SAT192 Non-syndromal Primary Hyperparathyroidism Presenting As Asymptomatic Hypercalcemia In A Teenage Patient.

Disclosure: S. Humayon: None. M. Shah: None. P.N. Kabir: None. C.A. Penaherrera: None. Introduction: Primary hyperparathyroidism is the most common cause of hypercalcemia in the general population, and is often discovered incidentally. The condition rarely presents in patients under age 18, particularly when it is not associated with genetic syndromes such as MEN 1. Case presentation: A previously healthy 17-year-old female was referred to Endocrinology clinic for evaluation of positive thyroid peroxidase antibodies with normal TSH and free T4. Review of laboratory results from 6 months prior, revealed an elevated total calcium level of 12.3 mg/dl. Patient at the time denied any symptoms of hypercalcemia. Repeat testing revealed a calcium level of 13.1 mg/dl, PTH level of 183 pg/ml, alkaline phosphatase 232 IU/L. Her vitamin D level was 28 ng/ml, with elevated calcitriol level of 362 ng/ml. The patient denied a history of kidney stones or other endocrine abnormalities in the past. She did mention a family history of hypercalcemia in her father requiring neck surgery. Patient was admitted to the hospital for management of hypercalcemia with intravenous fluid hydration. Subsequent work-up included a sestamibi parathyroid scan which revealed an asymmetric area of delayed uptake in the left thyroid gland, suggestive of a single parathyroid adenoma. The patient underwent single-gland parathyroidectomy, during which PTH levels decreased from 134 pg/ml to 15 pg/ml. She recovered uneventfully from the procedure and was started on oral calcium supplementation, which was tapered two months after surgery since there was no evidence of post-operative hypoparathyroidism. Conclusion: Primary hyperparathyroidism, when presenting prior to the age of 30, is most commonly associated with genetic syndromes such as MEN1 and typically presents as multi-glandular hyperplasia. Isolated primary hyperparathyroidism, secondary to a single parathyroid adenoma is seen less frequently in this younger subset of patients. This can be found in the absence of other endocrine abnormalities, with or without the presence of a family history. Prompt identification of hypercalcemia followed by evaluation of the same, may prevent delays in diagnosis and subsequent management of primary hyperparathyroidism. This can help prevent morbidity associated with hypercalcemia. Presentation: Saturday, June 17, 2023