Two causes of demyelinating neuropathy in one patient: CMT1A and POEMS syndrome.

In most cases, there is only one cause for a patient’s peripheral neuropathy (e.g. diabetes mellitus, uremia, inflammatory demyelination, vasculitic, inherited or other). However, occasionally more than one cause may be present and clinically important. The case illustrated here shows that inherited (CMT1A) and acquired (POEMS) demyelinating neuropathies can coexist and both contribute to the clinical presentation of a neuropathy. Charcot-Marie-Tooth 1A (CMT1A) is an autosomal dominant inherited neuropathy with insidious progression over years with disability due to distaland motor-predominant dysfunction. It usually presents before age 20,1 but it can also present later in life. There is usually uniform slowing of conduction velocities with little temporal dispersion or conduction block. Both the presence of paresthesias, which are unusual in CMT1A2 and acute worsening in an otherwise gradually progressive condition such as CMT1A, should alert the clinician to the presence of a second and possibly treatable form of peripheral neuropathy. POEMS syndrome is defined3,4 by the presence of Polyneuropathy (P), Organomegaly (O), Endocrinopathy (E), M protein (M) and Skin changes (S). In POEMS syndrome, peripheral neuropathy is frequently the presenting manifestation and it can be rapidly progressive. It is usually symmetric and distal predominant but proximal limb segments are often involved. It can be very severe and usually has both axonal and demyelinating features on electrodiagnostic studies. Most patients have sclerotic bone lesions from osteosclerotic myeloma or have Castleman’s disease. POEMS syndrome is a potentially treatable disorder.