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Hypercalcemia in Cats

Hypercalcemia is characterized by an abnormally high amount of calcium in the blood. A cat is considered hypercalcemic when its total serum calcium level is greater than 10.5 mg/dL.

Behind the thyroid gland in the neck, there are four parathyroid glands which secrete the hormones the body needs to regulate calcium and phosphorus. Parathyroid hormones and vitamin D interactions work to release calcium from the bones, gut, and kidneys for deposit into the bloodstream. When these interactions are disturbed, or when cancerous cells secrete hormones, hypercalcemia, or excess blood-calcium levels, can result.

Symptoms and Types

• Increased urination
• Increased thirst
• Lack of appetite (anorexia)
• Vomiting
• Decreased gastrointestinal function
• Constipation
• Lack of energy/fatigue/lethargy
• Confusion
• Depression
• Enlarged lymph nodes (swelling in neck)
• Bladder stones
• Hypertension
• Stupor and coma in severe cases

Causes

• Abnormal functioning of the parathyroid gland
• Over functioning of the parathyroid gland (hyperparathyroidism)
• Cancer or tumors
• Bone deteriorating diseases
• Kidney failure - sudden or long-term
• Under-functioning adrenal glands
• Vitamin D poisoning: from rodenticides, plants, or food (including supplements)
• Aluminum toxicity

Diagnosis

Your veterinarian will perform a complete physical exam, including a blood chemistry profile, a complete blood count, and a urinalysis. While a high serum is crucial to the diagnosis of hypercalcemia, the results of the other tests will help to indicate the origin of the hypercalcemia.

Radiograph and ultrasound imaging can also be used for diagnosing underlying conditions, such as kidney disease, bladder stones, or cancer. Fine needle aspirates (liquids) from the lymph nodes and bone marrow can be used for diagnoses of lymphoma, or cancer of the blood.