Uremia in Cats: Causes, Symptoms & Treatment

What is uremia?

Uremia is a life-threatening condition characterised by the buildup of toxic waste products in the bloodstream which occurs when the kidneys are no longer functioning properly. Instead of removing wastes from the blood via the urine, they begin to build up in the blood, affecting many of the body systems.

What causes uremia in cats?

There are many reasons why kidney function may be impeded; it may be sudden (acute) or chronic (slow and progressive).

• Urinary blockage, when an obstruction is present, and urine backs up, the kidneys stop functioning, and toxins begin to build up in the bloodstream.
• Kidney disorders such as inflammation, kidney stones, glomerulonephritis, polycystic kidney disease, and diabetes.
• Bladder rupture due to the urine leaking back into the bloodstream.
• Shock can lead to blood loss or rapid dehydration.
• Heart failure leads to low blood pressure, which reduces blood flow to the kidneys.
• Infection.
• Drug or other toxins damage do the kidneys.

A large percentage of senior cats will develop chronic kidney disease to some extent. Acute kidney failure can occur for several many reasons and is life-threatening. Poisoning, infection, blood loss, dehydration, drugs and toxins, blockage and trauma are all possible causes of acute kidney failure.

Clinical signs

Symptoms of uremic poisoning are similar to other types of poisoning and include the following:

• Lethargy and drowsiness
• Disorientation
• Loss of appetite
• Dehydration
• Difficulty breathing
• Increased urination and thirst (polyuria/polydipsia)
• Poor coat condition
• Mouth and tongue ulcers
• Intermittent diarrhea and vomiting
• Ammonia-like smell on the breath
• Seizures
• Coma

Other symptoms may be present depending on the underlying cause of uremic poisoning; for example, if your cat is in shock he may have pale gums appear confused, and his breathing may be rapid.

A cat who has a urinary blockage will strain to urinate, visit the litter tray frequently, show signs of pain or discomfort and cry in the litter tray. Many pet owners mistake a urinary blockage for constipation due to your cat straining in the litter tray.

Diagnosis

Your veterinarian will perform a complete medical history and perform a physical examination. He will need to know how long you have noticed symptoms and what symptoms are present. As we have already said, kidney failure may be acute (sudden onset) or chronic. Up to 70% of kidney function may be lost before outward signs of uremic poisoning become apparent.

Diagnostic workup:

• Biochemical profile to check BUN (blood urea nitrogen), phosphorus and creatinine levels. High BUN, phosphorus and creatinine levels can indicate reduced kidney function.
• Urinalysis may show blood in the urine (hematuria) and urinary crystals.
• Complete blood count to look for signs of infection.
• Ultrasound to check for signs of urinary blockage.
• ECG (electrocardiogram) to evaluate heart function. Elevated potassium levels can lead to abnormal heart rhythms.

Treatment

The goal of treatment is to address the cause of kidney failure and bring down potassium, BUN and creatinine levels.

Chronic kidney failure: Switch to a low protein and phosphate diet, phosphorous binders and supportive care such as fluids to treat dehydration.

Acute kidney failure: Address the underlying cause, such as poisoning, shock, urinary blockage, trauma etc., as well as provide supportive care such as fluid therapy and nutritional support.

Urinary blockage: Correct electrolyte imbalances, empty the bladder via cystocentesis (needle into the bladder) or catheter. Flush the urethra to remove an obstruction. Surgical removal of stones or stone dissolving diets for cats with struvite stones.

Supportive care:

Intravenous fluids to manage electrolyte imbalances and help flush the toxins out of the system as well as calcium gluconate to help stabilise the heart.