A 5-year-old boy presents to the clinic for evaluation of symptoms of left ear pain and associated fever. On physical examination, the left eardrum is inflamed with a small perforation in it and pus is seen in the external canal. A swab of the fluid grows S pneumoniae. Which of the following is the most likely mechanism for S pneumoniae to cause otitis media?: (A) hematogenous spread, (B) direct extension from the nasopharynx, (C) direct inoculation on the ear, (D) spread through lymphatic tissue
Answer is B. Infections of the middle ear, trachea, sinuses, bronchi, and lungs are caused by direct spread from nasopharyngeal colonization. Disease of the CNS, heart valves, bones, joints, and peritoneal are usually caused by hematogenous dissemination.