Muscular Effects Of Stroke: Understanding The Impact And Recovery

A stroke occurs when the blood supply to the brain is blocked or a blood vessel in the brain bursts. Depending on the severity and location of the stroke, the resulting tissue damage in the brain can lead to changes in how the brain and muscles communicate.

The brain controls both involuntary and voluntary muscle activity by sending neural messages to the muscles. When a stroke occurs, this complex process can be disrupted, leading to a range of muscular effects. These effects can include muscle weakness, fatigue, and problems with balance.

Muscle spasticity is a common effect of stroke, causing muscles to feel stiff and tight and resist movement. This can make it difficult to walk, affect balance and increase the risk of falling. It can also affect the ability to open the hand or reach for something, with movement requiring more effort and resulting in increased tiredness.

Other muscular effects of stroke include foot drop, contractures, changes in sensation, and seizures. Rehabilitation and support are crucial to help individuals manage these physical effects and improve their recovery.

Muscle weakness

There are several ways in which a stroke can affect muscle function, including:

• Hypotonia: Low muscle tone, where the muscles have a decreased level of contraction and may feel "floppy". This can lead to complications such as shoulder subluxation.
• Hypertonia: High muscle tone, resulting in increased tension and stiffness in the muscles. This can affect the limbs, causing stiffness and difficulty in movement. If left untreated, hypertonia can lead to contractures, which restrict joint movement.
• Spasticity: A type of hypertonia that often appears after a stroke, characterised by involuntary muscle contractions and spasms. It is caused by an imbalance of signals in the muscles due to disrupted communication between the brain and muscles.
• Hemiplegia and Hemiparesis: Paralysis or weakness on one side of the body, resulting from tissue damage within the brain that interrupts communication with the muscles. This can cause significant muscle weakness and loss of function.
• Muscle Atrophy: A progressive loss of muscle mass and strength, often occurring when stroke survivors are unable to move certain muscles regularly. This can lead to a decrease in muscle function and increased difficulty in performing daily activities.

To recover muscle function after a stroke, dedicated rehabilitation is essential. This may include passive range-of-motion exercises, where a therapist or caregiver moves the affected limbs, and active exercises that require muscle contraction. High-intensity training and consistent therapeutic exercises can help to improve muscle power and endurance, which are crucial for functional recovery. Additionally, nutritional interventions and management of malnutrition can also play a role in improving muscle function.

Muscle atrophy

Causes of Muscle Atrophy

There are three types of muscle atrophy: physiologic, pathologic, and neurogenic. Physiologic atrophy is caused by not using the muscles enough, and can often be reversed with exercise and better nutrition. Pathologic atrophy is seen with ageing, starvation, and diseases such as Cushing's disease. Neurogenic atrophy is the most severe type and can be caused by an injury to, or disease of, a nerve that connects to the muscle. This type occurs more suddenly than physiologic atrophy.

• Lack of physical activity for an extended period of time
• Alcohol-associated myopathy, a pain and weakness in muscles due to excessive drinking over long periods
• Injuries, such as a torn rotator cuff or broken bones
• Spinal cord or peripheral nerve injuries
• Long-term corticosteroid therapy
• Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, which affects nerve cells that control voluntary muscle movement
• Dermatomyositis, which causes muscle weakness and skin rash
• Guillain-Barré syndrome, an autoimmune condition that leads to nerve inflammation and muscle weakness
• Multiple sclerosis, an autoimmune condition in which the body destroys the protective coverings of nerves
• Muscular dystrophy, an inherited condition that causes muscle weakness
• Neuropathy, damage to a nerve or nerve group, resulting in loss of sensation or function
• Osteoarthritis, which causes reduced motion in the joints
• Polio, a viral disease affecting muscle tissue that can lead to paralysis
• Polymyositis, an inflammatory disease
• Rheumatoid arthritis, a chronic inflammatory autoimmune condition that affects the joints
• Spinal muscular atrophy, a hereditary condition causing arm and leg muscles to waste away

Treatment of Muscle Atrophy

Treatment of muscle atrophy depends on the individual case, but can include physical therapy, nutritional intervention, or surgery. Physical therapy involves performing specific stretches and exercises to prevent immobility, increase muscle strength, improve circulation, and reduce spasticity. Functional electrical stimulation (FES) is another treatment option, which uses electrical impulses to stimulate muscle contraction in affected muscles. Ultrasound therapy is a non-invasive procedure that uses sound waves to aid in healing. In some cases, surgery may be necessary to correct a contracture deformity or to repair a torn tendon.

Muscle stiffness

Spasticity can cause significant difficulty with daily tasks such as bathing, eating, and dressing, impacting a person's quality of life. It commonly affects the arm, hand, leg, and ankle, making it challenging to walk, affecting balance, and increasing the risk of falling.

To manage muscle stiffness, it is essential to stay active and perform recommended exercises. Physiotherapy and occupational therapy aim to improve movement and control and prevent further complications like pain. Electrical stimulation can be used if the affected area has limited or no movement.

In severe cases, doctors may prescribe medication such as botulinum toxin A or muscle relaxants. Additionally, assistive devices, home adaptations, and safety procedures recommended by therapists can help enhance safety and independence.

It is important to note that the effects of a stroke on the muscular system vary widely, and dedicated rehabilitation can help improve muscle function.

Muscle spasticity

Spasticity can cause painful muscle spasms and significantly impact daily living tasks such as bathing, eating, and dressing. It can also lead to overactive reflexes, pressure sores, chronic constipation, and urinary tract infections.

There are several strategies and treatments available to manage and recover from spasticity:

• Oral medications, such as muscle relaxers, can block the neurotransmitters that cause muscles to tighten. Baclofen and tizanidine are commonly prescribed medications.
• Injected medications, such as botulinum toxin (Botox), can specifically target the affected muscles and block the chemical signals that trigger muscle contractions.
• Stretching exercises are an important part of managing spasticity, helping to prevent stiffness, increase and maintain the range of motion, and treat contractures.
• Anti-spasticity orthoses, such as dynamic splints, can relieve pressure on the joints, reduce muscle spasms, and provide a prolonged muscle stretch.
• Functional electrical stimulation or neuromuscular electrical stimulation (NMES) delivers a shock to the affected muscle, activating nerves, and increasing movement.
• Intrathecal baclofen therapy (ITB) surgically implants a small pump to supply baclofen to the spinal cord, reducing side effects.
• Braces can hold a muscle in a normal position to prevent contractions.
• Surgical procedures may be considered for severe cases of spasticity that cause significant pain or limit independence.

It is important to work with a healthcare professional to determine the best treatment plan and combination of therapies for managing spasticity.

Muscle contractures

A contracture is a fixed tightening of muscles, tendons, ligaments, or skin that prevents the normal movement of the associated body part. They can occur in different parts of the body:

• Muscles: This involves the shortening and tightening of the muscles.
• Joints: Contractures in the joint capsule where two or more bones connect result in a limited range of motion in that area of the body.
• Skin: Skin may contract where it has been scarred from an injury, burn, or past surgery, limiting the ability to move that part of the body.

The main symptom of a contracture is a reduced ability to move an area of the body, often accompanied by pain.

Contractures can be treated with medicine, casts, and physical therapy. Doctors may also recommend electrical stimulation, nerve blocks, or surgery to lengthen muscles or repair ligaments, tendons, or bones.

In the context of strokes, contractures can develop due to hypertonia, which refers to increased muscle tone and tension caused by damage to the part of the brain that sends inhibitory signals to the muscles. This can lead to continuous muscle firing, resulting in increased muscle tension or stiffness. If left untreated, contractures can develop, further limiting the range of motion and restricting function.

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