Rule of 7s for Lyme Meningitis
Distinguishes Lyme meningitis from aseptic meningitis.
Use in pediatric patients (aged 2–18 years) in a Lyme endemic area with CSF pleocytosis, defined as CSF WBC ≥10 cells/mm³ (corrected for CSF RBC if >500 using a ratio of 1 WBC for every 500 RBC).
Advice
- This tool should be used to assist a clinician in decision-making and not replace clinical evaluation of a patient.
- Patients with scores 1–3 are NOT low risk for Lyme meningitis, and antibiotic therapy for LM should be considered.
- Patients with scores 0 are at low risk for LM. Symptoms may be due to aseptic meningitis or other etiology. Use clinical judgment and consider availability of follow-up with both the patient and primary care provider before electing to treat patient symptoms with antibiotics.
Management
If patient is low risk for LM, consider discharge and discuss with patient and primary care provider to ensure adequate follow-up. If patient is not low risk for LM, consider antibiotic therapy that will cover Borrelia burgdorferi, taking into account the patient’s age.
Critical Actions
The Rule of 7s is meant to aid in the decision to start antibiotics for suspected Lyme versus aseptic meningitis. It should not replace clinical judgement and clinician assessment of patients.