COVID-19 not only damages the lungs but can affect many other organs



Cough, fever and respiratory distress, these are three of the most typical symptoms to suspect a COVID-19, the new disease caused by the SARS-CoV-2 virus. Although these clinical manifestations are useful to guide a diagnosis, they are still a simplification of the complex reality of this disease. Dozens of different signs and symptoms associated with COVID-19 have already been identified, and with each passing week more of them are discovered.

When the coronavirus infects a person, the outcome can be extremely disparate: from an asymptomatic infection to death. A multitude of biological factors, many still unknown, make the difference between COVID-19 becoming an anecdote in life or putting an end to it.

We do have at least some certainties: Coronavirus has a predilection for the respiratory tract and lungs, where it causes more damage to vulnerable people and triggers the most serious and deadly health problems. The urgent need for respirators in countries affected by the COVID-19 pandemic is a true reflection of which organ is most affected by the virus. However, this narrative of events is, again, a simplification of reality.

COVID-19 can also affect many other organs and tissues such as the kidneys, heart, liver, brain, intestine, or blood vessels due, among other factors, to the fact that your cells have ACE2 receptors that the coronavirus can use. to infiltrate them.

What is behind the damage to multiple parts of the body?

Researchers are studying to what extent the damage detected in different parts of the human body by COVID-19 is due to the coronavirus itself, to the disproportionate reaction of the immune system (such as cytokine storm) or to the different treatments that are applied to the most serious patients in hospitals. One of the hypotheses that is being reinforced in the last week (by the scientific evidence that throw various studies) postulates that the damage to different tissues and organs caused by the coronavirus is due to the alteration of the internal surface of the blood vessels (the endothelium). The dysfunction of the vessels due to inflammation would favor the formation of blood clots (thrombosis) and vasoconstriction, which would produce a decrease in the blood supply in different regions of the human body, especially in the smallest vessels (the microvasculature).

This would explain why in certain patients, in addition to lung damage, they also occur skin lesions, liver damage, kidney and heart failure or even fulminant multi-organ failure within hours. A study on 191 patients in Wuhan, China, found that 90% of people with pneumonia had bleeding disorders that favored clot formation. In the Netherlands, another study found that 31% of COVID-19 patients admitted to the ICU they also had complications from thrombosis.

The findings of various Autopsies released so far support the idea that blood vessels play a key role in the more serious forms of COVID-19. This April 22, the first data were pre-published (still pending expert review) of lung autopsies of deaths from the coronavirus in Italy. Among the most interesting data, the scientists from Milan highlight the following: "The most relevant main finding is the presence of fibrin-platelet clots in the small arterial vessels; this important observation fits in the clinical context of coagulopathy that predominates in these patients and that it is one of the main therapeutic objectives. "

A long and bizarre list of atypical symptoms

With the spread of the coronavirus around the world and the exponential increase in people affected by COVID-19, strange and very different symptoms of a typical respiratory infection have been identified. An article published on April 17 in the magazine The British Medical Journal collects several of these unusual symptoms. Among them we find diarrhea, a symptom that can appear at the beginning of the infection and that can be found between 2 and 40% of patients. It is not yet known if this health problem is caused by the virus infection in the intestinal cells (which have receptors that the coronavirus uses to infiltrate), by involvement of the nerves that regulate intestinal transit or by the inflammatory reaction that occurs. as a reply.

Other rare symptoms are neurological, among which are strokes, dizziness, headache, musculoskeletal disorders, altered mental status, Guillain Barre syndrome or acute necrotizing encephalopathy. Cardiovascular symptoms are also present, and damage and inflammation have been observed in the muscle layer of the heart and in the pericardium (the outermost layer of the heart), arrhythmias, heart failure, and bleeding problems. The eyes can also be affected and show inflammation of the conjunctiva and increased secretions.

What the data set so far indicates is that, beyond the lung, almost any organ can be damaged in the most severe patients affected by COVID-19. Blood vessel disturbances and clotting problems may be one possible explanation, in which both the coronavirus and the immune system play their part, but this is most likely, again, only an incomplete part of the whole story. remains to be known. The SARS-CoV-2 virus is proving to be a challenge, not only for epidemiologists, but also for healthcare professionals.

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