Spinal Cord Disorders

Common symptoms: weakness/numbness/paresthesias, "MS Hug[…]" (banding sensation), gait disturbance, bowel/bladder dysfunction.

Localization clues: "Lhermitte[…]" sign (pain/tingling with neck flexion) → cervical myelopathy; Hyperacute symptoms → vascular[…] myelopathy; Prominent bowel/bladder dysfunction → chronic vascular (dAVF or AVM[…]); Selective vibration/proprioception loss → metabolic[…] myelopathy (B12, Cu); "Uhthoff[…]" sign (recrudescence with heat/exercise) → autoimmune myelopathy; Infectious myelopathies: systemic illness, mosquito or epidemiologic exposure; Vascular: worsening with exercise, steroids, extreme neck hyperflexion/extension, trauma.

Exam: UMN[…] signs: spasticity, hyperreflexia, clonus, Babinski+; LMN[…] signs: flaccid tone, areflexia; Gait: spastic or sensory ataxia; Sensory level.

Compartments: extradural, intradural-extramedullary, intramedullary. Lesion length: Longitudinally extensive[…] (≥3 vertebral segments) → NMO/MOG, sarcoid, spinal stroke (Adamkiewicz, dAVF/AVM); Short-segment (<3) or multifocal short → MS/CIS[…], other autoimmune; Tractopathies[…] (symmetric lateral CST or dorsal column changes) → metabolic (B12, Cu), toxic (NO toxicity), paraneoplastic (CRMP5), Sjögren, HIV, COVID-19.

Axial signs: "Owl eyes / snake eyes[…]" — selective anterior horn involvement → spinal cord stroke and acute flaccid myelitis[…]; "H[…]" sign — diffuse gray matter (anterior + posterior horns) → MOG; "Y[…]" sign — epidural lipomatosis (mostly thoracic in steroid users/obesity); Central canal hyperintensity → NMO/MOG; "Trident[…]" sign — enhanced posterior + lateral white matter → sarcoidosis; Inverted rabbit ears / inverted V → subacute combined degeneration (B12)[…]; "Pancake[…]" sign — focal thin transverse band at stenosis level → spondylotic myelopathy; "Missing piece[…]" sign — nonenhancing area within long enhancement segment → dAVF or AVM.

Tests: serum autoimmune antibodies (AQP4, MOG, GFAP); CT spine for trauma; CT myelography for arachnoid cysts/herniation; DSA[…] for dAVF/AVM workup.

General: cervical and lumbar affected > thoracic. Pathophys: disc degeneration → height loss → canal narrowing + altered biomechanics → ligamentum flavum hypertrophy + facet laxity → chronic ischemia + neuroinflammation + BBB disruption[…] → apoptosis of neurons/oligodendrocytes → gray matter atrophy + white matter demyelination.

Most commonly affected: C4-C7[…].

Thoracic watershed area at T10-T11[…].

Cervical myelopathy: Symptoms: usually chronic gradual onset; acute possible with preexisting myelopathy + trauma or prolonged neck flexion/extension (e.g., intubation); Dexterity[…] changes most characteristic: difficulty with buttons, utensils, zippers; Paresthesia in "glovelike[…]" hand pattern; LE symptoms typically symmetric; UE may be asymmetric; Gait dysfunction: subjective imbalance → falls (from proprioception + motor deficits) → spastic; Urinary retention/incontinence = advanced[…] myelopathy with poor prognosis. Thoracic myelopathy: lower thoracic most affected. Back pain more prominent. Pelvic girdle pain.

"Myelopathy hand": hand muscle wasting (thenar/hypothenar/interossei) — LMN findings in otherwise UMN process[…] from anterior horn cell dysfunction at C8-T1.

Grading: modified mJOA[…] scale (18-point); mild 15-17, moderate 12-14. Treatment: mild → conservative with low threshold for surgery; moderate → recommend surgery.

Complications: laryngeal nerve injury, adjacent segment disease, CSF leak[…].

Hirayama disease: Juvenile-onset painless weakness/amyotrophy in C7-T1[…] myotomes.

Pathophys: abnormal forward shifting of posterior dura during neck flexion[…] → anterior horn cell compression + reduced vascular supply. "Reverse split-hand[…]" syndrome (ulnar/hypothenar-predominant atrophy) — distinguishes from ALS ("split-hand" = thumb/thenar). Progresses 3-5 years then spontaneously stops.

MRI: asymmetric cord flattening, cervical atrophy (C4-C7), snake eyes[…] sign. Flexion MRI: crescent-shaped epidural mass from congested venous plexus.

Treatment: cervical collar[…] first-line → surgery if needed.

Spinal arachnoid cysts: typically dorsal thoracic; MRI shows extramedullary location with same signal as CSF; cord displaced anteriorly = "scalpel[…]" sign.

Syringomyelia: CSF-filled cavity; most commonly with Chiari[…] malformations.

Classic symptoms: loss of pain/temperature[…] with preserved touch, hand atrophy/clawing, lower limb spasticity, Horner, scoliosis, Charcot joints.

Idiopathic spinal cord herniation: cord herniates through anterior/lateral dural defect; exclusively thoracic[…]. Brown-Séquard syndrome: damage to one half of cord → ipsilateral motor + vibration/proprioception loss + contralateral pain/temperature loss. Often penetrating SCI. DDX: ALS vs cervical myelopathy: both cause hand weakness + hyperreflexia.

ALS has widespread fasciculations, split-hand (thenar > hypothenar)[…], no sensory symptoms. Myelopathy has paresthesia, glovelike sensory, fasciculations limited to hand/myotome. HSP vs myelopathy: HSP has early spasticity with preserved strength.

MMN[…]: painless UE weakness but diminished reflexes (vs increased in myelopathy).

Compartments: Intradural-intramedullary[…]: cord parenchyma.

Intradural-extramedullary[…]: dura/leptomeninges.

Extradural[…]: nerve roots, vertebrae, surrounding structures. Most common, usually metastases. Imaging: MRI entire spine wwo.

LP/CSF: include opening pressure[…] (LMM may cause high ICP). Primary intradural-intramedullary tumors:

Ependymomas[…] (most common): perivascular pseudorosettes or true ependymal rosettes with central lumen.

Inactivation of NF2[…].

MYCN[…]-amplified spinal ependymoma is aggressive subgroup (hypercellularity, atypia, necrosis, microvascular proliferation; lacks NF2; poor prognosis with dissemination).

All patients should be screened additionally for meningiomas and schwannomas[…].

Myxopapillary ependymoma[…]: WHO grade 2; arises in conus medullaris and filum terminale[…]; high rate of neuraxis dissemination and relapse. Spinal subependymoma: WHO grade 1; often asymptomatic; recurrence rare after resection.

Pilocytic astrocytomas[…]: most common in kids; bipolar hairlike cells + myxoid + Rosenthal fibers[…]. Typically cervicothoracic, may be cystic.

Associated with germline NF1[…] inactivation.

Molecular: MAPK[…] pathway (KIAA1549-BRAF fusion or BRAF V600E).

Treatment: surgery; for BRAF V600E: dabrafenib + trametinib[…]; contraindicated in BRAF fusion tumors (paradoxical activation). Diffuse midline gliomas: midline structures (pons, bilateral thalami, spinal cord). WHO grade 4.

H3K27M[…] variation. Very refractory.

Hemangioblastomas: highly vascular; nearly all with von Hippel-Lindau (VHL)[…]. Avidly enhancing masses, often cystic with mural nodule.

Treatment: surgery; belzutifan[…] (HIF-2α inhibitor).

Intradural-extramedullary: Meningiomas[…] (most common primary tumor of spinal cord, from pachymeninges/dura): WHO grade 1; risk factors: NF2, ionizing radiation; MRI: enhancing mass with "dural tail[…]" + frequent calcified areas.

Schwannomas: benign peripheral nerve sheath tumors of Schwann cells[…]; associated with NF2 (bilateral vestibular). MRI: avidly enhancing.

Histology: S100 and SOX10[…] expression.

Treatment: surgery and bevacizumab[…] for surgically inaccessible/multiple symptomatic lesions.

Neurofibromas: mixture of neoplastic Schwann cells + non-neoplastic cells[…] (vs pure Schwann in schwannomas). Hallmark of NF1 (neurofibromin loss → unregulated RAS).

Plexiform[…] neurofibromas can transform into malignant peripheral nerve sheath tumors.

Treatment: surveillance + MEK inhibitors[…] for surgically inaccessible NF1-related plexiform. Solitary fibrous tumors (formerly hemangiopericytomas): mimic meningiomas (may have dural tail).

Molecular: NAB2-STAT6[…] gene fusion. Can metastasize.

Extradural metastases (solid cancers): most common from breast, lung, prostate[…]. LMM most common from breast, lung, melanoma.

DLBCL[…]: most common lymphoma subtype to affect spine.

Hematologic malignancies: more prone to intradural[…] spinal metastasis vs solid tumors.

CNS LMM from leukemia mostly due to ALL[…] → prophylactic intrathecal chemo.

High-dose MTX or cytarabine; dasatinib[…] for BCR-ABL or Philadelphia Chromosome ALL.

Epidural spinal cord compression: most important prognostic indicators = pretreatment motor function and rapidity of symptom onset[…].

All patients receive dexamethasone[…] first → immediate surgical decompression + stabilization + XRT.

Commonalities: Mostly UMN[…] symptoms; chronic slowly progressive; family history; MRI: most commonly shows cord atrophy without signal change[…]; Best test: whole-exome sequencing[…] (~30% yield); Always exclude acquired/treatable causes first.

Hereditary Spastic Paraplegia: Degeneration of CST and DCML tracts; "Uncomplicated": predominantly weakness + spasticity; "Complicated": adds neuropathy, cognitive issues, EPS, seizures, dysarthria, ataxia, optic atrophy, hearing loss; Most common: SPG4 (AD, spastin)[…] or SPG11 (AR, lysosome recycling)[…]; SPG7 may add cerebellar ataxia; SACS may add neuropathy; SPG11: thinning of corpus callosum causing "ears of the lynx[…]" sign (dark on T1, bright on T2 FLAIR).

Familial ALS: Most common gene: C9orf72[…] (also associated with FTD); Other genes: SOD1, FUS, TDP-43; Treatment: riluzole, edaravone, relyvrio, tofersen[…] if SOD1 mutation.

SMA (Spinal Muscular Atrophy): AR SMN1[…] gene mutation → reduced SMN protein → loss of anterior horn cells; Treatment increases SMN expression: nusinersen[…] (antisense oligonucleotide), risdiplam[…] (small molecule splicing modifier), Zolgensma[…] (gene therapy).

Kennedy disease (Spinal Bulbar Muscular Atrophy): X-linked recessive; CAG repeat expansion[…] in androgen receptor[…] gene. Proximal muscle atrophy + bulbar + perioral fasciculations + gynecomastia + reduced fertility. Primary Lateral Sclerosis: predominantly UMN syndrome, mid-life onset, stiffness, corticobulbar dysfunction.

Hexosaminidase A deficiency: HEXA[…] gene. Infantile form = Tay-Sachs; adult form = LMN weakness + cerebellar atrophy + psychiatric symptoms.

X-linked Adrenoleukodystrophy/Adrenomyeloneuropathy: ABCD1[…] gene on X chromosome → encodes peroxisome protein → VLCFA[…] accumulation; Childhood form (Adrenoleukodystrophy): adrenal insufficiency, cognitive issues, optic atrophy, hearing loss, seizures, spasticity; Adult form (Adrenomyeloneuropathy): adrenal insufficiency + progressive spastic paraparesis + peripheral neuropathy; May develop cerebral demyelination with rapid progression; Diagnostics: high serum VLCFA[…] + genetic testing + adrenal insufficiency markers.

Other leukodystrophies with spinal cord involvement: Alexander[…] disease: GFAP gene; Leukoencephalopathy with Brainstem/Spinal Cord Involvement and Lactate Elevation: DARS2[…] gene; Adult Polyglucosan disease: GBE1[…] gene.

Friedreich ataxia: AR inheritance; GAA[…] trinucleotide repeats in FXN[…] gene; Triad: ataxia + neuropathy + UMN findings[…] + optic atrophy + hearing loss; HOCM[…] — assess all patients; Treatment: omaveloxolone[…] (restores mitochondrial function).

Spinocerebellar ataxia (SCA): SCA1 or SCA3: ATXN1 or ATXN3[…] gene → CAG trinucleotide repeats (also seen on different gene in Huntington's).

Vertebral osteomyelitis/spondylodiscitis: most commonly Staph aureus[…] or E. coli.

Risk factors: IVDU, recent surgery, immunocompromised[…]. Diagnostics: elevated ESR/CRP, MRI spine wwo, biopsy + culture. Treatment: delay antibiotics until biopsy if stable.

Intramedullary abscess → surgical drainage[…]. Neurosyphilis (Treponema pallidum): Early (Meningovascular): meningitis + endarteritis-driven stroke + oto-/oculo-syphilis.

Late (Tertiary): tabes dorsalis[…] — degeneration of dorsal columns and dorsal root ganglia → lancinating pain, sensory ataxia, loss of vibration, bowel/bladder dysfunction. Diagnostics: sensitive serum + specific CSF.

Screen with FTA-ABS or TP-PA[…] (treponemal — sensitive); confirm with CSF VDRL[…] (high specificity). Nontreponemal tests (RPR, VDRL) can be negative in late stages.

Treatment: IV PCN G[…].

Watch for Jarisch-Herxheimer[…] reaction (fever/chills/skin eruptions from spirochete release).

Lyme (Borrelia burgdorferi; Ixodes tick): Erythema migrans[…] → neuroborreliosis (cranial neuropathies esp CN VII, meningitis, painful radiculoneuritis, myelitis); Diagnostics: IgM/IgG screen → Western blot → LP/CSF; Treatment: IV ceftriaxone, cefotaxime, or PCN G[…] for spinal cord involvement. TB (Mycobacterium tuberculosis): Spread to CNS via hematogenous route → tuberculoma → rupture → subarachnoid space → meningitis/arachnoiditis.

Vertebral spread → Pott disease[…] with kyphotic gibbous deformity. MRI: longitudinally extensive myelitis with enhancement; tuberculomas with rim of homogeneous enhancement. CSF: pleocytosis + hypoglycorrhachia + positive culture.

Treatment: RIPE × 2 months → RI × 7-10 months[…] + steroids if significant inflammation.

Acute flaccid myelitis: Enterovirus D68/71, poliovirus, flavivirus, WNV[…], other arboviruses. Prodrome: URI or GI illness. Exam: weakness + hyporeflexia + hypotonia + bowel/bladder dysfunction.

MRI: changes in gray matter involving anterior horn cells[…]. WNV: CSF IgM can remain positive for years — pair with plasma IgM/IgG for acuity. Japanese encephalitis CSF IgM better than serum.

Treatment: WNV/JEV supportive; others may benefit from early IVIG or PLEX[…].

HIV-associated myelopathy: typically vacuolar[…] myelopathy — progressive spastic paraparesis with dorsal column sensory loss resembling subacute combined degeneration (but B12 normal). Treatment: ART + IVIG, test for coinfections. HTLV-1-associated myelopathy (Tropical Spastic Paraparesis): endemic to Caribbean, Central/South America, equatorial Africa, Middle East, southern Japan.

Most severely affects lateral columns[…] → LE weakness → spastic paraparesis within 1-2 years, urinary/bowel dysfunction, lumbar back pain, vibration loss. MRI: cord atrophy in thoracic. Treatment: high-dose steroids.

Herpesviruses: HSV-2[…] > HSV-1 causes radiculomyelitis affecting conus and lumbosacral region. Treatment: IV acyclovir 10 mg/kg Q8H.

Elsberg syndrome[…]: VZV-induced radiculomyelitis of conus medullaris. VZV can cause angiopathy → spinal cord infarction.

CMV[…] (HIV with CD4 <100): longitudinally extensive myelitis or lumbosacral polyradiculitis. Treatment: ganciclovir or foscarnet. COVID-19: longitudinally extensive myelitis. Treatment: IV steroids + IVIG vs PLEX.

Fungal: All: 1,3-β-D-glucan[…] assay (positive in invasive fungal but not specific).

Aspergillus[…]: angioinvasive; abscess + vasculopathy → granuloma + spinal cord infarction. Diagnose with galactomannan Ag. Treatment: IV voriconazole.

Coccidioides[…]: endemic to West Coast/Mexico/Central America. CNS = meningitis. Treatment: fluconazole.

Histoplasma[…]: Ohio/Mississippi River valleys. Treatment: liposomal amphotericin B → itraconazole.

Cryptococcus[…]: opportunistic; meningoencephalitis → myelopathy; nearly half of crypto meningitis patients are HIV+[…]. CSF: high opening pressure, protein, lymphocytic pleocytosis, hypoglycorrhachia, +CrAg. Treatment: liposomal amphotericin B + flucytosine; serial LPs or ventricular drainage for high ICP.

Watch for IRIS[…].

Parasitic: Neurocysticercosis[…]: Taenia solium. MRI shows cystic lesions + visible scolex + ring enhancement + pericystic edema.

Treatment: albendazole + steroids + surgery[…].

Neuroschistosomiasis[…]: Schistosoma; freshwater exposure (larvae penetrate skin). Lumbar/radicular pain + LE weakness + sensory loss + bladder dysfunction (lumbosacral). Diagnose: stool/urine for eggs + serology + urine Ag; CSF may show eosinophilia.

Treatment: praziquantel + steroids + surgery[…].

Sparganosis[…]: Spirometra tapeworm from undercooked meat.

MRI: ring-enhancing lesions + "tunnel sign[…]" (tubular linear enhancement from larval migration). Treatment: surgical removal + albendazole/praziquantel/steroids × 1 month.

Longitudinal arteries: 3 running the entire length of spinal cord.: Anterior spinal artery (ASA)[…]: 1; Posterior spinal arteries (PSAs)[…]: 2 paired.

Level supply: Cervical: bilateral V4 segments of vertebrals + PICA branches + artery of Lazorthes[…] (from C3 and C6-C7); Upper thoracic: subclavian artery branches; Mid-lower thoracic/lumbar: segmental aortic branches → radiculomedullary arteries; Lower thoracic/lumbar: artery of Adamkiewicz[…] (characteristic hairpin turn, anastomoses with ASA); ASA may have disconnected segments[…] in thoracic cord → vulnerable to border-zone infarcts with hypotension.

Axial distribution within cord: ASA → sulcocommissural (sulcal)[…] artery in anterior median fissure → supplies anterior 2/3[…] of cord (CST, STT, anterior horns, central gray); PSAs → posterior 1/3 (dorsal columns + dorsal gray horns); Vasocorona[…]: anastomotic network from surface to center.

Venous drainage: sulcal veins + radial veins → anterior or posterior median spinal vein → leave via radiculomedullary veins; largest = great anterior radiculomedullary vein[…] in thoracolumbar region.

Background: Thoracic[…] spinal cord most vulnerable (least gray matter, lowest blood flow); Typically hyperacute back pain; Etiologies: periprocedural (aortic surgery 64%, cardiac surgery, spinal decompression, epidural injection)[…]; spontaneous (atherosclerosis, aortic pathology); other (trauma, subclavian steal, coarctation, AVM shunting, fibrocartilaginous embolism).

Syndromes: Anterior cord[…] syndrome: ASA territory → bilateral weakness + pain/temperature loss below lesion + autonomic dysfunction (bowel/bladder; respiratory failure if upper cervical).

Dorsal columns spared[…] → preserved proprioception/vibration.

Posterior cord[…] syndrome: PSA territory → bilateral loss of light touch, proprioception, vibration.

Complete cord[…] syndrome: ASA + PSA → bilateral weakness + all sensory modalities lost.

Brown-Séquard[…]: lateral hemisection → ipsilateral weakness + ipsilateral DCML loss + contralateral STT loss (2 dermatomes below).

Sulcal artery occlusion[…]: partial Brown-Séquard with isolated ipsilateral weakness.

Diagnostics: CT spine: rule out epidural/subdural hematoma or compressive fracture; MRI: DWI restriction; T2 anterior horn hyperintensity = "owl eyes/pencil sign[…]"; longitudinally extensive lesion (>3 segments); CTA and DSA[…] to rule out dissection; superior to MRA for visualizing artery of Adamkiewicz.

Treatment: Induced HTN: maintain MAP > 85-90[…] mmHg; Reduce external pressure: consider lumbar drain[…] (highest benefit in first 8 hours); Prophylactic CSF drainage before high-risk surgeries (thoracoabdominal AAA repair); IV/intraarterial thrombolysis: case reports only, no RCTs.

Prognosis: ASIA[…] Impairment Scale (A = complete → E = normal).

Extramedullary hemorrhage: Epidural hematoma[…] more common than subdural; Causes: trauma, instrumentation, anticoagulation; Layering of blood products[…] suggests AC-related; enhancement suggests neoplasm/abscess (not simple hematoma); Spinal SAH: rare; severe neck/back pain + HA + meningismus; complications include vasospasm and hyponatremia[…]; needs DSA workup. Intramedullary hemorrhage (hematomyelia): most often from trauma; consider cavernous malformation or AVM. Spinal vascular malformations:

Non-shunting: Cavernous malformations[…]: clusters of veins, no parenchyma between, no feeding artery/draining vein.

Lower flow → lower rupture risk[…] than AVMs. Prior radiation is a risk factor.

MRI: "popcorn[…]" appearance + rim of T2 hypointensity from hemosiderin.

Shunting: AVMs[…]: direct arteriovenous connection without capillary network → venous HTN → hemorrhage or steal; Spinal dural AVF (Type I)[…]: most common; in dura near spinal nerve roots; high-pressure radiculomeningeal arteries shunt into draining veins → arterialization[…] of draining veins → diminished AV pressure gradient → venous congestion → backflow → edema → progressive myelopathy; Most located at thoracolumbar[…] levels (fewer venous outflow channels → more easily develop congestion); Symptoms: conus medullaris dysfunction even if shunt is higher → low back pain/paresthesias + gradual gait instability worse with activity[…] + bowel/bladder/sexual dysfunction; May worsen after corticosteroids[…] (unlike inflammatory myelopathies) → urgent DSA; MRI: cord edema + perimedullary flow voids; MRA can localize; DSA[…] confirms; Treatment: endovascular liquid embolic agent or open surgery.

MS: Attacks vs pseudorelapse[…] (old lesion unmasked by fever/infection — resolves with treating underlying problem); Typical attack: a week of numbness or heaviness in one leg; Red flags (not typical MS): paralysis, rapid progression over hours; MRI: enhancing lesion, usually small (~1 cm), focal, in white matter tracts (especially dorsal columns[…]); LP/CSF: OCBs positive[…] in majority; Serum: AQP4 and MOG should be negative; Treatment: corticosteroids → PLEX if needed.

NMOSD: Pathophys: autoimmune disease targeting AQP4[…] water channels (astrocyte foot processes).

Severe necrotic inflammation → weakness, sensory loss, bowel/bladder dysfunction; damage rarely heals completely[…] → persistent deficits.

MRI: longitudinally extensive lesions ≥3 vertebral segments[…] crossing white and gray matter bilaterally.

LP/CSF: significant pleocytosis (>50 WBC) with lymphocytes + granulocytes including eosinophils[…]. OCBs rare. Serum: AQP4 Ab ~100% specific. Treatment:. Acute: high-dose steroids × 3-5 days → PLEX if no improvement. Chronic preventive (all patients):.

Eculizumab[…] (C5 complement inhibitor) — requires N. meningitidis vaccine + prophylactic antibiotics.

Satralizumab[…] (IL-6 receptor blocker).

Inebilizumab[…] (CD19 monoclonal — depletes B cells + plasmablasts). Rituximab (off-label, more in kids).

MOGAD: MOG expressed on outer surface of myelin sheath; found only in CNS. Kids: most common = ADEM and optic neuritis[…].

Adults: most common = optic neuritis and myelitis[…]; can cause aseptic meningitis.

Can present identically to NMOSD in severity but distinguished by degree of recovery[…] (MOG patients recover well; can go from complete paralysis to walking unassisted in 3-6 months); often considered monophasic.

MRI: longitudinally extensive or focal; both gray and white matter; distinctive: old lesions may normalize on subsequent scans[…] ("MRI-negative myelitis"). LP/CSF: OCBs rare.

Serum: MOG IgG titer > 1:1000[…] matters (low titers c/f MS).

Treatment: high-dose IV steroids × 3-5 days + 2-3 month PO taper[…] (more common withdrawal in this population) + IVIG. Preventive: IVIG monthly or MMF/azathioprine in kids — not required in all patients given monophasic nature. GFAP encephalomyelitis: monophasic attack on astrocyte GFAP. Acute meningoencephalomyelitis. Treatment: high-dose IV steroids + prolonged taper + PLEX.

Other Ab-mediated: anti-GAD65, glycine receptor (progressive encephalomyelitis with rigidity and myoclonus), amphiphysin[…].

Seronegative relapsing inflammatory myelitis: "NMOSD-like" lesions (bright on T2 long after attack): respond to B-cell therapies or IL-6 blockers (tocilizumab)[…]; "MOG-like" lesions: recover well; respond to IVIG. Monophasic idiopathic inflammatory myelitis (transverse myelitis): triggers = vaccines and infections. MRI: spans <3 vertebral lengths. Treatment: high-dose IV steroids → PLEX or cyclophosphamide if poor response.

Prognosis "one-third[…]" rule (1/3 recover well, 1/3 walk with assistance, 1/3 poor).

Neurosarcoidosis: Pathophys: subacute-chronic non-necrotizing epithelioid granulomas[…] growing from spinal meninges → lymphocytic inflammation affecting white matter > gray matter → long tract signs.

90%[…] occur with systemic sarcoidosis (usually from lung). Diagnostics:.

CNS biopsy[…]: noncaseating granulomas + fibroblasts + lymphocytes. Lung or spleen biopsy.

MRI: avidly enhancing lesion attached to meninges with nodular appearance. "Trident[…]" sign axial (confluent central canal + dorsal subpial enhancement). Longitudinally extensive T2 lesions enhancing for weeks.

FDG-PET[…] to identify accessible biopsy targets in lungs/spleen.

LP/CSF: pleocytosis + distinctively low glucose (20-40)[…] + CSF ACE (specific but poorly sensitive). CSF IL-2 poorly specific. Serum IL-2: ~88%/85% sensitivity/specificity. Treatment: high-dose IV steroids → lower PO doses long-term.

Steroid-sparing: MMF, MTX[…]; infliximab[…] (TNF inhibitor).

Paraneoplastic myelopathy: Myelopathy + B symptoms over weeks-months in cancer (most commonly SCLC[…]); Common Ab: anti-Hu, CRMP5, amphiphysin[…]; MRI: longitudinally extensive lesions tracking along white matter = "tractopathy[…]"; can mimic NMOSD; necrotic destruction with enhancement and T1 hypointensity; Workup: CT CAP and/or PET; Treatment: directed at underlying cancer.

Vitamin B12 (cobalamin) deficiency: Cofactor for amino acid/DNA synthesis, fatty acid metabolism, myelin formation; Etiologies: vegan diet, pernicious anemia[…], malabsorption (GI/hepatobiliary), medications (PPIs, metformin[…]); Pathophys: deficiency → myelin sheath swelling → secondary axonal degeneration of dorsolateral white column; Symptoms: subacute combined degeneration[…] = dorsal columns + CST → UMN signs (hyperreflexia, Babinski+) + LMN signs (neuropathy, light touch loss, paresthesias, vibration loss) + sensory ataxia; Diagnostics:; Low serum B12 (<200; if 200-300 check MMA and homocysteine — if both high = true deficiency); Macrocytic anemia with hypersegmented neutrophils; Anti-IF[…] Ab if no medication/dietary cause; MRI: T2 hyperintensity in dorsal columns = "inverted V[…]" or "rabbit ears" on axial; Treatment: IM B12 1000 μg.

Nitrous oxide (N2O) poisoning ("whippets"): Inactivates[…] vitamin B12 → functional B12 deficiency → subacute combined degeneration; >20% develop concurrent demyelinating polyneuropathy[…]; Labs: serum B12 low and MMA/homocysteine high (may be normal in acute intoxication); Treatment: cessation + B12 repletion.

Konzo toxicity (cyanide-related): Ingested via bitter cassava root[…]; Symptoms: acute onset after physical exertion with LE cramps → irreversible spasticity[…] with "scissoring" gait and hyperreflexia; Labs: serum and urine thiocyanate[…] high; MRI/CSF normal. Lathyrism (BOAA): ingested via grass pea. Irreversible spasticity out of proportion to weakness; triggered after physical exertion. Clinical diagnosis.

Heroin toxicity: most commonly after chronic use resumed after months of abstinence[…]. Acute paraplegia upon waking from stupor with complete transverse myelopathy (motor + sensory + sphincter); dorsal columns may be spared. MRI: longitudinally extensive T2 hyperintensity in gray matter only or CST/DCML tracts.

Hepatic toxicity: pt with severe liver failure, often months after TIPS procedure[…] or spontaneously. Subacute progressive, pure motor, BLE-predominant paraparesis without UE/sensory/sphincter involvement. Labs: elevated AST/ALT/NH3, low albumin.

MRI: T1 hyperintensity in globus pallidus or substantia nigra[…] from acquired hepatocerebral degeneration. Treatment: liver transplant.

Intrathecal chemotherapy (MTX/cytarabine): MTX via folate deficiency → SCD-like findings; may also cause arachnoiditis[…] with nerve root enhancement.

LP/CSF: myelin basic protein (MBP)[…] may be elevated + cytology/flow cytometry to differentiate from LMM. Treatment: discontinue + folate metabolites. ICI myelitis: usually thoracic spinal cord after ~7 cycles median; concurrent meningoencephalitis or radiculitis. MRI: longitudinally extensive T2 lesion with patchy enhancement. Treatment by grade: mild → continue + observe; mod → stop + PO prednisone; severe → stop permanently + IVMP → IVIG/PLEX → cyclophosphamide.

Radiation-induced myelopathy: Pathophys: disruption of blood-spinal cord barrier → edema + VEGF[…] upregulation → demyelination.

Early: Lhermitte sign[…] in isolation → supportive.

Delayed: subacute-chronic progressive transverse myelopathy, may present as Brown-Séquard[…] initially. Treatment: steroids, AC, hyperbaric O2.

Spasticity = velocity-dependent[…] increase in tone interfering with movement.

PO meds: 1st line: baclofen and tizanidine[…]; Others: diazepam (addictive), dantrolene[…] (SE: hepatotoxicity).

IM: Botox[…] injections — block transmission at NMJ, lasts ~3 months. If Ab develop: aqueous phenol injections at motor points (doesn't need repeating like botox).

Invasive: Intrathecal baclofen pump[…]: useful for generalized/LE spasticity.

Sudden discontinuation (mechanical issue or missed refills) → life-threatening withdrawal with AMS, fever, muscle rigidity, seizures, multiorgan failure[…]. SE: overdose → somnolence + respiratory depression.

Neurectomy or selective dorsal rhizotomy[…]: permanent denervation for focal spasticity refractory to above.

Weakness: Orthotics or electrical stimulators (foot drop, tenodesis grip); Nerve or tendon transfers from healthy donor; Epidural SCS[…]: can improve ambulation even in complete SCI; Robotic exoskeletons. Neuropathic pain: from neuronal hyperexcitability.

Treatments: pregabalin, gabapentin, SNRIs (duloxetine), TCAs (amitriptyline)[…].

Progressive cape-like sensory loss of pain and temperature[…] over the hands and chest, with preserved vibration[…], and lower motor neuron atrophy of hand muscles is classic for syringomyelia[…].

Sudden lower limb weakness, back pain, loss of pain and temperature[…] but preserved vibration/position sense, with absent leg reflexes, is classic for spinal cord infarction (anterior spinal artery syndrome)[…].

GBS causes diffuse areflexia[…] but no sensory level.

Transverse myelitis usually impairs all[…] sensory modalities (not just pain/temperature).

Intractable hiccups[…] (area postrema syndrome) point strongly to NMOSD[…] and are rarely seen in MS.

Area postrema syndrome involves the dorsal medulla[…].

A spinal dural AVF can worsen[…] after corticosteroids (unlike inflammatory myelopathies) — this should prompt urgent DSA[…]. Symptoms include conus medullaris dysfunction with bowel/bladder/sexual dysfunction and gait instability worse with activity.

Hirayama disease: juvenile-onset painless weakness in C7-T1[…] myotomes with "reverse split-hand[…]" (ulnar/hypothenar > thumb/thenar atrophy, opposite of ALS). Pathophys: abnormal forward shifting of posterior dura during neck flexion.

Treatment: cervical collar[…] first-line.

Paraneoplastic myelopathy: myelopathy + B symptoms over weeks-months in cancer, most commonly SCLC[…].

Common antibodies: anti-Hu, CRMP5, amphiphysin[…].

MRI shows tractopathy[…] (longitudinally extensive lesions along white matter).

Eculizumab[…] (terminal C5 complement inhibitor) is used for chronic preventive therapy in NMOSD.

Risk: N. meningitidis[…] infection — requires vaccination + prophylactic antibiotics before initiation.

Konzo[…] toxicity from bitter cassava root (cyanide-related) and lathyrism[…] from grass pea (BOAA) both cause irreversible[…] spasticity triggered by physical exertion.