People who overcome the coronavirus may be left with lasting lung damage, experts have warned.
This chronic condition can make breathing so difficult that even getting dressed is a struggle.
Although there is no cure, treatments can ease pulmonary fibrosis’ symptoms and slow its progression.
Early research suggests the coronavirus is mild in four out of five cases, however, it can trigger a respiratory disease called COVID-19.
Scans ‘usually return to normal at six weeks’
One who knows the effects of the coronavirus all too well is Anthony McHugh, 68.
The retired taxi driver from Hertfordshire was admitted to hospital with the infection on 6 March.
McHugh spent 13 days on a ventilator in intensive care. In total he was in hospital for four weeks, as well as spending a fortnight in an NHS rehabilitation centre.
Although home since mid-April, he still suffers from breathing difficulties when walking up the stairs or even watering his garden.
An X-ray of McHugh’s lungs taken six weeks after he left hospital revealed thin white lines, known as reticular shadowing – an early sign of pulmonary fibrosis.
The coronavirus was only identified at the end of 2019, with doctors unable to say for sure what lasting effects it may have.
Nevertheless, X-rays like McHugh’s have caused concern.
“Usually with a virus or infection at six weeks you would expect the scan to have returned to normal”, Dr Sam Hare, of the British Society of Thoracic Imaging, told the BBC.
McHugh will have an additional scan at 12 weeks after his hospital discharge.
Coronavirus can ‘completely disrupt lung architecture’
This is not the first time fears of lasting lung damage have been raised amid the coronavirus.
A Chinese study published at the beginning of the outbreak found 66 out of 70 patients had some level of damage after being discharged from hospital.
Speaking of the situation in the UK, Dr Hare said: “In the six-week scans we're seeing so far, I would say between 20% and 30% of patients who have been in hospital appear to show some early signs of lung scarring.”
Professor Mauro Giacca from King’s College London previously told parliament the lungs of some people who died with the coronavirus were completely unrecognisable.
The deceased, who were in hospital for more than a month, had “complete disruption of the lung architecture”, he added.
“In some lights you can’t even distinguish that it used to be a lung”.
Professor Giacca studied the autopsies of patients who died in Italy after 30 to 40 days in intensive care. He found substantial amounts of the virus persisting in lungs, as well as “large numbers of very big fused cells”.
While most coronavirus patients have mild symptoms, some release excessive amounts of immune-fighting proteins. This is known as a cytokine storm, which can cause lasting damage.
Cells damaged by the coronavirus may then be replaced with inflexible scar tissue.
The coronavirus is one of seven strains of a virus class that are known to infect humans.
Others include severe acute respiratory syndrome (Sars) and Middle East respiratory syndrome (Mers), which killed 774 and 858 people in 2002/3 and 2012, respectively.
Between 20% and 60% of Sars and Mers survivors are said to have experienced a health problem similar to pulmonary fibrosis.
A 15-year follow-up study by scientists from Peking University People’s Hospital in Beijing found this generally eased over time.
The Faculty of Intensive Care Medicine warned in March thousands of coronavirus survivors could suffer damage to their lungs, with a recovery period of up to 15 years.
“My concern with COVID-19 is so much [more] of the population has been infected [than with Sars or Mers]”, said Dr Hare.
Experts have said more needs to be understood about the number of coronavirus survivors who develop lung damage and when treatment to prevent it is most effective.
NHS England is planning to open a number of COVID-19 rehabilitation centres.
In Scotland and Wales, officials will adapt existing services and provide more community rehabilitation. The situation in Northern Ireland is unclear.
What is pulmonary fibrosis?
Pulmonary fibrosis comes about when the air sacs in the lungs, where gas exchange takes place, become damaged and increasingly scarred.
This causes the lungs to stiffen, which can result in an insufficient level of oxygen reaching the blood.
Survival rates at five years used to be low, however, drug developments have improved patient longevity.
The rate of decline varies significantly and is hard to predict.
As well as difficulty breathing, symptoms include fatigue, a persistent dry cough, poor appetite, weight loss and rounded or swollen fingertips.
Pulmonary fibrosis’ cause is unclear, however, it has previously been linked to viral infections.
It is also associated with certain types of dust, a family history of the condition, smoking and acid reflux.
Most patients are between 70 and 75. Pulmonary fibrosis is rare in people under 50.
Stopping smoking, eating well and exercising regularly can all help.
Medication can also reduce the rate of scarring, while an oxygen mask can aid breathing.
In severe cases, a lung transplant may be required, however, donors are hard to come by.
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