Plasmapheresis timing is most effective when initiated within how many weeks of onset?

• A. Within 6 weeks
• B. Immediately after diagnosis
• C. Within 2 weeks
• D. Within 4 months

Answer: (C)

Early removal of circulating autoreactive antibodies is most beneficial before nerve damage becomes irreversible. In Guillain-Barré syndrome, initiating plasmapheresis within about two weeks of onset provides the strongest improvement in motor recovery and can shorten the need for ventilatory support. After this window, the potential to alter the disease course diminishes because demyelination and axonal injury have progressed beyond a point where antibody removal can reverse them.

Starting therapy immediately after diagnosis is helpful, but the data show the greatest benefit specifically when begun within two weeks. Timelines like six weeks or four months fall outside the optimal window, where the treatment’s impact on outcomes is markedly reduced.