Chronic inflammatory demyelinating polyneuropathy (CIDP) !

An immune attack on the myelin of peripheral nerves that causes weakness and numbness in arms and legs, worsening for more than 8 weeks.

Updated 2026-11-01

Structures involved

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Why it happens

What it is

An acquired, immune-mediated disease in which the myelin sheath of nerve roots and peripheral nerves is repeatedly damaged. It produces symmetric weakness of both proximal and distal muscles with loss of reflexes, progressing or relapsing over more than two months. It is often described as the chronic counterpart of Guillain-Barré syndrome and is treatable.

Who gets it

A rare disease, with a prevalence of a few cases per 100,000 people; it can start at any age but is more frequent in middle-aged and older adults and slightly more common in men. In Latin America it is probably under-recognised because nerve conduction studies and specialist neurology are concentrated in large cities, and some cases are first labelled as Guillain-Barré syndrome.

Causes

Autoimmune attack (cellular and antibody-mediated) against myelin of peripheral nerves and roots
Usually idiopathic; sometimes follows an infection or vaccination
Associated conditions: monoclonal gammopathy (MGUS), diabetes, HIV infection, hepatitis, lymphoma and connective tissue diseases
Variant forms with specific antibodies against nodal and paranodal proteins

Risk factors

Age over 50
Male sex
Monoclonal gammopathy
Diabetes mellitus
HIV infection and other chronic immune disorders

Pathophysiology

Macrophages and autoantibodies strip myelin from segments of nerve fibres, mainly at the nerve roots, plexuses and proximal nerves. Demyelination slows conduction and causes conduction block, which explains weakness and loss of reflexes. Repeated demyelination and remyelination form "onion bulbs" around axons and can thicken the roots. When inflammation persists, secondary axonal loss leads to muscle wasting and incomplete recovery.

Classification

Typical CIDP: symmetric proximal and distal weakness with sensory loss
Distal variant: mainly distal, often sensory, sometimes linked to IgM paraprotein
Multifocal variant (Lewis-Sumner): asymmetric, following individual nerves
Pure motor and pure sensory variants
Course: slowly progressive or relapsing-remitting

Symptoms and signs

Symmetric weakness of arms and legs affecting both proximal muscles (difficulty climbing stairs, rising from a chair) and distal muscles
Numbness, tingling and loss of vibration and position sense, with unsteady gait
Reduced or absent deep tendon reflexes
Progression or relapses over more than 8 weeks
Fatigue; cranial nerve or autonomic involvement is uncommon and mild

Diagnosis

Clinical: Suspected in a patient with symmetric proximal and distal weakness, sensory loss and areflexia that progresses for more than 8 weeks. The key distinction from Guillain-Barré syndrome is the time course (GBS reaches its worst within 4 weeks and is monophasic).
Tests: Nerve conduction studies are the key test: slowed conduction velocity, prolonged distal latencies and F-waves, conduction block and temporal dispersion (demyelinating pattern). Cerebrospinal fluid shows high protein with a normal cell count (albuminocytologic dissociation). Blood tests look for associated causes: serum protein electrophoresis and immunofixation, glucose, HIV and hepatitis serology, thyroid function and vitamin B12. Nerve biopsy is rarely needed.
Imaging: MRI of the spine or plexuses may show thickened, enhancing nerve roots; nerve ultrasound can show enlarged nerves.

Differential diagnosis

Guillain-Barré syndrome
Charcot-Marie-Tooth disease (hereditary, with family history and foot deformity)
Diabetic and other axonal polyneuropathies
Multifocal motor neuropathy
Polyneuropathy with monoclonal gammopathy, including POEMS syndrome
Amyotrophic lateral sclerosis and myasthenia gravis

Goal of treatment

Stop the immune attack early to prevent permanent axonal loss, restore strength and function, then find the lowest maintenance treatment that keeps the disease in remission.

Treatment

Medical: First-line immunotherapy: intravenous immunoglobulin or glucocorticoids; both are effective, and the choice depends on comorbidities and access. Subcutaneous immunoglobulin can be used for maintenance.
Procedure: Plasma exchange for severe disease or when the first-line options fail, usually as a short-term measure.
Medical: Steroid-sparing immunosuppressants (e.g. azathioprine, mycophenolate) or newer immune therapies such as neonatal Fc receptor blockers in refractory or relapsing cases; treat any associated disorder.
Conservative: Physiotherapy and occupational therapy, ankle-foot orthoses for foot drop, fall prevention and neuropathic pain control.
Follow-up: Regular strength and disability scores to judge response and taper treatment; monitor glucose, blood pressure and bone health on steroids and renal function and thrombosis risk with immunoglobulin.

Complications

Permanent weakness and muscle wasting from axonal loss
Falls and fractures
Chronic neuropathic pain and fatigue
Adverse effects of long-term immunotherapy (infections, osteoporosis, diabetes)
Disability and loss of work

Prognosis

Most patients (around 80%) improve with immunotherapy, but many need treatment for years and relapses are common. Earlier treatment gives better recovery; a minority are left with significant disability. Death from CIDP itself is rare.

Test yourself

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What time course separates CIDP from Guillain-Barré syndrome?

CIDP progresses or relapses for more than 8 weeks; Guillain-Barré syndrome reaches its nadir within 4 weeks and is monophasic.

What are the typical cerebrospinal fluid findings in CIDP?

High protein with a normal white cell count (albuminocytologic dissociation).

What does the nerve conduction study show?

A demyelinating pattern: slowed conduction velocity, prolonged distal and F-wave latencies, conduction block and temporal dispersion.

What are the first-line treatments for CIDP?

Intravenous immunoglobulin or glucocorticoids; plasma exchange in severe or refractory cases.

Which blood test should be done in every patient with CIDP?

Serum protein electrophoresis with immunofixation to look for a monoclonal gammopathy.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) - Neurology - MSD Manual Professional Edition (MSD Manual Professional Edition, 2026); Peripheral Neuropathy | National Institute of Neurological Disorders and Stroke (National Institute of Neurological Disorders and Stroke (NINDS), 2026).

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Representative model, for educational purposes only.

Neck nerve roots highlighted on the Durgical 3D model