Pyometra means, literally, "pus in the uterus". It is a severe bacterial infection which can lead rapidly to dehydration, kidney failure and death. It can occur in any unspayed female dog or cat, but it is most common in middle aged or older animals who have gone through several heat cycles without a pregnancy. It is also more common in animals treated with reproductive hormones, especially estrogen.
The uterus of a dog or cat in heat is a perfect breeding ground for bacteria. Most cases of pyometra occur soon after a heat cycle. Symptoms include fever, loss of appetite, weight loss, increased thirst and urination, and sometimes drainage of pus from the vulva. If your veterinarian suspects pyometra in your pet, blood tests, urinalysis and x-rays may be used to assist in diagnosis.
Surgery is almost always necessary to cure the disease. Usually the animal must be spayed -- in other words, the infected uterus must be removed. There is hormone treatment available for dogs that can resolve a pyometra but the medication causes vomiting, it’s costly and many dogs will develop a pyometra again at the next heat cycle. Pyometra in dogs usually scars the uterus and makes having future litters of puppies unlikely. Performing an ovariohysterectomy is the best treatment at this point. Antibiotics, fluids and treatment for any secondary problems, such as kidney disease, are also necessary.
If the disease is caught early the prognosis for complete recovery is good. However, the disease is often not diagnosed until it has reached a late stage, or the affected animal may be older and have other health problems, such as kidney or heart disease. The prognosis in these cases is much poorer.
Treatment is often prolonged and expensive because of the difficulty of the necessary surgery and the amount of skilled nursing and supportive care also required.
Pyometra is one of the best reasons for having female dogs and cats spayed - especially if they won't be used for breeding! Most female dogs will eventually come down with the disease if they aren't bred. Your female dog or cat will be a happier, healthier pet if she is spayed, and you will have the peace of mind of knowing that she will never come down with this life-threatening disease.