When bones hurt in many places: A diagnostic puzzle in a 13-year-old boy

Abstract

Background: Severe nutritional Vitamin D deficiency leading to secondary hyperparathyroidism can clinically mimic or mask underlying genetic bone disease. A key challenge is distinguishing whether diffuse skeletal osteosclerosis represents a metabolic reaction to elevated parathyroid hormone (PTH) or a primary defect in osteoclastic bone resorption like osteopetrosis.

Case summary: A 13-year-old male student presented with a 1-year history of intermittent, dull bone pain in his left shoulder and right lower back, aggravated by activity. At age 2.5, he had acute osteomyelitis of the right knee, treated conservatively. Evaluation for fever previously revealed a "Rugger-jersey spine" and secondary hyperparathyroidism (Calcium 8.8 mg/dl, Vitamin D 9 ng/ml, intact PTH 123.5 pg/ml, ALP 274 U/L) due to severe Vitamin D deficiency. Physical examination was normal. Radiographs showed a delayed bone age (11 years), metadiaphyseal widening of the distal radius and ulna, and cortical thickening of the sacrum and iliac bones. Notably, a DEXA scan revealed extremely elevated bone mineral density (BMD) with Z-scores ranging from +5.7 to +7.6. Follow-up X-rays showed diffuse osteosclerosis indicative of osteopetrosis. Standardized Vitamin D3 therapy normalized his serum calcium (9.8 mg/dl) and iPTH (48.9 pg/ml), though serum phosphate (5.6 mg/dl) and ALP (355 U/L) remained elevated. With this finding, the patient is diagnosed as osteopetrosis, genetic study is needed to confirm.

Conclusion: Adolescent osteopetrosis can coexist with and be clinically masked by severe Vitamin D deficiency and secondary hyperparathyroidism. Detailed skeletal surveys and BMD scans are vital in pediatric patients with persistent bone pain to prevent misdiagnosis of primary osteosclerosis and guide multidisciplinary conservative management.

[J Assoc Clin Endocrinol Diabetol Bangladesh, 2026;5(Suppl 1): S78]