Pediatric emergency medicine trisk 0550 0550
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FIGURE 24.1 Approach to the child with true vertigo. CT, computed tomography; TM,
tympanic membrane; CNS, central nervous system.
The cold caloric response tests for integrity of the peripheral vestibular system.
Slow and careful irrigation of either 100 mL of tap water 7°C below body
temperature or 10 mL of ice water into the external ear canal through a soft
plastic tube, with the child lying about 60 degrees recumbent, should induce a
slow movement of the eyes toward the stimulus and a fast movement away.
Instillation of warm water (44°C) will cause an inverse reaction. Vestibular
damage will suppress the response on the affected side. Absence of nystagmus
indicates absence of peripheral vestibular function. The test is contraindicated if
the tympanic membrane is perforated.
Ancillary Tests
Laboratory investigations have a limited role in the evaluation of vertigo. Useful
initial tests include complete blood count, serum glucose, and an
electrocardiogram. Together, these may help identify patients with
pseudovertiginous conditions caused by anemia, hypoglycemia, and rhythm
abnormalities. Further laboratory testing may reveal diabetes or renal failure, both
of which have been associated with vertigo. Toxicologic testing including specific
anticonvulsant levels and an ethanol level, if indicated, may be helpful. A lumbar
