Glomerular Disease in Cats: Symptoms, Causes and Care

Glomerular disease in cats is a rare but serious condition affecting the kidneys' filtering units, the glomeruli. These microscopic capillaries filter waste from the blood to produce urine. Inflammation or damage to the glomeruli disrupts this process, often causing protein to leak into urine, known as proteinuria, a key sign of the disease.

Understanding Glomerular Disease in Cats

This disorder typically develops when toxins, enzymes, or abnormal immune complexes accumulate in the glomeruli. The most common form in cats is immune-complex glomerulonephritis (ICGN), often linked to underlying immune system activity. Membranous glomerulonephritis is the most frequent type, predominantly seen in male cats. Unlike some other kidney diseases seen in dogs, certain forms like focal segmental glomerulosclerosis are rare in cats.

Recognising the Symptoms Early

In early stages, many cats show no obvious symptoms, making early detection challenging. Sometimes, protein is only found during routine urine tests at yearly vet check-ups. Signs can vary depending on the disease cause but often include:

• Weakness and lethargy
• Weight loss
• Excessive thirst and increased urination
• Lack of appetite and nausea
• Vomiting
• Difficulty breathing or severe panting
• High blood pressure, potentially leading to blindness
• Abdominal swelling due to fluid retention (ascites)

Common Causes of Glomerular Disease

Causes vary and can include:

• Inflammation from immune reactions or infections
• Infections affecting the kidneys or immune system
• Neoplasia (tumours)
• Diabetes mellitus
• Long-term use of certain medications and drugs
• Idiopathic cases where the underlying cause remains unknown

How Vets Diagnose the Condition

Veterinary diagnosis involves a thorough history and physical examination. Tests commonly required include:

• Urinalysis to detect proteinuria and other abnormalities
• Complete blood cell count and chemical blood profile for kidney function
• Biochemistry profile
• Imaging techniques such as abdominal X-rays and ultrasound
• In some cases, a kidney biopsy is necessary to determine the exact nature of glomerular damage

Treatment and Management

Treatment focuses on the underlying cause when identifiable. Unfortunately, glomerular disease can be difficult to treat, especially if detected at an advanced stage with significant kidney damage. Treatment options include:

• Prescription renal diets low in protein and sodium to reduce kidney workload
• Medications to control inflammation, blood pressure, and protein loss (such as ACE inhibitors or angiotensin receptor blockers)
• Omega-3 fatty acid supplements to help reduce inflammation and support kidney health
• Careful dosing of medications eliminated through the kidneys
• Regular veterinary monitoring and adjustment of treatment plans based on response and test results

Nephrotic Syndrome: A Serious Complication

Some cats with glomerular disease develop nephrotic syndrome — a cluster of symptoms caused by severe protein loss from the blood. The main features are significant proteinuria (protein in urine), low serum albumin (hypoalbuminaemia), and oedema (fluid accumulation under the skin or in the abdomen). Affected cats may also develop blood clots (thromboembolism), which can block arteries in the lungs or limbs and are often life-threatening.

Blood clot formation is one of the most serious risks associated with glomerular disease in cats. If your cat suddenly becomes lame in a hindlimb, cries out in pain, or shows rapid breathing, seek emergency veterinary attention immediately — these can be signs of an aortic thromboembolism, a condition requiring urgent treatment.

Dietary Management for Cats with Glomerular Disease

Diet plays a key role in slowing the progression of kidney damage. Veterinary nutritionists typically recommend a renal prescription diet that is:

• Restricted in phosphorus, which accumulates in the blood as kidneys fail and accelerates damage
• Moderate in high-quality protein — not zero protein, as total protein restriction worsens muscle wasting, but reduced to lower proteinuria
• High in moisture content; wet food or water-added food helps maintain hydration and urine dilution
• Supplemented with omega-3 fatty acids (EPA/DHA), which have been shown to reduce glomerular inflammation

Avoid organ meats (high in phosphorus), dried food as a sole diet, and any food containing high sodium. Always transition to a new diet gradually over two to three weeks to avoid digestive upset. Consult your vet before making any dietary changes — what's appropriate depends on the stage of kidney disease and your cat's individual bloodwork.

Promoting Responsible Cat Care

Regular health check-ups help catch kidney or urinary problems early, improving outcomes. Responsible pet ownership includes avoiding unnecessary medications, ensuring vaccinations and parasite control, and providing a balanced diet tailored to a cat's needs. If you notice signs such as increased thirst, urination, or sudden weight loss in your cat, consult your vet promptly.

When to Seek Veterinary Advice

If your cat shows any symptoms listed above, particularly increased drinking, urination, or lethargy, seek veterinary advice promptly. Early diagnosis and management provide the best chance of slowing disease progression and maintaining quality of life.

Frequently Asked Questions

Can glomerular disease cause blindness in cats?
Yes, glomerular disease often leads to high blood pressure, which can cause damage to the eyes and potentially result in sudden blindness through retinal detachment. Regular blood pressure monitoring and early treatment is essential to prevent this serious consequence.

How long can a cat live with glomerular disease?
Prognosis varies widely. Some cats live for several years with appropriate management, particularly when the underlying cause can be identified and treated. Cats diagnosed early, with mild proteinuria and stable kidney function, have the best outlook. Those with nephrotic syndrome or advanced chronic kidney disease at diagnosis have a more guarded prognosis. Regular monitoring allows treatment to be adjusted as the disease progresses.

For more general information about cats and responsible pet care, consider looking for reputable breeders or adopting a kitten from a trusted source. You can find a domestic shorthair kitten or explore other breeds suited to your home.