Introduction Acquired demyelinating neuropathies comprise a diverse spectrum of individual diseases and pathophysiological processes. Differential diagnoses can be distinguished through assessment of region of involvement, time course, neurophysiology and ancillary testing. Where an atypical presentation of chronic inflammatory demyelinating polyradiculoneuropathy arises, further investigation and changes to management are required. We present a single case report from the Townsville Hospital.

Case A 45 year old man presented with two months of altered sensation in the distal lower extremities. Lower limb weakness developed, and three months after symptoms onset the patient had bilateral foot drop, and developed sensory disturbance in the upper limbs. Electrophysiological testing revealed severely reduced lower limb CMAPs with demyelinating range conduction velocity without conduction block; upper limb SNAPs were normal in amplitude with conduction velocity slowing. A lumbar puncture revealed elevated CSF protein 870 mg/L without raised white cells. A trace lambda IgG band of uncertain significance was detected. IVIG was commenced and symptoms initially stabilised. After four months of monthly IVIG, symptoms worsened and neurophysiology revealed further neurogenic changes. Skeletal survey and whole Spine MR STIR sequences did not reveal any bony lesions, and bone marrow biopsy revealed 5% plasmacytosis. The patient’s functional status deteriorated to full-time wheelchair use despite escalation of therapy. Sural nerve biopsy revealed axonal loss and demyelination without inflammation. A final diagnosis of POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, skin changes) syndrome was confirmed with vascular endothelial growth factor elevation, and the patient underwent an autologous stem cell transplant with significant improvement in symptoms and functional status by day 100.

Conclusion POEMS syndrome is a rare disorder and should be suspected in atypical cases of CIDP particularly when treatment resistance is present. Extensive investigation is often required to meet diagnostic criteria for POEMS.