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The classic presentation of a headache caused by a CNS aneurysm is a new, unilateral and throbbing headache in a middle-aged patient.


  1. CNS aneurysm may present in 3 ways.

    1. Asymptomatic detection: This commonly occurs when a patient has a ruptured aneurysm and another, nonruptured aneurysm is found during the evaluation.

    2. Acute rupture or expansion (discussed later in this chapter)

    3. Chronic headache

  2. There are few studies of the chronic headaches caused by unruptured aneurysms.


  1. The headaches of unruptured aneurysms are nonspecific.

    1. One study looked retrospectively at the symptoms of 111 patients referred for therapy of unruptured aneurysms.

      1. 54 of the patients had symptoms referable to the aneurysm at the time of diagnosis.

      2. Of the 54 patients with symptoms, 35 (65%) had chronic symptoms.

      3. In 18 of these 35 patients, the chronic symptom was headache without other neurologic signs.

      4. Patient’s headaches were divided equally between unilateral and bilateral.

    2. A more recent study looked retrospectively at the symptoms of 5720 patients referred for therapy of unruptured aneurysms.

      1. 47% of these patients had headaches or dizziness prompting the imaging studies.

      2. Female sex and larger aneurysms were associated with higher risk of rupture.

  2. Neuroimaging

    1. CT angiography and magnetic resonance angiography are very sensitive means of detecting CNS aneurysms.

      1. CT and MRI are both very sensitivity for aneurysms > 1 cm in diameter (99–100%).

      2. When considering all aneurysms, CT is slightly more sensitive than MRI (90% vs 87% for MRI); MRI is more specific (95% vs 86%).

      3. CT and MRI are not sensitive for detecting aneurysms < 3 mm (CT, 61%; MRI, 38%).

    2. Traditional angiography

      1. Considered the gold standard for diagnosis

      2. Usually required prior to repair


  1. The treatment of CNS aneurysms can be accomplished with neurosurgical or endovascular procedures.

  2. Repair of aneurysms < 1 cm in a patient who has not had a previous rupture is generally not recommended since the rupture rates are so low.

  3. Management decisions are difficult in a patient with a small aneurysm and a suspicious headache because there is no definitive way to know whether the aneurysm is causing the headache prior to surgery.

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