Stroke Paralysis: Understanding The Risk And Impact

A stroke is a medical emergency that can be fatal and can cause paralysis. Paralysis is a condition where a person loses the ability to move some of their muscles. A stroke occurs when there is a disruption in the transmission of neural impulses between the brain and the muscles, often due to a change in blood flow in the central nervous system. This disruption can be caused by a blood clot, a ruptured blood vessel, or an obstruction within a blood vessel supplying blood to the brain or spinal cord. Paralysis after a stroke is common, with up to 90% of stroke patients experiencing some degree of paralysis. The effects of a stroke depend on the location and extent of the damage to the brain tissue. Rehabilitation and recovery from stroke paralysis can be a lengthy process and may require intensive therapy to regain function and independence.

Hemiplegia or hemiparesis: paralysis of one half of the body

Hemiplegia or hemiparesis is the paralysis or weakness of one half of the body, which can be caused by a stroke. Hemiplegia is the more severe condition, resulting in partial or total paralysis, whereas hemiparesis is characterised by weakness on one side. The conditions can be caused by damage to the nervous system, including the brain and spinal cord, which interferes with the body's ability to send or receive signals. This can be caused by a stroke, brain or spinal injuries, infections, or degenerative conditions.

Hemiplegia and hemiparesis can affect the left or right side of the body, with the affected side being determined by which side of the brain is damaged. For example, an injury to the right side of the brain will cause paralysis or weakness on the left side of the body. The conditions can cause a range of symptoms, including:

• Loss of motor control
• Inability to feel one side of the body
• General sensations of weakness
• Pusher syndrome (common in traumatic brain injuries)
• Difficulty with bowel or bladder control
• Changes or loss of sensation on one side of the body
• Difficulty swallowing or speaking
• Breathing difficulties

Treatment for hemiplegia and hemiparesis focuses on addressing the root cause. Physical therapy, occupational therapy, assistive devices, and alternative treatments such as acupuncture and dietary changes may be recommended. Recovery is possible, but it may take weeks or months of treatment.

Hemianopsia: a visual field cut, where vision to one side is absent

Hemianopsia is a visual field cut, where there is blindness or reduced vision in half of the visual field. This condition can occur after a stroke or brain injury, and it is important to understand the differences between hemianopsia and hemineglect, as they have different causes and treatments.

Hemianopsia is often the result of damage to the parietal, temporal, and/or occipital lobes, leading to a "cut" in the visual field. The left side is most commonly affected, known as a left visual field cut. It is important to note that the eye itself is not "broken", but rather, the brain struggles to process information from the affected visual field. This is because each half of the brain processes visual information from the opposite side of the body. Therefore, damage to the right hemisphere can impair the ability to process information from the left side.

On the other hand, hemineglect is an attention disorder where individuals do not notice their environment, objects, or stimuli on one side. This is usually the left side, referred to as left neglect. It often arises from a stroke in the right parietal lobe, causing problems with attention rather than visual processing. For example, a person with left neglect might not notice someone standing on their left side, not because they are being rude, but because they do not have enough attention on that side.

While both conditions can lead to similar manifestations, such as missing objects on one side or bumping into things, the underlying causes are distinct. Field cuts, like hemianopsia, involve partial blindness and issues with visual information processing in the brain. In contrast, hemineglect involves inattention and a lack of awareness on the affected side.

Treatment for hemianopsia focuses on helping the brain process visual information again. Oculomotor exercises teach patients to move their eyes and scan the affected environment, retraining the brain to process information. Field expanders and prisms can also be used as a compensation strategy to shift images from the blind field, aiding daily life. Additionally, visual restoration therapy incorporates exercises like saccadic eye movements to stimulate the border of the missing field of vision.

For left neglect, treatment aims to improve attention and awareness on the affected side. Visual scanning training involves turning the head to scan the left environment, helping the brain pay attention to that side. Limb activation treatment, which involves moving the left arm and leg within the neglected environment, has also been shown to be effective due to the link between visual attention and motor function.

While the conditions differ, a useful compensation technique for both is scanning, which involves turning towards the affected side to process the information.

Locked-in syndrome: the ability to speak is lost and muscles are paralysed, but the person remains conscious

Locked-in syndrome (LiS) is a rare and serious neurological disorder that occurs when the brainstem is damaged, often as a result of a stroke. People with LiS experience total paralysis but remain conscious, alert, and cognitively intact. They are able to hear and can communicate through eye movements and blinking, as well as with the assistance of technology.

There are three main types of locked-in syndrome: the classical form, the incomplete form, and the total immobility form. In the classical form, individuals have total immobility but retain the ability to move their eyes vertically and blink. They also maintain normal cognitive abilities, including the ability to hear. The incomplete form is similar to the classical form, but individuals may have some sensation and movement in certain body areas. In the total immobility form, individuals experience complete body paralysis and loss of eye movement but retain their cognitive abilities.

Locked-in syndrome is caused by damage to a specific part of the brainstem called the pons, which contains important neuronal pathways connecting the cerebrum, spinal cord, and cerebellum. This damage interrupts the nerves running from the brain through the spinal cord to the body's muscles, resulting in paralysis. It also affects the brainstem centres responsible for facial control and speech, leading to an inability to make facial expressions, chew, swallow, or talk.

The diagnosis of locked-in syndrome can be challenging as individuals lack motor responses, leading healthcare providers to mistakenly believe they are unconscious. Various tests are used to diagnose LiS, rule out other conditions, and determine the underlying cause. These tests include magnetic resonance imaging (MRI) or computed tomography (CT) scans, cerebral angiography, electroencephalography (EEG), evoked potentials, electromyography, blood tests, and cerebrospinal fluid (CSF) examination.

Currently, there is no cure or specific treatment for locked-in syndrome. Management focuses on supportive therapy for breathing and feeding, as well as communication training. Individuals with LiS often require artificial breathing support through a tracheotomy and receive food and water through a gastrostomy tube inserted into their stomach. Physical therapy is also provided to prevent complications due to immobilization and to rehabilitate any remaining or recovering voluntary movements.

While complete recovery from locked-in syndrome is highly unlikely, some individuals may recover minor motor functions and sensations in certain body areas. Most people with LiS do not regain lost nerve functions but can learn to communicate using eye movements and assistive technologies.

Autonomic Dysreflexia (AD): a medical emergency that puts those with a spinal cord stroke at a higher risk of a brain stroke

Autonomic Dysreflexia (AD) is a medical emergency that can occur in individuals with a spinal cord injury, usually when the damage is at or above the T6 level. It is a potentially life-threatening condition that arises from dysregulation of the autonomic nervous system, leading to an uncoordinated sympathetic response. This response can result in a hypertensive episode when there is a noxious stimulus below the level of the spinal cord injury.

The risk of AD increases significantly for those with a spinal cord injury, with up to 90% of patients with cervical spinal or high-thoracic spinal cord injuries being susceptible. The condition is characterised by a sudden, exaggerated increase in blood pressure, typically accompanied by a severe headache, bradycardia, facial flushing, and cold, pale skin in the lower part of the body.

The most common trigger for AD is a urological source, such as a urinary tract infection, a distended bladder, or a clogged Foley catheter. Other triggers include bowel issues, skin lesions, fractures, and infections.

AD puts individuals at a higher risk of a brain stroke due to the elevated blood pressure and cerebral vasodilation. This combination can lead to a potentially lethal stroke if left untreated. Therefore, prompt recognition and management of AD are crucial to prevent catastrophic consequences.

The treatment for AD involves first sitting the patient upright and removing any constrictive clothing to help lower blood pressure. Identifying and addressing the underlying trigger is essential, with bladder and bowel issues being the most common causes. If the trigger cannot be identified or resolved, emergency antihypertensive pharmacological treatment may be required to lower blood pressure and prevent a stroke.

Overall, AD is a serious condition that requires immediate attention and management to reduce the risk of stroke and other life-threatening complications.

Transient Ischemic Attack (TIA): a 'mini-stroke' that can be a warning sign of a full-blown stroke

Transient Ischemic Attack (TIA), sometimes referred to as a "mini-stroke", is a temporary blockage of blood flow to the brain. This blockage is usually caused by a blood clot and results in a range of symptoms, including:

• Weakness, numbness, or paralysis on one side of the body
• Slurred speech or difficulty understanding others
• Blindness in one or both eyes
• Severe headache with no apparent cause
• Trouble seeing in one or both eyes
• Difficulty with walking or dizziness
• Confusion or difficulty in talking or understanding speech
• Loss of balance and coordination

These symptoms typically last less than five minutes but can persist for up to 24 hours. During a TIA, the clot usually dissolves on its own or gets dislodged. While a TIA doesn't cause permanent damage, it is a warning sign of a potential full-blown stroke in the future. It is crucial to seek immediate medical attention if you experience any of these symptoms, even if they go away.

The risk of TIA increases with age, and people who have previously had a stroke are more likely to experience a TIA. Major risk factors include high blood pressure, diabetes, heart disease, atrial fibrillation, and smoking. Diagnosis and treatment of TIA involve a comprehensive evaluation, including imaging of blood vessels in the head and neck, as well as head CT, angiography, and MRI scans. Medical professionals may also assess vital signs, test brain function, and evaluate medical history and cardiovascular disease risks.

It is important to note that about one-third of individuals who experience a TIA will have an acute stroke in the future. However, many strokes can be prevented by heeding the warning signs of TIAs and addressing underlying risk factors. Lifestyle changes, such as a balanced diet, weight management, exercise, and smoking and alcohol cessation, can also help reduce the risk of stroke.

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