Hyperphosphatemia in Dogs: Symptoms, Causes, & Treatments

What is Hyperphosphatemia in Dogs?

High phosphorus levels in the dog's blood are referred to as hyperphosphatemia. The mineral phosphorus, which is present in bones, works with calcium to create a strong, healthy bone structure. Additionally, phosphorus participates in the creation of cell energy and maintains cell architecture. A minor amount of phosphorus is found in the blood of dogs, but the majority of it is stored in bone.

Phosphorus and calcium have an antagonistic connection. Calcium levels typically drop when phosphorus levels are high in the blood. As a result, the clinical symptoms of high phosphorus and low blood calcium levels are related (hypocalcemia).

In the small intestine, phosphorus is absorbed and excreted in the urine. Maintaining healthy phosphorus levels requires the cooperation of the kidneys and parathyroid glands. Hyperphosphatemia can be brought on by conditions affecting the kidneys, bones, parathyroid, or gastrointestinal system. Chronic renal failure is the most typical condition causing hyperphosphatemia (CRF).

The signs of high phosphorus levels in dog blood

When hyperphosphatemia is chronic or persistent, there may be indications of kidney damage. Increased thirst and urination, diluted urine, dehydration, or untimely urination are some of these symptoms. Hyperphosphatemia can hasten the progression of chronic renal failure in animals who already have this condition.

Phosphate and calcium can mix to form solids at high concentrations. Metastatic mineralization, a sickness brought on by this, refers to the breakdown of chemical molecules in apparently healthy tissues. The urinary system—particularly the kidneys—and the digestive system are the two bodily systems most frequently impacted by metastatic mineralization. Muscle tremors, muscle atrophy, or convulsions may be signs of metastatic mineralization.

Dog hyperphosphatemia can also result in depression, appetite loss, and sedentary behavior.

Causes of Canine Hyperphosphatemia

Depending on the dog's age, different causes of this condition are more prevalent.

It is most frequently brought on in older dogs by renal failure, intracellular dysfunction, a dysfunctional thyroid gland that produces less parathyroid hormone, or an overactive thyroid gland that causes muscle wasting and weight loss. Diabetes may also be connected to it.

It frequently results from increased intestine absorption and decreased renal absorption in adolescent dogs. It should be noted that because phosphorus is utilized to assist bone mineralization, young dogs, especially those of large breeds, may occasionally have higher phosphorous levels than adults (hardening). That is typical.

It can be brought on by dehydration, parasites, trauma, poisoning from raisins/grapes, or an excessive amount of vitamin D in people of all ages.

Hyperphosphatemia in Dogs: Diagnosis

You must take your dog to the vet immediately if they show signs of twitching muscles, excessive drinking, or growing lethargic. Give your veterinarian a complete history of any symptoms, including how long they have lasted and any associated ailments that may be present. The next step is a physical examination by your veterinarian to identify which organs have been most negatively impacted.

Your veterinarian must establish that your dog has elevated phosphorus levels before doing a diagnostic examination. A CBC, or complete blood count, is usually performed first, followed by a serum biochemistry panel and a urinalysis. It should be emphasized that issues with phosphorous uptake intracellularly can be an exacerbating factor for hyperphosphatemia. The possibility exists for a false-positive high reading of phosphorous if a significant number of blood cells die (hemolysis) either during or after the blood sample is obtained. These cells will release the mineral into the blood serum. Because hemolytic samples are not representative, the pet owner may need to collect multiple samples to get accurate values. This will be especially significant if your dog's readings are on the borderline.

Treatment for Canine Hyperphosphatemia In severe cases of hyperphosphatemia, hospitalization may be required. Your dog might be given IV hydration therapy in addition to phosphorus-lowering drugs such as dextrose, insulin, aluminum hydroxide, or calcium carbonate.

Phosphate binders are frequently given orally to dogs with chronically elevated blood phosphorus levels. You should move your dog to a low-protein or prescription renal care food to reduce the amount of phosphorus in his diet. Limiting calcium consumption is also advised in some circumstances since phosphorus and calcium bind together.

For the greatest outcome for your dog, the underlying cause of all cases of hyperphosphatemia must be identified and properly treated.

Recovery From Hyperphosphatemia 

Schedule routine examinations with your veterinarian to assess the success of your pet's treatment. Usually, this entails drawing more blood samples. Allow your dog enough peace and time to recover from a high phosphorus incident. Your dog will likely recover fast if the underlying cause was an acute episode of excessive vitamin D supplementation or consumption of grapes or raisins with little renal system impairment. Your veterinarian will review a long-term prognosis and care plan with you if your dog has a chronic thyroid gland, renal retention, diabetes, or cancer.