Bone Abstracts

Primary hyperparathyroidism is extremely rare in childhood and adolescence. Here we report a clinical case of a 15-year-3-month-old boy who began 2 years before with pain in his knees, genu varum, and fatigue. Physical examination showed severe genu valgum with an inter-malleolar distance of more than 30 cm. Biochemical tests showed hypercalcemia (12.2 mg/dl), hypophosphatemia (2.3 mg/ dl), hypercalciuria (6.4 mg/kg per day), high alkaline phosphatase (2812 IU/l), low 25-hydroxyvitamin D (6 ng/ml), and hyperparathyroidism (PTH: 2653 pg/ml, normal value 12–72). Skull X-rays showed salt-and-pepper appearance, and loss of lamina dura in the mandible, X-rays of the hands showed subperiosteal resorption and severe rickets, and X-rays of the knees showed rickets and osteomalacia. Kidney ultrasonography showed increased echogenicity on both sides. Urine catecholamines were normal. Neck ultrasonography and technesium-99 m Sestamibi revealed parathyroid adenomas. Spine, femora, and whole body bone densitometry disclosed markedly reduced bone mineral density: L2–L4: 0.87 g/cm², Z-score: −2.3, right femur 0.67 g/cm², left femur 0.76 g/cm², and whole body 0.82 g/cm², Z-score: −3.4. Two parathyroid adenomas situated on the upper and lower part of the right lobe of the thyroid gland were successfully removed. Histopathology reported parathyroid adenoma of chief cells. PTH fell to 38 pg/ml 30 min after the adenomas were removed. He developed severe hungry bone syndrome 96 h after surgery requiring up to 7.5 μg of calcitriol and 14.5 g of oral calcium/day and i.v. calcium for 19 days to normalize serum calcium and phosphate. Bone densitometry, repeated after 4 months, showed a dramatic increase of bone mineral density with normalization in all sites: spine: L2–L4: 1.192 g/cm², Z-score: +0.7; right femur: 1.097 g/cm², left femur: 1.088 g/cm², whole body: 1.065 g/cm², Z-score +0.4. In conclusion: Here, we report a case of primary hyperparathyroidism due to parathyroid adenomas in an adolescent boy. After surgery, the patient needed high doses of calcitriol and calcium to normalize calcemia and phosphatemia. Follow-up and outcome were good and 4 months after surgery he had completely recovered bone mass.