Lateral medullary syndrome
| Lateral medullary syndrome | |
 | |
|---|---|
| The three major arteries of the cerebellum: the SCA, AICA, and PICA. (Posterior inferior cerebellar artery is PICA.) | |
| ICD-10 | G46.3 |
| DiseasesDB | 10449 |
| MeSH | D014854 |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: Wallenberg's syndrome; posterior inferior cerebellar artery syndrome (PICA)
Overview
Lateral medullary syndrome is one of the most common clinical syndromes of brainstem caused by decresased blood supply to lateral medulla. It is also commonly known as Wallenberg's syndrome or posterior inferior cerebellar artery syndrome (PICA). The most common cause is thromboembolic occlusion of vertebral arteries. It was described in 1895.
Historical Perspective
- Gaspard Vieusseux, in 1808, was the first person to describe Wallenberg's syndrome
- This syndrome was later on further elaborated by Adolf Wallenberg, in 1895.
- Thomas William was the first person to document extensive anatomy and physiology of brain stem, the cerebellum, and the ventricles in 17th century. He performed necropsies and extensive dissections on his patients brains.
- Joseph Jules Dejerine (1849–1917) and his wife Dejerine-Klumpke demonstrated extensive visual illustrations of various brain stem and cerebellar lesions.
- Charles Foix (1882–1927) was the firdt person to write an extensive case series on posterior cerebral arteries occlusion related syndromes and lateral medullary syndrome.
- Vertebral Basal Insufficiency (VBI) was first introduced by clinicians at the Mayo Clinic, Bob Siekert and Clark Millikan in 1970s.
Pathophysiology
Lateral medullary syndrome is basically a manifestation of vasoocclusive disease of intracranial vertebral artery (ICVA) such as vertebral artery or posterior inferior cerebellar artery. The various pathophysiologic mechanisms involved can include;
- Atherosclerosis,
- Athero-embolic phenomenon (heart, aorta, or vertebral arteries)
- Dissection and increased vascular tortuosity
- Vascular insufficiency
- Virchow’s triad play an impoprtant role in understanding the pathogenesis of Wallenberg's syndrome
- An abnormality of the intima and vascular wall
- An abnormality of blood flow, and
- An abnormality of blood coagulability
Involvement of various structures in lateral medulla along with respective manifestation or clinical signs include;
- Nucleus ambiguus: dysphagia, dysphonia and dysarthria, laryngeal, pharyngeal and palatal paralysis
- Trigeminal nucleus: ipsilateral facial and corneal anesthesia
- Spinothalamic tract: loss of pain and temperature sensation to the opposite side of body
- Crebellum: ataxia
- Hypothalamic fibers: sympathetic nervous system abnormal c/w Horners syndrome
- Deiters' nucleus and other vestibular nuclei: nystagmus and vertigo
- Central tegmental tract: palatal myoclonus
Causes
- Atherosclerosis (VA>PICA>Medullary arteries)
- Embolism
- Dissection (especially in younger patients)
- Dolichoectasia
- Vasospasm
Risk Factors
- Uncontrolled hypertension
- Smoking
- Diabetes
- Neck manipulation or injury
- Marfan syndrome
- Ehlers Danlos syndrome
- Fibromuscular dysplasia.
Natural History, Complications and Prognosis
- The natural history, complications and prognosis of Lateral medullary syndrome depends upon the size and location of the infarct/hemorrhagic area of medulla.
- Some people may experience gradual improvement in their symptoms with complete resolution of the symptoms within week to months while other may worsen or show no improvement despite the treatment.
Diagnosis
History and Physical Examination
- Rostral lesions present as marked dysphagia and dysphonia (nucleus ambiguus)
- Caudal lesion present as vertigo, ataxia, nausea/vomiting, and Horner syndrome
Ipsilateral (same side of lesion):
- Ageusia or loss of taste on one side of the tongue
- Ataxia or incoordination
- Diplopia or double vision
- Oscillopsia
- Dizziness
- Dysphagia or difficulties with swallowing
- Dysphonia or hoarseness
- Dysarthria or slurred speech
- Ipsilateral sensory deficits (pain and temperature sensation) affecting the face and cranial nerves
- absence of pain on the ipsilateral side of the face, as well as an absent corneal reflex (Damage to the spinal trigeminal nucleus)
- Ataxia
- Horner's syndrome
- Ipsilateral vocal fold paralysis
- Palatal and pharyngeal paresis
- Palatal myoclonus
- Hiccups
- Hoarseness
- Nystagmus
- Vertigo
Contralateral (opposite side of lesion):
- Contralateral sensory deficits (pain and temperature sensation) affecting the trunk and extremities
- No or minimal hemiparesis
Evaluation:
Localization of the Lesion
| Dysfunction | Effects |
| lateral spinothalamic tract | contralateral deficits in pain and temperature sensation from body |
| spinal trigeminal nucleus | ipsilateral loss of pain and temperature sensation from face |
| nucleus ambiguus (which affects vagus X and glossopharyngeal nerves IX) | dysphagia, hoarseness, diminished gag reflex |
| vestibular system | vertigo, diplopia, nystagmus, vomiting |
| descending sympathetic fibers | ipsilateral Horner's syndrome |
| central tegmental tract | palatal myoclonus |
Treatment
- Treatment of Lateral medullary syndrome is symptomatic.
- Feeding tube or PEG tube may be considered for patients with severe dysphagia
- Patients with speech difficulties may benefit from speech therapy
- Acute and chronic pain management
References
External links
Template:Diseases of the nervous system Template:Lesions of spinal cord and brainstem