Endocrine Abstracts

Introduction: Hyponatremia is the most common electrolyte imbalance in hospitalized patients and frequent finding in intensive care units. Hyponatremia is characterized with serum sodium values less than 135 mmol/l and defined by the ratio of total sodium and total body water. It presents with lethargy, confusion, neuromuscular excitability, hyperreflexia, stupor and even coma. In addition to neurological signs and symptoms, assessment of hyponatremia is based on severity and duration. There are several etiological factors leading to hyponatremia, so diagnosis and treatment present a challenge in everyday clinical practice.

Case report: In this case report we present a 71-year-old woman who presented herself to the emergency department due to weakness. Besides general fatigue, she reported a tingling sensation in the whole body and flatulence which lasted for 3-4 days. She has been vomiting lately. No other neurological symptoms have been observed. Based on her previous medical documentation we ascertain that due to similar symptoms, she has visited the emergency department several times. In her medical history, she has been treated with indapamide due to arterial hypertension, and a month ago she was treated for COVID-19. In physical examination, euvolemia was present, with normal vital parameters. An initial examination was performed and severe hyponatremia was verified with a serum sodium level of 110 mmol/l. Urine analysis showed an osmolality of 406 mOsmol/kg and sodium level of 45 mmol/l, X-ray examination was described as normal. Endocrinological workup excluded adrenal insufficiency and hypothyroidism, thus the diagnosis of SIADH was the most probable one. Additional investigation of medical records revealed that a month ago, while being treated due to COVID-19 patient had unrecognized serum sodium levels of 127 mmol/l and 116 mmol/l, respectively. In the emergency department, hyponatremia was corrected by intravenous administration of 3% NaCl for 20 minutes, with an increase in serum sodium by 4mmol/l. The patient was hospitalized and the gradual increase in serum sodium levels was monitored with fluid withdrawal to 800 mL per day which led to complete recovery and correction of electrolyte disbalance.

Conclusion: In this case report we intended to emphasize how important it is to recognize hyponatremia in COVID-19 patients, which can be caused by two mechanisms: SIADH due to Interleukin-6 induced non-osmotic release of vasopressin or loss of Na due to diarrhea and vomiting. Distinguishing between the two is essential for timely and correct treatment to avoid severe hyponatremia that can have potentially fatal consequences.