Basilar dolichoectasia

FACTS

  • definition: elongation, dilation, tortuosity of basilar artery > 4.5mm
  • Diagnostic threshold (on MRI/MRA):
    • Basilar artery diameter >4.5 mm
    • Deviation >10 mm from normal course, or
    • Bifurcation above dorsum sellae.
  • Pathophysiology: Degeneration of the internal elastic lamina and medial atrophy → progressive arterial dilation and elongation.
  • Epidemiology: Seen in elderly, often hypertensive men.
  • Clinical relevance: May cause compression of brainstem or cranial nerves, ischemic events, or hemorrhage.

HPI

  • Common presentations:
    • Ischemic stroke or TIA (posterior circulation) due to turbulent or sluggish flow.
    • Cranial nerve compression symptoms:
      • CN VI: diplopia (abducens palsy).
      • CN VII or VIII: facial numbness, hearing loss, tinnitus.
    • Brainstem compression: progressive weakness, dysarthria, dysphagia, or gait disturbance.
    • Headache or trigeminal neuralgia (due to nerve root compression).
    • Subarachnoid or intraparenchymal hemorrhage (less common but catastrophic).
  • Ask:
    • History of recurrent posterior circulation ischemic events.
    • Cranial neuropathic symptoms (hearing, facial, ocular).
    • Vascular risk factors: long-standing hypertension, smoking.
    • Prior imaging showing vascular dilation or tortuosity.

PHYSICAL EXAM

  • Cranial nerves:
    • CN VI palsy (most common, horizontal diplopia).
    • CN V: sensory loss, neuralgia-like pain.
    • CN VII/VIII: facial weakness or hearing loss or hemifacial spasm
  • Brainstem signs: dysarthria, dysphagia, ataxia, or contralateral motor/sensory deficits.
  • Cerebellar findings: gait instability, dysmetria.
  • Fundoscopy: papilledema if raised ICP (rare, from hydrocephalus due to brainstem compression).
  • General: evaluate BP and cardiovascular risk profile.

IMAGING

Modality
Key Findings
MRI brain with MRA / CTA head
Shows enlarged, tortuous basilar artery often deviating laterally and compressing brainstem or cranial nerves.
MR Angiography criteria:
Basilar artery diameter >4.5 mm; lateral deviation >10 mm; bifurcation above dorsum sellae.
Diffusion MRI
May show infarcts in pons, cerebellum, or occipital lobes.
CT head
May reveal calcified, ectatic basilar artery.
DSA (angiography)
Used for precise vascular anatomy and to rule out aneurysm or dissection (if planning intervention).

A/P

Initial Management (Consult Level)
  • Admit or observe if symptomatic, especially with ischemia or brainstem compression.
  • Control vascular risk factors:
    • Strict BP control.
    • Antiplatelet therapy (aspirin ± clopidogrel) unless contraindicated.
    • Smoking cessation, lipid optimization.
  • Avoid hypotension → risk of brainstem ischemia.
  • Monitor for cranial neuropathy progression or recurrent strokes.
  • If acute stroke: manage per posterior circulation ischemic stroke protocol.
Strategy
Indication / Notes
Medical management
Mainstay for most cases — control hypertension, initiate antiplatelet therapy, monitor progression.
Endovascular intervention (rare)
For focal fusiform aneurysm, severe mass effect, or rapid enlargement; includes flow diversion or stent placement (high risk).
Microsurgical decompression
For refractory cranial nerve compression (e.g., trigeminal neuralgia or hemifacial spasm).
Serial imaging follow-up
MRI/MRA every 6–12 months initially, then yearly to assess progression.