Early differentiation of Lyme from enteroviral meningitis.

Background: Differentiating Lyme meningitis from enteroviral meningitis remains difficult because both occur mostly in the summer and early fall. This distinction is clinically important because pathogen-specific diagnostic test results are not available immediately and only patients with Lyme meningitis require parenteral antibiotic therapy.

Objectives: The objective of this study was to identify clinical and laboratory features that might help clinicians distinguish patients with Lyme meningitis from those with enteroviral meningitis.

Methods: This cross-sectional study compared patients diagnosed with Lyme or enteroviral meningitis evaluated at a large children's hospital between January 1, 1999 and September 20, 2002.

Results: Twenty-four patients with Lyme meningitis and 151 patients with enteroviral meningitis had median ages of 10.5 and 5.5 years, respectively (P < 0.0001). There was an equal proportion of boys with Lyme (63%) and enteroviral meningitis (62%; P = 1.0). The duration of symptoms before evaluation was longer for patients with Lyme meningitis (12 days) than with enteroviral meningitis (1 day; P < 0.0001). Cranial neuropathy was a presenting feature in 71% of children with Lyme meningitis. Cranial neuropathy, erythema migrans rash or papilledema occurred in 88% of patients with Lyme meningitis; no patients with enteroviral meningitis exhibited any of these findings (P < 0.0001). Lyme meningitis was unlikely when cerebrospinal fluid neutrophils exceeded 10% (negative predictive value, 99%).

Conclusions: We identified several clinical and laboratory features that may permit early differentiation of Lyme from enteroviral meningitis. These results may assist clinicians with decisions regarding additional testing and empiric antibiotic therapy.