Back in D.C., he took a few sick days, and when the feverishness and dizziness didn’t clear, he pushed himself to work half-time. His primary-care doctor shrugged when he explained his symptoms. He used his connections in the science world to visit the best neurologists in Washington and Baltimore. One doctor performed an MRI that showed damage to his upper spinal cord, but no one could give him a concrete diagnosis. Two months in, his limbs began to twinge with pins and needles, and he wondered if maybe he had multiple sclerosis.

That winter, he lost 30 pounds in two months. He went to a week-long scientific conference for work, and then crashed from the exertion. He would look at his thigh and see the muscles jump, and started thinking that maybe he had Lou Gehrig's disease.

In January, his right arm temporarily became paralyzed and his right eye temporarily went blind. He spent most of 2013 in bed, writing short articles for the Post when he could muster the strength. That summer, he saw a doctor at the National Institutes of Health, who took 29 vials of blood. (The NIH was unable to confirm Vastag’s story, citing patient confidentiality.) Vastag said the results didn’t point to any problem in particular. Frustrated, Vastag told the doctor, “I’m pretty sure I have ME.” (The term most patients, including Vastag, prefer for their disease is “myalgic encephalomyelitis,” or ME. For the sake of clarity and consistency with the existing medical literature, this article uses “chronic fatigue.” More on this naming controversy later.)

“That might be true,” Vastag remembers the doctor saying, “but then the question is, what can be done about it?"

The response encapsulated what Vastag felt was the medical community’s dismissive attitude. The subtext he heard was, “If you have this illness, there’s nothing that can be done about it, so we’re not going to bother with you,” he said.

The experience was just one of the many reasons Vastag has joined a chorus of chronic-fatigue patients who are, gradually and mostly through the Internet, joining forces to draw attention to their plight.

Vastag is working with other patient advocates to try to spur Congress to devote a pot of money—they believe $250 million is realistic—to chronic fatigue syndrome research. Others are running crowdfunding campaigns to fill what they say is a desperate need for funding. Still others are producing documentaries or writing impassioned blogs.

Justin Reilly, a former New York lawyer who also suffers from chronic fatigue syndrome, offered free legal advice for a recent documentary about the disease. He acknowledges it can be hard—and seemingly counterintuitive—for people who are so frail to become activists. But their attitude, he says, is, “I don't want to be like this forever, so I have to summon the energy to do something. Then a little something is done, and we crash.”