Does Chronic Inflammatory Demyelinating Polyneuropathy (CIPD) affect distal or proximal limbs first?

Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) Affects Proximal Limbs First

CIDP typically presents with symmetrical weakness that affects proximal muscles first, in contrast to most other neuropathies which begin distally. This proximal-predominant pattern is a distinguishing clinical feature of CIDP that helps differentiate it from other peripheral neuropathies.

Clinical Presentation of CIDP

Characteristic Motor Involvement

• CIDP presents with symmetrical weakness that predominantly affects proximal muscles first, with both upper and lower limbs commonly involved 1, 2
• At more severe disease stages, 94% of patients show both upper and lower limb weakness, with 56% developing both distal and proximal weakness in all four limbs 3
• This proximal pattern contrasts with most other neuropathies which typically begin distally in a "stocking-glove" distribution 4

Sensory Manifestations

• While motor symptoms predominate, sensory dysfunction is also common in CIDP 2
• Sensory symptoms include numbness, tingling, and pain that may develop later in the disease course 2, 5
• In some CIDP variants like pure motor CIDP (PM-CIDP), sensory symptoms may be absent entirely 3

Diagnostic Considerations

Clinical Examination

• Assessment should include careful history and evaluation of both proximal and distal muscle strength 4
• Deep tendon reflexes are typically reduced or absent in proportion to sensory loss 4
• Evaluation should include tests of small-fiber function (pinprick and temperature sensation) and large-fiber function (reflexes, vibration perception) 4

Electrophysiological Findings

• Nerve conduction studies reveal hallmark features of demyelination including:
  • Conduction blocks (present in 82% of motor CIDP patients) 3
  • F-wave abnormalities (88% of cases) 3
  • Slowed conduction velocities 1
  • Temporal dispersion 1

CIDP Variants

• Classical CIDP presents with symmetrical proximal and distal weakness 1
• Multifocal CIDP (Lewis-Sumner syndrome) presents with asymmetrical involvement 6
• Distal acquired demyelinating symmetric neuropathy (DADS) is a distal-predominant variant 6

Treatment Approach

First-Line Therapies

• Three well-established first-line treatments exist for CIDP 1:
  1. Intravenous immunoglobulin (IVIg) - most commonly used first-line therapy with rapid improvement
  2. Corticosteroids - slower effect but may induce remission more frequently
  3. Plasma exchange

Response to Treatment

• Approximately 75% of patients respond to IVIg 3
• Corticosteroids may be effective in patients with motor-predominant CIDP who are resistant to IVIg 3
• Treatment response should be judged by objective measures such as improvement in neurological examination 1

Prognosis and Outcomes

• Pure motor CIDP patients tend to have poorer outcomes compared to those with motor-predominant CIDP 3
• The disease often follows a progressive clinical course requiring long-term treatment 3, 5
• CIDP significantly impacts health-related quality of life, affecting physical functioning, activities of daily living, work capacity, emotional wellbeing, and social participation 2

Common Pitfalls in Diagnosis

• CIDP is often underdiagnosed due to its variable presentation 5
• It can be mistaken for other neuropathies, particularly in atypical variants 6
• Diagnostic challenges arise when distinguishing CIDP from other conditions that mimic it, such as diabetic neuropathy or monoclonal gammopathies 1
• Additional testing should be considered to rule out conditions that can mimic CIDP, including metastatic bone surveys, serum electrophoresis with immunofixation, and HIV testing 1

The proximal-predominant pattern of weakness in CIDP represents a key clinical feature that distinguishes it from most other peripheral neuropathies, which typically begin distally and progress proximally.