Pathophysiology of Strokes
An ischemic stroke occurs due to lack of blood flow to the brain. This can be due to an obstruction of blood flow, such as from an embolus or thrombus in the arteries, or from decreased oxygen availability to red blood cells, such as from hypovolemia or heart failure. Either of these conditions will result in ischemia (lack of cellular oxygen) and can lead to infarction (cell and tissue death). Within hours of ischemia, the affected area may swell, become necrotic and disintegrate. One the tissue has died, white blood cells called macrophages will eliminate the dead tissue. After about one to two weeks, a cavity surrounded by neural tissue scarring is left where the dead tissue once existed.
A hemorrhagic stroke occurs due to blood leaking into cerebral tissue or spaces surrounding the brain. Any amount of blood leakage can cause a hemorrhagic stroke as they are categorized into massive (2 or more centimeters), small (1-2 cm), slit and petechial (pinhead) strokes. Blood leakage into brain tissue is usually caused by hypertension (high blood pressure), blood clotting disorders, illicit drug use or tumors. Blood leakage into the spaces around the brain usually occurs due to a ruptured aneurysm (weakened and bulging artery) or brain trauma. Without discrepancy to how the blood leakage occurs, the mass of blood that escapes compresses adjacent cerebral tissue and can progress to increased intracranial pressure, edema (swelling), ischemia and tissue infarction. A massive cerebral hemorrhage usually leads to death. If death does not occur, in a matter of weeks macrophages and astrocytes (brain cells) eliminate leaked blood and necrotic tissue where a cavity and neural tissue scarring will remain.
Manifestations and Treatment
The clinical manifestations for both ischemic and hemorrhagic strokes are similar. Symptoms can occur suddenly or become evident with activity. They typically include some form of motor dysfunction and signs of neural damage. These include but are not limited to loss of speech, changes in level of consciousness, dizziness, unbalanced gait, headache and loss of bodily motor function contralateral to the side of the brain where the stroke occurred.
Regardless of the cause, treatment is focused on restoring proper oxygen perfusion to cerebral tissues and controlling the source of bleeding. An ischemic stroke caused by a thrombus or embolus involves a thrombolytic treatment such as TPA (tissue plasminogen activator), anticoagulation therapy or a surgical intervention in order to dissolve the clot. Treatment for a hemorrhagic stroke is aimed at stopping the bleeding, which includes draining the excess blood to relieve intracranial pressure and surgical intervention.
Repercussions of Strokes
The effects of strokes persist after healing and vary greatly depending on the type of stroke, degree of intensity and how soon the identification and treatment process occurred. The clinical manifestations stated above can remain as permanent effects if the progression the stroke was extensive. Neurological and motor function deficits vary from mild to major with some people regaining nearly full function and some people regaining very little to no function.
Losses of physiological function can dramatically alter lifestyle if a person is no longer fully functioning. They may not be able to walk, eat, or perform daily functions normally as they used to before their stroke. Resources for transportation, obtaining food, performing activities of daily living (ADLs) and perhaps even acquiring a new source income may be required if a person is no longer able to work. Without access to relatives that can assist them or resources to find assistance a person may end up in an unfit living situation or possibly become homeless.
Post-stroke life is usually very different for a person compared to their life before their stroke. Physiological effects on the body after a stroke may appear obvious, but the lasting effects of a stroke on the mind can be just as profound, if not more serious. Radical changes in level of abilities and independence can be challenging and have negative impacts on a person’s mental health and quality of life. Stroke survivors may have a mental battle coming to terms with grief, anger, depression and frustration and resulting post-stroke mental disorders are not uncommon. One-third of people who have had an ischemic stroke are diagnosed with a mood disorder, specifically post-stroke depression, within the next three years after occurrence.
Other psychological effects include decreased self-esteem and negative views of body image. Changes may not be immediate and can fluctuate over long periods of time. The lack of ability to perform normal activities such as walking may cause weight loss and loss of muscle tone. The decreased ability to speak, see, or process information properly may cause a person to feel inadequate or isolated. These changes can cause a patient to look and feel different than they previously did and negatively impact their self-esteem and body image; the degree of negativity is also influenced by the location in the brain the stroke occurred in.
Any medical or mental disorder has the potential to strain the relationships that a survivor has with other people. Typically, when a person has a debilitating stroke, a spouse or adult child becomes the primary caregiver because they have a medical background or because of the perceived sense of a familial “duty of care”. Depending on the extent of care needed, the level of care can be emotionally draining, especially for a close relative if they did not anticipate how extensive the level of care can be. This dramatically changes the family dynamics as relatives have acquire new roles in addition to the ones they already have. This can cause physical, emotional and financial strain for both the survivor and the caregiver. The caregiver may feel a sense of loss and sadness. The survivor may feel misunderstood, bothersome or isolated. This can be partially alleviated by having an outside caregiver provide support for the survivor entirely or only regarding specific areas of need.
Strokes are debilitating disorders and although isolated as a single occurrences, the effects they have on the body can last a lifetime. This puts strokes in the category of chronic illnesses. Whether a stroke is debilitating or not, the effects can have devastating physiological and mental effects on survivors. Fortunately, plenty of support groups and resources are available to survivors, their families and caregivers.