Osteopetrosis and congenital hypothyroidism complicated by slipped capital femoral epiphysis.

ABSTRACT

OBJECTIVE: To describe a 13-year-old girl with unilateral slipped capital femoral epiphysis (SCFE), who presented with an acute onset limp during follow-up for congenital hypothyroidism and osteopetrosis. METHODS: We present a case report detailing the patient's history as well as clinical, laboratory, and imaging findings and discuss the related literature. RESULTS: The patient had been diagnosed elsewhere with congenital hypothyroidism, and levothyroxine therapy was initiated when she was 20 days of age; however, adherence to the treatment was irregular. Both her weight and her height were below the 5th percentile, her breast development and pubic hair were consistent with Tanner stage 1, and she had mental retardation and atypical facies. Her gait was antalgic; no muscle atrophy or shortness in the affected leg was present. On laboratory investigation, thyroid function tests were concordant with primary hypothyroidism. Her bone age was estimated as 8 years. Dual-energy x-ray absorptiometry revealed increased bone mineral density. Radiographic studies disclosed striking opacity of the bones of the pelvis and sclerosis at the skull base. Computed tomography of the affected left lower limb showed a fragmented appearance of the capital femoral epiphysis and thickening and irregularities of the physis line on the left, consistent with SCFE. CONCLUSION: We underscore the possible facilitator role of osteopetrosis in the pathogenesis of SCFE, suggest the need to consider SCFE in the differential diagnosis when a lower extremity abnormality is detected in patients with congenital hypothyroidism or delayed puberty (or both), and emphasize this association with osteopetrosis.