Hypercalcemia in Cats

Hypercalcemia in Cats: Understanding Causes, Symptoms, Diagnosis, and Treatment

Hypercalcemia, or elevated calcium levels in the blood, is a serious condition that can affect cats of any age, breed, or gender. This condition may arise due to numerous underlying issues, and if left untreated, it can lead to critical health problems. Understanding hypercalcemia, its causes, symptoms, diagnosis, and treatment options is essential for cat owners to ensure the health and well-being of their feline companions.

What is Hypercalcemia?

Calcium plays a vital role in several bodily functions in cats, including bone health, muscle contraction, nerve function, and blood clotting. The normal range for calcium levels in cats is typically between 8.5 and 11.5 mg/dL. When calcium levels exceed this range, hypercalcemia occurs. This condition can cause various metabolic disturbances and lead to severe complications if not addressed.

Causes of Hypercalcemia in Cats

Many factors can lead to hypercalcemia in cats. The most common causes include:

1. Primary Hyperparathyroidism: This condition occurs when the parathyroid glands produce excessive parathyroid hormone (PTH), leading to increased calcium release from bones and decreased calcium excretion by the kidneys.

2. Chronic Kidney Disease (CKD): Cats with CKD may experience hypercalcemia due to impaired renal function, which affects the metabolism of calcium and phosphorus.

3. Malignancies: Certain cancers, such as lymphoma or anal sac adenocarcinoma, can lead to hypercalcemia through the release of parathyroid hormone-related peptide (PTHrP), mimicking the effects of PTH.

4. Vitamin D Toxicity: Excessive intake of vitamin D, whether from supplements or certain types of rodenticide, can lead to hypercalcemia by increasing intestinal absorption of calcium.

5. Granulomatous Diseases: Conditions such as feline tuberculosis or histoplasmosis can result in elevated calcium levels due to the production of calcitriol, a hormone that regulates calcium levels.

6. Idiopathic Hypercalcemia: In some cases, the exact cause of hypercalcemia remains unknown, leading to a diagnosis of idiopathic hypercalcemia.

Symptoms of Hypercalcemia

Symptoms of hypercalcemia can vary widely depending on the severity of the condition and the underlying cause. Common clinical signs include:

• Increased thirst and urination (polydipsia and polyuria)
• Lethargy and weakness
• Loss of appetite (anorexia)
• Vomiting
• Constipation
• Abdominal pain
• Dehydration
• Behavioral changes, including hyperactivity or depression
• Muscle tremors or twitching

If a cat exhibits any of these symptoms, particularly if they are severe or persistent, prompt veterinary consultation is crucial.

Diagnosis of Hypercalcemia

Diagnosing hypercalcemia in cats involves a combination of physical examination, blood work, and potentially imaging studies. A veterinarian will typically perform the following evaluations:

1. Physical Examination: A thorough physical examination helps to identify any potential signs of disease or underlying conditions.

2. Blood Tests: A serum chemistry panel will be conducted to measure calcium levels. Elevated levels will indicate hypercalcemia. Additional tests may be performed to assess kidney function, liver enzymes, and electrolyte balance.

3. Urine Tests: A urinalysis can provide information about the cat’s kidney function and concentration ability, which is crucial for diagnosing CKD.

4. Imaging Studies: X-rays or ultrasounds may be necessary to identify any tumors, kidney abnormalities, or other potential causes of hypercalcemia.

5. Endocrine Testing: If primary hyperparathyroidism is suspected, specific endocrine tests may be conducted to evaluate parathyroid hormone levels.

Treatment of Hypercalcemia

The treatment of hypercalcemia in cats aims to address the underlying cause while managing elevated calcium levels. The approach may vary based on the severity of the condition and the underlying diagnosis.

1. Intravenous Fluids: Administering fluids can help dilute the calcium in the bloodstream and support the cat’s kidneys in excreting excess calcium.

2. Medications: Bisphosphonates, such as pamidronate, may be utilized to inhibit bone resorption and lower blood calcium levels. In cases of malignancy, chemotherapy may be indicated.

3. Dietary Management: Adjusting the cat’s diet may help manage calcium intake and support overall health, especially in cases of chronic kidney disease.

4. Surgery: If primary hyperparathyroidism is diagnosed and a tumor is detected, surgical removal of the affected parathyroid gland is often recommended.

5. Monitoring: Regular follow-up visits will be necessary to monitor calcium levels and assess the cat’s response to treatment.

Conclusion

Hypercalcemia in cats is a complex condition that can stem from various underlying health issues. Awareness of the signs and symptoms, along with prompt veterinary care, can lead to effective management of the condition. Cat owners should remain vigilant and proactive in monitoring their pets’ health, ensuring regular check-ups and maintaining open communication with their veterinarians to safeguard their beloved companions from the potential complications associated with hypercalcemia.