When I was doing my residency decades ago, there were some very severe patients with complex neurological symptoms that no one could figure out. They were given five rounds of plasmapheresis followed by five rounds of IVIG treatment. In most cases, this approach actually helped, and in many instances, it saved lives. When I asked our professors why they used this treatment despite not knowing what was happening, they said, “We may not know what’s going on, but we have to try interventions that have a chance of saving their lives.” Medicine was more effective 25 years ago.