Hypoparathyroidism is defined as a deficiency of Parathyroid Hormone (PTH) produced by the parathyroid glands. In the context of the feline Chronic Kidney Disease (CKD) patient, this condition is almost never caused by the kidney disease itself. Instead, it is typically an "iatrogenic" complication, meaning it is accidentally caused by medical treatment for a comorbidity. Specifically, it occurs during the surgical treatment of Hyperthyroidism (Thyroidectomy). The parathyroid glands are tiny, grain-of-rice-sized organs attached directly to the thyroid glands. During surgery to remove a thyroid tumor, these delicate glands can be inadvertently removed or damaged.
Because the primary job of PTH is to keep blood calcium levels high enough for the body to function, the sudden loss of PTH causes calcium levels to crash (Hypocalcemia). This is an acute emergency. Within days of surgery, the cat may develop intense muscle spasms, twitching, "tetany" (stiffening of muscles), and seizures. Treatment involves immediate calcium supplementation and often lifelong administration of Calcitriol (active Vitamin D) to help the body absorb calcium without the help of the missing glands.
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.