What is glomerulonephritis?
Glomerulonephritis is a kidney disease characterized by inflammation of the renal glomeruli.
Glomerulonephritis occurs when a mixture of antibodies and antigens, called immune complexes, accumulate within the glomeruli. This deposit of immune complexes is at the origin of the inflammation of the renal glomeruli and then of damage to these structures essential to the proper functioning of the kidney.
Glomerular disturbances are the cause of protein leakage in the urine (proteinuria), which is not normally filtered.
Zoom in on the renal glomeruli
Renal glomeruli are structures present in the millions in the kidneys and made up of small "balls" of blood capillaries through which blood passes in order to be filtered. This mechanism is the first step in the formation of urine: it eliminates waste present in the bloodstream and maintains a good balance of minerals and water within the body. When the glomeruli are damaged, kidney function is greatly impaired and toxins accumulate in the body, causing serious illnesses.
What causes glomerulonephritis in dogs?
Any condition that causes intense or chronic stimulation of the immune system is likely to cause glomerulonephritis. Some of these possible causes include:
- various infectious diseases such as Rubarth hepatitis, bacterial endocarditis, brucellosis, dirofilariasis, ehrlichiosis, leishmaniasis, Lyme disease, pyometra, etc.
- tumor diseases,
- inflammatory diseases such as pancreatitis, systemic lupus erythematosus, polyarthritis, prostatitis and more generally all immune-mediated conditions,
- hypercorticism.
It also happens that the cause of glomerulonephritis is not known, and this is called idiopathic glomerulonephritis.
Certain dog breeds are hereditary or racially predisposed to the disease. This is the case of the Brittany Spaniel and most likely the Bernese Mountain Dog.
What are the symptoms of glomerulonephritis in dogs?
The clinical signs of the disease are linked to the protein leak it causes, to the renal failure which accompanies the glomerular lesions (but not systematically) and to the causal condition.
Mild to moderate symptoms of the disease may include non-specific symptoms such as weight loss.
In the event of nephrotic syndrome linked to protein leakage in the urine, more worrying clinical signs may be observed such as:
- ascites, i.e. the presence of fluid in the abdominal cavity,
- peripheral edema (swelling of the limbs),
- breathing difficulties related to the presence of liquid in the lungs (pleural effusion, thromboembolism),
- signs of high blood pressure.
Glomerulonephritis can also lead to the development of chronic renal failure, the symptoms of which include:
- polyuro-polydypsia (the dog drinks and urinates more),
- anorexia,
- nausea and vomiting,
- a lethargy,
- weight loss,
- halitosis (bad breath) and possible mouth ulcers in the event of a uremic crisis.
Other symptoms, related to the disease causing glomerulonephritis, may also be present.
How is glomerulonephritis diagnosed?
The definitive diagnosis of glomerulonephritis requires a kidney biopsy followed by a histological analysis of the tissues removed.
But, in most cases, urine tests are enough to suspect glomerulonephritis.
These analyzes can be supplemented by other examinations (kidney ultrasound, blood tests, serologies) necessary to assess kidney function and determine the underlying condition.
How is glomerulonephritis treated?
The treatment of glomerulonephritis depends above all on the possible underlying infectious, inflammatory or cancerous disease that causes the immune system to create immune complexes that are trapped in the glomeruli.
Apart from treatments specific to the causal condition, treatment for glomerulonephritis may include:
- immunosuppressive drugs to suppress the formation of immune complexes,
- anti-inflammatory and anti-coagulant treatments to limit inflammation and the formation of blood clots within the glomeruli,
- angiotensin converting enzyme inhibitors to minimize protein loss in urine and help control blood pressure,
- diuretics to treat effusions and oedemas.
Affected animals should be fed a diet low in protein and phosphorus, specially formulated for pets with kidney failure.