how-covid-19-affects-different-parts-of-the-body-summary

Context: While fever, cough, and difficulty in breathing are some of the most common symptoms of COVID-19, the disease has also been known to affect different parts of the body.

Findings of the various reports so far

  • The response of the immune system:
    • There have been reports on COVID-19 that the disease may overstimulate the immune system and lead to a cytokine storm, and in some other patients, doctors also noticed a swelling on their patients’ toes.
  • Presence of asymptomatic cases:
    • It is still not clear why some individuals infected with the disease remain asymptomatic, while there are others who develop mild or moderate symptoms and some who get critically ill and succumb to the disease.
  • Unpredictability of virus:
    • One of the reasons the pandemic was unpredictable was due to the virus affecting different parts of the body as a result of which different clinical manifestations were being noticed. 
    • Other viral epidemics generally have not had this speed of transmission, or this level of body involvement of multiple body parts.

Details about conditions that may be associated with COVID-19

Cytokine storm syndrome (CSS)

  • It is known that people above 60 years of age and with co-morbidities are especially vulnerable to COVID-19. However there have been reports of some young people, including teenagers, also succumbing to the disease.
  • This happens as COVID-19 might induce what is known as a “cytokine storm” in some patients. 
  • Such a storm is characterized by the overproduction of immune cells and cytokines themselves, which can be harmful since an excess of immune cells can damage the healthy tissue.

Covid toe

  • Some cases of the so-called “Covid toe” were reported from Spain and the US recently. 
  • This skin condition is characterized by purple, blue, or red discoloration of the toes and sometimes even the fingers.
  • However, it is not yet clear if there is a direct relationship between this skin condition and Covid-19.
  • Among the theories: Is it just inflammation triggered by an infection instead of the cold? Is the virus irritating the lining of blood vessels in the skin, or perhaps causing microscopic blood clots?

Multi-system inflammation in children

  • Children have formed a very small subset of those infected with Covid-19.
  • However, there have been observations of a rise in the number of children of all ages with “multi-system inflammation’.
  • This rare illness causes inflammation of the blood vessels, which leads to low blood pressure. 
  • It affects the entire body as it causes a build-up of fluid in the lungs and other organs and the condition is similar to Kawasaki disease.
    • Kawasaki disease is an acute inflammatory disease of the blood vessels and occurs in children below the age of five.

Neurological connection

  • Some of the neurological manifestations reported in various studies include dizziness, headache, acute cerebrovascular disease, impaired consciousness, loss of full control of body movements, seizures.
  • It also includes some manifestations in the peripheral nervous system, which include impairment in the sense of taste and smell.

Bowel abnormalities

  • Bowel abnormalities were seen in some of the COVID-19 patients and the presence of such abnormalities was more frequent in ICUs.
  • The cause of such abnormalities and if they are directly related to Covid-19 is not exactly clear yet.
  • However some possible explanations for the spectrum of bowel findings include direct viral infection and small vessel thrombosis.

 

About Cytokine storms

  • It is an overreaction of the immune systems, which triggers what is known as a “cytokine storm syndrome” (CSS).
  • A cytokine storm or CSS is characterized by the overproduction of immune cells and the cytokines themselves because of a dysregulation in the process.
    • Cytokines are signaling proteins that are released by cells at local high concentrations.
  • It is triggered when a virus (or antigen) enters the body for the first time.
  • A cytokine storm can occur due to an infection, auto-immune condition, or other diseases. Signs and symptoms include high fever, inflammation (redness and swelling), severe fatigue, and nausea.
  • Implications:
    • A severe immune reaction, leading to the secretion of too many cytokines in the bloodstream, can be harmful since an excess of immune cells can attack healthy tissue as well.
  • Few diseases in which CSS has been seen
    • Spanish Flu in 1918-20  that killed more than 50 million people worldwide
    • H1N1 (swine flu) and 
    • H5N1 (bird flu) 
  • Cytokine responses against human coronaviruses:
    • SARS-CoV-1 (which caused SARS), SARS-CoV-2 (which is responsible for the current COVID-19 pandemic), and MERS can result in acute lung injury and acute respiratory distress syndrome (ARDS).
  • Correlation with COVID-19:
    • Here a cytokine storm is associated with a surge of activated immune cells into the lungs, which, instead of fighting off the antigen, leads to lung inflammation and fluid build-up, and respiratory distress.
    • If the clinical features of CSS are not recognized and adequate treatment is not promptly instituted, multiple organ failure can result. 
    • Researchers writing in The Lancet recently have suggested that all severe COVID-19 patients should be screened for hyper inflammation.
Source:https://indianexpress.com/article/explained/how-covid-19-affects-different-parts-of-the-body-6415720/