Question of the Week
For October 13, 2020
A 40-year-old man is hospitalized for fever, headache, rash, and vomiting. He was well until 8 days ago, when he developed fever, chills, diaphoresis, a throbbing frontal headache, sore throat, diffuse myalgias and arthralgias, and a maculopapular rash on his torso, arms, and legs. He has not traveled recently. He smokes cigarettes, rarely drinks alcohol, and does not use recreational drugs. He is not taking any medications.
He has a temperature of 39.2°C, a respiratory rate of 21 breaths per minute, and an oxygen saturation of 98% while he is breathing ambient air. He has bilateral posterior cervical lymphadenopathy; the oropharynx is erythematous, without exudate or tonsillar enlargement. Neck flexion causes discomfort. An erythematous, blanching rash covers his chest and upper back. The rest of his physical examination is normal.
Laboratory evaluation reveals normal findings for complete blood count, serum electrolytes, total protein, and liver and kidney function tests. Blood and urine cultures show no growth, and serologic tests for syphilis are negative. A radiograph of the chest is normal.
A lumbar puncture reveals clear cerebrospinal fluid with a normal glucose level, a negative finding for herpes simplex virus DNA, a protein level of 132 mg/dL, and a leukocyte count of 23 per mm3 with 72% lymphocytes.
Which one of the following diagnoses is most likely in this case?