What is Chronic Inflammatory Demyelinating Polyneuropathy (CIPD)?

What is Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)?

CIDP is a chronic, acquired immune-mediated disorder of the peripheral nervous system characterized by progressive or relapsing symmetric weakness (both proximal and distal), sensory dysfunction, and areflexia that evolves over at least 2 months, distinguishing it from acute conditions like Guillain-Barré syndrome. 1

Core Clinical Features

CIDP presents with a distinctive pattern that helps differentiate it from other neuropathies:

• Motor involvement: Progressive weakness affecting both proximal and distal muscles of the limbs, with potential extension to cranial muscles 2
• Sensory dysfunction: Predominantly affects large fiber modalities (proprioception and vibration sense), causing sensory ataxia and wide-based gait instability 2
• Reflexes: Generalized areflexia or hyporeflexia, not limited to ankle reflexes alone 2
• Temporal pattern: Symptoms progress over more than 2 months, which is the key distinguishing feature from Guillain-Barré syndrome that reaches maximum disability in 2-4 weeks 1, 2

The sensory loss does not follow the typical "stocking-glove" distribution seen in axonal neuropathies, and symptoms may begin distally but advance toward proximal regions 2.

Pathophysiology

CIDP is an autoimmune disease where the immune system targets peripheral nerve myelin 3. Possible antigenic targets include myelin protein 0, myelin protein 2, peripheral myelin protein 22, Connexin 32, and myelin basic protein 3. Some patients have antibodies against Ranvier node proteins such as contactin-1, contactin-associated protein 1, and neurofascin 155 3.

Diagnostic Workup

The diagnosis requires integration of clinical, electrophysiological, and laboratory findings:

• Electrophysiology: Shows evidence of diffuse demyelination with reduced conduction velocities, temporal dispersion, and conduction blocks 1, 2
• CSF analysis: Typically demonstrates cytoalbuminologic dissociation (elevated protein with normal cell count) 1, 2. A critical caveat: marked pleocytosis (>50 cells/μL) suggests alternative diagnoses such as infectious or inflammatory polyradiculitis 2
• MRI: Imaging of brachial or lumbosacral plexus can identify focal or diffuse peripheral nerve abnormalities 1
• Nerve biopsy: May be useful in evaluating atypical forms 1

Important diagnostic pitfall: Only 50-60% of patients with typical clinical features fulfill strict electrodiagnostic research criteria, so clinical judgment remains paramount 4.

CIDP Variants

Approximately 10% of cases present as atypical variants 2:

• MADSAM (Multifocal Acquired Demyelinating Sensory and Motor Neuropathy): Also called Lewis-Sumner Syndrome, characterized by asymmetric involvement with preserved reflexes in unaffected areas 1, 2
• Chronic neurovisceral variants: Present with slower progression of neurological symptoms 1

Differential Diagnosis

Key conditions to exclude include:

• Guillain-Barré syndrome: Acute onset with progression over days to weeks 1
• Diabetic polyradiculoneuropathy 1
• Leptomeningeal metastases and infectious causes 1
• Systemic inflammatory disorders like lupus 1
• Metabolic disorders, toxins, or nutritional deficiencies 1

Treatment Approach

For severe or progressing symptoms, initiate pulse corticosteroids (methylprednisolone 1g IV daily for 3-5 days) plus IVIG 2g/kg over 5 days. 1

The treatment algorithm follows these principles:

• First-line therapies: Corticosteroids, IVIG, or plasma exchange are proven effective 4, 5
• Severe refractory cases: Plasmapheresis for patients not responding to initial therapies 1
• Treatment-resistant cases: Rituximab may be considered in consultation for cases with limited improvement 1
• Long-term management: Requires serial clinical assessments to determine if continued immunotherapy is needed, as there is no reliable disease activity biomarker 5

Critical treatment caveat: Early treatment is essential, as delayed therapy may result in irreversible neurological deficits even after the active inflammatory component is controlled 5. Treatment optimization must be personalized to determine the ideal dose and whether long-term therapy is necessary 5.

Prognosis and Complications

• CIDP generally affects older individuals with male predominance 3
• Some patients may have residual and irreversible neurological deficits requiring supportive interventions including physical therapy, adaptive equipment, pain management, and emotional support 5
• Additional symptoms may include dysphagia, neuropathic pain, cranial nerve involvement, autonomic symptoms, and ataxia 1, 3