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Difficulty: HardPhysical Examination Findings

A 68-year-old man with a history of hypertension, type 2 diabetes mellitus, and hyperlipidemia presents to the emergency department with a 4-hour history of severe, continuous vertigo, nausea, and an unsteady gait. The symptoms began abruptly while he was sitting and reading. He reports that any head movement severely exacerbates the nausea. He denies tinnitus, hearing loss, headache, or other focal neurologic symptoms. Vital signs are within normal limits. On physical examination, the patient appears distressed, prefers to keep his eyes closed, and has spontaneous nystagmus present in the primary position. The physician performs a targeted physical examination to differentiate between a central etiology (e.g., posterior circulation stroke) and a peripheral etiology (e.g., vestibular neuritis) for his acute vestibular syndrome.

Which of the following physical examination findings most strongly suggests a central etiology requiring urgent neuroimaging?

  1. A
    An abnormal (positive) head impulse test with a rapid corrective saccade
  2. B
    Unidirectional, horizontal-torsional nystagmus that decreases with visual fixation
  3. A normal (negative) head impulse test bilaterallyAnswer
  4. D
    Delayed-onset, fatigable nystagmus elicited by the Dix-Hallpike maneuver
  5. E
    Complete absence of vertical skew deviation during the alternate cover test

Answer

A normal (negative) head impulse test bilaterally
In the evaluation of Acute Vestibular Syndrome (AVS), the HINTS exam (Head Impulse, Nystagmus, Test of Skew) is used to differentiate peripheral from central causes. A normal (negative) head impulse test paradoxically points to a central etiology, such as a cerebellar or brainstem stroke. This is because the vestibulo-ocular reflex (VOR) arc, which relies on the peripheral vestibular apparatus, remains intact. Therefore, if a patient has severe continuous vertigo but an intact VOR, the source of the vertigo must be central. The HINTS exam is more sensitive than early MRI for detecting posterior circulation strokes in AVS.

Step-by-Step Solution

1
Identify the clinical syndrome
The patient has Acute Vestibular Syndrome (AVS), characterized by rapid onset of severe, continuous vertigo, nausea, and spontaneous nystagmus.
Categorizing the vertigo as episodic versus continuous dictates the appropriate physical examination maneuvers.
2
Select the appropriate diagnostic physical exam maneuver
The HINTS exam (Head Impulse, Nystagmus, Test of Skew) is the appropriate targeted physical examination for AVS.
The HINTS exam accurately differentiates central (e.g., stroke) from peripheral (e.g., vestibular neuritis) causes of continuous vertigo.
3
Interpret the specific components of the HINTS exam
A central lesion is indicated by any of the following: a normal head impulse test, direction-changing nystagmus, or presence of vertical skew deviation.
A normal head impulse test in a patient with AVS means the peripheral vestibulo-ocular reflex is intact, localizing the severe vertigo to a central brainstem or cerebellar lesion.

Key Concept

In Acute Vestibular Syndrome, a normal head impulse test strongly suggests a central etiology (such as a posterior circulation stroke) because it demonstrates an intact peripheral vestibulo-ocular reflex despite severe continuous vertigo.
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Topics

Physical Examination Findings

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