Hypocalcemia due to hypoparathyroidism in beta-thalassemia major patients

This is a retrospective analysis of case records of AA(2)-thalassemia major patients who developed hypoparathyroidism (HPT). The objective of this study was to assess the prevalence of hypocalcemia and hypoparathyroidism in AA(2)-thalassemia major patients being followed at King Khalid University Hospital (KKUH), Riyadh, Saudi Arabia.

Diagnosis was based on low serum calcium (S/Ca), high serum phosphate (Po4), normal serum magnesium and alkaline phosphatase, and low serum parathyroid hormone levels. Other parameters analyzed included age, sex, serum ferritin levels, age of onset of HPT, any symptoms of hypocalcemia, and presence of other complications in these patients.

Out of 40 patients, eight (20%) were diagnosed to have HPT. The mean age at diagnosis was 13.6 years (range 11-16 years), mean serum calcium was 1.88 mmol/L (range 1.58-2.04), mean serum ferritin was 7490 AA(1/4)g/L (range 2000-23,064) and mean serum phosphate was 1.88 mmol/L (range 1.50-2.73). Serum parathyroid hormone (PTH) levels were low in most of the patients. Only two patients (25%) had mild symptoms of hypocalcemia. Growth retardation was present in all patients, while four patients had liver dysfunction, two had diabetes mellitus and two had cardiac dysfunction.

HPT due to iron overload may develop in a significant number of thalassemia major patients, especially when chelation therapy is not optimal, therefore, all thalassemics should be carefully watched for this complication from early in their second decade.