My Dog Has High Urea — What Does It Mean? Causes

Uremia is the name given to the clinical picture resulting from elevated urea levels. This process affects the entire body's function and produces a series of relatively easy-to-detect symptoms.

Uremia also refers to the amount of urea measured in the blood during bloodwork. It's usually due to a failure in kidney function and requires veterinary treatment. Want to know all the details about uremia?

Urea and the Kidneys

The kidneys are organs that play a fundamental role in the body. They're part of the urinary system, along with the ureters, bladder, and urethra. Their job is to filter toxic substances out of the blood and eliminate them from the body as urine.

A healthy dog's urine should be yellow and clear. In addition, the kidneys regulate fluids, electrolytes, and acid-base balance. Urea, for its part, is the main component of urine.

It forms mainly in the liver and is the result of protein metabolism. In cases of uremia, urea is found elevated in the blood. The main cause is a failure in kidney function.

How Is Uremia Diagnosed?

If the vet suspects elevated urea, they'll take a blood sample. By analyzing it, it's possible to know its value. Many clinics have equipment to run this test within minutes. If not, it's sent to an outside lab. Either way, the results sheet notes the values considered normal for a dog.

This way, we can know whether urea is elevated and by how much. Usually, when this parameter is off, creatinine is too. This is a waste product also eliminated by the kidneys. Kidney failure raises both urea and creatinine, as well as phosphorus. The problem is that the kidneys compensate for their deficiencies for a long time.

So, by the time we notice symptoms of uremia, kidney damage is already quite advanced. In this sense, nowadays it's possible to test for a kidney function biomarker called SDMA. This shows up altered earlier, allowing treatment to start sooner. That's why annual bloodwork is recommended for dogs over seven years old.

Uremia and Kidney Failure

We say a dog has kidney failure when its kidneys fail to eliminate the waste products that build up in the blood. This allows urea to rise, resulting in uremia or uremic syndrome, which produces symptoms affecting the whole body.

Kidney failure can present acutely, if symptoms start suddenly, or chronically, if they develop gradually over months. The latter is more common, especially in older dogs. It's linked to aging, which affects how efficiently the kidneys can do their job.

Causes of Kidney Failure

Any cause that affects the kidneys can trigger uremia. The most common are nephritis and nephrosis. Nephritis is an inflammatory process associated with different diseases. Notable ones include hepatitis, ehrlichiosis, or borreliosis, also known as Lyme disease.

Nephrosis, meanwhile, develops from degenerative changes caused by substances toxic to the kidney. These nephrotoxic substances include acetylsalicylic acid, ibuprofen, or certain antibiotics such as gentamicin. In addition, acute kidney failure can occur in emergencies such as the following:

• Obstruction of the urinary tract, for example from a stone forming.
• Rupture of the bladder or urethra.
• Shock, which leaves the kidneys without the blood flow they need.
• Congestive heart failure, since blood pressure drops and blood supply to the kidneys is reduced.
• Poisoning, with antifreeze ingestion being especially serious.

Symptoms of Uremia in a Dog

If we notice one or more of these symptoms in our dog, it's recommended to see the vet for bloodwork to confirm whether it's a case of uremia:

• Increased water intake.
• Increased urine output, since damaged kidneys can't concentrate urine.
• Dehydration.
• Listlessness, depression.
• Loss of appetite, weight loss, poor coat condition.
• Brownish discoloration of the tongue, foul-smelling breath.
• Mouth ulcers and stomatitis, meaning inflammation of the oral mucosa, tongue, and gums. Edema.
• Vomiting, diarrhea, gastrointestinal bleeding.
• Loss of teeth.

What Is the Treatment for Uremia?

Unfortunately, kidney damage will be irreversible. Because of this, treatment is aimed at maintaining the dog's quality of life as much as possible and controlling symptoms. To reduce urea, diet is important. Since it's produced through protein metabolism, it's a good idea to change the dog's diet to one adapted for kidney patients.

This won't contain salt, and will have the right amount of phosphorus and good-quality protein. Since dehydration occurs along with changes in water intake and elimination, we need to make sure the dog drinks. Offering wet food is another way to improve its hydration.

Depending on the symptoms and severity of the case, the vet may prescribe different medications, vitamins, or phosphate binders. Dogs that decompensate will suddenly worsen. In these cases, they need to be hospitalized to receive intravenous fluids and be stabilized.

Bibliography Carlson and Giffin. 2002. Manual práctico de veterinaria canina. Madrid. Editorial el Drac.