--is that there are many, many inflammatory autoimmune nerve attacks that can be grouped under the CIDP rubric; it may well be that we are talking about several seperate disease processes that all just happen to involve segmental demyelination.

Generally, one gets diagnosed with CIDP if one shows inflammatory segmental demyelination (generally with cellular infiltrates) of motor nerves (though sensory ones can also be involved, a primarily sensory syndrome may mean another related conditon, such as anti-MAG or anti-sulfatide neuropathy), with characteristic NCV/EMG results that include conduction block. There may also be prolonged distal latencies and disrupted combined motor action potentials (CMAP's), all due to problems with myelin.

There are sometimes autoantibodies to be found, but this alone would not "clinch" a CIDP diagnosis. (Interestingly, anti-nuclear antibodies are not characteristic and their presence usually changes the diagnosis.) Similarly, high cerebrospinal fluid protein levels are often found, but this is not specific to CIDP.

One of the main differentials is a relapsing/remitting pattern of symptoms, with evidence of remyelination in between episodes.

Again, the problem is that a lot falls under the "demyelinating immune neuropathy" category. There are CIDP variants, and other clinical entities, such as multifocal motor neuropathy, that are closely related. And, a number of hereditary neuropathies, such as Charcot Marie Tooth x-linked types, have very similar clinical manifestations, but these are often not distinguished unless genetic testing is done.

See:

http://neuromuscular.wustl.edu/antib...imdem.html#mmn