What is a stroke?

In ischemic strokes, a blood clot blocks a blood vessel in the brain or the carotid artery in the neck.

A stroke, referred to by physicians as a cerebrovascular accident (CVA), is a "brain attack." Eighty percent of all strokes - including the type suffered by the prime minister - are ischemic (with the remainder caused by cerebral hemorrhage). In ischemic strokes, a blood clot blocks a blood vessel in the brain or the carotid artery in the neck leading to the head. The blockage causes nerve tissue to be deprived of oxygen. After four or five minutes of being completely deprived of oxygen, neurons begin to die. The early symptoms - even one of which require going immediately to a hospital emergency room - are sudden numbness or weakness in the face, an arm or leg (especially on one side of the body); sudden confusion, difficulty in speaking or understanding; difficulty in expressing or comprehending words; slurring; sudden trouble seeing through one or both eyes or double vision; unexpected trouble walking, dizziness, loss of balance or coordination; an abrupt, severe headache with no known cause; or a sudden decline in consciousness. At least some permanent functional damage from a stroke was almost inevitable until a few years ago, but new drugs and technologies have dramatically changed this. Jose Cohen, Hadassah-University Hospital medical center's top stroke expert, interventional neuroradiologist and leading neurosurgeon explained in an interview with The Jerusalem Post last May that there is a limited "window of opportunity" of about six hours after the appearance of these initial symptoms before damage becomes irreversible. Seven months ago Cohen and his multidisciplinary team of 20 physicians, nurses, computer experts, technicians and others inaugurated Hadassah's $3 million brain angiography room, which is believed to be the most advanced facility of its kind in the country. After a magnetic resonance imaging (MRI) brain scan is performed within an hour, stroke experts can view the penumbra, a broad area surrounding the initial site of the stroke, to determine whether clot-busting treatment is appropriate and would be useful. If so, a tiny catheter about 1.5 meters long and with a wire thinner than a human hair is pushed through the femoral artery in the groin, past the heart and through the carotid artery into the brain while the patient is fully conscious. In an extremely delicate procedure first carried out in Buenos Aires nearly a decade ago, a drug called urokinase is delivered directly to the site of the clot to dissolve it and restore blood flow. Thanks to this new technology, many stroke victims who received treatment soon after their symptoms appeared completely recover.