Clinical Reasoning: A 39-Year-Old Returning Traveler With Acute Encephalopathy and Strokes

On his sixth day of a Hawaiian cruise, a previously healthy 39-year-old man developed flu-like symptoms progressing over 10 days to include eye redness, rash, headache, and confusion.He returned to California on day 11 from illness onset and presented to a community-based emergency department where physical examination showed lethargy, mild disorientation, conjunctival erythema, and a nonblanching maculopapular rash involving his chest and dorsal hands.IV hydration and analgesia led to mild improvement, lowering initial concern for bacterial or herpetic meningoencephalitis, and he was admitted for observation.Headache and confusion worsened on day 14, however, and ceftriaxone, vancomycin, ampicillin, doxycycline, and acyclovir were initiated.CT of the brain was unremarkable, and lumbar puncture (LP) on day 15 demonstrated 83 leukocytes/uL (99% monocytes, 1% neutrophils), protein of 97 mg/dL, and glucose of 96 mg/dL (serum glucose 146 mg/dL).MRI of the brain showed multiple acute infarcts within bilateral cerebral cortices and subcortical white matter (Figure ,A). Questions for Consideration:1. What are possible mechanisms for the infarct pattern shown in Figure ,A? 2. What is the differential diagnosis for meningoencephalitis with cerebral infarcts?