A 17-year-old previously healthy boy presents with scleral icterus for 1 day. For approximately 10 days previously, he has had fever, arthralgias, and headache. He additionally complains of eye pain with movement, stiff neck, excessive thirst (drinking 64 oz of water a day), back pain, and nausea.
He denies rash, sore throat, cough, and congestion. He has not traveled anywhere. He has been taking approximately 8 g of acetaminophen daily for the past 2 weeks for joint pain.
On physical examination the patient's vital signs are normal except for fever (to 101.7°F [38.7°C]). He has scleral icterus, no periorbital swelling or edema, no meningismus, no hepatomegaly or splenomegaly, no swelling of the joints, and insect bites on his ankles but no rash.
Laboratory evaluation reveals the following values: sodium, 126 mEq/L (126 mmol/L); white blood cell count, 14,600/μL (14.6 × 109/L), with 75.5% neutrophils and 22% lymphocytes; hemoglobin,...