Stroke

Stroke is one of the leading causes of adult disability and death in the United States. The term refers to the rapidly developing loss of brain function resulting from an interruption of blood supply in the brain. It can be caused by embolism, thrombosis, or hemorrhage. Stroke can lead to permanent neurological damage or even death if not promptly treated.

Stroke is caused by the interruption of blood supply, leading to the depletion of glucose and oxygen in the affected area. The decrease of glucose and oxygen reduces or stops neuronal function and it also triggers an ischemic cascade resulting to the serious damage or even death of neurons.

What are the causes of stroke?
The major risk factors for stroke include: heart disease, hypertension, smoking, alcohol abuse, cocaine abuse, diabetes, high cholesterol level, and congenital or genetic conditions. Another major risk factor for stroke is advanced age. Ninety-five percent of strokes occur in people aged 45 or above, while two-thirds happen to people aged 65 or above. Sickle cell anemia also increases the risk of stroke.

Stroke can be categorized into two: ischemic and hemorrhagic. Ischemic stroke can be caused by embolism, thrombosis, or systemic hypoperfusion. It accounts for approximately 80% of strokes. In this condition, a blood vessel is blocked, resulting in the interruption of blood supply in the brain. Ischemic stroke can be classified into embolic, thrombotic, venous thombosis, or systemic hypopefusion. Meanwhile, hemorrhagic stroke can be caused by intrecerebral hemorrhage, subdural hemorrhage, subarachnoid hemorrhage, or epidural hemorrhage. Cerebral hemorrhage happens when a blood vessel in the brain is ruptured and bleeds. In this condition, the ruptured and bleeding vessel fails to carry blood to its target tissue, thus interrupting blood supply in the brain. Hemorrhagic stroke is more dangerous than ischemic because blood irritates the tissue of the brain and bleeding increases intracranial pressure. Cerebral hemorrhage can be divided into: subarachnoid and intracerebral hemorrhage.

What are the symptoms of stroke?
The symptoms of stroke vary depending on the type of stroke and the area of the brain that is affected. While ischemic strokes usually affect regional areas of the brain, hemorrhagic strokes affect local areas. If the affected area contains any of the three major pathways of the central nervous system (spinothalamic tract, dorsal column, and corticospinal), the symptoms may include: hemiplegia (muscle weakness), numbness, and reduction in vibratory sensation or sensory.

The symptoms of stroke affect only one side of the body, depending on which part of the brain is affected. Besides the three pathways of the central nervous system, the brainstem also contains 12 cranial nerves. As such, if the brainstem is affected, the symptoms may include: altered vision (partial or total), hearing, taste, or smell; weakness of ocular muscles and ptosis (drooping of eyelid); decreased reflexes (pupil reactivity to light, swallow, and gag); muscle weakness of the face and decreased sensation; nystagmus and balance problems; change in breathing and heart rate; weakness in sternocleidomastoid muscle; and weakness in tongue. If the cerebral cortex is affected, the symptoms may include: aphasia (inability to understand or speak language), apraxia (altered voluntary movements), defect in visual field, memory deficits (due to involvement of temporal lobe), hemineglect (due to involvement of parietal lobe), disorganized thinking, hypersexual gestures, and confusion. If the cerebellum is affected, the symptoms may include: trouble walking, disequilibrium, vertigo, and altered coordination of movement. Vomiting, headache, and loss of consciousness are usually experienced when a person suffers from hemorrhagic stroke due to the increased intracranial pressure.

Treatment overview
The earlier a person suffering from stroke is treated, the better are his chances of recovery and survival. If stroke therapies such as aspirin are administered immediately, a patient would have greater chances of recovering. Only detailed medical imaging and physical examination provide accurate information regarding the presence, type, and degree of the stroke.

Prevention of stroke
A healthy lifestyle is the best preventative measure for stroke. This includes: healthy diet, regular physical exercise, moderate drinking, and quitting the habit of smoking. In case you have one or more of the diseases that can trigger stroke, take the necessary treatments in order to avoid complications. If you have already suffered from stroke, it is important to take all the precautionary measures and treatments in order to avoid the risk of complications or having another stroke.