What exactly does COVID-19 do to your lungs?
COVID-19, short for coronavirus disease 2019, is a new illness caused by a novel coronavirus now called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There has been a lot of discussion about the symptoms of COVID-19, but not much is known about the condition after a patient has recovered from the illness. Perhaps, there’s little information available on whether COVID-19 can cause any permanent or long-term effects on the body, especially the lungs.
Early symptoms of COVID-19
The infection starts off with mild flu-like symptoms or no symptoms and further progresses to severe symptoms. Initially, COVID-19 infects the lung in the affected individual and, in severe cases, causes death due to ARDS (acute respiratory distress syndrome) and pneumonia. However, it is important to remember that COVID-19 does not lead to ARDS and pneumonia in all cases.
Worldwide, it has been observed that most people (about 80 per cent of total cases) infected with coronavirus will exhibit mild symptoms, 13 per cent will have pneumonia, 5 per cent will suffer from septic shock and organ failure (mostly respiratory failure) and 2 per cent of cases may result in fatality.
Some of the primary symptoms to look for in COVID-19 patients are fever, breathing problems, headache, dry cough (eventually results in phlegm) and in a few cases it may cause loss of smell and taste. Some patients could experience diarrhea and fatigue as primary symptoms.
COVID-19 primarily affects your lungs
The lung is the organ which is most commonly affected by COVID-19 and can result in a spectrum of adverse effects. However, the SARS-CoV-2 virus can cause devastating effects on your other organs, including the heart and blood vessels, brain, kidneys, liver, immune system, stomach and intestines - and not just the lungs.
“In case of pneumonia, the infection causes initial damage (inflammation) to the small air sacs present in the lungs and makes the lungs to be filled with fluid/puss, making it hard for the patients to breathe. If a large percentage of the lungs is affected, people struggle to absorb enough oxygen and are admitted to hospital with severe difficulty in breathing,” said Dr Govini Balasubramani, Senior Consultant - Cardiothoracic Surgery, Heart & Lung Transplantation, Gleneagles Global Health City, Chennai.
According to Dr Balasubramani, another severe complication is acute respiratory distress syndrome (ARDS) - also known as “wet lung”. This occurs due to the infection spreading quickly throughout the lungs. People who develop this condition may need assisted breathing i.e. mechanical ventilation in an intensive care unit. In some cases, the patient may also require a ventilator for a prolonged period of time. COVID-19 also causes marked clotting in the small blood vessels of the lungs as well as other organs.
Does COVID-19 have long-term effects on the lungs?
While the lungs can recover from severe COVID-19 disease, they can sustain long-term damage by leaving a scar behind.
“The SARS-CoV-2 virus enters the cells of the airway through angiotensin-converting enzyme receptor, a molecule that connects the inside of our cells to the outside via the cell membrane. When this happens, an intense immune response, known as cytokine storm occurs, along with increased blood clotting, all of which leads to damage of lung cells. The body replaces the cells damaged by the virus with scar tissue, which is thick and rigid. This can result in a condition called “pulmonary fibrosis”, which is mostly seen in people diagnosed with COVID-19. This condition is probably more likely to develop if the lungs are severely affected by the infection. The condition can make people experience breathlessness while doing routine activities that they would otherwise manage easily without any difficulty. Drugs that reduce scarring could help in preventing this complication,” added Dr Balasubramani.
Health experts are yet to better understand the impact of pulmonary fibrosis, but they believe that it may lead to long-term symptoms and a progressive fall in lung function that can be diagnosed by a pulmonary function test. Hence, follow-up care of these patients for deteriorating lung function is very important.
Follow-up care for COVID-19 patients
Available data shows that SARS can cause pulmonary fibrosis and a large analysis of SARS and MERS patients showed weakened lung function in some survivors up to six months after hospital discharge. However, 15 years follow-up of such patients showed improvement in lung function and less damage visible on CT scans over time. According to earlier studies done on people who were recovering from COVID-19, lung condition improves in the first few weeks after getting discharged from the hospital.
People who are getting treated for the disease may have an impact on their general fitness. Furthermore, those who underwent mechanical ventilation for a long time may lose a significant degree of muscle mass, leaving them weak even after their lungs have recovered.
People who are vulnerable to the infection especially older adults can become destabilised even after suffering from “mild” COVID-19. This may impact their ability to live independently, so it has important implications on the demand for social care services and pulmonary rehabilitation.
While the vast majority who contract with COVID-19 will recover completely, we’re likely to see more people with pulmonary fibrosis or persistent lung damage suffering from ARDS caused by COVID-19. These patients may need antifibrotics (after research data availability), home oxygen therapy, pulmonary rehabilitation, and regular follow-ups. Meeting such people’s long-term healthcare needs will pose a significant challenge.
Coronavirus can affect anyone, however, people with underlying conditions are more likely to have severe symptoms than those who don't have a medical condition that increases their risk. If you're particularly at risk due to a lung condition or other serious health issue, take extra precautions to reduce your risk and stay safe.