STROKE

STROKE

Nelson ASPESI, MD. Professor of Neurology and Neurosurgery at the State University Rio Grande do Sul (UFRGS).

 

What is it?

Stroke is a condition characterized by an acute onset of neurological deficit (reduction in the function) that persists for at least 24 h, reflecting the focal involvement of the central nervous system as a result of a circulation disorder in the brain; it begins all of a sudden, the neurological deficit being maximum at the onset and likely to develop over time.

The term transient ischemic attack (TIA) refers to the transitory neurological deficit that lasts less than 24 h until total return to normality; when the deficit lasts longer than 24 h, and then there's a return to normality, it is called reversible ischemic neurological deficit (RIND).

We can divide stroke into 2 categories:
 

	An ischemic stroke consists of an occlusion of a blood vessel that interrupts blood flow to a particular region in the brain, interfering with the neurological functions that depend on the affected region, causing characteristic symptoms or deficits.
	In the hemorrhagic stroke, there’s local hemorrhage (bleeding), with further complicating factors such as increase in intracranial pressure, brain edema (swelling), amongst others, leading to signs that aren’t always focal.

How does it develop?

Several risk factors are described and are confirmed in the origin of the stroke, among these are: arterial hypertension, heart condition, atrial fibrillation, diabetes, smoking, hyperlipidemia. Other factors we can mention are: use of contraceptive pills, alcohol, or other disorders that cause an increase in the individual's coagulability status (blood coagulation).

What does one feel?

By and large, it depends on the kind of stroke affecting the patient:

Ischemic? Hemorrhagic? Location, age, side factors.
 

	Weakness: The acute onset of weakness in one of the limbs (arm, leg) or face is the most common symptom of a stroke. It may indicate the occurrence of ischemia throughout a brain hemisphere or just in a small, specific area. The disorder can take place in different ways, presenting itself as a greater weakness in the face and arm than in the leg; or a greater weakness in the leg than in the arm or face; or, yet, the weakness can be accompanied by other symptoms. These differences depend on the location of the ischemia, the extension, and the brain circulation affected.
	Visual disorders: The loss of vision in one of the eyes, chiefly acute, alarms patients and usually impels them to look for medical evaluation. The patient can experience a sensation of "shadow" or "curtain" in their vision, or present transitory blindness (amaurosis fugax).
	Sensory loss: More often, numbness takes place along with a decrease in strength (weakness), confusing the patient; sensitivity is subjective.
	Language and speech (aphasia): Patients usually show altered language and speech; thus, some patients present short and laborious speech, resulting in frustration (awareness of the effort and impaired speech); other patients present another language alteration, speaking long, fluent sentences with little logic and greatly impaired understanding of language. Family and friends can describe this symptom to the doctor as a fit of confusion or stress.
	Convulsions: In cases of intracerebral hemorrhage, in the so-called hemorrhagic stroke, the symptoms can manifest as described above, usually severer and with quick development. Hemiparesis may occur (decreased strength on the opposite side to the bleeding), in addition to eye movement problem. The hematoma may grow, cause an edema (swelling) and reach surrounding structures, leading the individual to coma. The symptoms can quickly develop in a few minutes.

How does the doctor accomplish the diagnosis?

Patient history and the physical examination provide information pointing out to stroke as the possible cause of the symptoms. However, the acute onset of focal neurological symptoms must suggest a vascular disorder at any age, even without associated risk factors. Lab evaluation includes blood analyses and image studies (computer-aided tomography of the brain or nuclear magnetic resonance). Other tests: ultrasound exam of carotid arteries and vertebrae, echocardiography and angiography can be performed.

How is it treated and prevented?

First, one must differentiate ischemic stroke from hemorrhagic stroke.

Treatment includes the identification and control of risk factors, the use of antithrombotic therapy (against clotting), and carotid endarterectomy (surgery for removal of the clot from inside the artery) in some selected cases. Regular neurological evaluation and follow-up are part of the preventive treatment, as well as the control of hypertension and diabetes, quitting smoking and the use of certain drugs (anticoagulant agents) that contribute to a decreased incidence of strokes.

An ongoing stroke is an emergency and must be treated in a hospital.

The use of antithrombotic therapy is important so as to avoid relapses. Besides this, other complications must be controlled, especially in patients in bed (pneumonia, thromboembolism, infections, skin ulcers), for whom the implementation of physiotherapy prevents the disorder and plays a significant role in the patient's functional recovery.

The initial measures in case of hemorrhagic stroke are similar, and a bed at the intensive care unit must be secured for strict pressure control. In some cases, surgery is mandatory, aiming at the removal of the clot and exerting control over intracranial pressure.