Abstract
Tsutsugamushi disease, a febrile disease, is sometimes clinically indistinguishable from other acute infectious diseases. A 75-year-old woman developed systemic erythematous eruptions after treatment with ibuprofen for dizziness and chill. However, on the following day, her eruptions were exacerbated with consciousness disturbance; thus, she was transferred to our hospital for further treatments and evaluations. On admission, she exhibited no lymphadenopathy or distinct eschar formation, except for the presence of atypical lymphocytes in her peripheral smear. After four days of hospitalization, she developed disseminated intravascular coagulation (DIC) and hemophagocytic syndrome (HPS). After carefully checking several times her medical history including a tsutsugamushi-relevant contact history, it was suggested that she had tsutsugamushi disease. A serology test showed her recent exposure to Orientia tsutsugamushi. Administration of minocycline rapidly improved her symptoms. Regarding laboratory findings, the atypical lymphocytes increased in number up to 10% of her white blood cells after three days of hospital and thereafter decreased before the onset of DIC and HPS. We compared the characteristics of her lymphocytes between the time of onset and recovery. At the time of onset, most of the atypical lymphocytes were positive for CD8, and the CD4+/CD8+ ratio of all her lymphocytes was 0.5, whereas the ratio was 1.2 at the time of recovery. These findings suggest an infectious mononucleosis development in this patient, and that the presence of atypical lymphocytes may be a diagnostic predictor for tsutsugamushi disease, especially when bite marks or their eschar is not easily detected in systemic eruptions.
