Pyometra and Cystic Endometrial Hyperplasia (Uterine Infection) in Dogs

  • Occurrence: common
  • Location of illness: Abdomen/pelvis
Content
Download/Print

Pyometra and cystic endometrial hyperplasia are conditions of the uterus in dogs characterized by the accumulation of pus and thickening of the uterine lining. These conditions usually occur in older, intact female dogs and can be life-threatening if not treated promptly.

The most important facts at a glance

Pyometra and cystic endometrial hyperplasia (CEH) are diseases that commonly occur in dogs after hormonal changes in the reproductive cycle. CEH is caused by repeated cycles without pregnancy, which leads to thickening of the uterine lining and cyst formation, which promotes bacterial growth. Pyometra often develops after estrus, when progesterone weakens the uterus’s immune defenses, making it easier for bacteria such as Escherichia coli to enter. Typical symptoms include vaginal discharge, loss of appetite, increased thirst and urination, vomiting, weakness, and fever. Clinical symptoms, blood tests, and imaging techniques are used for diagnosis, with ultrasound examinations being particularly helpful. The main treatment is surgical removal of the uterus and ovaries, as this method eliminates the risk of recurrence. Antibiotics are also an important part of the treatment. The prognosis is good with timely diagnosis and treatment, although complications such as kidney failure and sepsis can occur. Spaying is recommended for prevention, while close monitoring is important for breeding female dogs. Research focuses on genetic, hormonal, and environmental factors, as well as the development of less invasive treatment methods and better diagnostic tests.

Causes

The uterus of the female dog consists of various layers, of which the mucous membrane (endometrium) plays an important role in preparing for a possible pregnancy. During the reproductive cycle, the endometrium undergoes changes controlled by hormones such as estrogen and progesterone.

Cystic endometrial hyperplasia (CEH) is caused by repeated cycles of hormonal changes without pregnancy. This leads to a thickening of the uterine lining and the formation of cysts. These changes create a favorable environment for the growth of bacteria, which can eventually lead to pyometra.

Pyometra usually develops a few weeks after estrus, when the uterus is under the influence of progesterone. This promotes the secretion of mucus and reduces the immune defenses, making it easier for bacteria to enter and multiply. The most common pathogens associated with pyometra are bacteria such as Escherichia coli.

Symptoms

The symptoms of pyometra are varied and depend on the severity of the disease. The most common symptoms include increased thirst (polydipsia) and increased urination (polyuria). These symptoms occur because the bacterial infection releases toxins that impair kidney function.

Other signs include lethargy, loss of appetite, and vomiting. Female dogs with open pyometra, in which the cervix is open, may have a foul-smelling, purulent discharge from the vagina. In closed pyometra, this discharge is absent, which can make diagnosis more difficult.

Fever is another possible symptom, although it does not occur in all affected dogs. In severe cases, a state of shock can occur, which is life-threatening and requires immediate treatment.

Diagnosis

The diagnosis of pyometra is based on a combination of clinical symptoms, blood tests, and imaging procedures. A complete blood count may show elevated white blood cells, indicating an infection. Kidney values may also be elevated, indicating impaired kidney function due to the toxins.

Ultrasound examinations are a valuable tool to identify an enlarged, fluid-filled uterus. X-rays can also be useful to assess the size and shape of the uterus, but provide less detailed information than ultrasound.

In some cases, a biopsy of the uterine lining may be necessary to confirm the diagnosis and rule out other conditions. An accurate diagnosis is crucial for choosing the right treatment method.

Therapy

Treatment for pyometra usually requires surgical removal of the uterus and ovaries, a procedure known as ovariohysterectomy. This surgery is the preferred method because it eliminates both the infection and the risk of recurrence.

In some cases, especially in young breeding female dogs, medical treatment may be considered. This involves the administration of prostaglandins to open the cervix and promote uterine contraction to expel the pus. However, this method is associated with risks and is less reliable than the surgical option.

Antibiotics are an essential part of the treatment, regardless of the method chosen. They help fight the infection and support recovery. The selection of antibiotics is ideally based on a culture and sensitivity tests of the bacteria.

Prognosis and follow-up care

The prognosis for female dogs with pyometra depends on the severity of the disease and the speed of treatment. With timely diagnosis and surgical intervention, the prognosis is usually good, and most dogs recover completely.

Complications can occur, especially if the pyometra is advanced or the female dog is already in a weakened condition. These include kidney failure, sepsis, and shock, which can significantly impair the chances of survival.

Long-term complications are rare, but in some cases, fertility problems can occur, especially if medical treatment has been attempted. However, a full recovery and return to normal activity is to be expected in most operated dogs.

Prevention

The most effective method for preventing pyometra is spaying, in which the uterus and ovaries are surgically removed. This not only prevents pyometra but also reduces the risk of other hormone-dependent diseases and certain cancers.

For breeding female dogs in which spaying is not immediately considered, close monitoring during and after estrus is important to recognize early signs of pyometra. Regular veterinary examinations can help monitor the health of the uterus and identify potential problems early.

A balanced diet and good general care also help to strengthen the female dog’s immune system and reduce the risk of infections. Avoiding unnecessary hormonal treatments can also reduce the risk of cystic endometrial hyperplasia and subsequent pyometra.

Outlook on current research

In current research on pyometra and cystic endometrial hyperplasia in dogs, scientists are focusing on the genetic, hormonal, and environmental factors that contribute to the development of these diseases. There is evidence that genetic predispositions may play a role, as some dog breeds are more commonly affected than others. Older, unspayed female dogs, especially of breeds such as the Bernese Mountain Dog, Golden Retriever, or Collie, are particularly susceptible. Researchers are investigating the genetic markers associated with an increased risk of developing these diseases to develop better prevention strategies.

Another focus of research is on the role of hormones, especially progesterone, which thickens the lining of the uterus, thus contributing to the development of cystic endometrial hyperplasia. Studies are examining how hormonal changes during the sexual cycle of dogs can lead to an increased susceptibility to infections and inflammatory conditions. The research aims to understand the exact mechanism by which progesterone and other hormones affect uterine health and how these processes can be modulated by therapeutic interventions.

In the field of treatment methods, alternative approaches to conventional ovariohysterectomy (spaying), which is currently the most effective treatment for pyometra, are being investigated. Scientists are experimenting with drug treatments that combine hormonal blockers or antibiotics to treat milder cases and reduce the need for surgery. However, these studies are still in the early stages, and it is still unclear to what extent such treatments can be a viable alternative to surgery.

Another promising area of research is the development of diagnostic tests that allow early detection of cystic endometrial hyperplasia and pyometra. Advances in imaging technology, such as high-resolution ultrasound or MRI, as well as the analysis of biomarkers in the blood, could facilitate diagnosis in the future and improve the prognosis. Such tests could allow veterinarians to detect the disease at an earlier stage, before serious symptoms occur, thus improving the treatment outcome.

In summary, research on pyometra and cystic endometrial hyperplasia in dogs aims to better understand the underlying causes of these diseases, develop more effective and less invasive treatment methods, and improve diagnosis. There is still much to be done, but advances in these areas could lead to better management and a higher quality of life for affected animals in the long term.

Frequently asked questions (FAQs)

  1. What is Pyometra? Pyometra is a serious and potentially life-threatening condition in dogs in which pus accumulates in the uterus. It often occurs in older, unspayed female dogs, typically a few weeks after a heat cycle. It is a hormonally mediated disease that is often caused by an infection.

  2. What symptoms does a female dog with pyometra have? The most common symptoms include vaginal discharge, increased drinking and urination, lethargy, loss of appetite, and vomiting. In severe cases, there may be fever, abdominal pain, and a bloated abdomen. If the uterus is closed, the symptoms may be more severe because the pus cannot drain.

  3. What is cystic endometrial hyperplasia? Cystic endometrial hyperplasia is a precursor to pyometra and describes a thickening of the uterine lining due to cystic changes. This thickening is caused by hormonal changes, especially by progesterone, and can make the uterus more susceptible to infections that can result in pyometra.

  4. How is pyometra diagnosed? Diagnosis is usually made through a combination of clinical examination, blood tests, and imaging procedures such as ultrasound or X-ray. These tests help assess the condition of the uterus and rule out other possible causes of the symptoms.

  5. How is pyometra treated? The most effective treatment for pyometra is surgical removal of the uterus and ovaries, called ovariohysterectomy. In mild cases, especially if the uterus is open, medical treatment with antibiotics and hormonal blockers can be attempted, but this is often less effective and carries the risk of relapse.

  6. Can pyometra be prevented? The most reliable method to prevent pyometra is spaying (ovariohysterectomy) before the first heat cycle. Since the disease is strongly hormonally influenced, removing the ovaries significantly reduces the risk. Regular veterinary examinations can also help detect early signs.

  7. Is pyometra only a problem in older dogs? While pyometra is more common in older dogs, younger, unspayed female dogs can also be affected. The female dog’s cycle plays a role, and any female dog that goes into heat carries a potential risk, especially as she gets older.

  8. What risk factors increase the likelihood of pyometra? Risk factors include age, breed, hormonal status, and whether the female dog has ever whelped. Certain breeds are at higher risk, as are female dogs that are repeatedly suppressed from going into heat or have received hormones for contraception.

  9. What are the chances of survival with pyometra? With prompt and appropriate treatment, especially through surgery, the chances of survival are good. Untreated, however, the disease can quickly become life-threatening. The earlier the treatment, the better the prognosis.

  10. Are there long-term consequences after treatment for pyometra? After a successful ovariohysterectomy, most female dogs recover completely without long-term health problems. In cases where surgery is not performed, recurrent infections and complications can occur, requiring ongoing monitoring.

Content
Download/Print