Table 1.
Comparison of the chronic acquired immune-mediated demyelinating polyneuropathies
| CIDP | DADS neuropathy | MADSAM neuropathy | MMN | |
|---|---|---|---|---|
| Clinical features | ||||
| Weakness | Symmetric; proximal + distal | Symmetric; distal only; mild or no weakness | Asymmetric; distal > proximal; upper limbs > lower limbs | Asymmetric; distal > proximal; upper limbs > lower limbs |
| Sensory deficits | Yes; symmetric | Yes; Symmetric | Yes; multifocal (distribution of individual nerves) | No |
| Reflexes | Reduced or absent symmetrically | Reduced or absent symmetrically | Reduced or absent (multifocal or diffuse) | Reduced or absent (multifocal or diffuse) |
| Electrophysiology | ||||
| Abnormal CMAPs: | ||||
| Demyelinating features | Usually symmetric | Usually symmetric Prolonged distal latencies | Asymmetric (multifocal) | Asymmetric (multifocal) |
| Conduction block | Frequent | Uncommon | Frequent | Frequent |
| Abnormal SNAPs | Usually symmetric | Usually symmetric | Asymmetric (multifocal) | SNAPs are normal |
| Laboratory findings | ||||
| CSF Protein | Usually elevated | Usually elevated | Usually elevated | Usually normal |
| Monoclonal protein | Occasionally present; Usually IgG or IgA | IgM-κ present in the majority; 50 %–70 % are MAG positive | Rarely present | Rarely present |
| Anti-GM1 Antibodies | Rarely present | Not present | Rarely present | Frequently present (50 %) |
| Sensory nerve biopsy: | ||||
| Demyelination/ remyelination | Frequent | Frequent | Frequent; Sometimes asymmetrical | Occasional; Minimal findings |
| Treatment response | ||||
| Prednisone | Yes | Poora | Yes | No |
| Plasma exchange | Yes | Poora | Possible (more study needed) | No |
| IVIg | Yes | Poora | Yes | Yes |
| Cyclophosphamide | Yes | Poora | Possible (more study needed) | Yes |
CIDP chronic inflammatory demyelinating polyneuropathy, CMAPs compound motor action potentials, CSF cerebrospinal fluid, DADS distal acquired demyelinating symmetrical, IVIg intravenous immunoglobulin, MADSAM multifocal acquired demyelinating sensory and motor, MAG myelin associated glycoprotein, MMN multifocal motor neuropathy, SNAPs sensory nerve action potentials.
a
When associated with an IgM-MGUS.
Treatment responses in DADS neuropathy patients without a MGUS are more similar to those with CIDP.