Respiratory System
COVID-19 is primarily a respiratory illness, caused by the novel coronavirus SARS-CoV-2. The virus can affect the lungs, throat, and nasal passages. Symptoms of COVID-19 can range from mild (such as a sore throat and runny nose) to severe (such as pneumonia or acute respiratory distress syndrome). The virus is spread through respiratory droplets, and direct contact with an infected person.
Cardiovascular System
COVID-19 can affect the cardiovascular system in various ways. It can cause inflammation of the heart muscle (myocarditis), inflammation of blood vessels (vasculitis), and clotting problems (thrombosis). Studies have also found that patients with severe COVID-19 are at increased risk of heart attack, stroke, and other cardiovascular problems.
Gastrointestinal System
COVID-19 can also cause gastrointestinal symptoms, such as diarrhea, nausea, and vomiting. The virus can also cause inflammation of the intestines (gastroenteritis). In some cases, these symptoms can be severe and can lead to dehydration.
Nervous System
COVID-19 can cause neurological symptoms, such as confusion, headache, and seizures. It can also cause inflammation of the brain (encephalitis). In rare cases, it can cause a condition called acute disseminated encephalomyelitis (ADEM). ADEM is a rare autoimmune disorder that affects the brain and spinal cord.
Kidneys
COVID-19 can also affect the kidneys. Studies have found that patients with severe COVID-19 are at increased risk of acute kidney injury (AKI). AKI is a condition in which the kidneys fail to filter waste and toxins from the blood. In severe cases, it can lead to kidney failure.