Endometrial hyperplasia

Endometrial hyperplasia is a condition in which cells of the endometrium, the lining of the uterus (womb), grows at a more rapid pace than is normal. It is a common condition seen in pet rabbits. The exact cause is controversial.

As rabbits age the endometrium, which are the cells in the lining of the rabbit’s uterus, undergo age-related changes linked to their hormones. These can include an increase in the collagen content and a reduction in the number of cells.

Endometrial hyperplasia will only ever affect entire female rabbits (those not spayed) and it can affect any breed or cross breed. The incidence of acquiring endometrial hyperplasia increases as the rabbit ages, so it’s more commonly seen in rabbits over the age of 3-4 years.

Previous pregnancies make no difference to the likelihood of developing the condition.

Clinical signs of endometrial hyperplasia include:

• Intermittent haematuria (blood in the urine): it’s important to differentiate between true blood in the urine and red urine. Red urine is not normally a cause of concern, but blood within the urine has several possible causes and needs medical treatment.
• Anemia (decreased red blood cells): your rabbit’s gums should be pink in colour. Pale gums are a sign of anemia (blood loss). Red blood cells carry oxygen to body tissues and organs so a lack of red blood cells decreases the amount of oxygen circulating in the rabbit’s system and can make them feel weak and tired.
• Lethargy (sluggish, tired): take note if your rabbit shows unusual unwillingness to play or move around, or not wanting to forage for food or if they sit in their own urine and feces. These may be signs of disease.
• Bloody vaginal discharge: blood from the vagina is a serious cause for concern and needs prompt veterinary treatment. This may appear as blood spots in the rabbit’s enclosure, or blood may be on the fur. The rabbit may also be licking the genital area more frequently in order to keep clean.
• Anorexia: rabbits who are eating less or have stopped eating altogether need urgent veterinary treatment. The condition can quickly lead to gastrointestinal stasis, which can be rapidly fatal. Many rabbits become anorexic over the course of several days, gradually going off their food, this will go hand in hand with fewer, smaller and irregular droppings being produced, until the production of these ceases altogether. Always keep an eye on the amount of droppings produced and contact your veterinarian if anything changes.

Many of these signs are non-specific and can be caused by a variety of different conditions. It is important to know what is normal for your rabbit, so you know what is abnormal and when they are ill. Always consult your veterinarian at the earliest opportunity if you notice any of these signs or you are worried about your rabbit.

Your veterinarian will examine your rabbit and also look at a clinical history. If your rabbit fits the criteria for endometrial hyperplasia (un-spayed, older female rabbit) the veterinarian may recommend further tests to aid a diagnosis. Your veterinarian will palpate (feel) your rabbit’s abdomen and on palpation the rabbit’s uterus may feel firm and irregular. This may not be the case in less advanced cases, so even if your veterinarian can not feel anything abnormal it doesn’t rule the condition out.

The veterinarian may also want to perform an ultrasound examination and perform radiographs (x-rays). Endometrial hyperplasia can lead to uterine adenocarcinoma (cancer in the uterus) and this can spread elsewhere in the body, especially causing tumours in the chest. Your veterinarian may want to try and rule this out. They may also suggest blood tests and collect a urine sample for analysis.

Ovariohysterectomy (spaying) is the treatment of choice for endometrial hyperplasia. However, if there are any signs of tumors in the chest or spread then spaying will not be curative and either palliative care to keep the rabbit as comfortable as possible for as long as possible, or euthanasia would be the only treatment options. If your veterinarian suggests spaying your rabbit, a sample of the uterus should be sent for histology after the surgery so it can be examined for a definite diagnosis. Spaying should be performed once the rabbit has been stabilized for surgery.

During surgery, your rabbit will be supported with fluids to ensure the rabbit is hydrated. After surgery, syringe feeding will keep the gastrointestinal tract moving, and pain relief and prokinetic medications will help ensure optimum digestive health.

The easiest way to prevent endometrial hyperplasia from occurring is to spay female rabbits at an early age. Spaying will remove the risk of endometrial hyperplasia and uterine adenocarcinomas from happening. Discuss spaying with your veterinarian. Female rabbits can be spayed from 4 months of age.