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Difficulty: HardPhysical Examination Findings

A 68-year-old man with a history of poorly controlled hypertension, hyperlipidemia, and a 40-pack-year smoking history is brought to the emergency department due to the sudden onset of severe, continuous room-spinning vertigo that began 3 hours ago. The vertigo is present at rest and is accompanied by intractable nausea and two episodes of emesis. He feels extremely unsteady and cannot walk independently. Vital signs include a blood pressure of 172/94 mm Hg, pulse of 88/min, and respirations of 16/min. He is alert and fully oriented. There is no facial asymmetry, dysarthria, or extremity weakness. To differentiate an acute posterior circulation stroke from a benign peripheral vestibular etiology (such as vestibular neuritis), the physician performs a targeted physical examination of the patient's eye movements. Which of the following constellations of physical examination findings would most specifically establish a central neurological etiology for this patient's acute vestibular syndrome?

  1. Absence of corrective saccades during rapid, passive head rotations; direction-changing nystagmus upon bilateral eccentric gaze; and vertical ocular misalignment during the alternate cover testAnswer
  2. B
    Presence of a rapid corrective catch-up saccade when the head is swiftly turned to the right; unidirectional, left-beating horizontal nystagmus; and absence of vertical ocular misalignment
  3. C
    Upbeat and torsional nystagmus that appears several seconds after transitioning from a sitting to a supine position with the head turned, which fatigues upon repeated testing
  4. D
    Unidirectional horizontal nystagmus that is completely suppressed when the patient is instructed to visually fixate on the examiner's finger, combined with a positive Romberg sign
  5. E
    Intact finger-to-nose testing, normal heel-to-shin testing, and symmetrically preserved deep tendon reflexes in all four extremities without Babinski signs

Answer

The constellation of an absent corrective saccade on head impulse testing, direction-changing nystagmus, and vertical ocular misalignment (skew deviation) establishes a central etiology.
The correct answer accurately describes the central findings of the HINTS exam, often remembered by the acronym INFARCT (Impulse Normal, Fast-phase Alternating, Refixation on Cover Test). In a patient with continuous vertigo, the absence of a corrective saccade during the rapid head impulse test indicates that the peripheral vestibulo-ocular reflex is intact, meaning the severe vertigo must be generated by a central brainstem or cerebellar lesion. Furthermore, direction-changing gaze-evoked nystagmus and vertical skew deviation are highly specific signs of central posterior circulation pathology.

Step-by-Step Solution

1
Identify the clinical syndrome from the presentation.
The patient has continuous, spontaneous vertigo, nausea, and gait instability without positional triggers, defining Acute Vestibular Syndrome (AVS).
Categorizing the vertigo as AVS dictates the specific physical examination pathway needed to separate benign peripheral causes from life-threatening central causes.
2
Determine the optimal diagnostic physical examination maneuver for AVS.
The HINTS exam (Head Impulse, Nystagmus, Test of Skew) is required.
HINTS is more sensitive than early MRI for diagnosing acute posterior circulation strokes in patients presenting with AVS.
3
Interpret the findings of the HINTS exam to identify central vs. peripheral pathology.
Central pathology is defined by the INFARCT mnemonic: Impulse Normal (no corrective saccade), Fast-phase Alternating (direction-changing nystagmus), or Refixation on Cover Test (vertical skew deviation).
A 'normal' head impulse test in a patient with continuous vertigo means the peripheral vestibulo-ocular reflex is intact, meaning the source of vertigo must be central.

Key Concept

The HINTS examination (Head Impulse, Nystagmus, Test of Skew) differentiates central from peripheral causes of Acute Vestibular Syndrome.
Estimated Time:1m 30s
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Physical Examination Findings

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