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Difficulty: Very hardPhysical Examination Findings

A 68-year-old man with a history of poorly controlled type 2 diabetes and hypertension is brought to the emergency department due to the sudden onset of severe, continuous room-spinning dizziness, intractable nausea, and difficulty walking that started 3 hours ago. He denies hearing loss, tinnitus, or headache. Blood pressure is 168/94 mmHg. On bedside evaluation, he exhibits spontaneous horizontal nystagmus that beats to the right on rightward gaze and to the left on leftward gaze. When the physician asks the patient to fixate on the physician's nose and rapidly rotates the patient's head to the right and left, the patient's eyes remain locked on the target without any refixation saccades. When an opaque card is alternately placed over each eye, there is a visible vertical refixation movement of the uncovered eye. Which of the following statements provides the most accurate interpretation of this patient's physical examination findings?

  1. The absence of corrective refixation saccades during rapid head rotation indicates an intact vestibulo-ocular reflex, localizing the pathology to the central nervous system.Answer
  2. B
    The direction-changing gaze-evoked nystagmus is a hallmark finding of an acute peripheral vestibulopathy, such as vestibular neuritis.
  3. C
    The ability to maintain visual fixation during rapid head rotation represents an abnormal vestibulo-ocular reflex, confirming a peripheral vestibular lesion.
  4. D
    The vertical refixation movement observed on alternate cover testing represents a benign otolithic dysfunction commonly seen in acute labyrinthitis.
  5. E
    The constellation of these findings demonstrates acute unilateral peripheral vestibular hypofunction, mandating immediate vestibular rehabilitation.

Answer

The physical examination findings indicate an intact vestibulo-ocular reflex (normal head impulse test), direction-changing nystagmus, and skew deviation. In a patient with continuous acute vertigo, an intact vestibulo-ocular reflex strongly localizes the pathology to the central nervous system, meaning the correct statement identifies that the absence of corrective saccades points to a central lesion.
The patient's clinical presentation is consistent with acute vestibular syndrome. The HINTS exam (Head Impulse, Nystagmus, Test of Skew) is utilized to differentiate central (e.g., cerebellar or brainstem stroke) from peripheral (e.g., vestibular neuritis) etiologies. A normal head impulse test (absence of corrective saccades) indicates an intact vestibulo-ocular reflex, meaning the peripheral vestibular apparatus is functioning normally. Paradoxically, this localizes the lesion to the central nervous system. The additional presence of direction-changing nystagmus and skew deviation (vertical refixation on alternate cover testing) further strongly confirms a central etiology.

Step-by-Step Solution

1
Identify the patient's clinical syndrome based on the history.
The patient has an acute onset of continuous vertigo, nausea, and truncal ataxia, defining acute vestibular syndrome (AVS).
Establishing the clinical syndrome is necessary to determine the appropriate diagnostic framework and physical examination maneuvers.
2
Analyze the nystagmus finding.
The patient exhibits direction-changing nystagmus (beats right on rightward gaze, left on leftward gaze).
Direction-changing nystagmus is a highly specific sign of a central nervous system lesion, whereas peripheral nystagmus is unidirectional.
3
Interpret the head impulse test.
The absence of corrective saccades indicates a normal, intact vestibulo-ocular reflex.
In the context of AVS, an intact vestibulo-ocular reflex strongly suggests the vertigo is originating from a central mismatch rather than a broken peripheral vestibular nerve.
4
Evaluate the alternate cover test result.
The presence of vertical refixation indicates a skew deviation.
Skew deviation points to a brainstem lesion disrupting otolithic pathways, further confirming a central etiology.
5
Synthesize the physical examination findings.
All three components of the HINTS exam (normal head impulse, direction-changing nystagmus, skew deviation) point to a central stroke.
Understanding how these physical signs localize the pathology is essential for preventing premature closure on a benign peripheral diagnosis.

Key Concept

The HINTS exam (Head Impulse, Nystagmus, Test of Skew) is a critical bedside physical examination tool used to differentiate central from peripheral causes of acute vestibular syndrome.
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Topics

Physical Examination Findings

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