Polio - Symptoms, Risk factors and Treatment

Poliomyelitis or polio is a serious infectious disease that affects the nervous system and can cause paralysis of the limbs.

What causes poliomyelitis?

Polio is caused by a virus called poliovirus.

How is polio transmitted?

Polio can be transmitted from one person to another through a fecal-oral route. A person with acute infection with polio sheds the virus in their feces. Ingesting food and water contaminated with feces containing poliovirus serves as a transmission route. Poliovirus is highly contagious and can also be transmitted through contact with the saliva of an infected person (oral-oral route).

What does poliovirus do inside the human body?

The poliovirus multiplies in the gastrointestinal tract. From here, it moves to different areas of the body and multiplies. Subsequently, it is absorbed into the bloodstream, allowing it to spread anywhere in the body. 

How does polio result in paralysis?

In rare cases, the virus spreads along the nerves and destroys the neurons, which damages the nerves and results in paralysis causing paralytic polio.

Types of polio:

Polio is divided into two types:

Non-paralytic (Abortive polio):

In this type, the virus produces mild symptomatic illness and may manifest itself with the following symptoms:

• Fever
• Malaise
• Headache
• Sore throat
• Vomiting
• Muscle stiffness
• Muscle weakness

Nonparalytic polio does not show neurological symptoms. It generally manifests after 3 to 5 days of exposure and may resolve in some days without any paralytic symptoms.

Paralytic polio:

Paralytic polio occurs when the virus spreads along the nerves and damages them, resulting in paralysis- inability to move muscles. Initially, it shows symptoms like that of nonparalytic polio such as fever, malaise, etc, followed by symptoms of paralysis such as:

• Neck stiffness
• Back stiffness
• Weakness of different muscles
• Muscle pain
• Muscle tenderness
• Difficulty swallowing (dysphagia)
• Loss of muscle reflexes
• Pins and needles (paresthesia)
• Irritability
• Constipation 
• Difficulty urinating
• Difficulty breathing

Diagnosis of poliomyelitis:

Polio is suspected in non-immunized individuals. History plays an important role, such as travel history to an endemic place, etc. The diagnosis is generally made on the basis of clinical presentation such as:

• Fever
• Weakness or paralysis on one side of the body
• No sensory loss
• Loss of reflexes

Other than this, the doctor may suggest the following tests to reach a definite diagnosis:

• Lumbar puncture
• Stool culture
• Throat swab
• Cerebrospinal fluid culture
• Blood tests

Treatment of polio:

Nonparalytic polio is mild, symptomatic illness and resolves without treatment.

For paralytic polio, there is no cure, but the disease can be cured. The treatment is supportive and may include:

• Painkillers for pain
• Mechanical ventilation to help with breathing
• Physical therapy 
• Occupational therapy

Prevention of poliomyelitis:

While there is no cure currently available for polio, fortunately, there is an effective prevention for it. The polio vaccine is very effective in preventing this disease from occurring. Polio vaccine is given shortly after birth and is continued to be administered at different ages to eradicate the disease. 

Conclusion:

While mostly, polio does not show any symptoms except a mild, viral illness, it can become paralytic, a condition that is serious and upsetting. Paralytic polio causes lifelong disability and affects the patient’s life drastically. The good news is that an effective vaccine is available to prevent this disease from occurring. Proper immunization throughout the world can help eradicate this disease completely. Therefore make sure that you and everyone around is vaccinated against it.