Submitted by: Shan Chen, MD
Edited by: Niranjan Singh, MD, DM
Hauw F, Fargeot G, Adams D, et al. Charcot-Marie-Tooth disease misdiagnosed as chronic inflammatory demyelinating polyradiculoneuropathy: An international multicentric retrospective study. Eur J Neurol
. 2021;28(9):2846-2854. doi:10.1111/ene.14950
Charcot–Marie–Tooth (CMT) disease, a common hereditary polyneuropathy, has no treatment besides symptomatic relief. Authors performed a large retrospective study in 16 university hospitals in three European countries (France, Belgium, and Switzerland).
Among 1,104 chronic inflammatory demyelinating polyneuropathy (CIDP) cases, there were 35 CMT patients (3.2%) misdiagnosed as CIDP. All were initially diagnosed with definite or probable CIDP (European Federation of Neurological Societies/Peripheral Nerve Society criteria). However, later genetic testing showed mutations in PMP22, MPZ, and 10 other CMT genes in 34%, 31%, and 35% of 35 total cases, respectively.
These misdiagnosed CMT patients, in comparison with CIDP patients in reference group, were younger (median age at disease onset = 39 vs. 56 years) and more frequently had motor weakness at disease onset (80% vs. 29%), hearing loss (14% vs. 0%), normal brachial plexus imaging (70% vs. 40%), lower cerebrospinal fluid protein content (median = 0.5 vs. 0.8 g/L), and lower treatment response (20% vs. 69%). The authors also estimated cost of treatment in that the treatment cost in these 35 misdiagnosed patients was approximately 4.6 million euros (M€), whereas the cost of CMT genetic analysis in all the 1,104 patients was estimated at 2.7 M€.
It is a large cohort of retrospective study in three European countries that concluded 35/1,104 (3.2%) of patients diagnosed with CIDP actually had CMT.
There is more financial burden in health economics in treating CIDP with IVIG or other therapeutic agents. In addition there are treatment associated side effects and complications. Doing genetic testing should be more widely used.
Interestingly, it is noted that 20% of CMT patients did have treatment response. Are these placebo effects or there is superimposed CMT/CIDP syndrome?
CIDP diagnostic pitfalls and perception of treatment benefit. Allen JA, Lewis RA. Neurology. 2015 Aug 11;85(6):498-504.