Hypercalcemia is defined as an abnormally high level of calcium circulating in the blood. In the feline patient, it is crucial to distinguish between Total Calcium (which includes calcium bound to proteins) and Ionized Calcium (the free, biologically active form), as the latter is the true indicator of toxicity. While Idiopathic Hypercalcemia (high calcium with no identifiable cause) is increasingly common in cats, in the context of Chronic Kidney Disease (CKD), the relationship is bidirectional and dangerous. High calcium levels can cause acute kidney injury by constricting blood vessels and causing mineral deposits (calcification) within the sensitive kidney tissue, permanently destroying nephrons. Conversely, CKD itself can cause calcium imbalances due to the disruption of Vitamin D and Parathyroid Hormone regulation. Clinical signs are often subtle but include severe nausea, vomiting, constipation, and stones in the urinary tract (nephroliths). Treatment depends on the cause but often involves switching to a diet lower in calcium, increasing hydration to flush the kidneys, or using medications like bisphosphonates in severe cases to lower blood calcium levels.
Disclaimer: This content is for educational purposes only and does not constitute veterinary medical advice. Always consult with your primary care veterinarian or a veterinary internal medicine specialist regarding your cat’s specific condition.