Marieke van Rosmalen

Chapter 8 134 Table 8.1 Diagnostic criteria for CIDP and MMN with their limitations CIDP Clinical criteria Typical 1. Chronic (> 2 months), progressive, symmetric, proximal and distal weakness and sensory dysfunction of all extremities 2. Absent or reduced tendon reflexes in all extremities Variants 1. Predominantly focal, distal, multifocal, pure motor or pure sensory neuropathy 2. Tendon reflexes may be normal in the unaffected limb Electrodiagnostic criteria Definite (at least one of the following): (a) motor distal latency prolongation ≥ 50% above ULN in 2 nerves; (b) reduction of motor conduction velocity ≥ 30% below LLN; (c) prolongation of F-wave latency ≥ 30% above ULN in 2 nerves; (d) absence of F-waves in 2 nerves + ≥ 1 other demyelinating parameter; (e) partial motor conduction block, i.e. ≥ 50% amplitude reduction of the CMAP; (f) abnormal temporal dispersion in ≥ 2 nerves; (g) distal CMAP duration increase in ≥ 1 nerve + ≥ 1 other demyelinating parameter in ≥ 1 other nerve. Probable: ≥ 30% amplitude reduction of the CMAP in 2 nerves, or in 1 nerve + ≥ 1 other demyelinating parameter in ≥ 1 other nerve Possible: as in ‘definite’ but in only one nerve Supportive criteria Laboratory findings Elevated CSF protein (CIDP); CSF protein < 1 g/L and elevated anti-GM1 antibodies (MMN) Treatment response Objective clinical improvement following immunomodulatory treatment MRI Nerve root thickening, increased signal intensity on T2-weighted images and/or enhancement with gadolinium of the cauda equina, lumbosacral or brachial plexus NCS Abnormal sensory electrophysiology in ≥ 1 nerve (CIDP only) Nerve biopsy Evidence of demyelination and/or remyelination (CIDP only) Diagnostic categories Definite Typical or atypical clinical presentation (1 and 2) + definite NCS; or probable CIDP + ≥ 1 supportive criterion; or possible CIDP + ≥ 2 supportive criteria Probable Typical or atypical clinical presentation (1 and 2) + probable NCS; or possible CIDP + ≥ 1 supportive criterion Possible Typical or atypical clinical presentation (1 and 2) + possible NCS Summary of the EFNS/PNS diagnostic criteria for CIDP 19 and the Utrecht criteria for MMN 24 with current limitations. Abbreviations: CIDP = chronic inflammatory demyelinating polyneuropathy; MMN = multifocal motor neuropathy; ULN = upper limit of normal values; LLN = lower limit of normal values; CMAP = compound muscle action potential; CSF = cerebrospinal fluid.