Temporal dispersion in demyelination of POEMS syndrome and Castleman disease

Yue Hui Lau; Hazfadzila Mohd Unit; Lay Peng Lee; Weng Khean Loh; Fu Liong Hiew

doi:10.1016/j.cnp.2020.05.001

Temporal dispersion in demyelination of POEMS syndrome and Castleman disease

Clin Neurophysiol Pract. 2020 May 31:5:112-117. doi: 10.1016/j.cnp.2020.05.001. eCollection 2020.

Authors

Yue Hui Lau¹, Hazfadzila Mohd Unit¹, Lay Peng Lee², Weng Khean Loh³, Fu Liong Hiew¹

Affiliations

¹ Department of Neurology, Kuala Lumpur Hospital, Jalan Pahang, 50586, Wilayah Persekutuan, Kuala Lumpur, Malaysia.
² Department of Medicine, Sibu Hospital, KM 5 1/2, Jalan Ulu Oya, 96000 Sarawak, Malaysia.
³ Haematology Unit, Department of Medicine, Kuala Lumpur Hospital, Jalan Pahang, 50586, Wilayah Persekutuan, Kuala Lumpur, Malaysia.

Abstract

Objective: We detailed the electrophysiological patterns of peripheral nerve temporal dispersion across spectrum of POEMS syndrome and Castleman disease (CD).

Methods: Compound muscle action potentials (CMAP) duration of 3 patients with POEMS syndrome and 2 with hyaline vascular type CD without clonal plasma cell dyscrasia were retrospectively analysed.

Results: Median and ulnar nerves distal CMAP duration were prolonged in all patients irrespective of plasma cell dyscrasia or M protein. All lower limbs distal CMAP responses were absent. Greatest distal CMAP duration prolongation was observed in median nerves for POEMS syndrome (17.0 ms, 158% upper limit normal) and in ulnar nerves for CD (9.8 ms, 47% upper limit normal). Distal/proximal CMAP duration ratio of <0.7 were seen in 33% of median and ulnar nerves studied among POEMS syndrome. Among nerves with ratio >0.7, all had distal CMAP duration prolongation (Range 7%-158% of upper limit normal).

Conclusions: Abnormal distal CMAP dispersion is not uncommon in POEMS syndrome and CD without clonal plasma cell dyscrasia or M protein. POEMS syndrome has greater distal CMAP duration in median and ulnar nerves, particularly in median nerve that can reach up to 150% of upper limit normal, compared to <50% in CD.

Significance: Detailed electrophysiological analysis of distal CMAP duration may help in distinguishing POEMS syndrome and CD.

Keywords: CD, Castleman disease; CIDP, Chronic inflammatory demyelinating polyneuropathy; CMAP duration; CMAP, Compound muscle action potentials; Castleman disease; Demyelination; M Protein, Monoclonal protein; MGUS, Monoclonal gammopathy of undetermined significance; NCS, Nerve conduction study; POEMS syndrome; POEMS syndrome, Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal protein and Skin changes Syndrome; Paraproteinemic neuropathy; SNAP, Sensory nerve action potentials; TLI, Terminal latency index; Temporal Dispersion; VEGF, Vascular endothelial growth factor; ms, milliseconds.