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glossary:stroke

Stroke Definition

The sudden death of some brain cells due to a lack of oxygen when the blood flow to the brain is impaired by blockage or rupture of an artery to the brain. A stroke is also called a cerebrovascular accident or, for short, a CVA. Also common referred to as a ”blood clot

There are two main types of stroke: ischemic and hemorrhagic. Ischemic stroke is caused by blockage in an artery that supplies blood to the brain, resulting in a deficiency in blood flow (ischemia). Hemorrhagic stroke is caused by the bleeding of ruptured blood vessels (hemorrhage) in the brain.

During ischemic stroke, diminished blood flow initiates a series of events (called ischemic cascade) that may result in additional, delayed damage to brain cells. Early medical intervention can halt this process and reduce the risk for irreversible complications.

Symptoms of a stroke depend on the area of the brain affected. The most common symptom is weakness or paralysis of one side of the body with partial or complete loss of voluntary movement or sensation in a leg or arm. There can be speech problems and weak face muscles, causing drooling. Numbness or tingling is very common. A stroke involving the base of the brain can affect balance, vision, swallowing, breathing and even unconsciousness.

A stroke is a medical emergency. Anyone suspected of having a stroke should be taken immediately to a medical facility for diagnosis and treatment.

The causes of stroke:

An artery to the brain may be blocked by a clot (thrombosis) which typically occurs in a blood vessel that has previously been narrowed due to atherosclerosis (“hardening of the artery”). When a blood clot or a piece of an atherosclerotic plaque (a cholesterol and calcium deposit on the wall of the artery) breaks loose, it can travel through the circulation and lodge in an artery of the brain, plugging it up and stopping the flow of blood; this is referred to as an embolic stroke. A blood clot can form in a chamber of the heart when the heart beats irregularly, as in atrial fibrillation; such clots usually stay attached to the inner lining of the heart but they may break off, travel through the blood stream, form a plug (embolism) in a brain artery to cause a stroke. A cerebral hemorrhage (bleeding in the brain), as from an aneurysm (a widening and weakening) of a blood vessel in the brain, also causes stroke.

The diagnosis of stroke involves a medical history and a physical examination. Tests are done to search for treatable causes of a stroke and help prevent further brain damage. A CT scan (a special X-ray study) of the brain is often done to show bleeding into the brain; this is treated differently than a stroke caused by lack of blood supply. A CAT scan also can rule out some other conditions that may mimic a stroke. A soundwave of the heart (echocardiogram) may be done to look for a source of blood clots in the heart. Narrowing of the carotid artery (the main artery that supplies blood to each side of the brain) in the neck can be seen with a soundwave test called a carotid ultrasound. Blood tests are done to look for signs of inflammation which can suggest inflamed arteries. Certain blood proteins are tested that can increase the chance of stroke by thickening the blood.

Stroke look-alikes:

Just because a person has slurred speech or weakness on one side of the body does not necessarily mean that person has had a stroke. There are many other nervous system disorders that can mimic a stroke including a brain tumor, a subdural hematoma (a collection of blood between the brain and the skull) or a brain abscess (a pool of pus in the brain caused by bacteria or a fungus). Virus in the brain (viral encephalitis) can cause symptoms similar to those of a stroke, as can an overdose of certain medications. Dehydration or an imbalance of sodium, calcium, or glucose can cause neurologic abnormalities similar to a stroke.

Warning Signs of a stroke:

Strokes, or brain attacks, are medical emergencies that require immediate medical attention. Warning signs of stroke include the following:

  • Sudden numbness or weakness, especially on one side of the body
  • Sudden confusion
  • Sudden vision problems in one or both eyes
  • Sudden difficulty walking, dizziness, loss of balance or coordination
  • Sudden, severe headache with no known cause
  • Sudden difficulty speaking or understanding speech

Treatment of a stroke:

Early use of anticoagulants to minimize blood clotting has value in some patients. Treatment of blood pressure that is too high or too low may be necessary. (Lowering elevated blood pressure into the normal range is no longer recommended during the first few days following a stroke since this may further reduce blood flow through narrowed arteries and make the stroke worse.) The blood sugar glucose in diabetics is often quite high after a stroke; controlling the glucose level may minimize the size of a stroke. Drugs that can dissolve blood clots may be useful in stroke treatment. Oxygen is given as needed. New medications that can help oxygen-starved brain cells survive while circulation is reestablished are being developed.

Rehabilitation:

When a patient is no longer acutely ill after a stroke, the aim turns to maximizing the patient's functional abilities. This can be done in an inpatient rehabilitation hospital or in a special area of a general hospital and in a nursing facility. The rehabilitation process can involve speech therapy to relearn talking and swallowing, occupational therapy for regaining dexterity of the arms and hands, physical therapy for improving strength and walking, etc. The goal is for the patient to resume as many of their pre-stroke activities as possible.

Footnote: The term “stroke” reflects the belief among the ancient Greeks and Romans that someone suffering a stroke (or any sudden incapacity) had been struck down by the gods.

ICD10:

I61 Intracerebral haemorrhage

Excludes:  sequelae of intracerebral haemorrhage ( I69.1 ) 

I61.0 Intracerebral haemorrhage in hemisphere, subcortical

Deep intracerebral haemorrhage 

I61.1 Intracerebral haemorrhage in hemisphere, cortical

Cerebral lobe haemorrhage 

Superficial intracerebral haemorrhage

I61.2 Intracerebral haemorrhage in hemisphere, unspecified I61.3 Intracerebral haemorrhage in brain stem I61.4 Intracerebral haemorrhage in cerebellum I61.5 Intracerebral haemorrhage, intraventricular I61.6 Intracerebral haemorrhage, multiple localized I61.8 Other intracerebral haemorrhage I61.9 Intracerebral haemorrhage, unspecified

I62 Other nontraumatic intracranial haemorrhage

Excludes:  sequelae of intracranial haemorrhage ( I69.2 ) 

I62.0 Subdural haemorrhage (acute)(nontraumatic) I62.1 Nontraumatic extradural haemorrhage

Nontraumatic epidural haemorrhage 

I62.9 Intracranial haemorrhage (nontraumatic), unspecified

ICD-9

ICD-9-CM Diagnosis 434.0

Cerebral thrombosis 434.0 is a non-specific code that cannot be used to specify a diagnosis 434.0 contains 20 index entries


ICD-9-CM Diagnosis 434.00

Cerebral thrombosis without cerebral infarction 434.00 is a specific code that can be used to specify a diagnosis


ICD-9-CM Diagnosis 434.01

Cerebral thrombosis with cerebral infarction 434.01 is a specific code that can be used to specify a diagnosis 434.01 contains 4 index entries


ICD-9-CM Diagnosis 434.1

Cerebral embolism 434.1 is a non-specific code that cannot be used to specify a diagnosis 434.1 contains 17 index entries

See also:

Deep Venous Thrombosis

Thrombophlebitis

glossary/stroke.txt · Last modified: 2012/10/16 14:40 (external edit)