ESPE Abstracts

Background: Primary hyperparathyroidism is a rare cause of persistent hypercalcemia in children and adolescents, with parathyroid adenoma being the most common underlying etiology. We are reporting a case of primary hyperparathyroidism due to parathyroid adenoma in an adolescent Pakistani girl with an unusual presentation of difficulty in walking due lower limb deformity (bilateral genu valgum).

Case summary: A 13-year-old girl presented with pain in both knees and difficulty in walking for the last 6 months. There were no other associated systemic complaints. On examination she had bilateral genu valgum without any clinical evidence of wrist widening, rachitic rosary, Harrison sulcus and joints swelling. Her investigation revealed that she had mild hypercalcemia, hypophosphatemia, raised Alkaline phosphatase, raised parathyroid hormone level, low 25 OH vitamin D level and raised urinary calcium to creatinine ratio. Skeletal survey reported bilateral genu valgum with generalized osteopenia, subchondral resorption on the distal ends of the clavicle and acro-osteolysis of distal phalanges Ultrasonogram of neck shows a large heterogeneous hyperechoic area (13 × 5 mm) at the back of right lower portion of thyroid gland, suggestive of enlarged right inferior parathyroid gland. Ultrasonogram of kidney suggested of normal study. A Technetium (99mTc) sestamibi scan showed right inferior parathyroid adenoma confirming the diagnosis of primary hyperparathyroidism due to parathyroid adenoma. She underwent right inferior parathyroidectomy with smooth post operative recovery. Biopsy reported encapsulated lesion made up of primary chief cell and oxyphils cells without any sign of malignancy or mitotic activity confirming the diagnosis of parathyroid adenoma. She is now off all medication and doing well without any symptoms for the last 6 months.

Conclusion: Primary hyperparathyroidism is a rare condition and its presentation with genu valgum is extremely rare. Exact mechanism of genu valgum is not known. It might be due to direct effect of raised PTH on growth plate especially during puberty. It is further believed it could be partly due to underlying co-existing vitamin D deficiency as most of the previous cases of genu valgum with hyperparathyroidism were reported from Asian population where vitamin D deficiency is prevalent. Our index case also presented at the pubertal age and had vitamin D deficiency, suggesting in the favor of the above mentioned explanation of genu valgum in primary hypoparathyroidism