A case of acute renal dysfunction and multiorgan dysfunction caused by Rickettsia japonica infection

This article reports a case of acute renal dysfunction and multi-organ dysfunction syndrome caused by Rickettsia japonica infection. The patient, a 79-year-old male, presented with unexplained fever, fatigue, anorexia, vomiting, and chest tightness, followed by oliguria and a decline in mental status. Laboratory tests revealed significant abnormalities, including elevated white blood cells, thrombocytopenia, hepatic and renal dysfunction, and coagulopathy. Imaging studies showed pulmonary infection and bilateral pleural effusion. Based on the history of tick bite, clinical manifestations, and metagenomic next-generation sequencing (mNGS) results, which detected R. japonica, the patient was diagnosed with Japanese spotted fever (JSF). He received multidisciplinary comprehensive treatment, including mechanical ventilation, continuous renal replacement therapy (CRRT), antimicrobial therapy, blood transfusions, and supportive care. After 15 days of treatment, the patient's fever resolved, inflammatory markers decreased significantly, and organ functions improved gradually, leading to eventual recovery and discharge. This case highlights the importance of early recognition and treatment of R. japonica infection, especially in endemic areas, to prevent rapid deterioration and multi-organ failure.