Independent Validation of Two Lyme Meningitis Clinical Prediction Rules

The Avery clinical prediction model calculates the probability of Lyme meningitis based on duration of headache, presence of cranial neuritis, and percentage of cerebrospinal fluid (CSF) mononuclear cells. The simpler Rule of 7's defines low-risk patients as those with <7 days of headache, <70% CSF mononuclear cells, and absence of seventh or other cranial nerve palsy. In a retrospective cohort study, researchers tested these prediction rules in 423 children (age range, 90 days to 19 years) who had presented to emergency departments in Lyme endemic areas (Boston, Delaware, and Philadelphia) and had undergone lumbar puncture (LP) and Lyme serology testing. Patients who required inpatient care or received antibiotics within 72 hours of LP wer…