Nephrotoxicity - toxicity in the kidneys
Toxicity in the kidneys is termed nephrotoxicity. It is caused by a poisonous effect on the kidneys. This can be either due to medications, toxic chemicals or substances which affect the renal function.
What do the kidneys do?
Rabbits have two kidneys. They are located in the abdomen and filter the blood to remove waste products which is then excreted out of the body as urine. The kidneys work 24 hours a day, 365 days a year and anything that disrupts this process can cause damage meaning the kidneys become less effective which can result in kidney failure.
What could cause nephrotoxicity?
A variety of drugs and toxins can cause nephrotoxicity leading to kidney failure. In fact, most drugs if overdosed can show some toxicity to the body, especially the kidneys. Some of the most common culprits for nephrotoxicity in rabbits are:
- Ethylene glycol (antifreeze) is extremely toxic within a matter of hours of ingestion. Even just ingesting a few drops can lead to rapid renal failure which is all too often fatal as the window for treatment is short and once clinical signs are shown treatment is futile. Thankfully this poisoning in rabbits is rare since most rabbits do not have access to sites where antifreeze is kept.
- Aminoglycosides antibiotics can have acute nephrotoxic effects. The antibiotics are not normally used in rabbits except in an eye drop form which is authorised for use in rabbits.
- Sulphonamide drugs can be a cause of nephrotoxicity in rabbits.
- Lead poisoning is a potential hazard especially in houserabbits. Old paint used to contain lead and many house rabbits like chewing walls which may be painted with this paint. Ingestion of lead can cause nephrotoxicity.
- Pesticides, herbicides and solvents – some of these are nephrotoxic to rabbits so it is important not to use these in the environment that rabbits have access to.
What signs may my rabbit show?
The clinical signs of nephrotoxicity are very non-specific and could be attributed to may conditions. However, rabbits that are in kidney failure may show some of the following clinical signs:
- Gastrointestinal stasis
- Grinding of the teeth in pain (bruxism)
Initially the rabbit may still produce urine but if the kidneys fail, they will be unable to produce any urine.
How can my vet diagnose the condition?
Your vet will need to take a blood sample from your rabbit to assess its kidney function and see if the kidneys are failing to remove waste products from the blood.
A urine sample might also be taken and examined for evidence of bacteria and to make sure that the kidneys are working properly to concentrate the urine. Your vet may also ultrasound the kidneys and bladder to see if they are a normal size and appearance.
If my vet diagnoses nephrotoxicity what can be done?
Treatment for kidney disease depends on how severe it is based on the test results. Rapid and intensive treatment gives the best chance of success.
Rabbits can lose up to 70% of normal renal function before any changes are seen on blood results. Therefore, by the time the blood results are abnormal there is already significant damage to the kidneys.
Your rabbit will usually be put on a high rate of intravenous fluids, to try and flush any toxins from the kidneys. Supportive treatment such as syringe feeding and medications for gastrointestinal stasis may be required if the rabbit isn’t eating properly. If there are any signs of infectious disease then the vet may also start antibiotic therapy.
How likely is it that my rabbit will recover?
This greatly depends upon the severity of the problem and how quickly treatment is started. If enough kidney function can be saved or the effect of the nephrotoxicity was mild, then the prognosis is good. However, full recovery may take several weeks or months.
If the kidneys cannot function adequately after treatment, then prognosis is guarded and the rabbit may sadly require euthanasia.