A 7-year-old boy is brought to the clinic due to 4 days of worsening left ear pain. The patient was healthy until last week, when he developed a low-grade fever and congestion, which resolved prior to the sudden development of left ear pain. Vital signs are normal. On examination, the patient appears uncomfortable but nontoxic. The left external ear is nontender with manipulation and has no visible deformities. Several mobile, 1-cm, anterior cervical lymph nodes are palpated on the left side of the neck. The left tympanic membrane is erythematous and bulging; there are no visible perforations. Right ear examination is unremarkable. Which of the following structures is most likely to become involved with progression of this patient's infection?
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This patient with ear pain and an erythematous, bulging tympanic membrane has acute otitis media (AOM), an infection of the middle ear space. AOM is common in children due to poor drainage through narrow, horizontally positioned eustachian tubes. Most cases are uncomplicated; however, patients are at risk for spread of infection to nearby structures.
One such structure is the facial nerve (CN VII), which emerges from the internal auditory meatus and travels through the middle ear into the mastoid air cells. Inflammation of the nerve in the middle ear space during an episode of AOM can result in unilateral facial paralysis. Common signs include inability to raise the eyebrow or close the eye, drooping of the corner of the mouth, and disappearance of the nasolabial fold.
Other structures in close proximity to the middle ear space include mastoid air cells; direct extension of infection can cause purulent fluid to fill the air cells, leading to mastoiditis. CNS complications (eg, meningitis, brain abscess) are rare sequelae of intracranial spread.
(Choices A and F) The ethmoid and sphenoid sinuses open into the superior nasal cavity and can become inflamed and filled with purulent material due to nasal congestion (eg, upper respiratory infection). However, these sinuses are not in direct contact with the middle ear space and are unlikely to be affected by AOM.
(Choice B) The external jugular vein drains blood from the scalp and face. Complications (eg, thrombophlebitis) are rare; jugular thrombosis most often affects the internal jugular vein (Lemierre syndrome).
(Choice C) The facial artery originates from the external carotid artery at the angle of the mandible and passes upward across the cheek, mouth, and side of the nose. In contrast, the blood supply to the ear is derived primarily from the posterior auricular artery.
(Choice E) The glossopharyngeal nerve (CN IX) travels down the neck with the internal carotid artery before entering the pharynx. The nerve provides innervation to the stylopharyngeus muscle and sensation to the posterior third of the tongue. Pathology of the middle ear is unlikely to affect this deep structure.
Educational objective:
Acute otitis media presents with an erythematous, bulging tympanic membrane and can be complicated by inflammation or infection of nearby structures. Spread of infection to the facial nerve (CN VII), which travels through the middle ear, can result in facial neuritis with unilateral facial paralysis.