Paralysis is the loss of muscle function in part of your body. It happens when something goes wrong with the way messages pass between your brain and muscles. Paralysis can be complete or partial. It can occur on one or both sides of your body. It can also occur in just one area, or it can be widespread. Paralysis of the lower half of your body, including both legs, is called paraplegia. Paralysis of the arms and legs is quadriplegia.

Most paralysis is due to strokes or injuries such as spinal cord injury or a broken neck. Other causes of paralysis include:

• Nerve diseases such as amyotrophic lateral sclerosis
• Autoimmune diseases such as Guillain-Barre syndrome
• Bell's palsy, which affects muscles in the face

Polio used to be a cause of paralysis, but polio no longer occurs in the U.S.

The Spinal Cord

The description of the CNS is concentrated on the structures of the brain, but the spinal cord is another major organ of the system. Whereas the brain develops out of expansions of the neural tube into primary and then secondary vesicles, the spinal cord maintains the tube structure and is only specialized into certain regions. As the spinal cord continues to develop in the newborn, anatomical features mark its surface. The anterior midline is marked by the anterior median fissure, and the posterior midline is marked by the posterior median sulcus. Axons enter the posterior side through the dorsal (posterior) nerve root, which marks the posterolateral sulcus on either side. The axons emerging from the anterior side do so through the ventral (anterior) nerve root. Note that it is common to see the terms dorsal (dorsal = “back”) and ventral (ventral = “belly”) used interchangeably with posterior and anterior, particularly in reference to nerves and the structures of the spinal cord. You should learn to be comfortable with both.

On the whole, the posterior regions are responsible for sensory functions and the anterior regions are associated with motor functions. This comes from the initial development of the spinal cord, which is divided into the basal plate and the alar plate. The basal plate is closest to the ventral midline of the neural tube, which will become the anterior face of the spinal cord and gives rise to motor neurons. The alar plate is on the dorsal side of the neural tube and gives rise to neurons that will receive sensory input from the periphery.

The length of the spinal cord is divided into regions that correspond to the regions of the vertebral column. The name of a spinal cord region corresponds to the level at which spinal nerves pass through the intervertebral foramina. Immediately adjacent to the brain stem is the cervical region, followed by the thoracic, then the lumbar, and finally the sacral region. The spinal cord is not the full length of the vertebral column because the spinal cord does not grow significantly longer after the first or second year, but the skeleton continues to grow. The nerves that emerge from the spinal cord pass through the intervertebral formina at the respective levels. As the vertebral column grows, these nerves grow with it and result in a long bundle of nerves that resembles a horse’s tail and is named the cauda equina. The sacral spinal cord is at the level of the upper lumbar vertebral bones. The spinal nerves extend from their various levels to the proper level of the vertebral column.

Gray Horns

In cross-section, the gray matter of the spinal cord has the appearance of an ink-blot test, with the spread of the gray matter on one side replicated on the other—a shape reminiscent of a bulbous capital “H.” As shown in image, the gray matter is subdivided into regions that are referred to as horns. The posterior horn is responsible for sensory processing. The anterior horn sends out motor signals to the skeletal muscles. The lateral horn, which is only found in the thoracic, upper lumbar, and sacral regions, is the central component of the sympathetic division of the autonomic nervous system.

Some of the largest neurons of the spinal cord are the multipolar motor neurons in the anterior horn. The fibers that cause contraction of skeletal muscles are the axons of these neurons. The motor neuron that causes contraction of the big toe, for example, is located in the sacral spinal cord. The axon that has to reach all the way to the belly of that muscle may be a meter in length. The neuronal cell body that maintains that long fiber must be quite large, possibly several hundred micrometers in diameter, making it one of the largest cells in the body.

White Columns

Just as the gray matter is separated into horns, the white matter of the spinal cord is separated into columns. Ascending tracts of nervous system fibers in these columns carry sensory information up to the brain, whereas descending tracts carry motor commands from the brain. Looking at the spinal cord longitudinally, the columns extend along its length as continuous bands of white matter. Between the two posterior horns of gray matter are the posterior columns. Between the two anterior horns, and bounded by the axons of motor neurons emerging from that gray matter area, are the anterior columns. The white matter on either side of the spinal cord, between the posterior horn and the axons of the anterior horn neurons, are the lateral columns. The posterior columns are composed of axons of ascending tracts. The anterior and lateral columns are composed of many different groups of axons of both ascending and descending tracts—the latter carrying motor commands down from the brain to the spinal cord to control output to the periphery.

What is a spinal cord injury?

A spinal cord injury (SCI) is damage to the bundle of nerves and nerve fibers that sends and receives signals from the brain. The spinal cord extends from the lower part of the brain down through the lower back.

SCI can be caused by direct injury to the spinal cord itself or from damage to the tissue and bones (vertebrae) that surround the spinal cord. This damage can cause temporary or permanent changes in feeling, movement, strength, and body functions below the site of injury.

Symptoms

The symptoms of spinal cord injuries depend on the extent and location of the injury. The higher up on the spinal cord an injury occurs, more of the body is affected. An injury higher on the spinal cord can cause paralysis in most of the body and affect all limbs (tetraplegia or quadriplegia). An injury that occurs lower down the spinal cord may only affect a person’s lower body and legs (paraplegia). Paralysis can happen immediately upon injury (primary damage) or develop over time from bleeding and swelling in the spinal cord and cell death (secondary damage).

A spinal cord injury can damage a few, many, or almost all of the nerve fibers that cross the site of injury. If the injury causes little or no nerve cell death, a person can make an almost complete recovery.

SCI can cause one or more symptoms, including:

• Numbness, tingling, or a loss of (or changes in) sensation in hands and feet
• Paralysis (loss of movement)
• Pain or pressure in the head, neck, or back
• Weakness in any part of the body

• Unnatural positions of the spine or head
• Loss of bladder and bowel control
• Problems with walking
• Difficulty breathing
• Changes in sexual function

Types of SCI

SCI can be described as complete or incomplete.

1. An incomplete injury means the spinal cord is still able to send some messages to or from the brain. People with incomplete injuries still have some feeling, function, and muscle control below the site of their injury.
   
2. A complete injury means that there is no nerve communication below the injury site; muscle control, feeling, or function below the injury is lost.

Anatomy of the spinal cord

The spinal cord is a soft, cylindrical column of tightly bundled cells (nerve cells and glia), nerve fibers that transmit nerve signals (called axons), and blood vessels. It sends and receives information between the brain and the rest of the body. Millions of nerve cells situated in the spinal cord itself coordinate complex patterns of movements such as rhythmic breathing and walking.

The spinal cord extends from the brain to the lower back through a canal in the center of the vertebrae. Like the brain, the spinal cord is protected by three layers of tissue and is surrounded by the cerebrospinal fluid (CSF) that acts as a cushion against shock or injury.

Inside the spinal cord are:

• A collection of nerve cells and their projections that connect with other nerve cells to transmit and receive information (gray matter)
• Bundles of nerve fibers (axons), some of which are coated with a whitish mixture of proteins and fat-like substances (white matter) that connects nerve cells over longer distances.

Other types of nerve cells sit just outside the spinal cord and relay information to and from the brain.

• Cervical spinal nerves (known as C1 to C7) in the neck control signals to the back of the head, the neck and shoulders, the arms and hands, and the diaphragm.
• Thoracic spinal nerves (known as T1 to T12) in the upper mid-back control signals to the chest muscles, some muscles of the back, and many organ systems.
• Lumbar spinal nerves (known L1 to L5) in the low back control signals to the lower parts of the abdomen and the back, the buttocks, some parts of the external genital organs, and parts of the leg.
• Sacral spinal nerves (known S1 to S5) in the low back control signals to the thighs and lower parts of the legs, the feet, most of the external genital organs, and the area around the anus.

The spinal column, which surrounds and protects the spinal cord, is made up of 33 rings of bone (vertebrae), pads of cartilage (discs), and narrow spaces called foramen that act as passages for spinal nerves to travel to and from the rest of the body. The spinal cord is particularly vulnerable to direct injury within the foramen.

Who is more likely to get a spinal cord injury?

Motor vehicle accidents and serious falls are the most common causes of SCI in the U.S. Other causes include acts of violence (primarily gunshot wounds and assaults), sports injuries, medical or surgical injury, industrial accidents, diseases, and conditions that can damage the spinal cord. Risk factors include age (either being between the ages of 16 and 30, or after age 65 for dangerous falls), alcohol use, certain diseases, or not wearing proper gear, such as a seat belt or protective sports equipment.

How is a spinal cord injury diagnosed and treated?

Diagnosing SCI

The emergency room physician will check for movement or sensation at or below a suspected SCI, as well as for proper breathing, responsiveness, and weakness. Medical tests for SCI include:

• Magnetic resonance imaging (MRI) can show brain and spinal trauma from injury, herniated discs (problems with the cartilage located between the vertebrae), vascular (blood vessel) irregularities, bleeding, inflammation that might compress the spine and spinal cord, and injury to the ligaments that support the cervical spine.
• Computerized tomography (CT) can detect bone fractures, bleeding, and spinal stenosis (narrowing of the spinal canal).
• X-rays can show vertebrae misalignment and fractures within minutes of injury.

Treating SCI

At the accident scene, if SCI is suspected, emergency personnel will place a rigid collar around the neck and carefully place the individual on a backboard to prevent further damage to the spinal cord. They may use sedatives to relax the person and prevent movement. A breathing tube may be inserted if there are problems breathing and the body isn't receiving enough oxygen from the lungs.

Doctors are now able to predict with reasonable accuracy the likely long-term outcome of SCI. This helps people experiencing SCI to set achievable goals for themselves and gives families and loved ones a realistic set of expectations for the future.

Immediate treatment at the trauma center or emergency room may include:

• Realigning the spine using a rigid brace or mechanical force, which is usually done as soon as possible to stabilize the spine and prevent additional damage.
• Surgery to remove any fractured vertebrae, bone fragments, herniated discs, or other objects that are pressing on the spinal column. Spinal decompression surgery to relieve pressure within the spinal column may also be necessary in the days after injury. Results of neurosurgical studies show that, in some cases, earlier surgery is associated with better functional recovery.

SCI may result in the following problems, which require treatment:

• Breathing problems—About one-third of people with a SCI will need temporary or permanent help with breathing and may require a breathing tube. Any injury to the spinal cord between the C1-C4 segments can stop breathing as the nerves in this region cause the diaphragm to move and the lungs to expand. Special training regarding breathing and swallowing may be needed for the individual with SCI as well as for the caregivers.
• Pneumonia—Respiratory complications are the leading cause of death in people with SCI, commonly as a result of pneumonia. Individuals using a ventilator to assist with breathing (intubation), are at increased risk of developing pneumonia. The person with a SCI must be carefully monitored and treated with antibiotics if symptoms of pneumonia appear. Pneumonia can be prevented by clearing the throat and taking precautions to avoid food and liquids being sucked into the lungs (aspiration).
• Circulatory problems—Changes in circulation can lead to unstable blood pressure, abnormal heart rhythms (arrhythmias), and blood clots that may appear days after injury. The injured person should be carefully monitored for each of these common post-SCI issues. People with spinal cord injuries are at increased risk for blood clots due to stagnation of blood flow in the large veins in the legs. Anticoagulant drugs and compression stockings to increase blood flow in the lower legs and feet and reduce the risk for blood clots.
• Stiffness and changes in muscle tone—Reflexes may become exaggerated over time, causing muscle stiffness and an increase in muscle tone (spasticity) that may require special treatment. Muscles below the injury site may deteriorate when they are not used.
• Autonomic dysreflexia—Autonomic dysreflexia is a life-threatening reflex action that primarily affects those with injuries to the neck or upper back. Symptoms may include flushing or sweating, a pounding headache, anxiety, sudden increase in blood pressure, vision changes, or goose bumps on the arms and legs. If possible, the person should be kept in a sitting position to keep blood flowing to the legs and feet and help reduce blood pressure.
• Pressure sores (also known as pressure ulcers)—Pressure sores are areas of skin that have broken down because of continuous pressure on the skin and reduced blood flow to the area. People with paraplegia and tetraplegia are susceptible to pressure sores. As a result, individuals must move and change their position periodically, either on their own or with the help of assistive devices or a caregiver.
• Pain—Some people with SCI develop neurogenic pain—an intense burning or stinging sensation. This pain may be constant or may come and go. It can be triggered by a variety of factors and may even be felt in parts of the body that have otherwise lost sensation. Treatments for chronic pain include medications, acupuncture, spinal or brain electrical stimulation, and surgery. However, none of these treatments are completely effective at relieving neurogenic pain long term.
• Bladder and bowel problems—Individuals may need to use a catheter to empty their bladder and learn new ways to empty the bowels. The person may need to change their diet.
• Sexual function—Depending on the severity and location of the injury, and the individual’s recovery after the injury, their sexual function and fertility may be affected. A urologist and other specialists can suggest different options to support sexual functioning and health.
• Depression—Many people living with SCI may develop depression due to lifestyle changes after the injury. Therapy and medicine can help treat depression and other mental health conditions.

Rehabilitation

Rehabilitation programs for people with SCI combine physical therapies with skill-building activities and counseling designed to provide social and emotional support and increase the person’s independence and quality of life. The rehabilitation team is usually led by a doctor specializing in physical medicine and rehabilitation and may include social workers, physical and occupational therapists, recreational therapists, rehabilitation nurses, rehabilitation psychologists, vocational counselors, nutritionists, a case worker, and other specialists.

The initial phase of rehabilitation after injury is usually focused on regaining communication skills and leg and arm strength. Adaptive or assistive devices may help people with SCI to regain independence and improve mobility and quality of life. Depending on the severity of the injury, the person may need braces, a wheelchair, electronic stimulators, assisted training with walking, neural prosthetics (assistive devices that may stimulate the nerves to restore lost functions), computer adaptations, and other computer-assisted technology. Adaptive devices can also help with communication skills such as writing, typing, and using the telephone.

• Physical therapy includes exercise programs geared toward strengthening muscles.
• Occupational therapy helps redevelop fine motor skills, particularly those needed to perform activities of daily living such as getting in and out of a bed, personal hygiene, eating, and using the toilet. The person may learn how to cope with spasticity, autonomic dysreflexia, and neurogenic pain as part of their occupational therapy.
• Vocational rehabilitation includes identifying basic work skills and physical and cognitive capabilities that can support paid work. Through this process, the person and their team can identify potential workplaces and any assistive equipment that will be needed and arrange for a user-friendly workplace.
• Educational training can help the person develop skills for a new line of work that may be less dependent upon a person’s physical abilities. People with SCI are encouraged to participate in activities that provide a sense of satisfaction and self-esteem, such as educational classes, hobbies, special interest groups, and participating in family and community events.
• Recreation therapy encourages people with SCI to participate in sports, arts, or other leisure activities that they can do with their new level of mobility. This can help people achieve a balanced lifestyle that provides opportunities for socialization and self-expression.

What are the latest updates on spinal cord injury?

NINDS, a component of NIH, is a primary funder of research on the brain and spinal cord. NIH is the leading supporter of biomedical research in the world.

NINDS investment in establishing the field of neural devices has supported significant advances with potential to improve post-injury quality of life for people with SCI. For example, researchers are developing an electrical stimulation system that is used as a network to restore functional independence through combined implants for hand function, postural control, and bowel and bladder control. Other research involves stimulating the spinal cord below the level of injury to help spared cells and fibers function. NINDS has also led development of experimental brain computer interfaces that enable people to control a computer cursor or robotic arm directly from their brains.

Current research on SCI is focused on advancing our understanding of the four key principles of spinal cord repair:

• Neuroprotection—Preventing cell death and protecting surviving nerve cells from further damage, including using drugs to reduce nerve cell death and lowering of the body's core temperature to reduce damage and improve functional outcome.
• Repair and regeneration—Encouraging the spinal cord to self-repair and stimulating the regrowth of nerve fibers. These efforts include exploring cell transplants, growth-promoting substances, and bioengineered growth scaffolds.
• Cell-based therapies—Replacing damaged nerve or support cells with other cell types, including stem cells, to jumpstart nerve cell growth and create new cell connections.
• Neuroplasticity—Retraining central nervous system circuits to restore body functions and form new nerve connections and pathways following injury or cell death through techniques like rehabilitation, electrical stimulation, robot-assisted training, and brain-computer interface technology that may help with voluntary muscle movement and coordination.

Further research includes basic spinal cord function studies on how the spinal cord develops, processes sensory information, controls movement, and generates rhythmic patterns like walking and breathing. Studies using cells and animal models provide an essential foundation for developing interventions for spinal cord injury. And research on injury mechanisms focuses on what causes immediate harm and on the cascade of reactions the body deploys that protect from (or contribute to) secondary damage in the hours and days following a SCI This includes testing neuroprotective interventions in animal models.

The Brain Research through Advancing Innovative Technologies® (BRAIN) Initiative brings multiple federal agencies and private organizations together to develop and apply new technologies to understand how complex circuits of nerve cells enable thinking, movement control, and perception. BRAIN’s SCI research includes:

• Exploring brain circuits to better understand the sensory and motor basis of behavior
• Next-generation neural prosthetics, or devices that connect to the nervous system and restore functions lost due to disease or injury
• Improved brain and spinal cord imaging
• New brain-computer interface devices

Your spinal cord is a bundle of nerves that runs down the middle of your back. It carries signals back and forth between your body and your brain. A spinal cord injury disrupts the signals. Spinal cord injuries usually begin with a blow that fractures (breaks) or dislocates your vertebrae, the bone disks that make up your spine. Most injuries don't cut through your spinal cord. Instead, they cause damage when pieces of vertebrae tear into cord tissue or press down on the nerve parts that carry signals.

Spinal cord injuries can be complete or incomplete. With a complete spinal cord injury, the cord can't send signals below the level of the injury. As a result, you are paralyzed below the injury. With an incomplete injury, you have some movement and sensation below the injury.

A spinal cord injury is a medical emergency. Immediate treatment can reduce long-term effects. Treatments may include medicines, braces or traction to stabilize the spine, and surgery. Later treatment usually includes medicines and rehabilitation therapy. Mobility aids and assistive devices may help you to get around and do some daily tasks.

What is polio?

Polio, or poliomyelitis, is a disease that spreads from person to person. It is caused by the poliovirus. The virus attacks the nervous system. In serious cases, it can cause paralysis (where you can't move parts of the body). The paralysis may be lifelong and can sometimes be life-threatening.

Because of vaccines, polio is rare in the United States. But polio does occur in some parts of the world, and travelers can spread the virus.

How does polio spread?

The poliovirus is very contagious. It spreads through contact with:

• The stool (poop) of person who has the infection
• Droplets from a sneeze or cough of someone who has the infection

This contact can happen if:

• You get contaminated stool or droplets on your hands and then touch your mouth
• A child puts contaminated toys or other objects into their mouth
• You share food or utensils with someone who has the infection

People who have the infection can spread it to others just before and up to several weeks after the symptoms appear. People who don't have symptoms can still spread the virus to others and make them sick.

Who is more likely to develop polio?

Polio mainly affects children under age 5. But people of any age (including adults) who are unvaccinated are at risk of developing polio. People who live in or travel to areas where there is polio are more likely to get polio.

What are the symptoms of polio?

Most people who get infected with poliovirus do not have any symptoms. But one out of four people who get polio will have flu-like symptoms. These symptoms usually last 2 to 5 days, and they include:

• Sore throat
• Fever
• Fatigue
• Nausea
• Headache
• Stomach pain

In rare cases, polio can be very serious. It can lead to:

• Meningitis, an infection of the covering of your spinal cord and/or brain.
• Weakness or paralysis in your arms, legs, or both. This paralysis or weakness can last a lifetime. It is possible for the paralysis to become life-threatening if it affects the muscles that you use to breathe.
• Post-polio syndrome (PPS), which happens later in life.

What is post-polio syndrome (PPS)?

Post-polio syndrome (PPS) is a condition that affects polio survivors many years after they recovered from polio. It usually happens 15-40 years later. It is not contagious.

People who get PPS start having new weakening in muscles that were previously affected by the polio infection. Symptoms may range from mild to serious. The symptoms of PPS include:

• Muscle weakness
• Muscle atrophy (wasting away of muscles)
• Loss of muscle function
• Mental and physical fatigue
• Joint pain
• Curving of the spine (scoliosis)

PPS is rarely life-threatening, but the symptoms can interfere with your daily life.

How is polio diagnosed?

If you think you or someone in your family has symptoms of polio, call your healthcare provider right away or go to an emergency room.

To find out if you or your child has polio, the provider:

• Will do a physical exam.
• Will take a detailed medical history, including your vaccination history and history of any recent travel.
• Will collect samples of body fluids, such as stool, saliva, blood, urine, and spinal fluid. Poliovirus is most likely to be detected in stool specimens.
• May do an MRI to look at pictures of the spinal cord.

What are the treatments for polio and post-polio syndrome (PPS)?

There is no cure or specific treatment for polio. For a mild case, getting rest and drinking plenty of liquids may help with some of the symptoms.

If the polio is more serious, you or your child may need:

• Physical or occupational therapy to help with arm or leg weakness. The earlier therapy is started, the better.
• Pain relievers to help with pain and treat fever. If your child is sick, do not give them aspirin unless their provider tells you to.
• A ventilator to help with breathing if the breathing muscles are weak or paralyzed.

There is no cure for PPS. Treatments may help you manage your symptoms. They include:

• Non-fatiguing exercises (exercises that do not cause pain or fatigue that lasts more than 10 minutes). These exercises may improve muscle strength and reduce tiredness. Your provider can help you figure out which exercises are best for you.
• Mobility aids.
• Ventilation equipment.
• Lifestyle changes, such as eating a healthy diet, getting enough sleep, and not smoking.

Can polio be prevented?

There are two types of vaccine that can prevent polio:

• Inactivated poliovirus vaccine (IPV) given as an injection in the leg or arm, depending on how old you are. Since 2000, this has been the only polio vaccine used in the United States.
• Oral poliovirus vaccine (OPV) is given as drops in the mouth. It is still used throughout much of the world.

Children in the United States get four doses of PV as part of their routine childhood immunizations. Most adults in the United States were vaccinated against polio as children.

There is a one-time IPV booster. It may be given to adults who have completed their polio vaccinations but are at higher risk of contact with poliovirus. You may be at higher risk if you are:

• Traveling to a country where the risk of getting polio is greater
• Working in a laboratory or healthcare setting and handling samples that might contain polioviruses
• A healthcare worker who has contact with patients who could have polio

Another way to help prevent the spread of polio is to wash your hands often with soap and water. Alcohol-based hand sanitizers will not kill poliovirus.

Polio, or poliomyelitis, is a disabling and life-threatening disease caused by poliovirus. The virus spreads from person to person and can invade an infected person’s spinal cord, causing paralysis (can’t move parts of the body). There is no cure, but there are safe and effective vaccines to prevent polio.

Key Facts

• Polio was eliminated in the United States in 1979. This means there is no ongoing spread of the disease for more than 12 months since then. We continue to vaccinate our nation’s children because the disease still occurs in other parts of the world and could easily be brought into the U.S.
• Most people infected with poliovirus have no symptoms. About 24 percent have minor flu-like symptoms that don’t last long. They may have a sore throat, fever, tiredness, nausea, headache, or stomach pain. Only a few people who get poliovirus will develop meningitis (infection of the covering of the spinal cord or brain) or paralysis in the arms or legs.
• Polio was once one of the most feared diseases in the U.S. In the early 1950s, before polio vaccines were available, polio outbreaks caused more than 15,000 cases of paralysis each year.
• While borders can’t stop diseases from spreading, vaccines can. Fortunately, we have a good level of protection against polio in the United States. Most of us have been vaccinated, and current polio vaccination coverage among young children in the United States is 93 percent.

Vaccination Schedule

For best protection, children should get four doses of polio vaccine. This vaccine is given as a shot in the arm or leg and is extremely safe. Ideally, your child should receive a dose at ages 2 months, 4 months, 6 through 18 months, and then a booster dose at age 4 through 6 years.

Polio and Travel

Polio still exists in a few countries in Africa and Asia. Even if you were previously vaccinated, you may need a one-time booster shot before you travel to a country where a risk of getting polio is greater. See your healthcare provider for more information.

Widespread Panic

In the late 1940s to the early 1950s, polio outbreaks in the United States increased in frequency and size. Polio paralyzed more than 35,000 people in the U.S. each year. Parents were frightened to let their children go outside, especially in the summer when the virus seemed to peak.

Prevention Tips

• Polio vaccine provides the best protection against polio.
• Children should get four doses of inactivated polio vaccine (IPV) to protect against polio, with one dose at each of the following ages:
  • 2 months
  • 4 months
  • 6 through 18 months
  • 4 through 6 years
• Children who will be traveling to a country where the risk of getting polio is greater should complete the vaccination series before leaving for their trip. If a child cannot complete the routine series above before leaving, an accelerated schedule is recommended as follows:
  • The first dose at age 6 weeks or older,
  • A second dose 4 or more weeks after the first dose,
  • A third dose 4 or more weeks after the second dose,
  • A fourth dose 6 or more months after the third dose.
• Most adults do not need polio vaccine because they were already vaccinated as children. But three groups of adults are at higher risk and should consider polio vaccination in the following situations:
  • You are traveling to a country where the risk of getting polio is greater. Ask your healthcare provider for up-to-date information on whether you need to be vaccinated.
  • You are working in a laboratory and handling specimens that might contain polioviruses.
  • You are a healthcare worker treating patients who could have polio or have close contact with a person who could be infected with poliovirus.
• Adults in these three groups who have never been vaccinated against polio should get three doses of IPV:
  • The first dose at any time,
  • The second dose 1 to 2 months later,
  • The third dose 6 to 12 months after the second.

• Post-polio syndrome (PPS) is a condition that can affect polio survivors decades after they recover from their initial poliovirus infection.
• Unlike poliovirus, PPS is not contagious.

PPS affects between 25 and 40 out of every 100 polio survivors. Starting about 15 to 40 years after the initial infection, people affected by PPS can begin experiencing a set of health problems such as:

• Muscle weakness
• Feeling tired (mental and physical fatigue)
• Joint pain

Some people with PPS have only minor symptoms, while others develop more visible muscle weakness and atrophy (a decrease in muscle size). PPS is rarely life-threatening, but the symptoms can make it difficult for an affected person to function independently.

Poliovirus is a member of the Enterovirus genus, family Picornaviridae. Enteroviruses are transient inhabitants of the gastrointestinal tract, and are stable at acid pH. Picornaviruses are small, ether-insensitive viruses with an RNA genome. Poliovirus causes polio, or poliomyelitis, a highly infectious disease.

There are three poliovirus serotypes (PV1, PV2, and PV3) with minimal heterotypic immunity between them. That is, immunity to one serotype does not produce significant immunity to the other serotypes.

Poliovirus infects only humans. Poliovirus is spread by the fecal-oral and respiratory routes. Infection is more common in infants and young children. Polio occurs at an earlier age among children living in poor hygienic conditions. In temperate climates, poliovirus infections are most common during summer and autumn. In tropical areas, the seasonal pattern is less pronounced.

What is polio?

• Polio, or poliomyelitis, is a disabling and life-threatening disease caused by the poliovirus.
• The virus spreads from person to person and can infect a person’s spinal cord, causing paralysis (can’t move parts of the body).

What are the symptoms of poliovirus infection?

Most people who get infected with poliovirus will not have any visible symptoms.

About 1 out of 4 people (or 25 out of 100) with poliovirus infection will have flu-like symptoms that can include:

• Sore throat
• Fever
• Tiredness
• Nausea
• Headache
• Stomach pain

These symptoms usually last 2 to 5 days, then go away on their own.

A smaller proportion of people with poliovirus infection will develop other, more serious symptoms that affect the brain and spinal cord:

• Meningitis (infection of the covering of the spinal cord and/or brain)occurs in about 1–5 out of 100 people with poliovirus infection, depending on virus type
• Paralysis (can’t move parts of the body) or weakness in the arms, legs, or both occurs in about 1 out of 200 people to 1 in 2000 people, depending on virus type

Paralysis is the most severe symptom associated with poliovirus because it can lead to permanent disability and death. Between 2 and 10 out of 100 people who have paralysis from poliovirus infection die, because the virus affects the muscles that help them breathe.

Even children who seem to fully recover can develop new muscle pain, weakness, or paralysis as adults, 15 to 40 years later. This is called post-polio syndrome.

Note that “poliomyelitis” (or “polio” for short) is defined as the paralytic disease. So only people with the paralytic infection are considered to have the disease.

Post-Polio Syndrome (PPS)

Polio has been around since ancient times. This ancient Egyptian tomb painting shows a man with a withered leg unable to bear weight without use of a walking stick. This means that most muscle fibers are replaced with scarring (muscle-wasting) that is permanent.

If someone had polio as a child or young adult but had kept or recovered some or all movement of weakened arms or legs, even to the point of being athletic afterward, they can become weaker in late adulthood. That is post-polio syndrome (PPS), a condition that can affect polio survivors decades after they recover from their initial poliovirus infection. Some PPS patients become wheelchair-bound when they had not been before.

Transmission

• Poliovirus is very contagious and spreads through person-to-person contact.
• It lives in an infected person’s throat and intestines.
• It can contaminate food and water in unsanitary conditions.

Poliovirus only infects people. It enters the body through the mouth. It spreads through:

• Contact with the feces (poop) of an infected person
• Droplets from a sneeze or cough of an infected person (less common)

You can get infected with poliovirus if:

• You have picked up minute pieces of feces on your hands, and you touch your mouth.
• You put in your mouth objects like toys that are contaminated with feces.

An infected person can spread the virus to others immediately before and up to 2 weeks after symptoms appear.

• The virus can live in an infected person’s intestines for many weeks. It can contaminate food and water in unsanitary conditions.
• People who don’t have symptoms can still pass the virus to others and make them sick.

Prevention

There are two types of vaccine that can prevent polio:

• Inactivated poliovirus vaccine (IPV) given as an injection in the leg or arm, depending on the patient’s age. Only IPV has been used in the United States since 2000.
• Oral poliovirus vaccine (OPV) is still used throughout much of the world.

Polio vaccine protects children by preparing their bodies to fight the poliovirus. Almost all children (more than 99 percent) who get all the recommended doses of the inactivated polio vaccine will be protected from polio.

It is also very important to practice good hand hygiene and wash hands often with soap and water. Note that alcohol-based hand sanitizers do not kill poliovirus.

Diagnosis

Healthcare providers who suspect a patient has polio should hospitalize the patient right away, do a physical exam, take detailed medical history, including vaccination history and history of any recent travel, collect samples (stool, throat swab, blood, urine, and spinal fluid), and obtain a magnetic resonance imaging (MRI) to look at pictures of the spinal cord. Poliovirus is most likely to be detected in stool specimens.

Treatment

There is no cure for paralytic polio and no specific treatment.

Physical or occupational therapy can help with arm or leg weakness caused by polio and might improve long-term outcomes, especially if implemented early in the course of illness. Healthcare providers should consider consulting neurology and infectious disease experts to discuss possible treatments and recommend certain interventions on a case-by-case basis.

If you think you or someone in your family has symptoms of polio, please call your healthcare provider right away or go to an emergency room.

Mobility aids help you walk or move from place to place if you have a disability or an injury. They include:

• Crutches
• Canes
• Walkers
• Wheelchairs
• Motorized scooters

You may need a walker or cane if you are at risk of falling. If you need to keep your body weight off your foot, ankle or knee, you may need crutches. You may need a wheelchair or a scooter if an injury or disease has left you unable to walk.

Choosing these devices takes time and research. You should be fitted for crutches, canes and walkers. If they fit, these devices give you support, but if they don't fit, they can be uncomfortable and unsafe.

Bell's palsy is the most common cause of facial paralysis. It usually affects just one side of the face. Symptoms appear suddenly and are at their worst about 48 hours after they start. They can range from mild to severe and include

• Twitching
• Weakness
• Paralysis
• Drooping eyelid or corner of mouth
• Drooling
• Dry eye or mouth
• Excessive tearing in the eye
• Impaired ability to taste

Scientists think that a viral infection makes the facial nerve swell or become inflamed. You are most likely to get Bell's palsy if you are pregnant, diabetic or sick with a cold or flu.

Three out of four patients improve without treatment. With or without treatment, most people begin to get better within 2 weeks and recover completely within 3 to 6 months.

Bell's palsy is a neurological disorder that causes paralysis or weakness on one side of the face. One of the nerves that controls muscles in your face becomes injured or stops working properly.

Symptoms include:

• Sudden weakness or paralysis on one side of your face
• A drooping eyebrow and mouth
• Drooling from one side of your mouth
• Difficulty closing an eyelid, which causes eye dryness

Most often these symptoms lead to significant facial distortions.

People living with Bell's palsy may also develop:

• Facial pain or abnormal sensations
• Excessive tearing in one eye
• Problems with taste
• Low tolerance for loud noises
• Pain around the jaw and behind the ear
• Problems eating or drinking

Symptoms appear suddenly over a 48- to 72-hour period and generally start to improve with or without treatment after a few weeks. They vary from person to person and can be mild to severe. Usually, you will recover some or all facial function within a few weeks to six months. Sometimes the facial weakness may last longer or be permanent.

Bell's palsy is the most common cause of facial paralysis, although its exact cause is unknown. It results from dysfunction of cranial nerve VII, which connects your brain to the muscles that control facial expression (the nerve also is involved with taste and ear sensation). In rare cases, Bell's palsy can affect both sides of your face.