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Difficulty: HardPhysical Examination Findings

Paramedics transport a 58-year-old hypertensive male to the trauma bay after he experienced acute-onset rotational vertigo and collapsed while shoveling snow. He is awake but speaks with a raspy, dysphonic voice and frequently coughs when attempting to swallow his saliva. Vital signs show a blood pressure of 185/105 mmHg, heart rate of 92/min, and respiratory rate of 18/min. Initial cranial nerve assessment reveals right-sided enophthalmos, a drooping right upper eyelid, and a constricted right pupil. His palate elevates asymmetrically, with the uvula pulled toward the left. Which of the following sensory examination deficits is most likely to accompany this patient's clinical presentation?

  1. A
    Impaired pinprick and temperature perception on the left hemiface and the right hemibody
  2. B
    Loss of two-point discrimination and vibratory sense over the left hemibody
  3. Impaired pinprick and temperature perception on the right hemiface and the left hemibodyAnswer
  4. D
    Global anesthesia affecting the right side of the face and the entire right hemibody
  5. E
    Dissociated sensory loss extending bilaterally across the shoulders and upper extremities

Answer

Impaired pinprick and temperature perception on the right hemiface and the left hemibody
The correct answer describes impaired pinprick and temperature perception on the right hemiface and the left hemibody. The clinical presentation is characteristic of a right lateral medullary (Wallenberg) syndrome, typically due to occlusion of the right posterior inferior cerebellar artery (PICA) or vertebral artery. The right-sided Horner syndrome and the deviation of the uvula to the left (indicating right nucleus ambiguus dysfunction) localize the lesion to the right lateral medulla. In this syndrome, infarction of the right spinal trigeminal nucleus causes loss of pain and temperature sensation on the ipsilateral (right) side of the face. Concurrently, damage to the adjacent right lateral spinothalamic tract causes loss of pain and temperature sensation on the contralateral (left) side of the body.

Step-by-Step Solution

1
Analyze the cranial nerve deficits to localize the side of the lesion.
Right-sided Horner syndrome (ptosis, miosis, enophthalmos) and uvular deviation to the left (indicating right CN X paralysis) localize the lesion to the right side of the brainstem.
Cranial nerve deficits in brainstem stroke syndromes typically occur ipsilateral to the lesion.
2
Identify the specific brainstem syndrome based on the constellation of clinical findings.
The combination of vertigo, dysphagia, hoarseness, and Horner syndrome is characteristic of a lateral medullary (Wallenberg) syndrome.
These findings map to the vestibular nuclei, nucleus ambiguus, and descending sympathetic tract located in the lateral medulla.
3
Determine the expected sensory deficits associated with a right lateral medullary lesion.
Damage to the right spinal trigeminal nucleus causes ipsilateral (right) facial pain/temperature loss, while damage to the right lateral spinothalamic tract causes contralateral (left) body pain/temperature loss.
The spinothalamic tract has already crossed in the spinal cord, while the spinal trigeminal tract represents ipsilateral facial sensation.

Key Concept

Localization of lateral medullary (Wallenberg) syndrome through integration of cranial nerve and sensory physical examination findings
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Topics

Physical Examination Findings

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