Chronic inflammatory demyelinating polyradiculoneuropathies (CIDP) with monotruncular onset: Frequency, clinical...

Multifocal chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is the most frequent variant of CIDP. It is characterized by asymmetric multifocal sensory and motor impairments. Few cases with monotruncular onset have been described. The aim of the study was to characterize the clinical, electrophysiological, and radiological features of these monotruncular-onset CIDP cases.

The records of 145 patients with focal/multifocal CIDP followed in the hospital department revealed 16 patients with an initial clinical involvement limited to one nerve for at least 6 months.

Median diagnostic delay was 24 months. The ulnar nerve was the most frequently involved nerve (44%, 7/16). Based on extensive electrodiagnostic testing at initial evaluation, 5 patients (31%) met the electrodiagnostic criteria for CIDP and 8 patients (50%) for possible CIDP. Conduction blocks (CB) were the most frequent conduction abnormalities. Motor evoked potentials using a triple-stimulation technique showed proximal CB in 12/13 patients. Plexus magnetic resonance imaging was abnormal in 13/15 patients (86%), with bilateral short tau inversion recovery (STIR)-hypersignal in 7 patients. Intravenous immunoglobulins (IVIg) were efficient for 12/15 patients (80%). During follow-up (median 8 years), 3 patients retained monotruncular involvement while 13 had a multitruncular worsening. The only difference was that IVIg treatment was started earlier in patients who were still monotruncular at the last visit (11 vs. 87 months, p = 0.015).

Monotruncular onset occurred in 11% of the focal/multifocal CIDP cases. Supportive criteria are highly valuable for positive diagnosis of this condition. The natural course tends to be progressive, involving more nerve trunks. Early treatment may prevent the disease from spreading.