Case Presentation: Learning Objectives: – To recognize ehrlichioisis as a possible cause of aseptic meningitis – To understand activities that increase the risk of tick-borne diseasesCase Presentation:A 69-year-old Black man presented to a Louisiana hospital with a two-day history of falls, intermittent disorientation, lower extremity weakness and pain, and urinary retention. He denied skin changes, insect bites, contact with animals, and typical risk factors for meningitis. The patient reported no abnormal food patterns or history of substance use, and he kept active by golfing daily prior to the onset of these symptoms. He was febrile to 100.8F and had signs of nuchal rigidity. He was admitted due to concern for meningitis and treated with empiric ceftriaxone after labs were drawn. Sodium returned low at 128 mEq/L, which was attributed to SIADH based on serum and urine studies. Radiographic imaging was unremarkable. Lumbar puncture was completed and CSF analysis returned with protein of 56 mg/dL, normal glucose, and WBC of 122 cells/uL (99% lymphocytes). CSF PCR was negative for bacterial and viral pathogens. Blood cultures were negative. No intracellular organisms were identified on peripheral blood smear. An MRI of the lumbar spine revealed severe stenosis at L2-L5. Rheumatologic work up of ANA, c-ANCA antibodies, and p-ANCA antibodies were negative. HTLV, HIV, RMSF, equine encephalitis viruses, and West Nile virus serologies all returned negative. On hospital day two, the patient became increasingly disoriented and unable to answer questions appropriately. The Infectious Disease service was consulted who recommended initiating intravenous doxycycline treatment for empiric coverage of Rickettsia and other tick-borne disease. A larger infectious panel was sent to the CDC to test for LCMV, Leptospira, Anaplasma, and Ehrlichia. After starting doxycycline, a rapid improvement of fever, mentation, and pain occurred. Results of the IFA assay arrived two weeks later with Ehrlichia chaffeensis IgG 1:128. The patient was transitioned to oral doxycycline to complete a 21-day course. He continued to recover and was discharged to inpatient rehabilitation for deconditioning.
Discussion: This case illustrates an infection of human monocytotrophic ehrlichiosis in a state where only 26 cases have been reported since 2006 in a patient with seemingly no risk factors. Initially there was little clinical suspicion for tick-borne diseases due to the low incidence in the region and the cluster of symptoms resembling aseptic meningitis. Patient had no leukopenia, thrombocytopenia, or elevated liver enzymes which are typical signs of ehrlichiosis. The diagnosis explained his stiff neck, altered mental status, and SIADH as ehrlichiosis may affect the central nervous symptoms causing neurological changes. The only exposure to ticks in wooded areas was his hobby of daily golfing. Ehrlichiosis has been reported in a retirement golfing community, however this occurred in a state with one of the highest incidences of infection.
Conclusions: Although ehrlichioisis remains an uncommon or rare diagnosis in many states, it should still be considered based on symptoms and any history of recent activities in wooded areas. This man’s clinical course serves as a reminder to investigative potential sources of tick exposure and to promptly start doxycycline if there is clinical suspicion of tick-borne diseases as it has been shown to decrease risk of severe complications.