Chronic inflammatory demyelinating polyneuropathy

Last revised by Rohit Sharma on 6 Oct 2024

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired demyelinating disease involving peripheral nerves, and is generally considered the chronic counterpart to Guillain-Barré syndrome (GBS).

CIDP is rare, with one systematic review finding an incidence rate of 0.33 per 100,000 person-years 10. It is slightly more common in males and is typically seen on an older adult demographic 10.

In typical CIDP, patients typically present with a subacute-to-chronic (>2 months) weakness of both proximal and distal musculature associated with areflexia and sensory changes 3. Rarely, in some patients, presentation can be acute and may closely mimic Guillain-Barré syndrome 2,4, known as acute-onset CIDP (A-CIDP).

In addition to the aforementioned typical presentation, many atypical variants of CIDP exist 7:

  • distal CIDP (distal acquired demyelinating symmetric (DADS) neuropathy)

  • multifocal CIDP (multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy or Lewis-Sumner syndrome)

  • focal CIDP (chronic inflammatory demyelinating mononeuropathy (CIDM))

  • sensory CIDP (pure sensory CIDP)

  • motor CIDP (pure motor CIDP)

Chronic inflammatory demyelinating polyneuropathy is an acquired demyelinating disease of the peripheral nervous system. Affected nerves demonstrate segmental infiltration with inflammatory cells (lymphocytes) and demyelination 4. Over time there is proliferation of Schwann cells and deposition of collagen resulting in thickening of the nerve and the characteristic onion bulb appearance 4. Involvement of the nerves results in changes of denervation in the supplied muscles 1

MRI is the modality of choice for imaging the changes of chronic inflammatory demyelinating polyneuropathy, the hallmark of which is thickening and enhancement of peripheral nerves, brachial and lumbosacral plexus and nerve roots. In many cases, the nerves become so thickened that they resemble onion bulbs. Approximately one-third of patients have cranial nerve involvement 5. Intercostal nerve involvement, although rare, has also been described 6.

In addition, the supplied muscles will demonstrate changes of denervation 1

  • acute to subacute

    • diffuse increase in T2 signal

    • diffuse increased enhancement (seen best on fat suppressed T1 C+)

  • chronic

    • fatty atrophy

Chronic inflammatory demyelinating polyneuropathy can be treated with corticosteroids, intravenous immunoglobulin, plasmapheresis and other immunosuppression (e.g. rituximab, efgartigimod) 4,8,9

  • Guillain-Barré syndrome (GBS)

    • acute-onset CIDP (A-CIDP) can be similar

    • difficult to differentiate in the first 6 weeks

    • after 6-8 weeks GBS should be improving whereas CIDP will demonstrate chronic inflammation 2

  • chronic immune sensory polyradiculopathy (CISP)

  • autoimmune nodopathies and paranodopathies

  • hereditary neuropathies with late-onset (e.g. some types of Charcot-Marie-Tooth disease)

Cases and figures

  • Case 1
  • Case 2
  • Case 3

Imaging differential diagnosis

  • Hereditary hypertrophic neuropathy
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