A 7-year-old female with two weeks of morning headache presented to a north-midwestern hospital with one day of neck pain and fever. She had an episode of emesis but denied sick contacts, head trauma, or diarrhea. Exam revealed nuchal rigidity and irritability but no papilledema, focal neurologic al findings, or rash. Lumbar puncture showed increased protein (111 mg/dL), normal glucose (73 mg/dL in CSF, 114 mg/dL in blood), 9 RBCs and 2518 WBCs (98% neutrophils). She was started on Vancomycin and Ceftriaxone with enterovirus the favored etiology.
CBC revealed thrombocytopenia (97×103/uL) and normal WBC count. When CSF was negative for enterovirus, HSV, and CMV DNA, the differential was reopened to include bacterial, oncologic, and NSAID-related causes. MRI ruled out an intracranial process, CSF and blood cultures showed no growth, enteroviral and parechoviral DNA were absent from all sources, and EBV testing revealed distant infection. With common etiologies ruled out, suspicion for tick-borne illness in the endemic locale, even without history of tick exposure, led to the addition of Doxycycline for Ehrlichia and Anaplasma coverage and orders for appropriate testing.
Fevers resolved by day four of admission; headaches persisted. Repeat LP to obtain more information showed still normal glucose, now normal protein, decreased pleocytosis (now 19 WBCs, 1% polys), yet an elevated opening pressure of 26 cm H¬2O. Cytology was negative and the serum tick-borne panel was negative. Meanwhile, the screening ELISA for Lyme antibodies returned positive (2.07 ISR) and confirmatory immunoblot positive for anti-Lyme IgM (two of three bands positive) but negative for IgG (one of ten bands positive), suggesting early disseminated Lyme disease with meningitis. The patient completed a 14 day course of antibiotics with complete symptom resolution, further supporting diagnosis despite the non-classic initial CSF findings.
Lyme can be difficult to distinguish from other meningitis etiologies, particularly enterovirus. One study seeking to distinguish Lyme from enterovirus found that children with Lyme meningitis tend to be older (median 10.5 years in contrast to 5.5 years) and present later in the disease course (on the 12th symptomatic day in contrast to after one day). While these findings favor Lyme in this case, the thrombocytopenia and highly neutrophilic CSF confounded diagnosis.
Lyme meningitis in children can present as intracranial hypertension resembling pseudotumor cerebri , demonstrated in this patient as daily headaches and elevated opening pressure.
Early antibiotic treatment prevents progression to late disseminated Lyme disease , which most commonly manifests as arthritis.
Hospitalists in Lyme-endemic areas must keep Lyme meningitis in their differential when there is a pleocytosis and intracranial hypertension, initiate empiric antibiotics when suspicion is present, and send appropriate testing. In this case, the hospitalists included Lyme in their differential despite non-classical CSF findings, which led to appropriate empiric treatment, testing and ultimately resolution of symptoms with treatment.