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Pyometra: An Overview

The word pyometra is derived from the Latin words "pyo" meaning pus and "metra" meaning uterus. Thus pyometra literally means pus filled uterus and that is exactly what the condition is. The infection normally occurs in middle-aged or older, non-spayed female dogs. Symptoms normally will present 4-6 weeks after the bitch has been in heat. There are two types of pyometra, closed and open. In open pyometra the cervix of the animal remains open while in closed pyometra the cervix is closed. Closed pyometra is more severe due to the fact that there is no way for the uterus to drain the infection inside it.

Causes of Pyometra

The main causes of pyometra are hormonal and structural changes in the lining of the uterus. Over many heat cycles the lining of the uterus thickens and in some instances this can become persistent. When the lining becomes persistent it is termed cystic endometrial hyperplasia. This persistent thick lining provides a perfect environment for bacteria to grow. Under normal circumstances the uterus is free of any bacteria. When the bitch is in heat the cervix is open and bacteria from the vulva can travel up into the uterus. Once there, the bacteria can thrive and will eventually lead to the uterus filling with pus. The main bacterium associated with this infection is E. coli. Estrogen injections given to prevent pregnancy in bitches that have been accidentally bred increase the risk of developing pyometra greatly and should be avoided.

Preventing Pyometra

Pyometra can be prevented by having your bitch spayed early in her life.

Symptoms of Pyometra

Clinical signs of pyometra vary from case to case but can include:

  • not eating
  • vomiting
  • lethargy
  • increased water intake
  • increased urination

In open pyometra there may be a pussy white or green colored discharge from the vulva. There may also be a foul smell being emitted from the vulva. In cases of closed pyometra the abdomen may look bloated or swollen due to the uterus being filled with pus. Clinical signs are not normally seen until the condition is in the late stages. Pyometra can progress rapidly and even cause shock or death due to toxins being leaked through the uterine wall into the abdomen of the bitch.

Diagnosing Pyometra

Due to the generality of the symptoms diagnosing pyometra can be difficult. The most effective way to confirm pyometra is by an ultrasound. An ultrasound will allow your veterinarian to see the fluid filled uterus and will also rule out pregnancy as the cause of the enlarged uterus. In addition to the ultrasound a vaginal cytology may be run to determine what type of bacteria is causing the infection. This is important as it will help determine what antibiotic should be used in the treatment of the infection.

Treating Pyometra

The usual treatment method is an ovariohysterectomy, or a spay surgery, where the uterus and ovaries are removed. This can be a complicated surgery since the bitch may be in poor condition due to the infection. The advantage to surgery is that there is no chance of pyometra reoccurring. The disadvantage is that the animal will not be able to be used for breeding again. Hormones, such as PGF2, can be used as non-surgical treatment. The hormones help expel the pus by causing uterine contractions and they also reduce the uterine lining. The advantage to hormone treatment is that the bitch will most likely be able to be used for breeding again. The disadvantage is that there is a risk of uterine rupture if used in cases of closed pyometra and reoccurrence if very likely. If the goal is to have puppies out of the bitch then she should be bred at her next heat cycle. Once she is no longer being used in a breeding program she should be spayed to prevent pyometra from reoccurring. In almost all cases intravenous fluids and a broad spectrum antibiotic will be given.

The prognosis with open pyometra is good with bitches being only slightly less fertile than before. The prognosis with closed pyometra is guarded and depends on the progression of the condition and if there are any other complications associated with the infection.

Care for Dogs with Pyometra

If your animal has been diagnosed with pyometra it is very important to follow you veterinarian's instructions carefully. If antibiotics are prescribed be sure to give the correct dose at the intervals specified. Always complete the round of antibiotics given. Do not stop giving them because your dog acts better. Following treatment the bitch should be monitored and her activity restricted. Encourage your dog to eat and drink to keep them hydrated. Any abnormal signs observed should be reported to your veterinarian and a follow up appointment should be scheduled.

The AKC Canine Health Foundation and Pyometra

The AKC Canine Health Foundation has funded research which aims to help recognize a potentially fatal secondary condition associated with pyometra. SIRS is a whole body immune response and can overwhelm the dog and cause death. By being able to recognize this condition in its early stages, it could be possible to stop it and save dog's lives.

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