Paralysis

Overview

Paralysis is the loss of the ability to move one or more muscles. It happens when the signals that travel between the brain, spinal cord, and muscles are interrupted. Depending on the cause and location of the problem, paralysis can be temporary or permanent, partial or complete, and may affect a small area or a large part of the body.

Paralysis is described by which body parts are affected: for example, one limb, one side of the body (as often happens after a stroke), the lower half of the body, or all four limbs. Sudden paralysis can be a sign of a stroke or serious injury and is a medical emergency. Care depends heavily on the underlying cause.

Movement relies on an unbroken chain of signals: the brain sends commands down the spinal cord, and nerves carry them to the muscles. Damage anywhere along this path, whether in the brain, the spinal cord, the nerves, or where nerves meet muscle, can cause paralysis. The location of the damage usually determines which part of the body is affected, which is why identifying where the problem lies is a key part of diagnosis and treatment.

Symptoms

The main feature is loss of movement, but it often comes with other changes:

• Inability to move part of the body, or weakness in the affected area
• Loss of feeling or unusual sensations in the affected area
• Muscle stiffness or, in other cases, floppiness
• Loss of bladder or bowel control with some spinal causes
• Drooping of the face, an arm, or one side of the body in stroke

Sudden weakness or paralysis, facial drooping, or trouble speaking can be a stroke. Call emergency services immediately.

Causes

Paralysis results from damage to or disruption of the nervous system. Common causes include:

• Stroke: A leading cause of paralysis on one side of the body.
• Spinal cord injury: From trauma, often causing paralysis below the level of injury.
• Nerve disorders: Such as Guillain-Barre syndrome or multiple sclerosis.
• Brain or spinal cord tumors and infections.
• Nerve compression: Such as spinal cord compression.
• Birth-related or genetic conditions: Such as cerebral palsy.

Risk Factors

• Risk factors for stroke, such as high blood pressure, diabetes, and smoking
• Activities or situations with a high risk of spinal injury
• Nervous system diseases such as multiple sclerosis
• Certain infections affecting the nervous system
• Tumors of the brain or spinal cord

Diagnosis

Finding the cause is essential and may involve:

• Neurological exam: Testing strength, sensation, reflexes, and coordination.
• Imaging: CT or MRI of the brain or spine to look for stroke, injury, tumors, or compression.
• Nerve and muscle tests: Studies that assess how nerves and muscles are working.
• Blood tests and other studies: To check for infections, inflammation, or other contributing conditions.

Treatment

Treatment depends on the cause and aims to address it, support recovery, and maximize function:

• Treating the underlying cause: Such as emergency stroke care, surgery to relieve spinal cord compression, or treatment of nerve disorders.
• Rehabilitation: Physical, occupational, and sometimes speech therapy to restore or adapt function.
• Assistive devices: Such as braces, wheelchairs, and other aids to support mobility and independence.
• Managing complications: Including skin care, bladder and bowel management, and prevention of blood clots.

Some paralysis improves over time, while other cases are permanent; rehabilitation helps people adapt and stay as independent as possible.

Prevention

Not all paralysis can be prevented, but risk can be reduced by:

• Controlling stroke risk factors such as blood pressure, cholesterol, and diabetes, and not smoking
• Wearing seat belts and helmets and following water-safety rules to prevent spinal injuries
• Treating infections and nervous system conditions promptly
• Seeking immediate care for sudden weakness or numbness

When to See a Doctor

Sudden paralysis is a medical emergency. Call emergency services right away if you or someone else has:

• Sudden weakness or inability to move the face, an arm, or a leg, especially on one side
• Sudden facial drooping, trouble speaking, or confusion
• Paralysis after a fall or injury, particularly to the head, neck, or back
• New loss of bladder or bowel control with leg weakness

See a doctor promptly for any gradual or unexplained weakness or loss of movement.

Related Topics

Frequently Asked Questions

References

1. MedlinePlus, U.S. National Library of Medicine. Paralysis.
2. National Institute of Neurological Disorders and Stroke (NINDS). Paralysis.
3. Centers for Disease Control and Prevention (CDC). Stroke Signs and Symptoms.
4. Christopher & Dana Reeve Foundation. About Paralysis.