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COVID-19 can cause lasting damage to multiple organs, including the lungs, heart, kidneys, liver, and brain. Learn about COVID-19 complications
COVID-19 can cause lasting damage to multiple organs, including the lungs, heart, kidneys, liver and brain. SARS CoV-2 first affects the lungs through the nasal passages. When the lungs are severely affected, it can affect the heart. When the heart is affected, the virus disrupts blood vessels, forming clots and eventually blocking blood supply to the brain. When this occurs, brain damage can lead to death.
The link between these organs is explained by the presence of angiotensin-converting enzyme 2 (ACE2) receptors on the cells of these tissues. SARS CoV-2 requires ACE2 receptors to bind to cells and enter them. These receptors are present predominantly in the lungs (which is why the lungs are damaged the most), followed by the heart and kidneys.
Once the virus invades the lungs and damages them, it moves to the renal area and heart and causes adverse tissue damage in the respective regions. This leads to multiple organ failure over a period of time and can cause permanent organ damage or eventual death.
Organ damage and associated complications due to COVID-19
Lung damage
- Pneumonia: COVID-19 can cause lung complications such as pneumonia and, in the most severe cases, acute respiratory distress syndrome (ARDS). Sepsis may also occur, which is a life-threatening condition in which the body damages its own tissues in response to infection. Pneumonia causes inflammation of the lungs and fills them with a fluid, causing breathing problems. In some cases, breathing problems may become so serious that they require hospitalization with oxygen therapy or machine monitoring. Although most people recover from pneumonia without any long-term effects, pneumonia caused by COVID-19 can be serious for those with preexisting or coexisting conditions. Damage to the lungs and other related problems can cause breathing issues that take months to resolve, leading to more overall complications.
- ARDS: Following pneumonia, COVID-19 can lead to ARDS, which is a process in which excess fluid gets collected in the lungs and causes blood oxygen levels to fall below normal (hypoxemia). ARDS symptoms are similar to those of COVID-19 and cause damage to the alveoli (air sacs in the lungs) and the capillaries that surround them. In typical COVID-19 cases, the virus attaches to the upper airway near the throat, triggering an immune response and subsequent symptoms. However, in some cases, the virus can go past the upper airway, through the lungs, and into the alveoli, leading to ARDS. ARDS usually appears 8 days after the onset of initial symptoms. Risk factors such as advanced age, diabetes, and high blood pressure increase the likelihood of developing ARDS.
Heart damage
Underlying comorbidities such as hypertension, obesity, and cardiovascular disease have been linked to severe illness with COVID-19, and heart complications, such as myocardial injury, heart failure, and arrhythmias have been linked to poor survival.
In one recent study. researchers discovered certain cardiac abnormalities and ongoing myocardial inflammation in 60% of patients who recovered from COVID-19. High levels of the blood enzyme troponin (a sign of heart injury) were discovered in 76% of individuals evaluated in the same trial despite the data that their heart function appeared to be preserved. Notably, the majority of the patients in the study did not need to be admitted to the hospital.
Kidney damage
Patients who reported no underlying renal problems before being infected with the coronavirus and some people with severe COVID-19 infections have both shown evidence of kidney impairment and tissue damage. Some data suggests that up to 30% of patients with COVID-19 who were hospitalized in China and New York experienced moderate or severe kidney injury. Signs of kidney damage include proteinuria (excess amounts of protein found in the urine) and abnormal blood components.
Because kidneys have ACE2 receptors, they are subject to attack from the coronavirus. This triggers an immune response that can kill kidney cells. Sometimes, the immune response is violent and causes a cytokine storm, which further damages the organ.
Liver damage
ACE2 receptors are also found in the liver. Increased levels of liver enzymes such as alanine aminotransferase and aspartate aminotransferase have been found in some patients with COVID-19. This is an indication of liver damage. Patients with a history of liver tissue damage (cirrhosis) and those with preexisting liver conditions (chronic liver disease) who are diagnosed with COVID-19 are at high risk of death.
Nervous system damage
There is an increase in the number of patients with COVID-19 who experience neurological symptoms such as brain inflammation, seizures, and hallucinations.
According to a study published in JAMA Neurology by a group of Chinese doctors, more than 33% of 214 patients with COVID-19 who were hospitalized due to severe symptoms in Wuhan had neurologic symptoms, the most common of which were dizziness, headaches, impaired consciousness, loss of taste and smell, and skeletal muscle injuries. Seizures and stroke were more dangerous complications, but these were less commonly reported according to the study.