Endocrine Abstracts

COVID-19 is an acute respiratory viral illness with associated long-term, multisystem effects. Known pituitary complications include hypopituitarism, pituitary apoplexy, and SIADH. Central diabetes insipidus (CDI), however, remains a rarely described consequence. A 44-year-old woman presented with typical CDI symptoms developing two weeks following symptomatic COVID-19 infection, including polydipsia, nocturia, and polyuria of 9.1L per day. Initial investigations demonstrated a normal serum sodium (142mmol/l), but a raised serum osmolality (300mmol/kg) and low urine osmolality (113mmol/kg) consistent with CDI. A water deprivation test confirmed the diagnosis, with normal serum osmolality (291mmol/kg), high urine output (470mL/hr), and low urine osmolality (120mmol/kg) at baseline progressing to a raised serum osmolality (304mmol/kg) with submaximal urine osmolality (373mmol/kg) and urine output (135mL/hr). A 2.3kg weight decrement was also observed. 2μg of intravenous desmopressin was administered, which achieved an increase in urine osmolality (604mmol/kg) and sodium (96mmol/l), reduction in urine output (30mL/hr), and normalisation of serum osmolality (284mmol/kg). MRI pituitary was unremarkable, with no focal lesions or pituitary stalk thickening identified. Desmopressin was commenced at 100μg orally twice daily, but later uptitrated to three times per day due to persistent interdose polyuria. This demonstrates the importance of awareness of potential pituitary complications following COVID-19 infection, including CDI. Given the association with other pituitary pathology, a full pituitary profile should be performed in these patients. Desmopressin appears to be an efficacious treatment in COVID-19 associated CDI, but requires titration based on clinical response.