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Monkey Intel
Disorders Affecting the Spinal Cord
• Lecture 17 •
Overview
Exam questions in this unit usually test the condition pattern (who, how it presents, hallmark sensory/motor signature, classic associations). Detailed workups are rarely emphasized; know just the pivotal tests that confirm the pattern or require urgent action.
Exam note: focus on presentation and distinguishing features. Imaging/serologies are lower yield unless they uniquely define the disorder (e.g., syrinx on MRI, VDRL for neurosyphilis, VLCFA for X-ALD).
Transverse Myelitis (TM)
autoimmune/inflammatory
Essentials
Acute–subacute bilateral deficits below a spinal level over hours–days with sensory level and early bladder involvement. Can be idiopathic or with MS, NMOSD, MOGAD, SLE/Sjögren, post-infectious.
Classic pattern
Band-like trunk pain → ascending numbness/paresthesias → weakness and sphincter dysfunction. UMN signs evolve after 24–48h.
Distinguish from
Compression (severe back pain, LMN root pain), AV fistula (stepwise), infarct (hyperacute, severe pain), B12/Cu (chronic, dorsal column bias).
High-yield test
MRI cord lesion spanning ≥1–2 segments; brain MRI if MS suspected. (Know concept, not sequences.)
Pearl
Isolated TM with normal brain MRI lowers near-term MS risk; longitudinally extensive lesions raise NMOSD/MOGAD suspicion.
Neurosyphilis — Tabes Dorsalis
late infection
Classic pattern
Lightning pains, sensory ataxia, wide-based gait, positive Romberg, loss of reflexes, Argyll Robertson pupils possible.
Association
Destroys dorsal columns → loss of vibration/proprioception.
Exam clue
History of untreated STI, neuropathic joints, Charcot arthropathy; confirm conceptually with CSF VDRL.
Syringomyelia
Chiari I, trauma, tumor
Classic pattern
Cape-like loss of pain & temperature across shoulders/arms with preserved light touch; hand weakness/atrophy (anterior horn) as cyst enlarges.
Key association
Chiari I malformation in young adults; post-traumatic syrinx years after injury.
High-yield test
MRI showing central canal cavity (the word “syrinx” is enough for exam).
Subacute Combined Degeneration (B12) & Copper Deficiency
dorsal + lateral columns
Classic pattern
Sensory ataxia (loss vibration/position), spastic paraparesis, paresthesias, bladder urgency; UMN signs with dorsal column loss.
Differentiate
B12 often with macrocytosis, glossitis, peripheral neuropathy; Copper deficiency after gastric/duodenal surgery or excess zinc.
Pearl
Neuro deficits may only partially reverse → early recognition is the point.
Vascular Malformations & Spinal Epidural Hematoma
cord perfusion issues
Dural AV fistula
Men > 50; stepwise or fluctuating myeloradiculopathy; leg heaviness; venous congestion. Think “flow voids” conceptually on imaging.
SEH
Anticoagulated or post-procedure; sudden severe back pain → rapid deficits. Urgency is the test: decompress if worsening.
Cord infarct
Hyperacute onset with severe pain; ASA territory → anterior cord syndrome (motor + pain/temp loss; dorsal columns spared).
Friedreich Ataxia
AR GAA expansion (FXN)
Classic pattern
Childhood–teen onset, progressive ataxia and areflexia with loss of vibration/position; pes cavus, scoliosis, dysarthria.
Key associations
Hypertrophic cardiomyopathy, diabetes; degeneration of spinocerebellar tracts, dorsal columns, corticospinals.
Exam hook
Ataxia + cardiomyopathy in a teen → think Friedreich.
Adrenoleukodystrophy (X-linked)
ABCD1 → ↑ VLCFA
Classic pattern
Boy or young man with progressive spastic paraparesis and adrenal failure (hyperpigmentation, hypotension); later cognitive decline.
Exam hook
“Spasticity + adrenal insufficiency” → think X-ALD; confirm conceptually with very-long-chain fatty acids.
Mini-Cases
Case 1 — “Cape and keys”
Young adult with Chiari I has burning hands and can’t feel hot water over shoulders but light touch intact → syringomyelia.
Case 2 — “Band then bladder”
Hours-to-days bilateral numbness with trunk band and urinary urgency after URI → transverse myelitis.
Case 3 — “Tertiary sting”
Elderly patient with lightning pains, sensory ataxia, absent knee jerks, pupils that accommodate but don’t react → tabes dorsalis.
Case 4 — “Stepwise legs”
Man in his 60s with progressive leg weakness that worsens after activity, exam shows myeloradiculopathy; think dural AV fistula.
Case 5 — “Macro mystery”
Gradual numb feet, spastic gait, positive Romberg, MCV 112 → subacute combined degeneration (B12).
Case 6 — “Bronze and stiff”
Teen boy with hyperpigmentation, orthostatic symptoms, spastic paraparesis → adrenoleukodystrophy.
Case 7 — “Sudden squeeze”
On anticoagulation; acute severe back pain then rapid weakness and numbness → spinal epidural hematoma (urgent decompression).
Self-Test (tap to reveal)
pattern recognition > exhaustive workup
Band-like trunk pain then urinary urgency over 24–48h. Dx?
Transverse myelitis.
Cape-like pain/temperature loss with preserved touch. Dx?
Syringomyelia.
Teen with ataxia + hypertrophic cardiomyopathy.
Friedreich ataxia.
Spastic paraparesis + adrenal failure in a young male.
Adrenoleukodystrophy.
Macrocytosis + sensory ataxia + spastic gait.
Subacute combined degeneration (B12).
Post-laminectomy years ago; now stepwise leg weakness worse after activity.
Spinal dural AV fistula.
Lightning pains, wide-based gait, absent reflexes, AR pupils.
Tabes dorsalis.
Anterior cord syndrome after hyperacute pain.
Spinal cord infarct (ASA territory).
Sudden severe back pain on anticoagulation → rapid deficits.
Spinal epidural hematoma.
Condensed Exam Table — Patterns & Hooks
workup de-emphasized
| Disorder | Who | Signature | One-line Hook |
|---|---|---|---|
| Transverse myelitis | Any age; post-infection; autoimmune | Rapid bilateral deficits + sensory level + early bladder | Band-like trunk pain → weakness → urgency |
| Syringomyelia | Chiari I; post-trauma | Cape-like pain/temp loss; hand weakness | MRI “syrinx” |
| B12 / Copper deficiency | B12 malabsorption; post-GI surgery or ↑ zinc | Sensory ataxia + spasticity (posterior + lateral columns) | Macrocytosis (B12) vs post-bariatric (Cu) |
| Tabes dorsalis | Late syphilis | Lightning pains, ataxia, areflexia | Argyll Robertson pupils possible |
| Dural AV fistula | Men > 50 | Stepwise myeloradiculopathy | “Flow-voids” idea |
| Spinal epidural hematoma | Anticoagulated / post-procedure | Acute back pain → rapid deficits | Urgent decompression if worsening |
| Friedreich ataxia | Child/teen | Ataxia + loss of vibration; areflexia | Hypertrophic cardiomyopathy |
| Adrenoleukodystrophy | Boys/young men | Spastic paraparesis + adrenal failure | ↑ very-long-chain fatty acids |
High-yield. Zero fluff. — Monkey Intel