Severe tsutsugamushi disease complicated by disseminated intravascular coagulation, acute respiratory distress syndrome, and multiple organ dysfunction: a case report

Background Tsutsugamushi disease (scrub typhus), caused by Orientia tsutsugamushi and transmitted by chigger mites, classically presents with fever, eschar, and lymphadenopathy. However, cases lacking an eschar often face delayed diagnosis and can rapidly progress to severe hyperinflammatory conditions like sepsis, disseminated intravascular coagulation (DIC), acute respiratory distress syndrome (ARDS), and multiple organ dysfunction syndrome (MODS), carrying high mortality. Case presentation A previously healthy adult male chef residing in Shenzhen, China, presented with a 10-day history of recurrent fever (peak 40.3 °C) and myalgia of the limbs and lower back. He reported unknown arthropod bites but had no typical eschar. On admission, he had thrombocytopenia (70 × 10^9/L) and elevated C-reactive protein (102.61 mg/L). He rapidly deteriorated to a platelet nadir of 33 × 10^9/L, complicated by DIC, ARDS, liver injury, and myocardial damage. Physical examination revealed a crater-like round ulcer on the left scrotum. The diagnosis was confirmed by positive O. tsutsugamushi antibodies at the Shenzhen Center for Disease Control and Prevention (CDC) and peripheral blood metagenomic next-generation sequencing (mNGS). Treatment included doxycycline, empirical meropenem and vancomycin, low-dose dexamethasone, intravenous immunoglobulin, plasma transfusion, and comprehensive organ support. He stabilized and was discharged after 9 days. Conclusion Severe tsutsugamushi disease can trigger a hyperinflammatory response leading to DIC, ARDS, and MODS, with a rapid and fulminant course. The absence of a typical eschar is a major cause of delayed diagnosis. In patients with unexplained fever, thrombocytopenia, and multi-organ injury even without an eschar careful inspection for atypical ulcers or eschars in concealed areas such as the perineum and axillae is warranted, especially in those with a history of exposure to endemic areas or bites of unknown arthropods. Diagnosis should rely primarily on clinical features and conventional serology. For critically ill patients with negative routine tests, metagenomic NGS may be considered as a supplementary diagnostic approach. Prompt recognition and timely administration of targeted antibiotic therapy are critical for improving prognosis.