How can clinicians ensure the diagnosis of meningitic angiostrongyliasis?

Meningitic angiostrongyliasis (MA), caused by Angiostrongylus cantonensis, is often diagnosed by clinical criteria alone, because the confirmative serologic tests are not always available in the rural endemic areas. In this study, we evaluated the relationship between various clinical parameters of MA and the sero-positivity to sort out the predictive parameters to ensure the diagnosis. We enrolled consecutive adults in whom MA had been clinically diagnosed, who had serologic results for A. cantonensis, and negative serologic results for Gnathostoma spinigerum. There were 75 eligible patients; 26 (34.7%) and 49 (65.3%) patients who had negative and positive serologic tests for A. cantonensis, respectively. Baseline characteristics and laboratory results were comparable between sero-positive and -negative groups. Only the cerebrospinal fluid (CSF) eosinophil counts of 40% or higher was significantly predictive for positive serologic test with the adjusted odds ratio of 4.970 (95% confidence interval of 1.337-18.477). In diagnostic facilities in the endemic areas with the limited availability of serologic tests, clinicians can ensure the diagnosis of MA by using CSF eosinophil level.