The pathophysiology and pathology of SARS-CoV-2 infection

SARS-CoV-2 infection is a major pandemic that has involved all continents in the world. It has caused almost seven million deaths since its onset. SARS-CoV-2 commonly enters cells by binding to angiotensin-converting enzyme 2 (ACE2) molecules on the surface of cells in the human body. SARS-CoV-2 infection, although mild in many patients, has the potential to cause dysfunction of many organ systems in the body. The body response to the internalisation of the virus in the epithelial cells of the lungs can lead to alveolar epithelial inflammation, commonly referred to as the exudative phase of acute respiratory distress syndrome (ARDS). Cardiac symptoms shown by patients infected with SARS-CoV-2 include chest tightness/pain and palpitations. These features can be because of newly developed or worsening ischaemic heart disease and arrythmias, respectively. SARS-CoV-2 infection is known to cause a clinical condition known as COVID-19-associated nephropathy (COVAN), a disease quite similar to HIV-associated nephropathy (HIVAN). Like HIVAN, COVAN is relatively more common in people of African descent and is associated with the APOL1 variant gene. Researchers have not identified unique morphological changes that could be used to identify the infection in tissues. Hence, the use of RT-PCR for diagnosis is still very important.