Uterine infections in dogs

Uterine infections are very common in dogs that have not had an ovariohysterectomy, often called a “spay.” Pyometra is a term used to describe a pus-filled uterus. The severity of this disease is influenced by whether the cervix is open and draining pus, or closed. Most affected dogs are 6 years or older and still have both her ovaries and uterus. The hormone progesterone normally causes the lining of the uterus to produce a fluid-like secretion. When the uterus is idle for a long time, such as between the periods of heat, this fluid may accumulate in the lining of the uterus and become thickened. If inflammation and bacterial contamination occur, commonly the secretions become infected. If the cervix is closed and the infected material cannot drain to the outside, the uterus may become very distended and infection may spread to other parts of the body, causing the animal to be seriously ill.

When female animals become ill with vaginal infections, they often will have some type of vaginal discharge. Many dogs have decreased appetite, lethargy, increased thirst and urination, vomiting and diarrhea. Most animals have a fever. Some animals have obvious uterine enlargement when the abdomen is palpated. Because pyometra affects other organs, laboratory tests are often recommended to look for evidence of infection, kidney disease, liver changes and anemia. X-rays of the abdomen often showed tubular, fluid-filled structures in the area of the uterus. Often, X-rays are inconclusive, and an ultrasound may be recommended to determine location in the uterus, thickness and size and the presence of fluid.

The treatment of choice is surgery to remove the uterus and the ovaries. This is called an ovariohysterectomy. Most animals require hospitalization with aggressive fluid therapy and antibiotics prior to surgery. There are drugs that can be used when the cervix is open that are called prostaglandins. These drugs can only be used when the cervix is open and draining. They are used only in rare instances when the owner of the animal wants that dog to be bred again.

Antibiotics are usually given and laboratory tests may be repeated until all tests are normal. Repeated X-rays and ultrasounds may be needed to monitor uterine size if medical therapy has been performed. The rate of recurrence of pyometra after medical therapy is high within the next 27 months. Animals surviving surgical correction of the problem have an excellent prognosis.


Dr. Karsten Fostvedt is a veterinarian at St. Francis Pet Clinic in Ketchum.

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