Is cerebrospinal fluid lactate useful in differentiating scrub typhus meningitis from aseptic, bacterial and tuberculous meningitis?

Scrub typhus is one of the most common causes of meningo-encephalitis in endemic areas of the Indian subcontinent. Numerous studies have established the reliability of cerebrospinal fluid lactate for differentiation of bacterial meningitis from aseptic meningitis. However, there are no reported data on the predictive value of cerebrospinal fluid lactate in scrub typhus meningitis. We thus conducted a cross-sectional study to examine the diagnostic accuracy of cerebrospinal fluid lactate in the differentiation of different causes of acute meningitis. Over two years, we studied 119 patients, with almost equal gender distribution, whose mean age was 43.58 (±18) years and their overall mean duration of fever was 11.7 (±21.0) days. Commonest clinical features overall were neck stiffness; values of cerebrospinal fluid lactate were lowest in aseptic meningitis, followed by scrub typhus, TB and bacterial meningitis. We conclude that cerebrospinal fluid lactate levels may be a useful adjunct to clinical features and laboratory investigations to differentiate between bacterial, viral, tubercular and scrub meningitis.