Why polio survivors may benefit from a lung function test

8 minute read

There is no gold standard to identify or screen for the Late Effects of Polio, but patients need special management as they start to age.

Australia was declared polio-free in 2000, but there is a major need to invest in medical care of many of the tens of thousands of people who contracted poliomyelitis (polio) during the 20th century polio epidemics and are now experiencing what is known as the Late Effects of Polio and its subset, the Post-Polio Syndrome (PPS).

Basic lung function tests could go a long way in preventing complications in polio survivors as they age. These patients often require specific respiratory assessment and recommendations for physiotherapy, orthotics and assistive technology to manage their condition, experts say.

“It is only in the last 20 to 30 years that there has been a better recognition of respiratory compromise in polio survivors,” Dr Stephen de Graaff, director of Pain Services and senior rehabilitation physician at Epworth HealthCare in Melbourne, tells ARR.

“Respiratory physicians have a better knowledge and understanding of Late Effects of Polio and PPS than previously, but we are still learning. Even within the universities and the medical fraternity, teaching emphasises the acute poliomyelitis condition rather than the Late Effects of Poliomyelitis or PPS.”

Causes of respiratory compromise in polio survivors

“The commonest cause of respiratory compromise in polio survivors relates to restrictive lung disease (a decrease in the total volume of air that the lungs are able to hold), but this is often confused with having obstructive lung disease as in asthma, chronic bronchitis or emphysema. However, it doesn’t exclude them from having obstructive lung disease”, says Dr de Graaff.

Causes of restrictive lung disease includes scoliosis, which interferes with the expansion of the chest wall; muscle weakness within the trunk wall and respiratory muscles including the diaphragm; bulbar neurological respiratory compromise; obstructive sleep apnoea with respiratory dysfunction; weight gain due to inability to mobilise to a level that elevates the metabolic rate to assist with weight control; and/or if the patient has had polioencephalitis, a viral infection of the brain that causes inflammation within the brain stem and deep brain structures with significant neurological compromise.

“We tend to see that there are more challenges with respiratory compromise in polio survivors, who are left with upper limb wasting and weakness compared to lower limb wasting and weakness. But patients with lower limb wasting and weakness can have significant scoliosis,” Dr de Graaff says.

“The number of patients who end up with respiratory problems is probably in the vicinity of 20 to 25%, principally because of the mechanical problems with scoliosis and muscle weakness. A small proportion, probably between one and 2%, have bulbar respiratory problems.”

“Shortness of breath with activity, increasing chest wall expansion problems, recurrent chest infections and waking up not refreshed and feeling more fatigued as the day progresses are all signs when a respiratory physician needs to be involved”, says Dr de Graaff, who is also a Board Member of the Australian Institute of Neuro-rehabilitation.

Preferably, that’s a respiratory physician with an interest in polio survivors because then they understand restrictive lung disease in this unique patient group rather than the more common obstructive lung disease, he adds.

Sleep and sleepiness are key

The symptoms that respiratory physicians are most interested in for polio survivors are measures of sleep quality and daytime sleepiness.

“Sleep disordered breathing due to polio often presents with vague symptoms during the day, such as sleepiness or fatigue,” says Dr Michelle Caldecott, respiratory and sleep disorders physician and senior consultant at the Victorian Respiratory Support Service based at Austin Health in Melbourne.

“This should be assessed with a sleep study before attributing new fatigue, sleepiness and functional changes in ageing polio survivors to Late Effects of Polio or PPS.”

“By diagnosing if the patient has sleep disordered breathing, a respiratory physician can play an important role in the education, validation and management of polio survivors facing respiratory impairment,” says Dr Caldecott, who is also the director of Melbourne Lung & Sleep Specialists and the Internal Medicine Clinical Institute at Epworth HealthCare.

“A lung function test is a really good screening tool that should be part of the basic assessment of a patient with a history of polio.”

Dr Caldecott classifies polio survivors with respiratory impairment into two groups: scoliotic patients whose diaphragm strength is well preserved and they are less likely to have sleep disordered breathing; and those that are scoliotic and also have diaphragm weakness.

“It is the second group that may have undiagnosed nocturnal hypoventilation, particularly during REM (rapid eye movement) sleep. The diaphragm is most challenged during REM and could lead to ventilatory failure during REM sleep in polio survivors. Such patients should be referred to a respiratory physician for a lung function test, including measurement of maximal respiratory pressures to evaluate the diaphragm strength, and a sleep study,” she recommends.

Dr Caldecott says that there is a gap in the understanding of sleep disordered breathing and nocturnal hypoventilation. Failure of ventilation during sleep in this patient group is not always considered as a cause for non-specific daytime symptoms, such as morning headaches or sleepiness.

“It’s not unusual to meet a polio survivor in a crisis state. Of the many polio patients, I’ve met in the past two and a half decades, they’ve often presented with established high carbon dioxide respiratory failure. This undiagnosed hypercapnic respiratory failure due to sleep disordered breathing can sometimes prove fatal for polio survivors,” she warns.

Anaesthesia in polio survivors

Dr Caldecott’s polio survivor patients are generally over 50 years old. These are patients who contracted the disease during the polio epidemics in Australia from the 1930s to the 1970s.

“The proportion of polio patients that we look after is actually dwindling. I haven’t had any younger patients referred to me,” she tells ARR.

“But we have had scenarios where a younger adult polio survivor has had a general anaesthetic and developed hypercapnic respiratory failure, and that’s when a respiratory physician comes into the picture,” she adds.

Anaesthetists and surgeons need to be aware that a patient with a history of poliomyelitis could be more sensitive to medications and anaesthetics and that could place them at risk, especially if the patient has any breathing difficulties at night such as excessive snoring or uses a C-PAP (continuous positive airway pressure) or a BiPAP (bilevel positive airway pressure) machine, is sleepy or fatigued during the day, or gets breathless at rest or with slight exertion.

“There are two components to having anaesthesia for a polio survivor,” Dr de Graaff explains.

“Firstly, polio survivors tend to be more sensitive to centrally acting medications and that has been well documented. Secondly, there may well be prolonged relaxation of muscles after an anaesthetic.

“For example, for a polio survivor undergoing a day procedure, I would often recommend an overnight stay as it may take them longer to wake up and there is usually a prolonged recovery phase following anaesthesia,” he advises.

Beyond the iron lung

There’s no cure for decrease in breathing ability in polio survivors, but it can be managed with treatments.

“In the past 30 years, there has been a groundbreaking change in managing respiratory issues in polio survivors. We have progressed from negative pressure ventilation, that’s using the iron lung which creates a negative external pressure to expand the lung, to positive pressure ventilation delivered via a mask interface,” says Dr Caldecott.

“We were able to transition patients who were in iron lungs onto positive pressure ventilators. In Victoria, we have a government-funded, state-wide Victorian Respiratory Support Service based at Austin Health, which has made it possible to deliver portable and accessible nocturnal ventilation ? IPPV (Intermittent positive-pressure ventilation) ? to support patients at home”, she adds.

Research published in 2020 suggests that systematic screening for sleep disorders and their consequences on daytime functioning, and measures such as respiratory muscle training and physical activity could help improve the quality of life for individuals with ageing polio sequelae.

Polio Services Victoria, in its 25th year, is one of the few dedicated polio clinics in the country that provides consultations, a comprehensive assessment and management plan that includes facilitating GP referrals and linking the patient with local services, such as physiotherapy and hydrotherapy.

“Annually, we see about 300 polio patients on Medicare in our specialist medical and health clinics, conducted once a fortnight in Melbourne and six times in regional areas of Victoria,” says coordinator and occupational therapist, Ms Denise Currie.

“About 50% of the people that visit the clinic are Australian-born and contracted polio here. The remaining 50% contracted polio in their home countries and have since migrated to Australia. Our youngest client is now 23 years old from Afghanistan,” she tells ARR.

The last reported case of polio in Australia was in 2007, when a student contracted the infection in Pakistan.

Dr Nigel Quadros, senior consultant in rehabilitation medicine at The Queen Elizabeth Hospital in Adelaide, says there is a continued need for services and for polio education programs for doctors and other health professionals because we are seeing the disease in younger migrant populations.

“If patients are assessed and diagnosed early, preventative measures such as correct orthotics, proper exercise regime etc. can be put in place early,” he says.

“This could save these patients from developing other complications that may result in hospitalisation and more comorbidities and deconditioning, placing an additional burden on the health system.”

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