Pattern Recognition Triggers Early Treatment: Severe Ehrlichiosis With Aseptic Meningitis

Introduction: In the absence of an immunocompromised state, a tetrad of fever, thrombocytopenia, leukopenia, and transaminitis, should prompt investigation for tick-borne illness in the appropriate season and geographic location. Our case highlights how pattern recognition and serial evaluation triggers decisive early treatment/diagnostics in life threatening Human Monocytic Ehrlichiosis (HME).


Description: 61-year-old female with baseline history of anxiety/depression was hospitalized after 4 days of progressive lethargy, fevers, vomiting and diarrhea. Initial laboratory tests were significant for leukopenia, transaminitis (AST 440 U/L, ALT 340 U/L), and thrombocytopenia (platelets 68,000/µL). She was empirically started on Doxycycline and Piperacillin-Tazobactam. Further history elicited the removal of a tick 4 weeks prior without the presence of skin findings. Presentation evolved to acute hypoxic respiratory failure (P/F ratio 51mmHg) with bilateral opacities on chest x-ray (non-dependent, preserved costophrenic angles) resulting in intubation. Prior to intubation, she demonstrated lethargy, neck/back pain, and bilateral lower extremity jerking movements (normal deep tendon reflexes). Considering tick-borne illness as a highly likely cause, Doxycycline was continued, and Piperacillin-Tazobactam switched to Ceftriaxone. EEG and CT head w/o contrast were normal. CSF analysis was consistent with aseptic meningitis. Clinical improvement followed with vent liberation and she did not have residual neurologic deficits. Final disposition included 14 days of Doxycycline. The initial PCR confirmed the presence of HME (Ehrlichia Chafeensis) in the blood (without coinfection of other tick-borne disease).


Discussion: Per CDC, 1,907 cases of Ehrlichiosis were reported in 2023 with highest incidence in the southeastern United States. Coinfection with Lyme and Babesiosis are common. Laboratory findings often mimic acute HIV, EBV, and acute hepatitis. E. Chafeensis species demonstrates findings for aseptic meningitis. PCR assays have the highest sensitivity/specificity within 1 week of symptom onset. Complications include seizures, coma, renal failure, and ARDS. Our case highlights how laboratory patterns, geography, and serial evaluations can streamline diagnostics leading to early treatment of Ehrlichiosis.