🧠Non-Compressive Myelopathy

🧠 Non-Compressive Myelopathy – High-Yield Overview

Spinal cord dysfunction without external mechanical compression. Pathology is intrinsic: inflammatory, vascular, metabolic, toxic, infectious, genetic, or infiltrative.

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🔥 1. Inflammatory / Immune-Mediated (Most common in neurology)

🧩 Multiple Sclerosis (MS)

• ⚡ Partial myelitis (<3 segments, asymmetric)
• 🧠 Often associated with brain plaques
• 🎯 Patchy short-segment lesions

💧 NMOSD (Aquaporin-4 IgG)

• 📏 Longitudinally extensive lesions (≥3 segments)
• 👁️ Severe myelitis + optic neuritis
• 🚑 Often profound deficits

🟠 MOGAD (MOG-associated disease)

• 🎭 Can mimic NMOSD or short lesions
• 😊 Better recovery compared to AQP4-NMOSD

🎯 Idiopathic Transverse Myelitis

• ⏱️ Acute/subacute
• 🎚️ Sensory level + sphincter involvement

🧬 Paraneoplastic Myelopathy

• 🔗 Anti-Hu, CRMP-5, amphiphysin
• 📉 Progressive course
• 🎗️ Associated malignancy

🌡️ Autoimmune Systemic (SLE, Sjögren, Sarcoidosis)

• 🔥 Granulomatous or vascular myelopathy
• 🪵 Sarcoid: Long lesions, dorsal subpial “Trident sign”

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🩸 2. Vascular Causes

❤️‍🔥 Spinal Cord Infarction

• ⚡ Hyperacute onset with severe back pain
• 🫀 Anterior spinal artery:
  • ❌ Motor + pain/temperature loss
  • ✔️ Vibration/position preserved
• 🦉 “Owl’s eyes” sign on axial MRI

🌊 Spinal Dural AV Fistula

• 🐌 Slowly progressive
• 💨 Worse with exertion
• 🌀 MRI: T2 hyperintensity + serpiginous flow voids
• 🚨 Treatable cause—don’t miss!

🧪 Venous Infarction / Hypercoagulable States

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🦠 3. Infectious Causes

🦠 Viral

• HIV, HTLV-1, HSV-2, EBV, CMV
• ⚖️ HTLV-1 → progressive spastic paraparesis

🧫 Bacterial

• Syphilis (tabes dorsalis / meningomyelitis)
• Lyme
• Tuberculosis

🪱 Parasitic

• Schistosomiasis (Egypt)
• Neurocysticercosis

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🧬 4. Metabolic & Deficiency-Related

🟦 Vitamin B12 Deficiency (Subacute Combined Degeneration)

• 🎯 Posterior columns + CST
• 👣 Sensory ataxia + spasticity

🟧 Copper Deficiency

• 🔎 Mimics B12 deficiency
• 🍽️ Often after gastric surgery/zinc excess

🟩 Vitamin E Deficiency

• Rare; posterior column involvement

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☣️ 5. Toxic Causes

• 🎈 Nitrous oxide → functional B12 deficiency
• 💉 Chemotherapy (cisplatin, vincristine)
• ☢️ Radiation-induced (months–years delayed)

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🧬 6. Genetic / Degenerative

🧵 Hereditary Spastic Paraplegia (HSP)

• 🐌 Slowly progressive spastic paraparesis
• 🧠 MRI often normal or subtle

🌐 Leukodystrophies / Mitochondrial Disorders

• 🌀 Diffuse white-matter + spinal involvement

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🦠 7. Neoplastic / Infiltrative (Intrinsic Cord)

(Not compressive but inside the cord)

• 🧫 Astrocytoma
• 🧪 Ependymoma
• 🟣 Lymphoma
• 🩸 Leukemic infiltration

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🧲 MRI Hallmarks – Quick Differentiation

📏 Longitudinal (≥3 segments)

• NMOSD
• Sarcoidosis
• Vascular congestion (dAVF)
• B12/copper deficiency

🎯 Posterior column–predominant

• B12
• Copper deficiency
• HIV vacuolar myelopathy

🧩 Patchy short lesions

• MS

🌲 Dorsal subpial enhancement

• Sarcoidosis (“Trident sign”)

🦉 Owl’s eyes

• Spinal cord infarction

🎯 Central gray matter involvement

• Viral (enteroviruses)
• Ischemia
• MOGAD

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🔍 Approach to Diagnosis

1️⃣ MRI with contrast

• Enhancement pattern
• Longitudinal extent
• Tract involvement

2️⃣ CSF Analysis

• 🧪 OCBs → MS
• 🔥 Neutrophils → infection
• 📈 High protein / low cells → GBS-variant (rare ascending myelitis)

3️⃣ Serum Studies

• AQP4-IgG, MOG-IgG
• B12, MMA, copper
• ANA, ENA, ACE (sarcoid)
• HIV, HTLV-1, VDRL/TPHA (syphilis)

4️⃣ Spine Angiography

• If dural AV fistula suspected

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🚨 Red Flags Requiring Emergent Treatment

• ⏳ Rapidly progressive weakness
• ⚠️ Sphincter dysfunction
• 🔥 Suspected NMOSD flare
• 💉 Severe transverse myelitis → IV methylprednisolone ± plasmapheresis