SUN-LB049 Unusual Presentation of Large Parathyroid Adenoma with Acute Cerebellar Ataxia in a Pediatric Patient

Background: Severe hypercalcemia is the initial manifestation of primary hyperparathyroidism, typically manifesting with irritability, constipation, and relative muscle weakness. Central nervous system symptoms are however unusual in children, although they have been reported in adults. Clinical case: A 6 year 4-month-old previously healthy African-American girl presents with progressive difficulty walking. Hip X-rays were negative. She continued to attend school despite limping. She also developed constipation, polyuria and enuresis. She had trouble keeping up with schoolwork and was diagnosed with attention deficit and hyperactivity disorder, amphetamine/dextroampethamine was started. Laboratories obtained showed serum calcium of 17mg/dl (8.5 -10.1). No family history of parathyroid or other tumors. She was then referred to Peds Endo. On exam, she was not acutely ill, she had normal deep tendon reflexes, but sustained tetany of the quadriceps noted when reflexes were elicited; gait was wide-based and stiff-legged, favoring the left side. Laboratories: Calcium: 16.5mg/dl Phosphorus: 3.1 mg/dl (3.1-5.9) PTH: 2417 pg/ml (12-72) Vit D 25 OH: 19 ng/ml (≥30) Urine Ca/Cr: 0.93 Neck and parathyroid ultrasound: a 1.9 x 1.7 x 1.5 cm solid mass was noted at left inferior thyroid lobe suggestive of a parathyroid adenoma. Sestamibi ((99m)Tc) scan: intense focus of radiotracer uptake inferior to the left lobe of thyroid gland. Hospital Course: Patient admitted to ICU and treated with IV fluids, calcitonin and zoledronic acid. Calcium decreased to 9.7 mg/dl. She had intermittent hypertension, but plasma metanephrines were normal. Once patient was stable, the mass was surgically removed, measuring 2.0 x 1.7 x 1.5 cm and weighing 4gm. Pathology was compatible with benign parathyroid adenoma. PTH within 1hr post op was 171 pg/ml, 24 hrs later was 22pg/ml. As expected, child had considerable post-op hypocalcemia (7.2mg/dl), treated with calcium IV and PO, calcitriol and cholecalciferol. Despite normalization of her chemistries, her ataxia however worsened, she was unable to walk without assistance, requiring a walker for stability. Exam showed wide-based gait, truncal ataxia, negative Romberg sign; muscle strength normal in all extremities. Brain MRI was normal. She was discharged with physical rehabilitation and a walker. On follow up, ataxia had completely resolved by the fourth week post-op. Conclusions: This case illustrates a rare neurological presentation of hypercalcemia in a child. The diversity and subtle development of symptoms contributed to the delay in diagnosis. Although mechanisms of this association are unknown, hyperparathyroidism mimics motor neuron disease and skeletal muscle is a target organ for PTH, decreasing energy production and transport. Hyperparathyroidism should be in the differential diagnosis of acute ataxia in children. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.