Congenital Circle of Willis Aneurysms: Symptoms, Diagnosis, Treatment, and Risk Factors

A congenital aneurysm of the circle of Willis is a focal dilation of one of the arteries forming this critical cerebral arterial ring at the skull base.

Clinical Presentation

• Often asymptomatic, discovered incidentally on imaging.
• Symptomatic: Headaches (sentinel or chronic), cranial nerve palsies (III, IV, VI), seizures, TIA/stroke from thromboembolism.
• Rupture → subarachnoid hemorrhage (SAH): thunderclap headache, meningismus, photophobia, decreased consciousness. Mortality ~40–50%.

Diagnosis

• MRA (Magnetic Resonance Angiography): Non-invasive, good for screening.
• CTA (Computed Tomography Angiography): Higher spatial resolution; preferred for pre-surgical planning.
• DSA (Digital Subtraction Angiography): Gold standard; used for endovascular treatment.

Treatment Options

• Observation: Small (<7 mm), asymptomatic, anterior circulation — serial imaging.
• Endovascular Coiling: Platinum coils induce thrombosis; less invasive.
• Surgical Clipping: Craniotomy; durable for wide-neck, complex aneurysms.
• Flow Diversion: Stent-like device (Pipeline) for large/giant aneurysms.

Risk Factors

• Family history (1st-degree relative → 3–5x risk)
• Connective tissue disorders (Ehlers-Danlos IV, Marfan, Loeys-Dietz, ADPKD)
• Hypertension, smoking, atherosclerosis