Lateral medullary syndrome
Lateral medullary syndrome (also called Wallenberg syndrome and posterior inferior cerebellar artery syndrome) is a disorder in which the patient has a constellation of neurologic symptoms due to injury to the lateral part of the medulla, resulting in tissue ischemia and necrosis.
Classically attributed to PICA occlusion, but in 80–85 % of cases the vertebral artery is also involved 1). No cases have been reported arising from brainstem hemorrhage.
Findings
This syndrome is characterized by sensory deficits affecting the trunk (torso) and extremities on the opposite side of the infarction and sensory deficits affecting the face and cranial nerves on the same side with the infarct. Specifically, there is a loss of pain and Thermoception on the contralateral (opposite) side of the body and ipsilateral (same) side of the face. This crossed finding is diagnostic for the syndrome.
Clinical symptoms include swallowing difficulty, or dysphagia, slurred speech, ataxia, facial pain, vertigo, nystagmus, Horner's syndrome, diplopia, and possibly palatal myoclonus.
Affected persons have difficulty in swallowing (dysphagia) resulting from involvement of the nucleus ambiguus, as well as slurred speech (dysarthria) and disordered vocal quality (dysphonia) . Damage to the spinal trigeminal nucleus causes absence of pain on the ipsilateral side of the face, as well as an absent corneal reflex.
The spinothalamic tract is damaged, resulting in loss of pain and temperature sensation on the opposite side of the body. The damage to the cerebellum or the inferior cerebellar peduncle can cause ataxia. Damage to the hypothalamospinal fibers disrupts sympathetic nervous system relay and gives symptoms analogous to Horner syndrome.
Nystagmus and vertigo may result in falling, caused from involvement of the region of Deiters' nucleus and other vestibular nuclei. Onset is usually acute with severe vertigo.
Palatal myoclonus may be observed due to disruption of the central tegmental tract.
Case report
A 53-year-old female patient presenting with impaired Thermoception on the left half of her body, from the neck down, following a small infarction of the right midlateral medulla. The chronological changes in the patient's introspection regarding impairment of thermoception and the results of detailed somatosensory tests, including thermal sense, are shown in this report.
Thorough somatosensory tests, personal descriptions of symptoms, and electrophysiological quantification of similar cases are needed to improve our understanding of the neurological separation of the sensations of pain and temperature at the medullary level 2).
A case of a 64-year-old female with acute-onset vertigo, nausea, and vomiting. In an emergency imaging examination, the results of computed tomography (CT) and diffusion weighted imaging (DWI) were negative. However, on 1 day post-hospital admission, a small acute infarct in the posterolateral aspect of the left medulla was detected by DWI. Extra attention should be payed to the false-negative imaging results to avoid diagnosis and treatment delay 3).