Subarachnoid Hemorrhage: When a Brain Aneurysm Bleeds

Spontaneous subarachnoid (pronouncedotherwise healthy arteries passing through this space
sub-uh-RACK-noid) hemorrhage is rightfully the mostto go into spasm. The spasm decreases blood-flow to
feared cause of sudden headache. Usually due tothe parts of the brain ordinarily nourished by these
rupture of aneurysms (abnormal, balloon-likearteries and thereby inflicts additional damage. Or, said
outpouchings of arteries) located near the base of theanother way, a blocked artery causes a new stroke,
brain, subarachnoid hemorrhages involve bleeding intothis time of the non-bleeding type. For reasons that are
the space between the brain and its surroundingnot entirely understood, these spasms of the arteries
membrane, known as the meninges. A traumatic blowdo not occur within the first few days after the initial
to the head can also cause subarachnoid hemorrhage,hemorrhage. Instead, they typically develop after a
but this is a completely unrelated process and is notdelay of 4-9 days.What can be done to reduce these
the subject of this essay.About 10% of people withcomplications? In the case of blood-vessel spasm, the
spontaneous subarachnoid hemorrhages die beforebest treatment is a preventive one. Administering a
they even get to a hospital and over a third die withindrug called nimodipine (prononounced
the first four weeks following the bleed. Survivors cannye-MO-dih-peen) intravenously makes spasming less
have significant impairments due to brain damage.Andlikely to occur. But in order to prevent the other major
while the effects of the initial bleed are bad enough, incomplication, re-bleeding, the best treatments are those
the following few weeks individuals with subarachnoidwhich physically stabilize the aneurysm. In one such
hemorrhage can suffer additional, serious complications.procedure, a surgeon places a metal clip across the
One complication is that the aneurysm responsible foraneurysm where it joins the otherwise normal artery.
the initial hemorrhage can bleed a second time andAn alternative surgery is to wrap the outside of the
cause even more damage. This occurs in 4% ofaneurysm with surgical gauze or plastic sheeting. A
cases within the first 24 hours and there is anothernewer procedure involves filling the aneurysm with tiny
1.2% chance of re-bleeding each day thereafter formetal coils inserted via a flexible catheter snaked
the first two weeks. Thus, without treatment 20% ofthrough the arteries.How can one tell if a particular
cases have a second hemorrhage within the first twoheadache is caused by a bleeding aneurysm? It can
weeks.The other serious complication is that the bloodbe a tough call, but certain features make a ruptured
deposited in the subarachnoid space can causeaneurysm more likely.