Understanding Cerebral Aneurysms

Signs and Symptoms
A large number of cerebral aneurysms will never produce symptoms and are found incidentally while evaluating a patient for another medical issue. When a brain aneurysm produces symptoms, the patient may develop neurological signs (e.g. visual disturbances or facial paralysis) from the compression of the brain due to a change in the size or shape of aneurysm, or the patient may develop symptoms from the rupture of the aneurysm that can include a sudden, severe headache, acute nausea and vomiting, stiff neck, seizures, alteration in level of consciousness or paralysis. 

The classical description of the headache associated with the rupture of a cerebral aneurysm is “the worst headache of your life." The headaches usually occur suddenly and violently. Since headaches are common in the population, it is important to be able to identify a headache that may require medical attention. The key is the headache associated with an aneurismal rupture is typically uncharacteristic of prior headaches experienced throughout one’s lifetime. A change in the nature of a headache, particularly if it occurs suddenly in association with neurological symptoms, deserves a prompt medical evaluation.

Clinical Outcome
The rupture of a cerebral aneurysm and development of subarachnoid hemorrhage (SAH) is a neurological emergency. Studies have demonstrated approximately 40% of individuals with ruptured brain aneurysms do not survive the first 24 hours. In addition, up to 25% die from complications within 6 months while others are left with permanent neurological disability. Notably, ruptured cerebral aneurysms are most likely to re-bleed within the first day (2-4%), underscoring the need for urgent evaluation and treatment. The risk of re-bleeding remains high for the first 2 weeks with estimates of approximately 25%, if the ruptured aneurysm is left untreated. Many factors influence the clinical outcome, including age, pre-morbid medical history, degree of brain injury and delay in medical attention. The rupture of the cerebral aneurysm initiates a series of events resulting in the brain injury and neurological deficits.