🧠 CIDP (Chronic Inflammatory Demyelinating Polyradiculoneuropathy) – Variants & High-Yield
Definition:
Chronic, immune-mediated demyelinating neuropathy 🧬, >8 weeks, often relapsing or progressive. Chronic counterpart of AIDP/GBS ⚡.
🔹 1️⃣ Typical CIDP (Classical Form)
- Symmetric proximal + distal motor & sensory deficits 💪🦶
- Slowly progressive or relapsing course >8 weeks
- Areflexia ⚡ universal
- NCS: diffuse demyelination, conduction block, prolonged distal latency, slowed velocity, F-wave delay
🔹 2️⃣ MADSAM (Lewis–Sumner Syndrome)
- Asymmetric, multifocal neuropathy 🦵🖐️
- Begins in one limb (usually upper), spreads
- Motor + sensory deficits along individual nerves
- Mimics mononeuritis multiplex (without ischemic pain)
- NCS: multifocal conduction blocks
- Response: good to IVIg 💉 or corticosteroids
🔹 3️⃣ DADS (Distal Acquired Demyelinating Symmetric Neuropathy)
- Distal, symmetric sensory > motor neuropathy (legs > arms)
- Often IgM paraproteinemia 🧪, anti-MAG antibodies
- Features: sensory ataxia 🦵, tremor, mild weakness
- Chronic, slowly progressive; sometimes poor steroid response
🔹 4️⃣ Pure Motor CIDP
- Only motor weakness 💪, no sensory loss
- May resemble motor neuron disease ⚡ but treatable
- NCS: demyelination in motor nerves; sensory normal
- Responds well to IVIg 💉
🔹 5️⃣ Pure Sensory CIDP
- Sensory loss 🦶 & ataxia without motor weakness
- Deep sensory loss → gait imbalance & pseudoathetosis
- NCS: sensory demyelination, absent SNAPs; CMAPs normal
- Partial improvement with immunotherapy 🧬
🔹 6️⃣ Focal CIDP
- Localized involvement of single nerve or plexus 🦵🖐️
- May mimic entrapment neuropathy or plexopathy
- NCS: focal conduction block; demyelination restricted
🔹 7️⃣ Sensory Ataxic Variant
- Severe proprioceptive loss 🦶, ataxic gait, pseudoathetosis
- Reflexes absent ⚡, motor strength preserved
- NCS: markedly reduced sensory conduction
🔹 8️⃣ Combined Central & Peripheral Demyelination (CCPD)
- Rare overlap: peripheral neuropathy + CNS demyelination 🧠
- Features: optic neuritis 👁️, myelitis
- Often anti-NF155 or anti-CNTN1 antibodies 🧬 positive
🔹 9️⃣ Antibody-Associated CIDP Variants (Nodopathies / Paranodopathies)
- Autoantibodies against nodal/paranodal proteins 🧬
- Anti-NF155 → tremor, ataxia, poor IVIg response, younger onset
- Anti-CNTN1 / CASPR1 → motor-predominant, aggressive, good response to rituximab 💉
- Distinct from classic CIDP: no macrophage-mediated demyelination
🔹 CIDP Spectrum Mnemonic
“Typical – MADSAM – DADS – Pure Motor – Pure Sensory – Focal – Sensory Ataxic – CCPD – Nodopathies
