Meningitis with Normal Cerebrospinal Fluid: Lactate and FilmArray Can Save my Life? Case Report

Cytological and biochemical examination from cerebrospinal fluid are key essentials in the diagnosis of bacterial meningitis. In most cases, cerebrospinal fluid (CSF) yields white cell counts > 100 mm 3 , hyperproteinorachia, and hypoglycorrhachia. However, in some patients, these findings do not appear especially in the elderly, pediatric, and the immunocompromised. A 78-year-old immunocompromised woman was admitted for fever and headache. Despite typical meningeal clinical signs, lumbar puncture showed absence of pleiocytosis, normal glycorrhachia, and normal proteinorachia. The lactate level in CSF was high (3.8 mmol/L). The FilmArray ® Meningitis/Encephalitis (ME) panel was positive for Human Herpesvirus 6 ( HHV6 ). Gram staining was negative. In front of a high probability of bacterial meningitis, a second lumbar puncture was performed and showed normal cell counts and high lactate level (4.4 mmol/L). The FilmArray ® ME panel was positive for HHV6 and Streptococcus pneumoniae . The antimicrobial therapy was conducted for 14 days. She was treated with cefotaxime then amoxicillin. This case indicates the importance of repeating a lumbar puncture even if the examination of CSF is normal, whereas the patient has typical meningeal clinical signs. Lactate levels in CSF with a diagnostic cutoff value of 3.8 mmol/L and the FilmArray ® ME panel could help physicians in this situation in order to decrease a poor outcome.