Kidney Inflammation in Horses

By PetMD Editorial on Nov. 10, 2011

Nephritis in Horses

Nephritis, inflammation of the kidneys, is relatively rare overall in the equine population. In most cases, nephritis does not affect adult horses, as their immune systems are strong enough to resist such an infection. This disease usually affects young foals.

Nephritis is characterized by a severe kidney infection and a high body temperature. Because the kidney often continues to function sufficiently, many of the other symptoms might go unnoticed for some time. Indeed, nephritis may not become fully apparent until it has reached a severe and life-threatening stage. At that point, as the kidneys lose their ability to filter toxins and pass them out of the body through the urine, the toxins build up in the blood, resulting in toxemia, or blood poisoning.

Symptoms and Types

Symptoms of nephritis are typically seen in foals and rare affect adult horses. They include:

  • Fever
  • Pain in kidneys
  • Swelling or inflammation of the kidneys
  • Blood in urine
  • Pus in urine
  • Heightened levels of serum protein found in blood
  • Higher than normal levels of urea and creatinine in blood


Nephritis is the direct result of an infection of the kidneys. While it is not always clear what leads to the infection, there is research to suggest that foals are more susceptible since their immune systems are less capable of fighting off the toxins and other infectious agents that have the potential to cause nephritis.


There are multiple methods that may be used to diagnose nephritis in foals. The most common is a rectal palpation. This is the best way to determine whether or not the kidneys are swollen and, based on the horse's response, can also help to determine if there is any pain surrounding them as well.

A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, a urinalysis and an electrolyte panel. The presence of blood or pus in the urine is a strong indication of infection in the kidney. If infection is present, the blood test should show shifts in the levels of certain products in the blood, such as urea and creatinine.


Treatment will vary based on the extent of the infection, the overall health of the horse, the strength of its immune system, and a variety of other factors. Normally, nephritis can be treated with a long course of antibiotics specifically designed to treat this type of infection. In addition, potentiated sulphonamides – bacterial inhibitors – can also be used to treat this infection and to prevent further infection of the body as well.

Living and Management

Because of the potential for a fatal outcome, it is important to pay close attention to all of the instructions your veterinarian provides you with. All prescriptions should be administered in their entirety, especially those that are for antibiotic treatment as they are prescribed in certain amounts for a reason: to cure infection and to prevent reinfection.

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