What is Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)?

Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)

CIDP is an acquired immune-mediated disorder of the peripheral nervous system characterized by inflammatory demyelination of peripheral nerves, leading to progressive weakness, sensory loss, imbalance, pain, and impaired ambulation that can result in substantial disability. 1

Pathophysiology and Classification

CIDP is primarily an autoimmune disease that targets the myelin sheath of peripheral nerves through both cellular and humoral immune mechanisms. The condition involves:

• Inflammatory demyelination of peripheral nerves
• Possible secondary axonal loss if left untreated
• Immune attack against myelin proteins and nodal/paranodal proteins

CIDP belongs to the category of inflammatory neuropathies and is specifically classified as a chronic form, distinguishing it from acute variants like Guillain-Barré syndrome (GBS) 2.

Clinical Presentation

The typical presentation includes:

• Progressive or relapsing weakness affecting proximal and distal muscles
• Sensory dysfunction (numbness, tingling, pain)
• Reduced or absent tendon reflexes
• Possible cranial nerve involvement
• Autonomic symptoms in some cases
• Ataxia and impaired balance
• Neuropathic pain

Unlike other autoimmune diseases, CIDP:

• Generally affects older individuals
• Has a male predominance
• Presents with an insidious onset that can develop over up to 8 weeks
• Often follows a relapsing-remitting pattern 3

Diagnosis

Diagnosis is based on:

1. Clinical features: Progressive or relapsing motor and sensory dysfunction in more than one limb
2. Electrophysiological studies: Evidence of demyelination (conduction block, slowed conduction velocities)
3. CSF analysis: Elevated protein with normal cell count (albuminocytologic dissociation)
4. Nerve biopsy: May show demyelination and inflammation (not always required)

CIDP must be differentiated from:

• Acute inflammatory demyelinating polyneuropathy (AIDP/GBS)
• Multiple mononeuropathies
• Other causes of polyneuropathy (diabetic, toxic, etc.)

Treatment

Treatment of CIDP aims to address both the immune-mediated inflammation and manage residual symptoms:

First-Line Therapies (Evidence-Based)

1. Intravenous Immunoglobulin (IVIG):

   • Standard first-line therapy with robust evidence
   • Typical regimen: 2g/kg divided over 2-5 days initially, followed by maintenance therapy
   • Subcutaneous immunoglobulin may be an alternative in some cases

2. Corticosteroids:

   • Oral prednisone or pulse dexamethasone
   • Often effective but with significant side effects with long-term use

3. Plasma Exchange:

   • Effective alternative first-line therapy
   • Typically 5 exchanges over 2 weeks

Second-Line/Alternative Therapies

For patients who fail to respond to first-line treatments or cannot tolerate them:

• Immunosuppressants (azathioprine, mycophenolate mofetil)
• Rituximab (anti-CD20 monoclonal antibody)
• Cyclophosphamide
• Cyclosporine A
• Other immunomodulatory agents

Treatment Principles

1. Early intervention is crucial to prevent secondary axonal damage
2. Personalization of therapy based on individual response
3. Regular clinical assessments to monitor treatment response
4. Long-term management may be necessary due to the chronic nature of the disease

Prognosis

The prognosis of CIDP varies:

• Early diagnosis and treatment generally yield better functional recovery
• Some patients achieve remission with treatment
• Others require ongoing therapy to maintain improvement
• A subset may develop residual neurological deficits despite treatment

Supportive Care

Regardless of immunotherapy status, supportive interventions are essential:

• Physical therapy
• Adaptive equipment
• Pain management
• Emotional support 4

CIDP represents a significant cause of acquired neuropathy that, while challenging to manage, often responds to immunomodulatory treatment. Early diagnosis and appropriate therapy are critical to improving outcomes and quality of life for affected patients.