Supervisor Elham AbolFateh
Editor in Chief Mohamed Wadie

Post-COVID Pulmonary Fibrosis: Tsunami Follows Earthquake


Wed 06 Jan 2021 | 12:22 PM
opinion .

Pulmonary fibrosis is a lung disease that occurs when lung tissue becomes damaged and scarred. This thickened, stiff tissue makes it more difficult for the lungs to work properly.

The scarring associated with pulmonary fibrosis can be caused by a multitude of factors. But in most cases, doctors can't pinpoint what's causing the problem. When a cause can't be found, the condition is termed idiopathic pulmonary fibrosis.

Medications and therapies can sometimes help ease symptoms and improve quality of life. For some people, a lung transplant might be appropriate.

Symptoms of Pulmonary Fibrosis

The main symptoms of pulmonary fibrosis are breathlessness, a cough that doesn’t go away, feeling tired all the time and clubbing.

The first symptom a lot of people notice is getting out of breath when they’re exerting themselves, such as climbing a hill or stairs. Many forms of pulmonary fibrosis tend to occur after the age of 60, so some people wrongly think they’re getting breathless because they’re getting older.

Shortness of breath can also be caused or affected by other long-term conditions, such as chronic obstructive pulmonary disease , heart disease and being overweight.

A cough that doesn’t go away and feeling very tired all the time are two other symptoms of pulmonary fibrosis. Another sign is clubbing. The nails become like a drumstick , the tips of the fingers get bigger and the nails curve around the finger tips, and the base of the nail feels spongy. Clubbing can also occur with other lung conditions, and as a result of heart or liver disease.

Some people with conditions associated with pulmonary fibrosis can lose weight or have a fever or aching or stiff joints and muscles. Others might have rashes, dry mouth and eyes, or poor circulation in fingers and toes.

The course of pulmonary fibrosis — and the severity of symptoms — can vary considerably from person to person. Some people become ill very quickly with severe disease. Others have moderate symptoms that worsen more slowly, over months or years.

Some people may experience a rapid worsening of their symptoms (acute exacerbation. Severe shortness of breath may last for several days to weeks. People who have acute exacerbations may be placed on a mechanical ventilator.

Causes of Pulmonary Fibrosis

Pulmonary fibrosis scars and thickens the tissue around and between the air sacs (alveoli) in the lungs. This makes it more difficult for oxygen to pass into the bloodstream. The damage can be caused by many different factors — including long-term exposure to certain toxins, certain medical conditions, radiation therapy and some medications.

Long-term exposure to a number of toxins and pollutants can damage the lungs. These include silica dust, asbestos fibers, hard metal dusts, coal dust, grain dust, bird and animal droppings.

Many drugs can damage the lungs, especially medications such as chemotherapy drugs, some heart medications, some antibiotics and some anti-inflammatory drugs.

Lung damage can also result from a number of conditions, including dermatomyositis, polymyositis , mixed connective tissue disease , systemic lupus erythematosus, rheumatoid arthritis, sarcoidosis , scleroderma and pneumonia

Many substances and conditions can lead to pulmonary fibrosis. Even so, in most cases, the cause is never found. Pulmonary fibrosis with no known cause is called idiopathic pulmonary fibrosis.

Risk Factors

One of the risk factors for the development of lung fibrosis in COVID-19 is advanced age and this finding is the same as in MERS and SARS-CoV. Although pulmonary fibrosis has been diagnosed in children and infants, the disorder is much more likely to affect middle-aged and older adults.

Second risk factor is increased disease severity which includes comorbidities such as hypertension, diabetes, and coronary artery disease and Lab findings like lymphopenia, leukocytosis, and elevated lactate dehydrogenase (LDH). Serum LDH level has been used as a marker of disease severity following acute lung injury. It is an indicator of pulmonary tissue destruction and correlates with the risk of mortality.

Third risk factor is prolonged ICU stay and duration of mechanical ventilation. While disease severity is closely related to the length of ICU stay, mechanical ventilation poses an additional risk of ventilator-induced lung injury (VILI). Abnormalities of pressure or volume settings underlie this injury leading to a release of proinflammatory modulators, worsening acute lung injury, and increased mortality or pulmonary fibrosis in survivors.

Sex, idiopathic pulmonary fibrosis is more likely to affect men than women.

Smoking, far more smokers and former smokers develop pulmonary fibrosis than do people who have never smoked. Smokers are 1.4 times more likely to have severe symptoms of COVID-19 and 2.4 times more likely to need ICU admission and mechanical ventilation or die compared to nonsmokers. Pulmonary fibrosis can occur in patients with emphysema.

Certain occupations increase the risk of developing pulmonary fibrosis as work in mining, farming or construction. Genetic factors, some types of pulmonary fibrosis run in families, and genetic factors may be a component.

Complications

Complications of pulmonary fibrosis may include pulmonary hypertension, right-sided heart failure, respiratory failure and lung complications.

High blood pressure in the lungs (pulmonary hypertension),unlike systemic high blood pressure, this condition affects only the arteries in the lungs. It begins when the smallest arteries and capillaries are compressed by scar tissue, causing increased resistance to blood flow in your lungs. This in turn raises pressure within the pulmonary arteries and the lower right ventricle). Some forms of pulmonary hypertension are serious illnesses that become progressively worse and are sometimes fatal.

Right-sided heart failure is a serious condition. It occurs when the heart's lower right ventricle has to pump harder than usual to move blood through partially blocked pulmonary arteries.

Respiratory failure is often the last stage of chronic lung disease. It occurs when blood oxygen levels fall dangerously low. Long-standing pulmonary fibrosis. As pulmonary fibrosis progresses, it may lead to complications such as blood clots in the lungs, a collapsed lung or lung infections.

Post-COVID Pulmonary Fibrosis

About 40% of patients with COVID-19 develop acute respiratory distress syndrome (ARDS) and 20% of ARDS cases are severe. Abnormal immune mechanisms initiate and promote pulmonary fibrosis, possibly as a consequence of a cytokine storm.

Of note, the average age of patients hospitalised with severe COVID-19 appears to be older than that seen with MERS or SARS, which is perhaps a consequence of wider community spread. In inflammatory lung disorders, such as those associated with autoimmune disease, advancing age is a risk factor for the development of pulmonary fibrosis. Given these observations, the burden of pulmonary fibrosis after COVID-19 recovery could be substantial.

It is known that a substantial proportion (about 25%) of patients who developed ARDS in the pre-COVID era, irrespective of etiology , experienced residual and long-term impairment of their pulmonary function, with radiographic evidence of pulmonary fibrosis on computed tomography. Progressive, fibrotic irreversible interstitial lung disease, which is characterised by declining lung function, increasing extent of fibrosis on CT, worsening symptoms and quality of life, and early mortality.

Although the virus is eradicated in patients who have recovered from COVID-19, the removal of the cause of lung damage does not, in itself, preclude the development of progressive, fibrotic irreversible interstitial lung disease. Furthermore, even a relatively small degree of residual but non-progressive fibrosis could result in considerable morbidity and mortality in an older population of patients who had COVID-19, many of whom will have pre-existing pulmonary conditions.

At present, the long-term pulmonary consequences of COVID-19 remain speculative and should not be assumed without appropriate prospective study. Nonetheless, given the huge numbers of inpiduals affected by COVID-19, even rare complications will have major health effects at the population level. It is important that plans are made now to rapidly identify whether the development of pulmonary fibrosis occurs in the survivor population. By doing this, we can hope to deliver appropriate clinical care and urgently design interventional trials to prevent a second wave of late mortality associated with this devastating pandemic.

Pulmonary Fibrosis Prevention Tips

The best way to prevent pulmonary fibrosis is, therefore, to avoid potential risks and to undergo regular medical examinations. In addition to being aware of risk factors that can increase the likelihood of developing pulmonary fibrosis, patients should also pay attention to specific symptoms.

1. Mask and distance to limit exposure to COVID-19.

2. Don’t smoke – and if you do, quit today! Smoking is the primary cause of lung cancer, chronic obstructive pulmonary disease (COPD) and damages lung tissue.

3. Avoid indoor and outdoor pollutants and make sure you wear a mask to protect your lungs against harsh chemicals. People should also take care not to be exposed to other toxins, such as asbestos and bird and animal droppings, and to use a mask when necessary to eliminate the risk of exposure.

4. Stay up to date with adult immunizations – including flu and pneumonia vaccines. Vaccines help keep us healthy and can reduce inflammation caused by avoidable illnesses.

5. Exercise – Keep those lungs pumping with a good exercise routine and breathe deep.