Hyponatremia during a Severe Pneumococcal Meningitis with Renal Salt Wasting: A Cerebral Salt Wasting Syndrome?

Background: The existence and prevalence of cerebral salt wasting and its differentiation from syndrome of inappropriate antidiuretic hormone have been controversial. This controversy stems from overlapping clinical and laboratory findings and an inability to assess the volume status of these patients. Objectives:To present a case of a cerebral salt wasting syndrome secondary to a bacterial mengitis and to emphasize the difficulty to assess the diagnosis. Case report: A 51-year-old male admitted to the ICU for a severe bacterial meningitis who developed, four days later, hyponatremia associated with hypovolemia due to a renal salt wasting. Clinical and biological parameters were collected; electrolytes balances and salt clearances were calculated to best investigate this hydroelectrolytic disorder. Patient's volume status and improvement after fluid and sodium replacement highly suggests the diagnosis of a cerebral salt wasting syndrome. Conclusion: A thorough analysis of this case showed that occurrence of hyponatremia and renal salt wasting after brain agression is not univocal underlying the fact that the diagnosis of cerebral salt wasting should be assessed only after a careful examination of the different determinants of the hydroelectrolytical balance.