Evaluation of hyponatraemia in patients with tick-borne encephalitis--a preliminary study.

Abstract Hyponatraemia is one of the most frequently observed, but sometimes overlooked, electrolyte disorder. Patients with meningitis are predisposed to develop hypovolaemic hyponatraemia. However, hyponatraemia in meningitis may also be caused by the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Proper differentiation of these pathomechanisms is crucial in patient's treatment as dehydration requires fluid supplementation, while SIADH is treated with fluid restriction. The aim of the present study was the evaluation of frequency, potential causes, and risk factors of hyponatraemia in patients with tick-borne encephalitis (TBE). A total of 61 patients (22 women, 39 men) aged 18–80 years, with a history of TBE was included in the study. Hyponatraemia was diagnosed when sodium concentration was below 135 mmol/l. Hyponatraemia was considered mild when sodium concentration was 130–134 mmol/l, moderate when 125–129 mmol/l, and severe when R Spearmann – 0.27, p 60 years of age with TBE are more susceptible to hyponatraemia than younger patients.