National Physical Therapy Examination (NPTE) Practice Exam

Which symptom is most associated with a brainstem infarction resulting in left lateral medullary syndrome?

1. Hemiparesis in the left side of the body

2. Hemiparesis in the right side of the body

3. Loss of discriminative touch and proprioception in the left side of the body

4. Loss of pain and temperature sensation in the right side of the body

The correct answer is: Loss of pain and temperature sensation in the right side of the body

The most associated symptom with a brainstem infarction leading to left lateral medullary syndrome is the loss of pain and temperature sensation on the right side of the body. This condition is a result of the disruption of the pathways involved in sensory processing. The left lateral medullary syndrome, also known as Wallenberg syndrome, occurs due to occlusion of the posterior inferior cerebellar artery, which affects the lateral medulla oblongata. In this area, the spinothalamic tract carries pain and temperature sensations from the contralateral side of the body; thus, an infarction on the left side leads to the loss of these sensations on the right side of the body. This is a classic presentation characteristic of this syndrome, differentiating it from other types of neurological deficits. Other symptoms commonly associated with this syndrome might include dysphagia, vertigo, and ataxia, but the distinctive loss of pain and temperature sensation on the opposite side of the body is a key identifier in clinical presentations of left lateral medullary syndrome.