Types of strokes
Strokes can be grouped into two broad categories depending on the reasons behind them:
- Ischemic strokes: these make up approximately 80-85% of cases. They can be caused by the formation of a clot that completely obstructs a cerebral artery that was previously narrowed by an accumulation of fat, cholesterol or other substances (atheroma plaque), causing cerebral thrombosis or thrombotic stroke. They can also be caused by a clot from the brain itself or from another region (usually the heart) becoming detached and moving through the arteries to reach the brain, causing a stroke due to cardioembolism.
- Haemorrhagic strokes: these occur in the remaining 15-20% of cases and are caused by the rupture of a cerebral vessel, caused by elevated blood pressure (hypertension) or by defects of the cerebral vessels (tobacco, drugs, alcohol, etc.). This haemorrhage compresses the system, making it difficult for the brain to irrigate normally, and causing tissue damage by altering the chemical balance that neurons need to function.
When blood flow is temporarily interrupted (for between one and 24 hours), this is known as a Transient Ischemic Attack (TIA); however, if the duration is longer or the brain scanner detects necrosis (neuronal death), it is considered an ischemic stroke. TIA is a predictor of vascular disease and, in the case of stroke, is a warning that the person is at risk. In fact, 40% of people who suffer a stroke have previously suffered a TIA.
In the event of the sudden onset of one or more of the following symptoms, action should be taken quickly by calling 112:
- The most common symptom is the loss of strength affecting one side of the body or face. If it affects one limb it is called monoparesis, but if it affects both limbs on one side of the body, it is known as hemiparesis. There can also be complete paralysis of one extremity (monoplegia) or both (hemiplegia), weakness on both sides (paraparesis) or complete paralysis on both sides (paraplegia).
- Thesudden alteration of sight is the loss of vision in one eye or partial in both, seeing double, or an inability to appreciate objects somewhere in the visual field.
- Difficulty speaking, understanding or articulating language can occur in the form of alteration in articulation and pronunciation that makes it hard to talk and be understood (dysarthria) or a problem with expressing oneself or understanding what is being said to you (aphasia).
- A loss of feeling in the face, arm and/or leg on one side of the body is the abnormal sensation of senses or sensitivity, often accompanied by weakness in the region, in the form of tingling, numbness, or itching (paresthesia); reduced sense of touch, and sensitivity to heat and/or pain (hypoaesthesia); the complete absence of all forms of sensitivity in the affected area (anaesthesia); or the inability to perceive simultaneous stimuli on both sides of the body (sensory extinction).
- Instability, imbalance and inability to walk is when the person presents irregularities in the rhythm, amplitude, and strength of movements, which are imprecise and uncoordinated (asynergy).
- Intense, sudden onset headaches are commonly associated with cerebral haemorrhages, although they may also appear in ischemic strokes.
Who can suffer a stroke?
Anyone can suffer a stroke, regardless of age and physical condition, although they are more common in the elderly. About 75% of cases occur in people over 65, although they increasingly affect young adults due to their lifestyle habits (between 15 and 20% are under 45). Strokes can also affect children: in Catalonia alone, 900 children live with a disability as a result of a stroke.
This disease can also be known by other names, such as apoplexy, cerebral vascular accident, seizure and thrombosis. In Catalonia, more than 13,000 people are admitted each year for a stroke and, unfortunately, they are not always reached in time to save the patient.
To determine the cause of a stroke it is necessary to perform a brain scan (CT). The scan can be completed by reviewing the condition of the cerebral and cardiac vessels, taking into account risk factors and chronic diseases presented by the patient. However, it is not always possible to discover the origin.
Knowing the cause of a stroke allows us to establish the most appropriate treatment to prevent it from happening again. Depending on the aetiology (cause), it can be classified as:
- Atherothrombotic: a narrower-than-usual vessel is detected as a result of fat accumulated in the arteries (cholesterol). Regular checks are needed to ensure that the artery is not clogged. In more severe cases, surgery may be necessary.
- Cardioembolic: a cardiac arrhythmia is located that alters the normal rhythm of the heart, producing clots or causing such clots to come loose. Drugs are supplied to correct the arrhythmia and it is advisable to follow anticoagulant treatment.
- Lacunar: the result of an obstruction in the small arteries of the brain (called perforators) due to hypertension.
- Uncommon: strokes due to less common causes, such as the presence of systemic diseases (infection, neoplasia, coagulation disorders, etc.) or other unusual factors (arterial dissection, aneurysm, arteriovenous malformation or cerebral venous thrombosis, etc.).
- Indeterminate: when the above subtypes have been discarded or more than one possible cause coexists.
If a stroke is suspected, a neuroimaging test (a CT or MRI) should be performed as soon as possible, which will tell us about:
- The type of stroke (ischemic or haemorrhagic).
- Location and condition of the brain injury.
- Assessment of brain tissue at risk, useful data in determining therapy.
Specialists may request other tests such as a chest x-ray (performed upon admission as a first assessment), a doppler or transcranial duplex (to see whether there is a possible intracranial occlusion or stenosis, and where it is located), blood tests (to find out the status of risk factors, immunological and coagulation study, serologies, hormones, renal function, etc.) or a cardiological study (if a cardioembolic stroke is suspected).
After diagnosis, specialists may ask to repeat the tests to detect any changes by comparing the images, or request other tests.
Stroke treatment should be applied immediately, as rapid action can lessen the effects. However, a rehabilitation period is usually needed to eliminate or reduce possible after-effects.
After suffering a stroke, the risk of having another is higher, so it is necessary to take medication to reduce the risk, always following medical guidelines. The first year after suffering a stroke is when there is the highest risk of relapse.
Suffering a second stroke may have a fatal outcome. In survivors, it leads to an increase in the degree of disability and risk of dementia, as well as a higher rate of institutionalisation.
The impact may be different for each patient. Symptoms will be more or less severe depending on the area and volume of the brain affected, as well as the general state of health prior to the event.
In the case of a transient ischemic attack (TIA), which does not usually leave after-effects, or ischemic strokes, if the patient responds well to treatment, recovery is virtually immediate. At other times, the recovery is longer term and takes weeks or months, leaving some sort of after-effects.
There may also be a worsening of the patient due to neurological causes or complications such as fever, infections or others. In more severe cases, it can lead to death.
Once the patient is discharged, the primary care team takes responsibility for the patient, and will monitor risk factors and other chronic diseases. In complex cases, patients will need to visit specialists, such as neurologists.
The return home after hospital discharge will vary depending on the severity of the incident and the patient's family situation. Similarly, reintegration into daily life will depend on the after-effects experienced by each patient.
Research nurse. Coordinator of research and clinical trials at the Stroke Research Group at the Vall d'Hebron Research Institute.
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