Coma Secondary to Rickettsia typhi

Abstract

SESSION TITLE: Student/Resident Critical Care SESSION TYPE: Student/Resident Case Report Slide PRESENTED ON: Tuesday, October 31, 2017 at 04:30 PM - 05:30 PM INTRODUCTION: Rickettsia typhi is an obligate intracellular gram-negative organism that is transmitted by fleas. It causes murine typhus, which is often misdiagnosed due to its indolent and non-specific disease course and underestimated incidence, making it a diagnostic challenge (1). CASE PRESENTATION: An indigent male was brought in by ambulance for seizures during the summer. Physical examination was unremarkable except for fever and Glasgow Coma Score (GCS) of 3. He was intubated for airway protection. Laboratory values were significant for leukocytosis, thrombocytopenia, hyponatremia and elevated lactate dehydrogenase (LDH) of 400 units. Lumbar puncture and computed tomography brain were normal. Despite two weeks of empiric antibiotic therapy, cultures remained negative and the patient continued to have persistent fevers with GCS 3. At the end of the two weeks, a rash was discovered and a rickettsia panel was sent. It returned positive for murine typhus. After initiating treatment with doxycycline, patient became more responsive within a day, was liberated from the ventilator by day 4, and subsequently made a full recovery. DISCUSSION: Murine typhus, which is transmitted by Rickettsia typhi, is characterized by a classic triad of fever, rash and headache, but the entire triad is only reported in 35.1% of cases. In a large review of 1756 patients, only 26.1% developed complications, with 121 patients developing pulmonary infiltrates, 69 patients developing central nervous system involvement and 3 patients developing seizures. This finding makes the patient's presentation exceedingly rare. The review also observed a characteristic tetrad of laboratory abnormalities consisting of transaminitis, elevated LDH, a high erythrocyte sedimentation rate, and hypoalbuminemia. The tetrad was followed by thrombocytopenia and hyponatremia, which were also observed in this patient in addition to the tetrad. This case study demonstrates the diagnostic challenge presented to clinicians in a patient with altered mental status. Treatment of choice is empiric coverage with doxycycline, chloramphenicol, or quinolones, which should not be delayed while awaiting diagnostic confirmation (1,2,3). CONCLUSIONS: We present a case of a rare but possibly life threatening murine typhus, which should be kept in the differential for patients with fever and altered mental status. Reference #1: Tsioutis, C et al. (2017). Clinical and laboratory characteristics, epidemiology, and outcomes of murine typhus: A systematic review. Acta Tropica, 166, 16-24. Reference #2: Phongmany, S. et al. (2006). Rickettsial infections and fever, Vientiane, Laos. Emerging infectious diseases, 12(2), 256. Reference #3: Chang, K. et al. (2014). Identification of factors for physicians to facilitate early differential diagnosis of scrub typhus, murine typhus, and Q fever from dengue fever in Taiwan. Journal of Microbiology, Immunology and Infection. DISCLOSURE: The following authors have nothing to disclose: Ki-Yoon Kim, John Kern, Ahmet Baydur, Zea Borok, Terese Hammond No Product/Research Disclosure Information