Hypoparathyroidism: Diagnosis and evaluation

PTH: parathyroid hormone; AIRE: autoimmune regulator; CaSR: calcium-sensing receptor; PAS 1: polyglandular autoimmune syndrome type 1.

* Postsurgical hypoparathyroidism can occur after thyroid, parathyroid, or radical neck surgery for head and neck cancer. It may be transient, with recovery in days, weeks, or months; permanent; or even intermittent.

¶ In patients with hypoalbuminemia or hyperalbuminemia, measurement of serum ionized calcium is preferable. If a laboratory known to measure ionized calcium reliably is not available, the measured serum calcium concentration should be corrected for the abnormality in albumin.

Δ Hypomagnesemia can cause functional hypoparathyroidism and must be excluded. Intravenous magnesium supplementation to restore normal serum magnesium levels leads to a rapid rise in PTH levels and subsequent correction of hypocalcemia.

◊ A serum PTH within the reference range in a patient with hypocalcemia is inappropriately normal.

§ Suspect autoimmune hypoparathyroidism in children or young adult patients with a personal or family history of autoimmune disease. In families with PAS 1, chronic mucocutaneous candidiasis is an early manifestation followed by hypoparathyroidism. Suspect autosomal dominant hypocalcemia in children or young adults with longstanding hypocalcemia, family history of hypocalcemia, and recurrent nephrolithiasis and nephrocalcinosis during treatment with calcium and active vitamin D.