Paralysis is the loss of movement in one or more body parts. It may be a symptom of a disease of the nerves or muscles or injury to the brain or spine. In some cases, paralysis is also accompanied by the loss of sensation in the affected area.
Patients experience varying degrees of paralysis depending on the cause. It may be permanent or temporary. It may also occur sporadically or become progressively worse, with larger portions of the body becoming impacted or attacks lasting longer. The extent of its effects on the body ranges widely. A patient may lose the ability to move all or most of the body (quadriplegia), the trunk and legs (paraplegia), the right or left side of the body (hemiplegia), or only certain muscle groups (localized paralysis).
In most cases, paralysis is a symptom of a condition that affects the ability of nerve cells (neurons) to communicate with muscles in order to initiate movement. A stroke or head injury may damage parts of the brain involved in initiating movement or transmitting signals to other portions of the body. Spinal cord injuries have the potential to reduce or sever nerve communication to large portions of the body. Injuries that damage areas higher along the spinal cord may cause paralysis over a greater portion of the body than lower spinal injuries.
Many diseases also cause nerve damage that may progress to paralysis. These include cerebral palsy, amyotrophic lateral sclerosis, and multiple sclerosis. In patients with muscular dystrophy, paralysis results from muscle degradation rather than problems with neuron function.
When paralysis occurs, it is likely to be accompanied by several other symptoms. These may include difficulty breathing, abnormal heart rhythms, blood clots, incontinence and uncontrollable limb movements (spasticity). Without proper care, patients may also experience pressure sores and bladder infections.
The cause of the paralysis helps determine any potential treatment routes. Corticosteroid medications may be given immediately following a spinal cord injury to reduce inflammation that may cause further nerve damage. Medications are also available to slow the progression of some diseases that may cause paralysis. Surgery may provide benefit to some patients who have been injured, have paralysis-causing disease, or are born with spina bifida. Physical therapy is also available to help paralyzed patients regain some mobility.
Paralysis is the loss of ability to move a body part. It is often the result of nerve cells (neurons) losing the ability to signal a muscle reaction. In addition to the inability to move, paralysis may also be accompanied by the loss of sensation from the affected body part. In some cases, the nerves may retain their function, but disease (e.g., muscular dystrophy) causes the muscles to waste away.
In most people, movement is caused by muscle contraction or relaxation. The process of most movement begins in the brain, where neurons are stimulated. The neurons then transmit electrical signals to the muscles, instructing them how and when to move. Reflex reactions (e.g., blinking, coughing) are initiated in a different manner, bypassing the brain to enable a quicker response. Some parts of the neurons are coated with myelin, a fatty substance that helps conduct nervous signals along the length of the cell.
Many of the nerves that control muscle movement receive signals from the spinal cord, a group of nerves in the back that carry information to and from the brain. Together, the brain and spinal cord form the central nervous system, which is responsible for most aspects of thought and movement.
The spinal cord is surrounded by ring-like bones called vertebrae that are designed to protect the back while allowing it to move. Nerves enter and leave the spinal cord from spaces between the vertebrae. Each part of the spine contains nerves that control different parts of the body. Therefore, damage to the spinal column usually results in paralysis to the parts of the body associated with that portion of the spinal cord, as well as those areas of the body located below the site of the injury. The parts of the spine include:
- Cervical spine. Refers to the vertebrae in the neck. The nerves that exit this part of the spine control muscle signals to the neck, arms and hands.
- Thoracic spine. Located below the cervical spine in the center of the back. Nerves from the thoracic spine control movement in the torso and parts of the arms.
- Lumbar spine. The lower portion of the spine. Nerves from the lumbar spine connect to the hips and legs.
- Sacrum. Part of the spine located between the pelvis. Nerves leave this part of the spinal cord to connect to the groin, toes, parts of the legs and pelvic floor muscles.
- Coccyx. The fused vertebrae at the end of the spinal column. Nerves leaving the coccyx are primarily involved in sensation.
There are also certain areas of the brain that are associated with movement. For example, the cerebellum, located in the rear of the brain, is responsible for many aspects of movement and motor function. Additionally, the frontal lobe is thought to be related to some features of movement and muscle control. Damage to these parts of the brain may result in paralysis.
Other symptoms related to paralysis
Patients with paralysis are likely to experience many associated symptoms. They may range from mild and benign to severe and life threatening. Possible associated symptoms include:
- Breathing difficulties. Patients with injuries to certain parts of the cervical spine may experience difficulty breathing and require ventilator support. Others may not require mechanical assistance, but have rapid, shallow breathing. In some cases, patients may have difficulty coughing, which can lead to other health problems.
- Arrhythmia. The patient may experience abnormal heart beat rhythms. This often occurs in conjunction with changes in blood pressure.
- Blood clots. According to the National Institute of Neurological Disorders and Stroke, paralyzed patients face three times the risk of blood clots. These clots may travel through the circulatory system and lodge in the brain or heart, leading to a stroke or heart attack.
- Spasticity. Paralysis may be accompanied by uncontrollable limb movements and rapid muscle contractions. Spasticity most often affects the elbows and knees and some patients have been able to use this symptom to help maintain muscle tone. It is recommended that paralyzed patients who experience changes in spasticity consult their physician because the change may result from a cyst or cavity in the spinal cord.
- Autonomic dysreflexia. A severe reflex reaction to stimulation of the paralyzed part of the body. Autonomic dysreflexia results from the peripheral nervous system overcompensating for the inability to communicate with the central nervous system. It affects internal systems rather than the muscles and may cause high blood pressure or a rapid heart beat that can lead to stroke, seizures or death. It is usually associated with paralysis caused by injuries to the neck or upper back.
- Pressure sores (bed sores). Skin ulcers that occur on places where the body supports weight. These sores result from the blood supply to certain areas being blocked. They can be prevented by regular assisted movement when the patient is seated or lying down.
- Bladder and bowel dysfunction. Loss of nervous control of the muscles may also result in incontinence of the bladder and bowels. The organs may empty suddenly or fill without releasing. If not treated, dysfunction may lead to kidney or urinary tract infections.
- Sexual dysfunction. Lack of sensation in the paralyzed area may affect the sexual health of paralyzed patients. Men may have trouble getting and maintaining erections and ejaculating. Women can typically experience orgasms, although they may have difficulty with vaginal lubrication. Female paralyzed patients can usually conceive and bear children. However, they may have difficulties during the pregnancy and birth and may require specialized care.
Types and differences of paralysis
There are many types of paralysis, which are defined by the parts of the body affected. The types of paralyses also differ in whether they are usually permanent conditions or temporary. Typically permanent paralyses include:
- Quadriplegia. Paralysis of most of the body, including the arms and legs. Typically results from injury to the cervical spine. It may also be referred to as tetraplegia.
- Paraplegia. Paralysis of the legs and trunk of the body that may result from a spinal injury or other damage to the thoracic spine or below.
- Hemiplegia. Paralysis of one side (right or left) of the body. May result from injury to one side of the brain due to a stroke or disease such as cerebral palsy.
- Localized paralysis. Only certain areas of the body are immobilized. There are several possible causes of localized paralysis, including stroke or brachial plexus injury. Temporary paralysis of one side of the face may also occur due to Bell’s palsy.
There are also some types of paralyses that occur during periodic attacks. Temporary forms of paralysis include:
- Todd’s paralysis. A temporary form of paralysis that may follow a seizure. The patient is unable to move one side of the body for up to 48 hours.
- Familial periodic paralyses. A genetic (inherited) nerve disorder. During attacks, the patient’s muscles do not function properly, restricting the ability to move.
- Alternating hemiplegia. A rare disorder that develops during childhood, usually before the patient is four years old. Patients experience temporary paralysis on one side of the body that may affect limbs or facial muscles, including those that control the eyes. Some alternating hemiplegia attacks occur in conjunction with seizures.
Potential causes of paralysis
Paralysis can be caused by a variety of factors. It may result from disease or injury to the nerves that signal muscles to move or the breakdown of the muscles themselves.
Paralysis may result from injuries to the part of the brain that initiates movement. Strokes and head injuries can cut off the oxygen supply to brain cells and cause cell death. Paralysis is more likely if the frontal lobe or the motor tracts that descend from the frontal lobe (known as corticospinal tracts)are damaged. This may result in various patterns of paralysis, including hemiplegia (paralysis of the right or left side of the body) on the opposite side of the body to the brain injury.
Spinal cord injuries can damage the nerves that carry signals from the brain to the muscles. These injuries do not always lead to paralysis and those that do are not always permanent. The degree of the patient’s paralysis depends on which part of the spinal cord was injured and the severity of the damage. Patients with an incomplete spinal injury may retain some sensory or muscle function below the injured area. These patients may regain part or all of the lost function over time. Patients who experience a complete injury of the spinal cord lose all communication between the brain and the nerves below the site of the injury. Permanent paralysis typically results from this type of injury.
Brachial plexus injuries are another form of trauma that can lead to paralysis. The brachial plexus is a group of nerves that run from the cervical spine to the shoulders, arms and hands. Injuries to a brachial plexus nerve usually result in the localized paralysis of a single arm. These types of injuries are often caused by car accidents, sports injuries, or the vaginal birth of a large baby. Patients usually recover use of the affected arm, but some may have permanent loss or reduction in function.
Paralysis is also a potential outcome of many diseases. These include:
- Cancer. Uncontrolled growth of cells that form tumors. When tumors occur in the brain or spinal cord, they may push against or crush nerves involved in movement and lead to paralysis.
- Cerebral palsy. Neurological disorder characterized by damage to parts of the brain that control movement. Most patients are born with the condition, but it can also develop in the first few years of life due to brain infections (e.g., meningitis) or head injuries.
- Spina bifida. A birth defect in which the spinal column does not completely close. There are several types. The most severe can lead to paralysis in parts of the body below the opening in the spinal column.
- Multiple sclerosis (MS). Breakdown of nerve insulation (myelin), which is replaced with scar tissue. The scar tissue slows, distorts or blocks nerve signals that initiate muscle movement. Patients experience weakness and some forms of MS may gradually progress to paralysis.
- Muscular dystrophy. Genetic disorder that causes degeneration of muscles involved in voluntary movement. The disease causes muscular weakness and in some cases paralysis.
- Bell’s palsy. Inflammation of a facial nerve, causing paralysis of muscles on one side of the face. This may affect facial expressions and the ability to open and close the eyes.
- Transverse myelitis. Inflammation of part of the spinal cord that damages or destroys the myelin. When the myelin is replaced by scar tissue, there is disruption of nerve signals that may cause paralysis of the legs, bowels and bladder. Some cases of transverse myelitis are caused by viral or bacterial infection and others may be the result of an autoimmune reaction. Some patients regain control over previously paralyzed areas.
- Amyotrophic lateral sclerosis (Lou Gehrig’s disease). A motor neuron disease that leads to the loss of nerves that control the muscles. As a result, the patient’s muscles weaken and waste away. Eventually, many patients with amyotrophic lateral sclerosis develop paralysis.
- Friedreich’s ataxia. An inherited, progressive nervous disorder. The myelin sheath around nerves in the spinal cord wastes away and patients eventually lose the ability to move their legs.
- Guillain-Barré syndrome. An autoimmune disorder that usually leads to progressive weakness and paralysis in the legs and arms. The body’s immune system attacks the nerves of the peripheral nervous system, which limits the ability to transmit signals to the muscles.
- Tethered spinal cord syndrome and syringomyelia. Diseases characterized by scar tissue formation that causes cysts to form in the spinal column. The cysts may grow large and block nerve signals. Depending where the cysts occur, patients may eventually lose the ability to move their arms and legs.
- Hereditary spastic paraplegia. Inherited genetic disease that causes progressive nerve damage. Patients experience muscle weakness and some eventually lose the ability to move their legs.
Treatment and prevention of paralysis
The treatment of paralysis varies depending on its cause. In some cases, there is no treatment available. In other circumstances, such as with Bell’s palsy, patients may recover with or without treatment over a period of weeks to months.
Medications are available to reduce the severity and delay the onset of some forms of paralysis. Following spinal cord injuries, patients are often given corticosteroids. These medications are used to reduce further cell damage by limiting inflammation and the release of excess neurotransmitters that cause cell death. In addition, there are some medications available to slow the progression of certain diseases that cause paralysis. Medications are also used to treat symptoms that accompany paralysis, including abnormal heart rhythms (arrhythmia), blood clots and spasticity.
Surgery may be helpful in treating or reducing the severity of some forms of paralysis. Removing cysts can prevent paralysis in patients with tethered spinal cord syndrome or syringomyelia. Surgery to repair the spinal column of infants with spina bifida may prevent potential paralysis-causing nerve damage depending on the severity of the condition. In other forms of paralysis, surgery may help improve sensation and movement for some patients.
However, in most cases, patients have no choice but to learn to live with their paralysis. Physical therapy helps patients strengthen muscle and sometimes recover certain limb functions. Adaptive devices (e.g., walkers, wheelchairs) are available for paralyzed patients to aid mobility and communication. Patients may also need to learn new personal care routines to reduce the risk of potentially severe complications (e.g., autonomic dysreflexia, which can be triggered by stimulus such as a full bladder). Support groups are often recommended for paralyzed patients to help them cope with their disability and learn new ways to function.
In recent years, medical advances have helped extend life expectancy for many paralyzed patients. A survey by the National Spinal Cord Injury Statistical Center found that patients who survive the first year after paralysis due to spinal cord injury tend to live nearly as long as the rest of the population.
Preventing paralysis depends on the cause. It many cases, paralysis results from the progression of a disease and cannot be prevented. One exception is in cases of familial periodic paralyses. Patients with this disorder can reduce the number of attacks by avoiding strenuous exercise and following their physician’s dietary recommendations.
Preventing spinal or brain injuries can reduce the cases of paralysis due to these causes. Defensive driving techniques and wearing seatbelts are recommended to avoid automobile accidents, which are one of the leading causes of spinal injuries, according to the National Spinal Cord Injury Statistical Center. The risk of spinal or brain injuries can also be reduced by wearing appropriate helmets, face guards, mouth guards and other protective equipment while playing sports or engaging in physical activities.
Questions for your doctor regarding paralysis
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following paralysis-related questions:
- What caused my paralysis?
- Is my paralysis permanent?
- Will my paralysis spread to other parts of my body?
- Is there any treatment for my paralysis?
- What type of adaptive devices can I use to regain some mobility?
- Can you recommend a support group for dealing with paralysis?
- How can I get more information about living with paralysis?
- How will paralysis affect my ability to have sex and have children?
- Is there anyway to prevent paralysis in my family members?
- Can the disease that caused my paralysis be spread to other people?