Parasites as etiological agents of meningitis: neglected causes among so few options

Abstract

Cases of meningitis are considered a growing public health problem on a global scale. The main limitations in the rapid and correct diagnosis of parasitic etiology is the difficulty in finding parasitic forms in the cerebrospinal fluid (CSF) and clinical suspicion. The present review aims to identify gaps in laboratory diagnosis and reduce possible errors that lead to unfavorable clinical outcomes. A search in three different electronic databases was carried out in order to identify the most common parasites that cause meningitis and the best laboratory approach for an assertive diagnosis. Pleiocytosis stands out as the most common characteristic (95.5%), with a predominance of eosinophils in infections by Angiostrongylus cantonensis and neutrophils in infections by Naegleria fowleri and Strongyloides stercoralis. Glucose and protein values are below and above normal values, respectively. Particularly in A. cantonensis infections, it is uncommon to find larvae in the CSF, with eosinorrhachia being a useful parameter. The parasitic origin was not the first clinical suspicion, which may have contributed to the worsening of cases due to the delay in therapeutic interventions. Our findings point to negligence and lack of knowledge regarding the parasitic origin of infections in the Central Nervous System.