USMLE® Step 1 style questions USMLE
A 4-year-old boy is brought to the emergency department by his parents due to fever accompanied by severe headache and myalgias for the past 2 days. Since then, he has felt nauseous and has vomited multiple times. He was born at term through normal vaginal delivery and reached all milestones. Immunizations are up to date, and his parents deny sick contacts but are not sure if any of the other kids in the daycare have been sick. Temperature is 39.0°C (102.2°F), pulse is 110/min, and blood pressure is 90/60 mmHg. On physical examination, the child is lethargic, and the knees flex upon neck flexion. Lumbar puncture is obtained, and the results are shown below:
Cerebrospinal fluid Opening pressure 250 mm H2O Protein 100 mg/dL Glucose 60 mg/dL RBCs none WBC count 400/µL Neutrophils 40% Lymphocytes 60%
Cultures and gram stain results are pending. Which of the following is the most likely diagnosis?