One of those life-threatening complications Nick suffered is blood clotting, which doctors tried to combat with blood thinners. Unfortunately, that treatment caused internal bleeding and ultimately the lack of blood flow to his lower right leg necessitated amputation.
Nick has had additional complications including septic shock and severe damage to his lungs. But the good news is that as he emerges from his coma, the Waitress star is showing positive signs that he may have escaped severe brain damage.
Though he is not out of the woods and still has a lung infection on top of the damage the virus has wrought on his respiratory system, his wife and family are hopeful that he is turning the corner.
Nobody knows for sure why some otherwise healthy people like Nick react so severely to this virus. Researchers have only known of this novel coronavirus since late 2019, so studies of its effects on different populations are still ongoing. However, there are some theories. One avenue of research may involve sequencing the genomes of young patients who did not have underlying health conditions to determine whether they have genetic markers in common that may have led to their severe reactions.
Another theory is that for some young patients, the severity of the reaction could be due not to a suppressed immune system but a hyper-reactive one.
The phenomenon is called a “cytokine storm” because it is caused when the cytokine proteins that are part of the immune system cause an overreaction to an unfamiliar pathogen, such as a virus. But in its fight to suppress the foreign invader, the immune system also attacks the lungs, which might lead to the severe damage doctors have been seeing on scans, as well as the acute respiratory distress, clotting, and other issues.
Source : https://www.distractify.com/p/did-nick-cordero-have-underlying-health-issues