April 7, 2020 / GEOFF BRUMFIEL
It’s a strange and tragic pattern in some cases of COVID-19: The patient struggles through the first week of illness, and perhaps even begins to feel a little better.
Then suddenly they crash. 
“We’ve seen some patients rapidly worsen,” says Dr. Pavan Bhatraju, an assistant professor at the University of Washington who works in the intensive care unit at Harborview Medical Center in Seattle. “They initially were just requiring a little bit of oxygen. In 24 hours they’re on a ventilator.”
A recent study by Bhatraju and others found that the patients’ lungs appeared to deteriorate quickly. The crash typically happens seven days into the disease and can occur in young, otherwise healthy victims of COVID-19.
Now doctors and researchers are increasingly convinced that, in some cases at least, the cause is the body’s own immune system overreacting to the virus. The problem, known broadly as a “cytokine storm,” can happen when the immune system triggers a runaway response that causes more damage to its own cells than to the invader it’s trying to fight.
Cytokines are a wide cast of small molecules in the body that are released by certain cells to help coordinate the battle against infection.
Although there’s limited data on how the release of too many of these molecules (the cytokine storm) affects COVID-19 patients, some doctors are already treating people who have the disease with powerful anti-inflammatory drugs to try and slow or stop the process. Anecdotally, they say that the approach appears to be helping.
“The impact was dramatic,” says Dr. Daniel Griffin, chief of infectious disease for ProHEALTH Care Associates, a group of physicians that serves the New York City area. The first six patients he treated all appear to be improving, at least for now, he says. “Yesterday was a good day.”
But other researchers caution that the untested treatments carry significant risks. Suppressing the body’s immune system at the exact moment it’s trying to fight off the deadly coronavirus could have all sorts of unintended consequences, warns Dr. Tobias Hohl, the chief of infectious disease at Memorial Sloan Kettering Cancer Center in New York City. “The infection could get worse,” Hohl says.