What artery is most commonly associated with medial medullary syndrome?

Medial Medullary Syndrome: Associated Artery

The vertebral artery, particularly at its terminal portion, is most commonly associated with medial medullary syndrome. 1

Pathophysiology and Vascular Supply

Medial medullary syndrome (MMS), also known as Dejerine syndrome, results from infarction in the medial territory of the medulla oblongata. The vascular anatomy involved includes:

1. Primary Culprit: Vertebral Artery

   • Terminal portion occlusion of the vertebral artery is the predominant vascular pathology 1
   • In a study of 11 patients with medial medullary infarction, vertebral artery occlusion at its terminal portion was found in 7 patients (64%) 1

2. Secondary Arterial Involvement

   • Anterior spinal artery (branch of the vertebral artery) 2
   • Penetrating branches from the vertebral artery that supply the anteromedial medulla 3

Anatomical Considerations

The medulla oblongata receives its blood supply from:

• Anterior spinal artery
• Branches of the vertebral arteries
• Posterior inferior cerebellar arteries 4

The medial medulla contains important structures including:

• Pyramids (corticospinal tract)
• Medial lemniscus
• Hypoglossal nerve nucleus and fibers

Clinical Presentation

Patients with medial medullary syndrome typically present with:

• Contralateral hemiparesis (due to pyramidal involvement)
• Contralateral loss of position and vibration sense (medial lemniscus)
• Ipsilateral tongue weakness/deviation (hypoglossal nerve) 5

Additional symptoms may include:

• Vertigo and nausea
• Ipsilateral limb ataxia
• Contralateral truncal lateropulsion
• Nystagmus
• Dysarthria 5

Risk Factors

The most common risk factors for medial medullary syndrome include:

• Atherosclerosis of the vertebral arteries
• Hypertension
• Male gender
• Smoking 1

Diagnostic Imaging

MRI with MRA is the preferred imaging modality for diagnosis:

• Contrast-enhanced CTA, MRA, and catheter-based contrast angiography are useful for diagnosis of cervical artery pathology 4
• Imaging should focus on the posterior fossa, posterior skull base, and neck 4

Etiological Considerations

1. Most common cause: Large artery atherosclerosis

   • Particularly of the vertebral artery 3

2. Other causes:

   • Small vessel disease (more common in medial MIs) 3
   • Arterial dissection 1
   • Cardioembolism 5
   • Rarely, inflammatory arteritis (e.g., Takayasu arteritis) 2

Management Considerations

1. Acute management:

   • Standard acute stroke management protocols
   • Antithrombotic therapy with either anticoagulant or antiplatelet medication 4

2. Secondary prevention:

   • For atherosclerotic disease: Antiplatelet therapy, statins, and risk factor modification
   • For dissection: Antithrombotic treatment for at least 3-6 months 4

Prognosis

The outcome for patients with medial medullary syndrome is variable:

• Unilateral medial medullary infarctions often have favorable outcomes 1
• Bilateral involvement carries a worse prognosis 6
• Lesions involving the anteromedial territories are associated with early progression and poorer functional outcomes 3

Clinical Pearls

• Despite being a classic component of the syndrome, ipsilateral tongue weakness is not always present (only in about 27-43% of cases) 1, 5
• Medial medullary syndrome represents less than 1% of all posterior circulation strokes 5
• The clinical presentation can be more heterogeneous than classically described 5