An adolescent boy with thalassemia major presenting with bone pain, numbness, tetanic contractions and growth and pubertal delay: Panhypopituitarism and combined vitamin D and parathyroid defects

A 16-year-old boy with transfusion-dependent thalassemia major presented with tetany, numbness, bone pain, short stature and pubertal delay. His height SDS score = -2.6, BMI = 22.4, spleen was palpable 5 cm and liver 7 cm below the costal margins. The cardio-vascular examination was normal. Laboratory investigations showed a hemoglobin level (8 g/dL), hypocalcemia, hyperphosphatemia and elevated alkaline phosphatase (ALP) with serum 25-OH D below 3 ng/ml and a normal magnesium level. Serum parathyroid hormone (PTH) level was lower (21 pg/mL; normal 16-70 pg/mL) than expected for the degree of hypocalcemia. Serum ferritin concentration was 4442 ug/L, insulin-like growth factor I (IGF-I) was 31μg/L (normal 122-286 μg/L), free T4 was 13.1 μg/dL, TSH 1.2 mlU/ml. These results revealed a combined vitamin D-parathyroid defect. Peak growth hormone (GH) responses to clonidine and glucagon tests were 7.6 ng/ml and 6.2 ng/ml, respectively. Serum LH and FSH concentrations were below 0.5 U/L and testasterone was below 10 ng/dl. Radiographs revealed osteopenia of the phalanges and long bones and DXA scanning revealed low BMD Z-score of the femoral neck and 4th and 5th lumbar spines. MRI showed evidence of hemosiderin deposition in the pituitary. The patient was started on oral daily calcium carbonate (1500 mg elemental calcium) and vitamin D2 (calciferol) 25,000 IU/day and intensive iron chelation therapy. A low dose of IM testosterone enanthate (1mg/kg/month) was injected for 6 months. Follow-up after 4, 8 and 12 months revealed normal Ca, PO4, ALP, and 25-OH D concentrations and disappearance of spasms and numbness and increased growth velocity. In conclusion, investigating calcium homeostasis at regular intervals and early management of any abnormality can preclude the occurrence of complications.