Introduction

Poliomyelitis or simply polio is a highly contagious viral disease caused by the poliovirus. According to the latest data from the World Health Organisation, in 2021 only 6 cases were reported worldwide from more than 3 lakh cases about four decades ago. Though the havoc of polio has dramatically subsided, awareness of contagious diseases and their long-term consequences is still relevant. Post-polio syndrome is one of such long-term consequences of being infected by the virus.¹

Since the formation of the Global Polio Eradication Initiative in 1988, and the robust response by the responsible stakeholders, the disease is now endemic to only a few countries such as Pakistan and Afghanistan. In the next section, we will inform you of how one gets it and what the symptoms are.¹

Understanding post-polio syndrome

Post-polio syndrome (PPS) is a disorder of the nerves that only occurs in those who have been diagnosed with poliomyelitis at an early age. It takes about 15-20 years for the condition to develop and about 40% of the polio survivors develop the condition. Unlike poliomyelitis which is a highly contagious disease, PPS is not contagious at all. Post-polio syndrome just reflects the neurological manifestations after being affected by polio at earlier stages of life.^1,2

There is no longitudinal risk associated with post-polio syndrome but as PPS occurs in those who have once suffered from poliomyelitis, it can be said that children below 5 years of age form the high-risk group for poliomyelitis but not PPS. With ongoing robust vaccination drives throughout the world since the 1950s it can be said that if a child is vaccinated against polio then they can be considered as safe.¹

Causes of post-polio syndrome

Though it is still unclear how PPS develops in a person, some close assumptions have been made by the researchers so far regarding this condition that might answer this question. But we need to look at the factors and mechanisms of polio infection to conclude. The long incubation period (period from exposure to the virus to the clinical symptoms of the outcome condition) associated with the condition makes it challenging for researchers to observe patients.³

The Polio virus is transmitted through food materials such as water or vegetables contaminated with the faeces of an infected person. It can pass from one person to another through the saliva. Inside the body of a healthy person the virus eventually invades the blood and lymphatic system and at last, invades the central nervous system(brain and spinal cord). After invading the central nervous system the virus rapidly multiplies itself and starts destroying the nerve cells.^1,3

The motor neurons (the neurons that are destined to obey the command or respond to the messages) are the prime targets of these viruses. Motor neurons in our body are responsible for responding to any stimuli such as the movement of body parts or muscle activity in general. Due to intense damage and destruction caused by the viruses, the motor neurons fail to respond to the commands of the brain.³

Now it is thought that after intervention, during the recovery phase, as a response to damage caused by the virus, our body produces a large number of branched nervous system cells that are not well suited to resume the entire work done mostly by the specialized motor neurons. These highly branched cells are called the dendritic cells. Due to years of malfunction and overload of work, the nervous system at last fails to maintain these small branched cells and the entire system starts to shut down causing a lack of muscle function.³

This theory is the most convincing so far. Other theories are also there which are more complex and based on biochemical pathways of the body and mostly beyond the apprehension of the common people.

Symptoms of post-polio syndrome

Though there are a myriad of symptoms that could be associated with a syndrome like PPS and some symptoms are more common than the other, the following symptoms are more significant and are mostly reported.⁴

Muscle and joint pain: Muscle and joint discomfort are common in post-polio syndrome, similar to arthritis symptoms. The joint feels uncomfortable and stiff, and limits movement. Muscle pain comes as cramps and spasms, causing discomfort. It gets worse after using those muscles, especially in the evenings after a long day of activity.⁴

Muscle and joint weakness: In post-polio syndrome, heightened muscular weakness emerges as another hallmark symptom. This weakness is often mistaken for muscle exhaustion, yet they differ fundamentally. While exhaustion means a temporary state of fatigue following exertion, muscular weakness signifies a progressive inability to utilise affected muscles, irrespective of fatigue levels.⁴

Additionally, individuals with post-polio syndrome might notice a reduction in muscle size, indicating muscle shrinkage or atrophy.⁴

Generalized weakness: Generalized weakness is the other most important symptom of muscle fatigue. In the case of PPS patients often feel severe exhaustion and lack of energy and motivation to perform daily chores. As a result of fatigue, these patients may feel sleepy during the day as well.⁴

Other Symptoms.⁴

Mental exhaustion: Generally these patients feel profuse mental exhaustion as lack of mobility may lead to depression, the severity of which can vary from person to person. It has also been found that PPS affects memory and mimics other diseases like Parkinson’s at times. Dementia is a common finding in this case and lack of concentration has also been reported earlier.

Cold intolerance: It has been found that patients who are suffering from PPS have a lower threshold than a normal person to cope with low temperature.

Dysphagia: Dysphagia means difficulties in swallowing. Some patients may feel changes in the process of swallowing food or drinks due to altered muscle strength and activity. These changes may lead to feeling uncomfortable while swallowing or in cases where the patient feels extreme difficulties with swallowing.

Altered posture and difficulties with mobility: Patients with PPS due to lack of muscle activity and weak muscles may feel a change in posture and it has mostly been found that these patients have reduced mobility. Most of the patients need some sort of walking aid to keep themselves mobile.⁴

Diagnosis of post-polio syndrome

Diagnosis of PPS is too specific and complex at the same time as well. Since it is only associated with prior polio infection an accurate history is necessary to make its diagnosis. However, a consultation with a specialist professional and further testing is necessary to rule out other conditions and make the exact diagnosis. Further testing may also facilitate understanding of the disease progression.^4,5

Some tests that may be employed to evaluate the condition are:^4,5

1. Magnetic Resonance Imaging(MRI) scans to assess the muscles and internal organs
2. Electromyography test to assess the electrical activity of the muscles and nerves. The electrical activity of these gives an idea of the extent of the damage caused by the virus
3. A Computed Tomography(CT) scan is not routine but is done sometimes to assess the condition of the bony structure of the body as lack of movement and muscle shrinkage affect the bony structures as well
4. Sleep study and Spirometry (to assess the condition of the lungs)
5. Psychiatric observation to assess mental health

Management of post-polio syndrome

Unfortunately, no specific treatment is available for a patient who is suffering from PPS but in most cases, the treatment is mediated by a multidisciplinary medical team that is constituted of a General practitioner(GP), a neurologist, an internal medicine specialist, a physiotherapist and a mental health professional.⁵

To get relief from pain over the counter (OTC) medicines such as Non-steroidal anti-inflammatory drugs (NSAID) like ibuprofen or paracetamol are prescribed.

Gabapentin is also recommended if NSAIDs fail. Gabapentin is a drug that is recommended for severe conditions of epilepsy but in cases of PPS, it has been found to be helpful.⁵

For muscle-related issues help from a physiotherapist is crucial and several exercises are recommended that are helpful to reclaim partial mobility. Walking aids such as walking sticks or wheelchairs are generally necessary for these patients.⁵

Due to the lack of mobility of the lung muscles these patients are particularly prone to diseases such as pneumococcal meningitis so vaccination is recommended for these patients. Other regular vaccines are also mandatory for these patients as lack of mobility makes them prone to get infectious diseases easily.⁵

Psychological support is extremely necessary for these patients as they become more or more socially isolated and become prone to severe mental issues such as chronic depression. Support from a nutritionist is also crucial for planning meal strategies.⁵

Conclusion

In conclusion, despite the fact that polio has become far less common over time as a result of extensive immunisation campaigns, survivors still have to deal with long-term effects, including post-polio syndrome (PPS). PPS greatly affects day-to-day functioning and is typified by weakness, weariness, and discomfort in the muscles and joints. A comprehensive review, generally comprising a number of medical tests, is necessary for diagnosis. PPS does not currently have a particular treatment; however, supportive interventions and multidisciplinary care can help control symptoms and enhance quality of life. Sustained investigation and consciousness are crucial for enhancing comprehension and tackling the intricacies of post-polio syndrome.

FAQs

Do I get polio if I come in contact with a PPS patient?

No, it is not possible to get polio from a PPS patient as PPS is not a contagious condition.

How severe is PPS?

Though it is not generally considered to be a life-threatening condition quality of life is greatly impacted by the condition. So these patients need continuous care.

Does PPS affect the immune system?

In one way or another yes it does. It is debatable if it causes any autoimmune condition where immunity cells attack their own tissues but loss of mobility, poor mental health and improper nutrition have been associated with reduced immunity.

I am feeling generalised weakness and muscle loss. Do I have PPS?

Not necessarily as it depends on your history. If you were affected by polio at an early age then it might be PPS but in general, these two symptoms are associated with a range of diseases and conditions. Please consult with your GP for more information.