The term ‘stroke’ refers to a sudden interruption in blood flow to part of the brain, leading to an alteration in brain function
Because of this interruption, not enough blood reaches the brain, which means that the oxygen and nutrients needed for proper brain function are also prevented from reaching the brain. In short, an initial problem with vascular function ultimately affects the tissue of the brain, which ceases to function correctly, leading to a range of symptoms depending on the affected area.
Effects of a stroke
As a general rule, the following symptoms may manifest themselves following a stroke, depending on the affected area.
Left hemisphere
- Weakness in the right side of the body
- Loss of sensation in the right side of the body
- Loss of sight in the right visual field
- Trouble with linguistic comprehension and expression
- Trouble with speech
- Muteness
- Substitution of words or syllables
- Mistakes when naming objects
- Trouble reading and writing
Axial cross section of the computed tomography (CT). The arrow shows an ischemic stroke in the left hemisphere (the dotted line indicates the separation between the left and right hemispheres).
Right hemisphere
- Weakness in the left side of the body
- Loss of sensation in the left side of the body
- Loss of sight in the left field of vision
- Lack of awareness of the left side of the body or surroundings
- Trouble maintaining attention, frequent distractions, loss of concentration
- Little awareness of current or future problems, in some cases without acknowledgment of the disease itself
- Behavioural problems (mainly impulsiveness and mood swings)
- Brainstem and cerebellum
- Loss of consciousness
- Difficulty swallowing
- Trouble speaking
- Double vision
- Instability when walking
- Loss of coordination
Axial cross section of the brain MRI. The arrow indicates a brainstem stroke (ischemic stroke in the right pontomesencephalic region)
Red flag symptoms
Rather than acting as a means of locating the damaged area, however, these symptoms often act as ‘red flags’. In short, the best course of action in response to the red flag symptoms is to see a specialist who can assess the severity of these symptoms.
Types of stroke
Ischemic strokes are the most common types of strokes, accounting for around 85% of all strokes. strokes are due to a drop in the supply of blood to the brain. There are different types ischemic strokes.
Transient ischemic attack (TIA)
When the symptoms that cause the stroke are temporary and are resolved in less than 24 hours, the stroke is referred to as a transient ischemic attack (TIA). TIAs can cause any of the aforementioned red flag symptoms. Awareness of the red flag symptoms and the possibility of having suffered a TIA is crucial, but one out of every three TIA sufferers will suffer a stroke within one year if appropriate measures are not taken.
Atherothrombotic stroke or thrombosis
This type of stroke gets its name from the buildup of ‘atheroma’ or ‘atherosclerosis’ on the walls of some of the blood vessels that supply the brain with blood. This buildup then forms a clot or ‘thrombus’ that blocks the flow of blood to part of the brain. This type of stroke is the most common stroke in people with a history of cardiac disease related to atherosclerosis such as angina pectoris and heart attacks. The atherosclerosis that causes these two problems is related to vascular risk factors that patients and health professionals should be aware of and try to prevent.
Embolic stroke or embolism
In these strokes, the obstruction of the blood vessels that supply blood to the brain is due to a blood clot that forms in the heart or in another part of the body. After becoming partially or totally dislodged, this blood clot travels towards the brain in the blood supply. This clot is known as a ‘thrombus’. Once this clot reaches the small arteries in the brain, it can obstruct the blood flow if it is larger than the interior diameter of the vessels, thereby causing an ischemic stroke.
Haemodynamic strokes
A haemodynamic stroke is the least common kind of ischemic stroke. In haemodynamic strokes, the drop in blood supply is due to a strong, persistent drop in blood pressure. Cardiac arrest, serious arrhythmia, and severe, sustained low blood pressure are some of the causes of haemodynamic strokes.
Haemorrhagic strokes
Haemorrhagic strokes are less common than ischemic strokes (they account for around 15% of all strokes), but they are typically associated with a higher death rate, especially in the first few hours after the stroke occurs. Haemorrhagic strokes often cause a secondary ischemic stroke because the rupture of the blood vessel reduces the blood supply to the part of the brain that depends on this artery. Furthermore, some of the leaked blood compresses the brain structures and other blood vessels, which increases the size of the affected area.
The most common haemorrhagic strokes are intracerebral haemorrhages, and the second most common type of haemorrhagic strokes is subarachnoid haemorrhages.
Intracerebral haemorrhage
This type of haemorrhage occurs inside the brain tissue due to the rupture of an artery. This causes blood to leak out, flooding and harming the surrounding brain tissue. This type of stroke is especially serious because it not only causes local damage, but also leads to an increase in pressure within the skull, which affects the whole brain and places the affected individual’s life at risk. The most common cause of this type of haemorrhagic stroke is high blood pressure.
Subarachnoid haemorrhage
In this type of haemorrhage, the bleeding occurs on the brain’s surface, in the space between the brain and the inside of the skull. The most common cause of subarachnoid haemorrhages is a burst aneurysm (an abnormally thin portion of an artery wall that forms a bloodfilled balloonlike bulge).
Intraventricular haemorrhage
Although this type of haemorrhage is relatively uncommon, it is the main neurological complication in premature babies. Primary intraventricular haemorrhages, whose main cause is high blood pressure, are uncommon. Most of these haemorrhages are secondary, and occur when an earlier intracerebral or subarachnoid haemorrhage causes the blood to reach the ventricles of the brain and spread into the ventricular system.
Strokes in figures
In Western countries, strokes are the cause of 10–12% of all deaths. In 2002, strokerelated disability was in sixth place in terms of loss of disabilityadjusted life years (DALYs). Because of population aging, it is estimated that strokes will become the fourth most important cause of loss of DALYs by 2030.
Incidence
Several studies report the incidence of strokes in different Spanish populations. According to the raw data reported in these studies, the incidence of strokes is 174 per 100,000 population in Girona and 132 per 100,000 population in Asturias. In the Spanish National Strategic Plan for the Treatment of Neurological Disease (Plan Estratégico Nacional para el Tratamiento Integral de las Enfermedades Neurológicas) produced by the Spanish Neurological Society in 2002, the annual incidence of strokes was estimated at 200 new cases per 100,000 population. This incidence equates to approximately 84,000 new cases of strokes in Spain each year. The IBERSTROKE study reports preliminary raw annual incidence rates for the European population of 190.3 strokes per 100,000 population.
Prevalence
In terms of the prevalence of strokes, a recent NEDICES study of the population aged over 65 reports an adjusted prevalence of 4.9% (4.3–5.4%) for cerebrovascular disease, 3.4% (2.9–3.9%) for strokes, and 1.3% (1.0–1.6%) for TIA.
Prevalence of brain damage
According to the EDAD survey, of the 329,544 disabled people living in Spain with acquired brain injury (ABI) due to cerebrovascular accidents (CVA), 54% are women and 46% are men. There is a direct relationship between age and the number of cases of ABI due to CVA. From the 45–49 age group upwards, the number of such cases of ABI increases considerably.
Table. Distribution of people with ABI due to CVA (Spain, 2008). Source: Spanish Survey of Disabilities, Personal Autonomy, and Dependence Situations (EDAD, 2008)
The cost of strokes
Strokes consume 3–4% of health care spending in highincome countries, with 76% of these costs owing to direct health costs in the first year after the event, mostly in hospital costs. In subsequent years, the direct health costs fall because of lower hospital costs, although costs are higher in other areas, particularly rehabilitation, medication, and outpatient services. According to these studies, the average cost per patient in Spain is around 5,000 Euros. When indirect costs are included, studies in Spain and in other European countries show that costs increase massively to more than 20,000 Euros per patient. Overall, health costs are roughly 622 million Euros, indirect costs are 320 million Euros, and informal care costs are 297 million Euros. Other studies report different estimates of informal care costs. In the base case, these costs range from 801.7 million to 1.24 billion Euros, whereas in other estimates, costs range from 1.13 to 1.75 billion Euros.
Glosary
- Aphasia: The inability to use or understand language. Agraphia: The inability to write properly.
- Agnosia: Lost or reduced capacity to correctly recognize or perceive environmental stimuli.
- Alexia: The inability to read correctly.
- Aneurysm: An abnormally thin portion of an artery wall that forms a bloodfilled balloonlike bulge.
- Atherosclerosis: Damage to the artery wall caused by deposits of fat and other substances. Apathy: Behaviour characterized by a lack of emotion, motivation, and enthusiasm.
- Ataxia: Poor coordination of movements or unstable balance and gait.
- Diplopia: Double vision of a single object.
- Dysarthria: Poor articulation of words.
- Dysphagia: Trouble swallowing.
- Spasticity: An increase in muscle tone caused by an injury of the central nervous system that causes sustained muscle contraction and impedes movement.
- Hemiparesis: Weakness or loss of strength in one side of the body. In the case of complete loss of strength, the condition is called hemiplegia.
- Hemianopsia: Blindness affecting only half of the field of vision.
- Hemispatial neglect: A lack of selfperception and awareness of the care needed to orient oneself, act, or respond to stimuli or actions that occur in the environment.
- Magnetic resonance imaging (MRI): An imaging technique that uses magnetic fields to view brain structures with greater precision and detail than is possible with CT.
- Tetraparesis: Trouble moving all four limbs. Complete inability to move all four limbs is called tetraplegia.
- Computerized tomography (CT): An imaging technique that uses Xrays to view brain structures and identify a stroke.