A large spectrum of symptoms
Stroke or cerebral infarction is a sudden neurological deficit caused by an infarction (85% cases) or a hemorrhage (15% cases) in the brain. It is characterized by a quick onset (instantaneous or within minutes) and is most of the time affecting one half of the body: hemiplegia, unilateral blindness but also speech impairment.
This large spectrum of symptoms varies from patient to patient but also depending on the hemorrhagic or ischemic origin of the stroke and the location of the neurological damage. However, in all cases, the sudden onset of a deformed mouth, a weakening of one side of the body (arm or leg) and/or difficulties to speak are the indication of a neurological problem that should be considered a potentially life-threatening medical emergency.
After onset, symptoms can disappear spontaneously within seconds or hours. In this case the event is referred to as Transient Ischemic Attack (TIA). Even if no neurological trouble sustains, this is a diagnostic and therapeutic emergency. All patients experiencing this type of symptoms must visit a doctor or the closest emergency service available.
It usually takes a long time for survivors to recover spontaneously, from several weeks to several months, followed by a slower recovery phase that lasts for years.
The two types of stroke
Approximately 85% of strokes are the ischemic type. They are caused by the occlusion of an artery delivering blood to the brain (brain arteries but also carotids and vertebral arteries). When this happens, a part of the brain is deprived of oxygen and nutrients. This deprivation results in a cerebral infarction, which provokes neurological damages that result in severe disabilities or death if it lasts more than several minutes or hours.
The remaining 15% of strokes are hemorrhagic, subsequent to the rupture of a cerebral artery wall.
The probability of experiencing an ischemic stroke increases with age whereas hemorrhagic strokes occurrence is age independent. However, even if the mean age for stroke is 73 years (in Europe), 25% of strokes occur in patients below 65. Stroke can occur at all age, including childhood.