MRCP UK EXAMINATIONS

Detailed explanation-1: -Needle electromyography is usually unremarkable in AIDP because most cases are demyelinating and not axonal. However, with axonal involvement, EMG studies may demonstrate signs of active denervation, positive sharp waves/fibrillation potentials, increased duration, increased amplitude, and fiber reinnervation signs.

Detailed explanation-2: -Demyelination can readily explain conduction failure within the affected axon. If conduction does not completely fail, conduction velocity can nonetheless be slowed and differential slowing across different axons can cause variable conduction delays that result in desynchronized spiking.

Detailed explanation-3: -The pathophysiological mechanisms leading to a figure of conduction block include segmental demyelination, recent axonal interruption, or various axonal excitability abnormalities due to ion channel dysfunction or membrane potential changes.