Given the clinical picture, the initial differential diagnosis included sepsis, bacterial or viral pneumonia, disseminated intravascular coagulation (DIC), idiopathic thrombocytopenic purpura, pulmonary embolism, and acute coronary syndrome.

Broad spectrum antibiotics were promptly initiated to cover community-acquired pneumonia, with the patient initially receiving ceftriaxone and azithromycin. His fever and systemic symptoms persisted despite this regimen; antibiotics were escalated to vancomycin and cefepime. Even with the change in therapy, the patient continued to exhibit febrile episodes, and his respiratory and systemic symptoms showed no improvement.

On the seventh day of hospitalization, clinicians revisited the possibility of an unusual infectious etiology. Given the epidemiologic context and high clinical suspicion, murine typhus was considered as a possible diagnosis. The patient resided in Southeast Texas, an endemic area for murine typhus, a zoonotic disease transmitted through fleas often associated with rodents.¹ Although no clear risk factors were identified, the clinical team started doxycycline empirically, given the lack of response to previous therapies and the constellation of findings, including thrombocytopenia, splenomegaly, elevated liver enzymes, and a characteristic rash.

Subsequently, serological testing confirmed the diagnosis, with positive immunoglobulin M titers for murine typhus. After initiating doxycycline, the patient’s clinical condition began to significantly improve. His fever resolved, his respiratory symptoms diminished, and his general condition stabilized. By day 14, he was well enough to be discharged in stable condition, with instructions to complete his course of doxycycline at home.

Discussion

Murine typhus, a disease transmitted by fleas, is caused by the intracellular bacterium Rickettsia typhi.¹ Characterized by a range of nonspecific symptoms, including fever, myalgia, and rash, murine typhus often presents a diagnostic challenge that can be elucidated through a careful exposure and travel history. Most cases diagnosed in the United States have been identified in California, Hawaii, and Texas, although returning travelers from Southeast Asia are also at higher risk.^2-4T his report discusses a case of murine typhus that initially presented as severe pneumonia and sepsis and illustrates the importance of timely diagnosis and appropriate treatment.