I’ve been interested in the diseases and disorders that can be mis-diagnosed as CMT (or vice versa) for a while. One that has come up a lot is Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP). CIDP can look like CMT cases where demyelination is prominent, usually Type 1/1A. In one international study of more than 1,100 people diagnosed with CIDP, 3.2% actually had CMT.
People with CIDP showed a higher Compound Muscle Action Potential (CMAP) than people with CMT
People with CIDP showed a higher Compound Muscle Action Potential (CMAP) than people with CMT in one recent study with a small test pool of 58 people in Japan. The researchers also noted some potential diagnostic value in using nerve ultrasounds to measure the width of nerves in patients, which tend to be wider in people with CMT.
Additionally, people with CMT1A tend to have nerve conduction velocities of 21.10±10.60m/s as compared with 31.52±12.46m/s, according to a Chinese study. The potential overlap between the two groups makes this less useful as a key diagnostic, but the same research also showed the CMT1A group was about 30% more likely than the CIDP group not to elicit an F wave in nerve conduction tests.
These are useful diagnostic tools that should be added to neurologists’ toolkits.
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