[Diagnosis and management of immune-mediated neuropathies]

Immune-mediate neuropathies, or inflammatory neuropathies are neuropathies due to the dysregulation of the immune system. The injury to peripheral nerves can be divided into two phases: an early stage of immune injury, and a later stage of structural damage. The overall effects are axonal degeneration or demyelination depending on the target of immunological attacks. According to time course, there are two major types: Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP). Clinical manifestations of both diseases include progressive motor weakness and sensory disturbance with some variations among different patients. The major findings of nerve conduction studies on GBS patients are prolonged distal motor latencies and minimal F-wave latencies with variable reduction of nerve conduction velocities. In CIDP patients, slowed nerve conduction velocities are the usual findings in addition to prolongation of distal motor latencies and minimal F-wave latencies. Certain subtypes of immune-mediated neuropathies are associated with high titers of anti-gangliosdie antibodies. Patients with GBS and CIDP can benefit from immunotherapy. For GBS, plasma exchange and intravenous immunoglobulin (IVIG) are equally effective in reducing complications and neurological disability. Steroid of high dose is, however, harmful to GBS. Plasma exchange and IVIG can alleviate neurological deficits of CIDP with steroid to maintain the effects of plasma exchange and IVIG. In conclusion, careful clinical observations and judgment are the most important issue to manage patients with immune-mediated neuropathies.