Feline Hyperparathyroidism

Jonathan Miller, DVM, MS, DACVS (Small Animal), Eclipse Specialty & Emergency Pet Care, Whippany, New Jersey

ArticleLast Updated August 20192 min read

In the Literature

Singh A, Giuffrida MA, Thomson CB, et al. Perioperative characteristics, histological diagnosis, and outcome in cats undergoing surgical treatment of primary hyperparathyroidism. Vet Surg. 2019;48(3):367-374.


The Research …

Parathyroid disease in cats is rare. In this study, 32 cases were identified in a medical record search encompassing a 12-year period in 10 different institutions. Clinical signs were vague but included lethargy, weight loss, anorexia, and vomiting; no signs were noted in 18.8% of the cases, and polyuria/polydipsia was seen in <20%.

Diagnosis was made based on a combination of cervical ultrasonography, presence of hypercalcemia, and a parathyroid hormone concentration in or above reference range. Surgery was performed in all cats, with 6 out of 32 requiring bilateral tissue removal. Adenoma was diagnosed in 62.5% of cats, with carcinoma, hyperplasia, and cystadenoma diagnosed less frequently. No difference in survival time was noted based on histologic diagnosis.

In most cats (65.6%), serum calcium decreased to normal levels within 24 hours postoperation, although some cats remained hypercalcemic and others became hypocalcemic. Thus, serial monitoring of serum calcium for the first few days postoperation is important. No correlation was found between serum calcium levels preoperatively and postoperatively. Median survival time was 1109 days and was not associated with serum calcium levels or histologic findings of the mass.


… The Takeaways

Key pearls to put into practice:

  • Parathyroid disease is rare in cats, and clinical signs are often vague.

  • A high serum calcium level should trigger further diagnostic tests (eg, ultrasonography of the neck, parathyroid hormone concentration testing).

  • Surgery is associated with a favorable long-term prognosis, with a median survival time of just over 3 years, regardless of histopathology results.