanized to prevent further suffering.

If a lump develops at the site of a vaccination, the Vaccine-Associated Feline Sarcoma Task Force recommends the 3-2-1 rule. A biopsy should be performed if the lump has been present for more than 3 months, the lump is > 2 cm in size or if the lump increases in size after 1 month. All injection sites should be monitored closely for formation of a lump.

Sources:

-Axiak, Sandra. “Feline Injection-Site Sarcoma: You have asked…What is the ideal way to identify and approach feline injection-site sarcoma?” Ask the Expert/NAVC Clinician’s Brief/February 2012.

-Day, MJ, et al. “A kinetic study of histopathological changes in the subcutis of cats injected with non-adjuvanted and adjuvanted multi-component vaccines.” VACCINE. 2007 May 16;25(20):4073-84. Epub 2007 Mar 7.

-Hartman, Katrin. ‘Feline Injection Site Sarcoma’ Update Sept 24, 2015. First published J. of Feline Medicine and Surgery(2015)17:606-614.