Pediatric emergency medicine trisk 0549 0549
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drug or intoxicant use is important, as is a family history of migraine. Age of the
patient is especially useful—benign paroxysmal vertigo is unusual after age 5
years, whereas Ménière disease is unusual before age 10 years. The physical
examination focuses on the middle ear and on neurologic and vestibular testing.
Visualization of the external ear canal may reveal cerumen impaction, foreign
body, or zoster lesions (Ramsay Hunt syndrome). Perforation or distortion of the
tympanic membrane should be noted. A pneumatic bulb will enable the examiner
to see whether abrupt changes in the middle ear pressure trigger an episode of
vertigo, a suggestion that a perilymphatic fistula may be present (Hennebert sign).
The neurologic examination must be complete, focusing closely on the
auditory, vestibular, and cerebellar systems. Both vestibular and cerebellar
disorders may present with an unsteady gait. If there is a unilateral lesion, the
child will fall toward the side of the lesion. The two may at times be
distinguishable by the nature of the nystagmus (described below). If cerebellar
dysfunction is present, the patient may have dysmetria and ataxia. All cases of
suspected vestibular or cerebellar dysfunction require close follow-up evaluation
because of the risk of a posterior fossa mass.
Nystagmus is a highly specific sign for both central and peripheral vertiginous
disorders. A patient complaining of dizziness with vertigo may not have
nystagmus at the time that he or she is examined. Tests to elicit positional vertigo
and nystagmus can therefore be helpful in identifying and even distinguishing
central and peripheral vestibular dysfunction, particularly if the tests elicit or
increase the patient’s complaint.
Nystagmus should be sought in all positions of gaze and with changes in head
position. The Nylen–Hallpike test can be used to elicit nystagmus if not apparent
on initial examination. It is performed by moving a child rapidly from a sitting to
a supine position with the head 45 degrees below the edge of the examining table
and turned 45 degrees to one side. Nystagmus and a vertiginous sensation may
result as the vestibular system is stressed. Certain features of nystagmus may be
helpful in distinguishing central from peripheral vestibular dysfunction. In central
dysfunction, for example, onset of nystagmus is immediate; in peripheral
vestibular disorders, it is delayed. Central lesions are characterized by nystagmus
with the fast component toward the affected side and reversal of the fast
component when changing from right to left lateral gaze. Peripheral vestibular
disorders are characterized by a “jerk” nystagmus with the slow component
toward the affected side. Finally, visual fixation does not affect nystagmus from
central causes, but tends to dampen peripheral nystagmus.
