Paralysis: Definition, Types, Causes, Signs, Symptoms, Diagnosis and Treatment

It means the total inability to move, feel touch, or control bodily sensations.

As with most things we learn as children, the true meaning of paralysis is significantly more nuanced.

Paralysis is the inability, either temporary or permanent, to move a part of the body.

In almost all cases, paralysis is due to nerve damage, not injury to the affected region.

For example, an injury to the middle or lower regions of the spinal cord is likely to disrupt the function below the injury, including the ability to move the feet or feel sensations, even though the actual structures are healthier than ever.

Types of paralysis

Actually, there are many types of paralysis because there are countless ways the body can be injured.

However, there are four main categories of paralysis that have to do with the part of the body affected.


Monoplegia is the paralysis of a single area of ​​the body, more typically a limb.

People with monoplegia generally retain control over the rest of the body, but cannot move or feel sensations in the affected limb.

Although cerebral palsy is the leading cause of monoplegia, several other injuries and ailments can lead to this form of partial paralysis, these include:

  • Hits.
  • Tumors
  • Nerve damage due to injury or illness.
  • Nerve impingement.
  • Damage to the motor neuron.
  • Brain injuries.
  • Impacted or severed nerves in the affected location.

Monoplegia is sometimes a temporary condition, and it is especially common after a stroke or brain injury .

When the nerves affecting the paralyzed area are not completely severed, it is often possible to regain significant function through physical therapy.


Hemiplegia affects an arm and a leg on the same side of the body, and as with monoplegia, the most common cause is cerebral palsy.

With hemiplegia, the degree of paralysis varies from person to person and can change over time.

Hemiplegia often begins with a pins-and-needles sensation, progresses to muscle weakness, and escalates to complete paralysis.

However, many people with hemiplegia find that their degree of functioning varies from day to day, and based on their general health, activity level, and other factors.

Hemiplegia should not be confused with hemiparesis, which refers to weakness on one side of the body.

However, hemiparesis is often a precursor to hemiplegia, especially in people with neurological problems.

Hemiplegia is sometimes temporary, and the overall prognosis depends on treatment, including early interventions, such as physical and occupational therapy.


Paraplegia refers to paralysis below the waist and generally affects the legs, hips, and other functions, such as sexuality and the elimination of urinary and fecal waste.

Although stereotypes of paraplegia hold that people with this condition cannot walk, move their legs, or feel anything below the waist, the reality of paraplegia varies from person to person, and sometimes from day to day.

Therefore, paraplegia refers to a substantial impairment in function and movement, not necessarily permanent and total paralysis.

In rare cases, people with paraplegia recover spontaneously. This may be due to brain or spinal cord functions that are not yet understood, such as the regeneration of neurons.

More typically, paraplegics can regain some function with physical therapy, which works to retrain the brain and spinal cord to avoid limitations while strengthening muscles and nerve connections.

Spinal cord injuries are the most common cause of paraplegia. These injuries impede the brain’s ability to send and receive signals below the injury site.

Some other causes include:

  • Spinal cord infections.
  • Spinal cord injuries.
  • Brain tumors.
  • Brain infections
  • In rare cases, nerve damage in the hips or waist causes a variety of monoplegia or hemiplegia.
  • Oxygen deprivation to the brain or spinal cord due to suffocation, surgical accidents, trauma, and similar causes.
  • Congenital malformations of the brain or spinal cord.


Quadriplegia, which is often referred to as tetraplegia , is paralysis below the neck. All four limbs, as well as the torso, are normally affected.

However, as with paraplegia, the degree of disability and loss of function can vary from person to person, and even from moment to moment.

Likewise, some quadriplegics spontaneously regain some or all of their function, while others slowly retrain their brains and bodies through physical therapy and exercise.

Occasionally, quadriplegia is a temporary condition due to brain injury, stroke, or temporary compression of the nerves in the spinal cord.

Some spinal cord injury survivors temporarily experience tetraplegia immediately after injury, then experience a less systematic form of paralysis as swelling decreases, nerves are less compressed, or surgery reverses some damage.

As with paraplegia, spinal cord injuries are the leading cause of tetraplegia.

The most common causes of spinal cord injuries include car accidents, acts of violence, falls, and sports injuries, especially injuries due to contact sports such as soccer.

Traumatic brain injuries can also cause this form of paralysis.

Other sources of quadriplegia include:

  • Acquired brain injuries due to infection, stroke, and other disease-related processes.
  • Loss of oxygen to the brain and spinal cord due to suffocation, anesthesia-related accidents, anaphylactic shock, and some other causes.
  • Spinal and brain injuries.
  • Spinal and brain tumors.
  • Spinal and brain infections.
  • Catastrophic neural damage throughout the body.
  • Congenital anomalies.
  • Early brain injuries, especially prenatal or childbirth injuries that lead to cerebral palsy, which can produce a variety of symptoms, including varying degrees of paralysis.
  • Allergic reactions to drugs.
  • Drug or alcohol overdose.


In the causes of paralysis, at least one of the following factors is at play:

  • The brain cannot transmit a signal to an area of ​​the body due to injury to the brain.
  • The brain is capable of feeling touch and other sensations in the body, but cannot effectively transmit a response due to spinal cord injuries.
  • The brain cannot send or receive signals to an area of ​​the body due to spinal cord injuries.

The spinal cord is like the brain’s relay system, so when something in the spinal cord doesn’t work or is injured, the result is often paralysis.

Most spinal cord injuries are incomplete, which means that some signals still travel up and down the cord.

With an incomplete injury, you may retain some sensation and movement all the time, or the severity of the paralysis may change, sometimes in highly unpredictable ways.

A complete spinal cord injury, by contrast, completely compresses or cuts the nerves in the spinal cord, making it impossible for the signal to travel.

In rare cases, injuries to the affected area cause paralysis. This is more common among people who have another medical condition, such as diabetes.

For example, damage to diabetic nerves can cause nerves in some area of ​​the body, particularly the feet, to stop working. You can still move, but you may have little feeling.

This can result in more labored movements, loss or decrease in your ability to walk, and an increased risk of other health problems, such as cardiovascular events.

Muscle is a special type of tissue that allows our bodies to move in turn and is controlled by the nervous system.

The nervous system is in charge of processing all messages and there is a connection to all parts of the body. On many occasions, nerve cells or neurons responsible for controlling the body’s muscles are injured.

The four most common causes of paralysis are:


A stroke is a serious medical condition that occurs when the blood supply to the brain is disturbed.

Like all organs, to function properly, the brain needs a constant supply of blood that contains oxygen and nutrients.

If the blood supply is restricted or stopped, brain cells will begin to die, which can lead to brain damage that often results in paralysis.

Head injury

A serious head injury can cause brain damage.

The surface of the brain can tear or bruise when it hits the skull, damaging blood vessels and nerves.

Paralysis can occur if a part of the brain that controls specific muscles is damaged during a serious head injury.

Damage to the left side of the brain can cause paralysis on the right side of the body, and damage to the right side of the brain can cause paralysis on the left side of the body.

Spinal cord injury

The spinal cord is part of the central nervous system.

It is a thick bundle of nerves that runs from the brain, down through the neck and spine, into a canal of vertebrae. Its main function is to transmit signals to and from the brain and the body.

For example, the spinal cord passes nerve signals, such as hot or cold sensations, back to the brain. If the neck or spine is injured, the spinal cord can also be damaged.

This means that the brain can no longer transmit signals to the muscles, causing paralysis.

The exact location where the spinal injury occurs can have a significant effect on the severity and extent of the paralysis.

The higher up the spine the injury occurs, the worse the paralysis.

For example, an injury to the middle of the spine will usually cause paraplegia (paralysis of the lower extremities).

A neck injury, such as a neck fracture, will usually lead to tetraplegia (paralysis of all four limbs, also known as quadriplegia), as well as a loss of normal lung function, meaning the person will need to wear a respirator for breathing.

The most common causes of spinal cord injury are:

  • Car accidents, work accidents, during the practice of sports or other types of activity.
  • Falls
  • Spinal cord paralysis due to disease rather than injury.

The nature of these causes means that the majority of spinal cord injuries occur in men (who account for 80% of all cases) and in younger people.

It is estimated that half of all spinal cord injuries occur in people 16 to 30 years of age.

Multiple sclerosis

Multiple sclerosis is a condition in which the nerve fibers in the spinal cord are damaged by the immune system (the body’s natural defense against infection and disease).

The immune system mistakenly attacks a substance called myelin, which surrounds nerve fibers and helps with the transmission of nerve signals.

In multiple sclerosis, the myelin around nerve fibers is damaged, disrupting messages to and from the brain.

This can result in paralysis.


Cancers that develop in the brain, such as a high-grade brain tumor, can cause paralysis, usually on one side of the body.

Alternatively, cancers can spread (metastasize) from other parts of the body to the brain or spinal cord, causing paralysis.

Cerebral palsy

Cerebral palsy is a group of neurological conditions (those that affect the brain and nervous system) that affect a child’s movement and coordination.

Cerebral palsy is caused by brain damage that usually occurs before, during, or shortly after birth. Some possible causes of cerebral palsy include:

  • Infection during early pregnancy.
  • A difficult or premature delivery.
  • Bleeding in the baby’s brain.
  • Abnormal brain development in the baby.

The most severe type of cerebral palsy is called spastic tetraplegia, where a person has such a high degree of muscle stiffness (spasticity) in all of their limbs that they cannot use them.

Ataxia de Friedreich

Friedreich’s ataxia is a rare genetic condition. It is caused by a mutation in a gene known as the GAA gene.

The mutation results in the body not making enough frataxin, which is a protein.

Frataxin is believed to play a role in regulating iron levels within nerve cells.

Due to the lack of sufficient frataxin that is produced, the level of iron and other toxic substances begins to accumulate within the nerve cells, damaging them.

Many people with Friedreich’s ataxia experience a gradual increase in paralysis in their legs.

Eventually they will need to use a wheelchair or some other type of mobility aid.

Guillain-Barré syndrome

Guillain-Barré syndrome is a rare and little-known condition caused by damage to the peripheral nervous system.

The peripheral nervous system is the network of nerves that controls the senses and movements of the body.

This nerve damage produces a tingling sensation in the arms and legs, which can lead to temporary paralysis of the arms, legs, and face.

Most patients with Guillain-Barré syndrome make a full recovery within a few weeks to a few months.

Lyme’s desease

This disease is caused by a bacterial infection transmitted by infected ticks.

Ticks release bacteria that can damage nerves, leading to temporary paralysis of the face.

Motor neuron disease

This disease is a very rare but incurable condition. Over time, the nerves in the brain and spine gradually lose function (neurodegeneration).

Nerve cells known as motor neurons are affected.

Motor neurons are specialized nerve cells that control voluntary muscle movements, such as walking.

Motor neuron disease causes progressive muscle weakness, eventually leading to total body paralysis.

Spina bifida

Spina bifida is a term that describes a series of birth defects that affect the development of the spine and the nervous system.

Myelomeningocele is the most serious type of spina bifida, occurring in one in every 1,000 births.

It causes extensive damage to the nervous system that can often result in permanent partial or total paralysis of the lower extremities.

Signs and symptoms

Paralysis is the loss of muscle movement in the body.

Our sense of movement is controlled by communication between the sensory nerves (which are part of the peripheral nervous system) and the central nervous system (made up of the brain and spinal cord).

Disruption of the communication of nerve impulses anywhere along the path from the brain to the muscles can affect control of muscle movement and cause muscle weakness and loss of coordination.

Muscle weakness can progress to paralysis, loss of ability to move muscles. Symptoms of paralysis can vary.

When the spinal cord is crushed, as in the Sang Lan injury, a person is immediately paralyzed and loses sensation in the affected limbs.

When paralysis is caused by a progressive disease or disorder, symptoms develop gradually and often begin with fatigue and muscle weakness.

With polio and stroke, paralysis comes on suddenly, with little or no warning.

Paralysis usually occurs on the side of the body opposite the side of the brain damaged by a stroke and can affect any part of the body.

You may experience unilateral paralysis, known as hemiplegia, or unilateral weakness, known as hemiparesis.

Blockage syndrome is an example of severe paralysis that leaves the stroke survivor unable to move any muscles except those that control the eyes.

Symptoms of paralysis after stroke may include, but are not limited to:

  • Hemiparesis.
  • Spasticity and muscle stiffness.
  • Dysphagia : difficulty swallowing.
  • Hemiplejia.
  • The foot drop.
  • Soft spot.
  • Incoordinación.
  • Sensory deficits.
  • Balance problems.


Information about the symptoms and their occurrence helps the doctor identify the cause of the paralysis.

The history of genetic diseases provides important data.

The diagnosis of paralysis is usually not necessary if the cause is obvious, for example, if paralysis occurred after a stroke.

If tests are needed to help diagnose paralysis, the type of tests required will depend on the underlying cause.

Some tests used to help determine the extent of paralysis include:

  • X-ray: where small doses of radiation pass through your body to create a picture of the densest areas, such as your bones; X-rays can be a useful way to assess damage to the spine or neck.
  • CT scan: where a computer is used to assemble a series of x-ray images to create a more detailed picture of your bones and tissues. CT scans are often used to assess the degree of damage after a serious head injury or spinal cord injury.
  • MRI scan: Using strong magnetic fields and radio waves to produce a detailed picture of the inside of your body, an MRI can help detect brain damage or spinal cord damage.
  • Myelography: a way to check the nerve fibers in the spinal cord in more detail (a special liquid called contrast dye is injected into the nerves that makes them show up very clearly on an X-ray, CT scan, or MRI).
  • Electromyography: where sensors are used to measure electrical activity in muscles and nerves. Electromyography is often used to diagnose Bell’s palsy (temporary facial palsy).


There is currently no cure for permanent paralysis.

The goal of treatment is to help a person adjust to life with paralysis by making them as independent as possible.

Another important goal of treatment is to address health problems and associated complications that arise from paralysis, such as pressure ulcers.

Several treatment options and aids available for people with paralysis are described below:

Mobility aids

A range of mobility devices, such as wheelchairs, are available for people with paralysis.


There are two main types of wheelchairs:

  1. Manual wheelchairs – designed for people with good upper body muscle strength.
  2. Power wheelchairs – designed for people with low upper body muscle strength or quadriplegia (paralysis in all four limbs).

There is also a relatively new type of wheelchair known as a standing chair, which functions like a wheelchair but allows the person to stand up.

This helps reduce the risk of developing pressure ulcers. However, standing chairs can be expensive and are heavier than standard chairs.


Orthotics are an alternative to wheelchairs.

They are braces generally made of plastic or metal designed to improve limb function and compensate for muscle weakness.

Examples of orthoses include:

  1. Wrist orthosis – designed to transfer force from a functional wrist to paralyzed fingers.
  2. Ankle and foot orthosis: designed for people with some lower limb function to help them move their feet while walking.
  3. Knee and Ankle Orthosis – Designed for people with tetraplegia (paralysis of the lower extremities, also known as quadriplegia) to stabilize the knee and ankle and allow them to swing their legs when walking.

A neuroprosthesis is a newer type of orthosis. Neuroprostheses are based on a technique called functional electrical stimulation.

In this type of stimulation, electrodes (small metal discs attached to the skin) are used to deliver electrical currents to the muscles of the legs or arms.

The currents stimulate the muscles to move in the same way that the brain would normally.

Functional electrical stimulation is not suitable for people with conditions that directly damage the nerves in the legs, such as motor neuron disease and Guillain-Barré syndrome.

This is because the nerves will not react to electrical currents.

Wearing an orthosis can be physically demanding, so it may not be suitable for everyone.

Assistive technology

There is also a wide range of assistive technology that can help a person with paralysis maintain their independence and improve their quality of life.

Examples include:

  • Room Control Units – Voice-activated control units that you can use to control things like lighting, temperature, or the telephone in your home.
  • Specially adapted computers : such as voice-activated computers, special keyboards that can be controlled with equipment placed in the mouth, and cursors that can be controlled with a laser beam attached to the head.
Bladder and bowel management

Almost all types of spinal cord injury and many types of generalized paralysis result in loss of normal bowel and bladder function.

This is because the nerves that control the bowel and bladder are located at the base of the spinal cord.

Most people use a catheter to empty urine from the bladder.

A catheter is a thin, flexible tube that is inserted into the urethra (the opening in the penis or vagina that urine comes out of) or through a hole in the abdomen.

The catheter is guided into the bladder, allowing urine to flow through it and into a drainage bag.

There are many methods that can be used to control a paralyzed bladder.

The recommended method will depend on the capacity of the patient, the condition of the bladder, and the resources available.

It is important to ensure that the bladder is emptied regularly because an overly full bladder can trigger a serious complication called autonomic dysreflexia in spinal cord injuries.

There are two main treatment options to help people with paralysis empty their bowels:

  • Bowel Retraining – which aims to improve stool consistency and establish a regular schedule for emptying your bowel, as well as helping you find ways to stimulate your bowel to empty it.
  • Alternative methods: such  as enemas, where liquid is injected into the intestine to help stimulate it to empty.
  • A colostomy: which is an operation in which a section of the intestine is bypassed and connected to an opening in the abdominal wall.
Neuropathic pain

Neuropathic pain is pain caused by damage to the nerves.

Many people with a spinal cord injury and others with other types of paralysis have long-term pain that persists for weeks, months, or even years after the injury or incident that caused the paralysis.

Unlike most other types of pain, neuropathic pain generally does not respond well to common pain relievers, such as acetaminophen or ibuprofen.

Alternative medications, such as amitriptyline or pregabalin, are usually required.

These types of medications can cause a wide range of side effects, so it can take time to identify one that is suitable and effective for managing symptoms without causing unpleasant side effects.

Possible side effects include dry mouth, sweating, drowsiness, and vision problems.

There have been reports of people having suicidal thoughts while taking amitriptyline.

Breathing difficulties

When a spinal cord injury is sustained in the upper neck, the diaphragm will become paralyzed.

Since the diaphragm, which is in charge of inhaling and exhaling, will not be able to help you breathe, you will need ventilation with a ventilator.

A ventilator is a machine that does the work of the diaphragm by controlling lung pressure.

This can be done in one of two ways, using either a:

  • Negative pressure ventilator : where the ventilator creates a vacuum (a complete lack of air) around the lung, causing the chest to expand and inhale the air.
  • Positive pressure ventilator : where the ventilator pushes oxygen directly into the lungs.

Positive pressure fans are more widely used because they are generally smaller and more convenient.

A positive pressure fan can be:

  • Invasive : in which an incision is made in the throat and a tube is inserted into the windpipe.
  • Non-invasive – where a tube is inserted into the nose or air is supplied through a mouthpiece.

A non-invasive ventilation system carries a lower risk of causing a lung infection, such as pneumonia.

However, non-invasive ventilators are not suitable for people with more extensive paralysis who have difficulty swallowing.

An alternative to using a ventilator is a device called a phrenic nerve stimulator. The phrenic nerve controls the diaphragm.

The device is surgically implanted in the chest and sends regular electrical impulses to the phrenic nerve, causing the diaphragm to contract and expand and fill the lungs with air.

Cough reduction

Another problem that affects most people with paralysis is that their ability to cough is reduced.

This is because the cough reflex is triggered by the muscles in the abdomen and between the ribs, pressing into the lungs.

If these muscles are paralyzed, the force of a person’s cough can be greatly reduced.

This is potentially serious because a person’s ability to cough allows them to clear their lungs of a buildup of mucus and other secretions.

A reduced cough can cause the lungs to become congested, increasing the risk of a lung infection. One technique used to compensate for this is known as assisted coughing.

It involves a relative or caregiver pushing against the outside of your stomach while trying to cough.

There are also several devices available to help you cough.

They usually consist of vests that can contract against the lungs, compensating for the loss of muscle action.

It is important to take these precautions to reduce your risk of developing a lung infection:

  • Sit up every day and roll over regularly while lying down to prevent phlegm build-up.
  • Make sure to cough regularly.
  • Drink plenty of water to dilute any phlegm and facilitate expectoration.
  • Avoid smoking or being in close contact with people who smoke.
  • Get vaccinated against the flu and against pneumococcus because it helps reduce the risk of developing influenza and pneumonia.
Spasticity and muscle spasms

Spasticity is a medical term that means abnormally stiff muscles.

Many people with paralysis develop involuntary muscle spasms and spasms.

Spasticity and muscle spasms are usually caused by the section of the spinal cord below the point where the injury ‘fails’ and sends abnormal signals to the extremities.

In some cases, spasticity and muscle spasms can be helpful.

For example, if you have partial paralysis of your legs, stiff muscles can make your legs easier to control.

Some people also find that a series of muscle spasms make it easier for them to empty their bladder or bowel.

However, in other cases, spasticity and muscle spasms can be painful, affect mobility, and interfere with daily activities.

Treatments for spasticity and muscle spasms are treated with:

Muscle relaxants
The first type of medicine that may be prescribed for you is a muscle relaxant, such as baclofen, tizanidine, or dantrolene, usually taken in tablet form.

Sedatives like Diazepam should be avoided except in severe cases.

All of these medications can cause sedation as a side effect.

Botulinum toxin

If muscle relaxants are not effective, a botulinum toxin (Botox) injection may be given for localized spasms.

It works by blocking signals from the brain to affected muscles.

The effects of the injection usually last up to three months.

Treatment is most effective when used in conjunction with a stretching and physical therapy program.

Intrathecal baclofen therapy

Another possible treatment is intrathecal baclofen therapy.

This involves surgically implanting a small pump on the outside of the body connected to the spinal cord.

The pump delivers regular doses of a medicine called Baclofen directly to the spine.

It blocks some of the nerve signals that cause muscle stiffness.