Guillain-Barré syndrome
An acute, immune-mediated attack on peripheral nerves, typically triggered by molecular mimicry after infection, that strips myelin or damages axons from the roots outward, producing an ascending, symmetrical weakness that can progress to respiratory failure within days, which is why forced vital capacity is monitored more closely than the limb weakness itself.
First principles
Molecular mimicry turns an antecedent infection into an attack on peripheral nerve
Guillain-Barré syndrome typically follows an infection, classically Campylobacter jejuni but also respiratory viruses, by one to three weeks. Antibodies raised against infectious antigens cross-react with structurally similar gangliosides on peripheral nerve myelin or axonal membranes, a process called molecular mimicry, triggering an autoimmune attack on peripheral nerves once the antecedent infection has often already resolved. This is why the trigger is frequently absent or forgotten by the time weakness appears.
Educational content pending clinical review. Not medical advice.