Glomerulonephritis in Cats

The term glomerulonephritis refers to the inflammation and subsequent dysfunction of the glomeruli — the small mass of capillaries in the kidney that filters waste products from the blood and into the urine so they can be secreted from the body. The most common cause of glomerulonephritis is the deposition and entrapment of antigenantibody complexes (such as a toxin or enzyme) within the glomeruli. Moreoever, the disease affects both genders, but occurs in more often in males.

Symptoms and Types

Symptoms may vary depending on the underlying cause, like inflammation, infection, or neoplasia. In some cats, the only presenting symptom may be weight loss and weakness. In fact, many times, the condition is discovered incidental to a routine annual health screening, when increased concentrations of proteins are found in the urine. If the protein loss into the urine is severe, the cat may develop an abnormal collection of fluid in the abdominal cavity (ascites).

In cats suffering from advanced disease with kidney failure, there may be symptoms of increased thirst and frequency of urination, lack of appetite, nausea, and vomiting. Those with a severe deficiency of the blood protein albumin (hypoalbuminemia), may suffer from a blockage of the lung’s blood vessels, which causes respiratory difficulties or severe panting. High blood pressure, meanwhile, may cause sudden blindness.

Causes

  • Inflammation
  • Infections
  • Idiopathic (unknown)
  • Neoplasia (growth of tissue, tumor)
  • Diabetes mellitus
  • Long-term use of certain drugs

Diagnosis

You will need to give a thorough history of your cat’s health, onset of symptoms, and possible incidents that might have led to this condition. A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, and a urinalysis. The results of the complete blood count test are usually not significant. In severe cases, the biochemistry profile may reveal abnormally low levels of blood protein albumin (hypoalbuminemia) and high levels of cholesterol in the blood (hypercholesterolemia). The presence of blood protein albumin and other proteins in the blood may help your veterinarian in making the initial diagnosis. In cats with kidney failure, the urinalysis will reveal corresponding changes in urine.

Creatinine is a waste product normally excreted by the kidneys, and its presence in the urine is measured as a diagnostic indicator of kidney function. Urine protein testing is also performed, as the amount of protein found in the urine can also be used to evaluate and monitor kidney function.

A more specific test calculates the urine protein and creatinine ratio in order to give your veterinarian an idea of the degree of kidney damage. The extent of protein loss in the urine roughly correlates with the severity of the kidney disease. Therefore, measuring protein and creatinine ratio also helps in assessing treatment response and progression or regression of disease.

Diagnostic imaging can also be used for determining how diseased your cat’s condition is, and what treatment needs to be applied. These procedures are helpful in the diagnosis of concurrent diseases and in evaluating the kidney size. Abdominal X-rays and ultrasound can be used to evaluate the kidneys and other abdominal organs, and can be helpful in performing a less invasive type of tissue collection for biopsy purposes. Your veterinarian may take a kidney tissue sample (kidney biopsy) to rule other causes of kidney failure, such as neoplasia or cancer.

glomerulonephritis

A medical condition in which the glomeruli become inflamed

enzyme

A substance that causes chemical change to another

prognosis

The prediction of a disease’s outcome in advance

renal failure

The failure of the kidneys to perform their proper functions

urinalysis

An in-depth examination of the properties of urine; used to determine the presence or absence of illness

blood pressure

The amount of pressure applied by the blood on the arteries.

biopsy

The process of removing tissue to examine it, usually for medical reasons.

albumin

A type of protein that can be dissolved in water; found in milk, egg white, certain muscle, blood, and some urine.

antibody

A protein in the body that is designed to fight disease; antibodies are brought on by the presence of certain antigens in the system.

antigen

Any substance or item that the body of an animal would regard as strange or unwanted; a foreign disease or virus in the body (toxin, etc.)

ascites

The collection of fluid in the peritoneal cavity.

abdominal cavity

The space in the abdomen that holds the major digestive organs in an animal. Normally referred to as the area between the diaphragm and the pelvis. Also referred to as the peritoneal cavity.

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