Pyometritis (Greek: Pyo = "pus" and Metritis = "inflammation of uterus") has long been a disease feared by the purebred dog breeder. The treatment was performed with one thing in mind: saving the affected bitch's life, with no hope of her being used for breeding again. In this paper, I will describe a wonderful treatment being used that gives us hope not only for saving an infected bitch's life, but also returning her to normal reproduction.
The causes and conditions necessary for a bitch to contract Pyometritis are indeed complex. The disease usually affects the middle to older bitches (over 5 years) approximately one to three months after their having been in heat. This is referred to as the diestrus period of the heat cycle. A combination of hormonal changes, along with a contamination of pathogenic (disease-causation) bacteria within the uterus, allows the infection to begin. The cervix then closes, shutting off the uterus. Glands lining the uterine wall continue to discharge their materials having been geared to do so by the heat cycle. These glandular discharges, plus the body warmth with no circulating air, are perfect for bacteria growth. The bacteria and their by-products fill the uterine cavity.
The signs of a bitch with Pyometritis are fever (frequently 104-106 degrees Fahrenheit), weakness, and in some cases, a very foul vaginal discharge (depending upon whether the cervix is open or closed). As the disease advances, other changes begin to occur.
The toxins (poisons) produced by the bacteria are absorbed into the bloodstream; hence, Pyometritis is a disease affecting multiple organs, not just the uterus. Other than the uterus, the main organs affected are the kidneys, whose primary function is to remove impurities and toxins from the blood. The kidneys begin to fail for a number of reasons. Since most of the bitches with Pyometritis are older, there may already be an underlying kidney disease present. Secondly, most bitches with Pyometritis are ill, vomiting being a major sign. The vomiting causes dehydration in the body, reducing blood pressure which inhibits the kidneys' filtering ability. Another reason is that renal (kidney) cells lose their ability to concentrate urine, leading to further dehydration. The inability to concentrate urine leads to another cardinal sign of a bitch with Pyometritis -- a craving for water.
A veterinarian should be contacted at the first signs of a bitch becoming ill with the aforementioned symptoms. The DNM will have to differentiate Pyometritis from other diseases causing fever and lethargy. The diagnosis will be made by taking a good history and by giving a good physical examination. Often the doctor will choose to do a white cell count. The white blood cells increase in any bacterial infection, but often greatly in Pyometritis (normal 7000-12000/ul, with pyo 30,000-60,000/ul or greater). The abdomen oftentimes is enlarged and pendulous due to the filling of the uterus. Pregnancy must be ruled out, but usually the signs of illness preclude pregnancy. The vet can sometimes palpate the uterus. (Caution should be taken by the lay person trying to palpate the uterus as overzealous palpation can cause uterine rupture and almost certain death). A radiograph may be necessary. However, ultrasoundography is the choice to diagnose Pyometritis.
Diabetes mellitus, primary and secondary kidney failure, as well as other disease processes must be considered in any dog showing polydipsia (increased liquid consumption). Tests for blood glucose and blood urea nitrogen (a kidney function test) are performed to support the diagnosis of Pyometritis.
The treatment of choice for Pyometritis have been found strictly surgical. Ancillary support such as IV fluids and antibiotics etc. were used to stabilize the patient, making her an acceptable anaesthetic-surgical candidate. Since many of the bitches with Pyometritis showed endotoxic shock, dehydration, kidney failure and other near fatal complications, the vet and owner were placed in the precarious position of deciding whether the treatment or the disease was the most life threatening. With no other course than to remove the infected uterus, surgery was often performed on a dog not able to handle the stress of the anaesthetic and uterine removal.
The actual surgical procedure consists of doing a complete ovario-hysterectomy (removal of ovaries and uterus) commonly known as spaying. This operation leaves the bitch sterile.
Currently the medical management of Pyometritis in our clinic involves the use of prostaglandin. The treatment is hormonal rather than surgical, and requires no anaesthetic. The infected bitch can recover without being spayed. In many cases the uterus is able to accept fertilization and carry puppies. By giving daily injections of the prostaglandin over a 2-10 day period, the uterus is stimulated to contract and expel the fetid discharge. It is even possible for the prostaglandin to open the cervix of the uterus in pyometrias that are not discharging.
Prostaglandins are used in conjunction with the IV fluids and antibiotics, and other supportive therapy as previously mentioned. Reactions of a bitch to prostaglandin therapy are ones of weakness, trembling, and collapse. Usually hospitalization during treatment is necessary because the enactuated uterus is still susceptible to future pyometria development. Spaying of mixed breeds or non-purebred bitches will continue to be the treatment of choice. But, oh what magic, if a valuable breeding bitch could once again conceive after having the dreaded disease -- Pyometritis!
Author Dr. R.V. Hutchinson practices at the Animal Clinic of Northview, Ohio. Many thanks to Alyson Lockwood for facilitating publication of this article.