It is widely understood that a "heart attack" (myocardial infarction) is due to the heart's muscle tissue being irreversibly damaged through loss of its blood supply, i.e., its supply of oxygen and other nutrients is cut off. This loss of supply is typically due to severe fatty-blockage (atherosclerosis) within one or more main arteries feeding a region of the heart, and may result in impairment of the heart's ability to pump blood. This can be fatal.

A "brain attack" is the brain's version of a heart attack, and it occurs when the blood supply to a region of the brain is lost ("stroke" or cerebral infarction). Symptoms of a brain attack may be short-lived (< 24 hrs in duration as occuring in a transient ischemic attack or TIA), or may be part of a full (completed) stroke. They are typically sudden in onset. Symptoms may include one or more of the following: visual impairment like a darkish curtain coming across the eye (amaurosis fugax), or partial or complete blindness involving one or both eyes (e.g., central retinal artery thromboembolism, or retinal venous ischemia, or occipital lobe stroke), impairment of clarity of speech (dysarthria) or language function (dysphasia or aphasia), impairment of limb muscle strength (paresis or paralysis, hemiparesis, etc.) or sensory disturbance (e.g., hemianesthesia). Other symptoms include a sudden spinning sensation (vertigo), gait imbalance, loss of consciousness, incoordination, double vision, etc., depending on the region of brain involved.

As in the case of the heart, the most frequent cause of loss of blood supply to brain tissue is atherosclerosis (sometimes it also occurs with carotid dissection or occlusion; take me to the Section on Carotid Artery Disease). However, blood supply may be lost due to another important reason: a ruptured blood vessel. Consider an aneurysm ( take me straight to Brain Aneurysms). When a brain aneurysm ruptures (or reruptures), the blood flowing in the parent artery from which the aneurysm arose is suddenly no longer flowing to the nerves and other cells that make up normal brain tissue; in effect, this blood now gushes out into the subarachnoid space (the space surrounding brain tissue that is normally filled with circulating clear cerebrospinal fluid). The region of brain which was once supplied by that parent artery whose aneurysm has now burst becomes ischemic (i.e, dysfunctional owing to impairment of its blood supply), and may thereafter become infarcted (i.e., the tissue dies owing to irreversible damage to the nerves whose blood supply was impaired). It should be noted that loss of brain blood supply due to cerebral vasospasm following aneurysmal rupture (subarachnoid hemorrhage) is another way via which an aneurysm may cause a stroke, albeit a delayed stroke in the case of vasospasm whose onset typically occurs 3 - 8 days after the original bleed ( take me straight to Cerebral Vasospasm).

Just as a heart attack has a "signature" [e.g., severe and prolonged crushing chest pain associated with one or more of the following: pain that radiates to the jaw or along an arm; profuse sweating; shortness of breath; feeling of abnormal heart rhythm ("palpitations"); or even physical collapse], a brain attack due to an aneurysm also has a "signature". In this regard, below is a checklist of symptoms and signs that may alert a person to the presence of an aneurysm or a bleed from an aneurysm that can cause a brain attack. Note that the list below does not include every symptom or sign known to be associated with aneurysms; instead, it includes the more common of the symptoms and signs that have been described in the literature. Also, some of the symptoms below can occur in conditions not related to aneurysmal disease, e.g., migraine, epilepsy, brain tumor, meningitis, symptomatic carotid or brain artery occlusive-inflammatory diseases (associated with nonaneurysmal "transient ischemic attack" (TIA) or completed stroke; see above).

Any specific concerns should be discussed with your physician. In the event of an emergency, seek medical help immediately. To call an ambulance, dial 9-1-1 in the USA. In Australia, dial 000.

Aneurysm Alert Checklist

Unruptured Aneurysm New or unusual headaches (including regular morning headaches) Unexplained nausea and vomiting Headache with neck stiffness Neurological impairment [e.g., new double vision, episodic loss of vision, vertigo (dizziness), limb weakness, gait imbalance] New-onset seizure disorder