SAT227 A 17-year old Teenager With Recurrent Syncopes In The Setting of Hypocalcemia

Disclosure: D.V. Chartoumpekis: None. P. Bountouris: None. K. Dimitropoulos: None. I.G. Habeos: None. Background: One of the main reasons of syncope is the long QT syndrome. The exercise-induced hypocalcemia in a background of primary hypoparathyroidism is sometimes overlooked in the differential diagnosis. Clinical Case: A 17-year old female was transferred to the emergency room of the University Hospital of Patras after having experienced a syncope while swimming. She described in the past 6 months similar episodes during exercise (running, cycling). A basic investigation with full blood count, sodium, potassium, cortisol and TSH levels along with a brain MRI and an ECG were performed at her primary care physician. Due to a discovered long QT she was addressed to a cardiology private office for further investigation. However, before the planned appointment she had this episode while swimming and she was admitted to the cardiology department. During her hospitalization a serum calcium of 4.7 mg/dl and a serum P of 9.4 mg/dl were discovered with a non-detectable PTH. The endocrinology division was called for further evaluation. Chvostek and Trousseau’s signs were positive. The patient was administered a calcium gluconate drip and in parallel a treatment with calcium carbonate and alphacalcidol was initiated. The possibility of an autoimmune polyendocrine syndrome was excluded as the patient did not present candidiasis, adrenal insufficiency, autoimmune thyroid disease or diabetes. After her exit from the hospital she was followed up at the outpatient endocrinology clinic and her daily doses of calcium carbonate and alphacalcidol was modified several times as the [CaxP] was always higher than 55 mg(2)/dl(2) and when the dose of calcium carbonate was lowered she developed symptomatic hypocalcemia. During the first month of her follow-up a cataract in the right eye was discovered and a brain MRI unveiled basal ganglia calcifications. No signs of renal stones or nephrocalcinosis were seen in the ultrasound. As the calcium and phosphate levels, after almost 9 months of changes in the treatment schemes, were not optimal, a treatment with recombinant PTH was initiated. This treatment aided the patient to reach low normal levels of calcium and [CaxP] lower than 55 mg(2)/dl(2). The patient is followed up every six months in the endocrinology outpatient clinic. Conclusion: This is an interesting case of primary hypoparathyroidism possibly of autoimmune origin. The presence of syncopes during exercise could be due to a further drop of calcium levels due to transient respiratory alkalosis. This case can be useful in the teaching of differential diagnosis of long QT syndrome, the management and evaluation of an hypocalcemia and the rule out of autoimmune polyendocrine syndromes in the context of a primary hypoparathyroidism. Presentation: Saturday, June 17, 2023