Abstract 37: Adolescent primary hyperparathyroidism masquerading as rickets

Introduction: Primary hyperparathyroidism (PHPT), is a rare disorder in pediatric age-group, with an estimated incidence of 2–5 cases in 100,000 live births. Around 80% children are symptomatic with renal or gastrointestinal manifestations. Presentation with skeletal symptoms is rare with less than 30 reported cases with most cases being misdiagnosed and treated as rickets. Case Synopsis: 14 year old boy presented with pain in both the legs and knock knees for 1 year. He was treated as nutritional rickets with oral calcium and vitamin D supplements for 1 month. He subsequently developed abdominal pain and recurrent vomiting. He was diagnosed to have abdominal tuberculosis and was started on empirical Anti- tubercular treatment. He continued to worsen symptomatically and was send to Endocrinology for evaluation of worsening leg deformity- ? Resistant Rickets On examination his weight was <3(rd) centile, height 3-10(th) centile, waddling gait with genu valgum. Other systemic examination was normal. Investigations showed, corrected S. Calcium of 14.9 mg/dl, Phosphorus -2.9 mg/dl, ALP- 1277 IU/L, iPTH- 1900 pg/ml, 25(OH)D – 17 ng/dl, S. Creatinine -0.4 mg/dl and Hb-9.7 gm/dl. Ultrasound neck showed a 30 x19 x13 mm left parathyroid lesion with concordance in the Tc 99 Sestamibi scan. A clinical Exome sequencing for young onset PHPT was negative. He underwent a Left inferior parathyroidectomy and histopathology showed parathyroid adenoma. 4 months post-surgery, his S. calcium is 9.1 mg/dl on oral Calcium 500 mg twice a day. He gained 8 kilos and his bone pain and proximal myopathy has improved with persistent genu- valgum.