A 52-year-old man arrives at your clinic in central Florida complaining of 3 days of fever, headache, and myalgia. On examination, he has a petechial rash on his palms and soles. When asked about recent travel, he reports a camping trip in Tennessee 2 weeks ago. Which of the following laboratory test results would be most likely for this patient?
a. Hypernatremia, normal platelet levels, elevated creatinine
b. Hyponatremia, thrombocytosis, normal liver function tests
c. Hypernatremia, thrombocytosis, elevated liver function tests
d. Hyponatremia, thrombocytopenia, elevated liver function tests
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Answer: D. Given the patient’s symptoms and his recent camping trip in a region where Rocky Mountain spotted fever is endemic, there is high clinical suspicion for the disease. The petechial rash is a sign of progression to more severe disease in Rocky Mountain spotted fever, typically appearing on day 5 or 6 of the illness. Laboratory findings at this stage of the disease would typically include hyponatremia, thrombocytopenia, and elevated liver function tests.