Case Presentation: A 59-year-old female presented to the emergency department with a 5-day history of cough, chest pain, shortness of breath, and fever. She also reported nausea, vomiting, right upper quadrant abdominal pain and arthralgia. She denied any headaches. Past medical history was remarkable for gallstones. On physical exam, she appeared in moderate distress, was febrile and tachycardic. A fine, non-pruritic, maculopapular rash was present on bilateral upper extremities and trunk. Abdominal exam was unremarkable. Lab results were significant for lactic acidosis, thrombocytopenia, and transaminitis. Infectious work-up showed negative blood cultures and urinalysis. CT chest, abdomen, pelvis revealed concern for metastatic breast cancer. She was initially treated for pneumonia (PNA) due to cough and fever, though initial chest X-ray (CXR) was normal. A repeat CXR revealed aspiration PNA. She received supplemental oxygen, ceftriaxone and azithromycin. During this time, the medicine team had changed with a sign out of simple PNA, discharge in a day. We noticed there was lack of improvement in 96 hours of typical PNA therapy and had ruled out other conditions causing clinical decline (fungal infection, autoimmune process). We reviewed all the history and data again and noticed a constellation of fever, rash, thrombocytopenia and transaminitis with worsening respiratory failure and leukocytosis, which raised suspicion for Murine Typhus. Rickettsia typhi was positive serologically. Patient was started on doxycycline. Within 48 hours, her symptoms improved and thrombocytopenia resolved.
Discussion: Murine Typhus, also known as Endemic Typhus, is a flea-borne disease caused by the bacteria Rickettsia Typhi. The disease can be transmitted by rat, cat, or mouse fleas. Of note, the patient in this case lived with a pet with known flea infestation. Although the classic clinical triad of murine typhus is fever, headache, and rash, patients can present with non-specific symptoms. California, Texas and Hawaii comprise the majority of U.S. outbreaks1. The disease is often self-limited; however, it can be fatal2. The recommended treatment is doxycycline3 for a duration of at least 48 hours to 10 days.
Conclusions: The present scenario demonstrates a case of Murine Typhus without the classic triad of fever, headaches, and rash presenting as a pneumonia. Murine Typhus is commonly underdiagnosed given its normal quick resolution and self-limiting nature. In this case, worsening symptoms on typical PNA treatment led the medical team to reevaluate all the clinical data leading to a diagnosis of Murine Typhus. In an appropriate geographic setting, Murine Typhus should be considered when rash, thrombocytopenia, or mildly elevated liver function tests accompany an otherwise undifferentiated viral illness. Also important to learn from this case is that complacency has no role in patient care. Most infectious processes will respond to appropriate therapy within 48 hours. If 48 hours have passed and there is no improvement, then it’s time to reassess all clues the patient and tests provided and make the correct diagnosis.