A stroke is the rapidly developing loss of brain function(s) due to disturbance in the blood supply to the brain. This can be due to lack of glucose & oxygen supply caused by thrombosis or embolism or due to a hemorrhage. As a result, the affected area of the brain is unable to function, leading to inability to move one or more limbs on one side of the body, inability to understand or formulate speech, or inability to see one side of the visual field. A stroke is a medical emergency and can cause permanent neurological damage, complications, and death

The traditional definition of stroke, devised by the World Health, is a "neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours". The 24-hour limit divides stroke from other conditions.

Signs and Symptoms

Stroke symptoms typically start suddenly, over seconds to minutes, and in most cases do not progress further. The symptoms depend on the area of the brain affected. The more extensive the area of brain affected, the more functions that are likely to be lost. Some forms of stroke can cause additional symptoms: in intracranial hemorrhage, the affected area may compress other structures. Most forms of stroke are not associated with headache, apart from subarachnoid hemorrhage and cerebral venous thrombosis and occasionally intracerebral hemorrhage.

Other Symptoms

If the area of the brain affected contains one of the three prominent Central nervous system pathways—the spinothalamic tract, corticospinal tract, and dorsal column (medial lemniscus), symptoms may include:

• muscle weakness of the face
• numbness
• reduction in sensory or vibratory sensation

In most cases, the symptoms affect only one side of the body (unilateral. However, the presence of any one of these symptoms does not necessarily suggest a stroke, since these pathways also travel in the spinal cord and any lesion there can also produce these symptoms.

• altered smell, taste, hearing, or vision (total or partial)
• drooping of eyelid and weakness of ocular muscles
• decreased reflexes: gag, swallow, pupil reactivity to light
• decreased sensation and muscle weakness of the face
• balance problems
• altered breathing and heart rate
• inability to turn head to one side
• weakness in tongue (inability to protrude and/or move from side to side)

If the cerebral cortex is involved, the CNS pathways can again be affected, but also can produce the following symptoms:

• inability to speak or understand language
• altered voluntary movements
• vision is obscured
• loss of memory
• a deficit in attention to and awareness of one side of spacedis or ganized thinking, confusion,
• hypersexual gestures (with involvement of frontal lobe)
• anosognosia (persistent denial of the existence of a, usually stroke-related, deficit)

If the cerebellum is involved, the patient may have the following:

• trouble walking
• altered movement coordination
• vertigo and or disequilibrium (dizziness)