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White matter diseases
 

White matter diseases

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  • G35 - G37Demyelinating diseases of the central nervous system G35Multiple Sclerosis G35._0Relapsing remiting MS G35._1Primary progressive MS G35._2Secondary proressive MS G35._8Other symptomatic form of MS G36Other acute disseminated demyelination G36.0Neuromyelitis optica(Devic)Demyelination in optic neuritis G36.1Acute and subacute haemorrhagic leukoencephalitis(Hurst G36.8Other specified acute disseminated demyelination G36.9Acute disseminated demyelination,unspecified G37Other demyelinating diseases of central nervous system G37.0Diffuse sclerosisPeriaxial encephalitis,Schilder's disease G37.1Central demyelination of corpus callosum G37.2Central pontine myelinolysis G37.3Acute transverse myelitis in demyelinating disease of cAcute transverse myelitis NOS G37.4Subacute necrotizing myelitis G37.5Concentric sclerosis(Balo) G37.8Other specified demyelinating diseases of central nervo G37.9Demyelinating disease of central nervous system,unspeci
  • Caps over the anterior horns of the lateral ventricles or diffuse halo surrounding the lateral ventricle Periventricular T2 and PD hyperintensites of variable thickness often become evident after 40y and seen in 40% of elderly. They have no impact on cognitive function but indicates underlying disorders of fluid dynamics. They are more prominent in Alzheimer disease. The pathologic correlates of the periventricular caps and bands is a spongiform zone separated from the ventricular lumen by a rim of subependymal gliosis. There is demyelination in the spongiform zone. Discontinuities within the adjacent ependymal lining are common. Theses changes are likely the result of chronically elevated quantities of interstitial periventricular fluid. There is no evidence for microscopic infarction within these lesions and thus vascular disease presumably does not play a role in the pathophysiology. Because the brain has no lymphatics, extracellular fluid circulates through the ependyma and into ventricles (extrachoroidal CSF production). Processes that increases the extracellular fluid volume (such as ischemia or infarction) or impaired subependymal fluid resorption (such as increased intracranial pressure associated with hydrocephalus) may result in a backup of fluid in the periventricular space. The tip of the anterior horns have a particularly rich venous plexus, and large veins pass along the ventricular walls making these regions especially vulnerable to venous transudation (as may occur when the central venous pressure is increased in congestive heart failure). Additionally, the discontinuities in the ependymal lining may promote leakage of CSF into the periventricular tissue. The demyelination, gliosis and, to some extent the increased extracellular fluid results in the T2 hyperintensities surrounding the lateral ventricles. If the periventricular hyperintensities are irregular or extend into the central white matter, a pathologic vascular cause is much more likely. Diffuse periventricular hyperintensities may occur in multiple sclerosis, lymphoma, CSF seeding of intracranial malignant disease, or periventricular infections such as CMV, HIV, or Lyme neuroborreliosis. Contrast enhancement occurs with most of the malignant, infectious, and inflammatory causes, making the differentiation easy.
  • Punctate high-signal T2 and PD lesions within the subcortical and periventricular white matter. These hyperintensities are present in 30-80% of people over 40years old and increase in frequency and size with increasing age, chronic, hypertension, other vascular risk factors, past stroke or transient ischemic attack. Although the frequency of scattered punctate UBOs is higher in older age They may be the result of an inadequate supply of nutrients necessary to sustain and replace normally catabolized myelin, with the loss of myelin leading to reactive gliosis. Atrophic periventricular demyelination appears as high signal on T2 and PD images. Some, if not most, UBOs are part of continuum of vascular disease, which is the most extreme form present in multi-infarct dementia. As the bulk of white matter diseases increases, decreased attention and speed of mental impairment develops.

White matter diseases White matter diseases Presentation Transcript

  • White matter diseases
  • ICD10NA - G35 - G37 (Demyelinating diseases of the central nervous system)
      • G35 Multiple Sclerosis
        • G35._0 Relapsing remitting MS
        • G35._1 Primary progressive MS
        • G35._2 Secondary progressive MS
        • G35._8 Other symptomatic form of MS
      • G36 Other acute disseminated demyelination
        • G36.0 Neuromyelitis optica (Devic) Demyelination in optic neuritis
        • G36.1 Acute and subacute haemorrhagic leukoencephalitis (Hurst)
        • G36.8 Other specified acute disseminated demyelination
        • G36.9 Acute disseminated demyelination, unspecified
      • G37Other demyelinating diseases of central nervous system
        • G37.0 Diffuse sclerosis Periaxial encephalitis, Schilder's disease
        • G37.1 Central demyelination of corpus callosum
        • G37.2 Central pontine myelinolysis
        • G37.3 Acute transverse myelitis in demyelinating disease
        • G37.4 Subacute necrotizing myelitis
        • G37.5 Concentric sclerosis (Balo)
        • G37.8 Other specified demyelinating diseases of central nervo
        • G37.9 Demyelinating disease of central nervous system, unspecified
  • Metabolic disorders
    • Leukodystrophies
      • Metachromatic leukodystrophies
      • Krabbe leukodystrophies
      • Adrenoleukodystrophy
      • Canavans disease
      • Alexander disease
      • Pelizeus-Merzbacher disease
      • Cockyne syndrome
    • Metabolic disorders
      • Lipidosis
      • Mucopolysaccharidoses
      • Mucolipidosis
      • Metabolic acidosis
      • Hypoglycemia
      • Anoxic encephalopathy
    • Bilateral
        • Hydrocephalus
        • Chemotherapy
    • Unilateral or bilateral
      • Infection
        • HIV
        • PML
      • Inflammatory
        • Sarcoidosis
        • Vasculitis
      • Tumor
        • Lymphoma
        • Glioma
      • Trauma
        • Shear injury
      • Radiation therapy
      • Vascular
        • Binswanger
        • Thromboembolic
        • Migraine
        • Angippathies
  • Diffuse periventricular T2 hyperintensities
    • Normal aging
    • MS
    • Infection
      • CMV
      • HIV
      • Lyme neuroborreliosis
    • Secondary seedling
    • Lymphoma
  • UBO’s
    • Normal aging
    • Migraine above 40y
  • MRI in MS
    • MRI findings that strongly suggestive of MS
      • 4 or more white matter lesions (each > 3mm)
      • 3 white matter lesions, 1 periventricular Lesions
      • 6 mm diameter or greater
      • Ovoid lesions, oriented perpendicular to ventricles
      • Corpus callosum lesions
      • Brainstem lesions
      • Open ring appearance of gadolinium enhancement
  • Diagnosis MR
    • Supportive
      • 3-4 scattered lesion without mass effect throughout white matter
    • Specific
      • >6mm
      • Oval shape in parasagital region
      • Infratentorial and spinal
  • Methods
    • Gadolinium
      • BBB breakdown
    • PD
      • Inflammation
    • T2
      • Established lesion
    • MRS
      • Loss of NAA for DD
    • Magnetization transfer imaging
      • Lesion in otherwise normal appearing white matter
  • Prognosis Sensitivity
    • Gad – Twice sensitive than T2 monthly MR (0.1mmol/kg)
    • Weekly Gad MR more sensitive
    • Spinal imaging
    • Triple load Gad (0.3mmol/kg) 70% more sensitive and 50%more new lesions
    • Magnetization transfer T1
    • Delayed scanning
    • Thinner slices 3mm
    • Fast flair 1mm and 3mm 3D increases 30% lesion in sub cortical and cortical lesion.
  • MRI:Prognostic indicator
    • MRI as a prognostic indicator in clinically isolated syndromes:
      • MRI normal at presentation
        • 5 years follow-up: 6% with clinically definite MS
        • 10 years follow-up: 10% with clinically definite MS
      • MRI with 1.2 cc or greater T2 involvement
        • 5 years follow-up: 96% with clinically definite MS
        • 10 years follow-up: 86% with clinically definite MS (some patients in the 5 year cohort not included in 10 year cohort)
    • Patients with early, relapsing-remitting MS studied by monthly MRIs over several months
      • approximately 70% have at least one enhancing lesion during a 3 month period.
      • frequency of contrast enhancing lesion activity fluctuates from month to month.
  • Lesion extent
    • Poor correlation between lesion load and EDSS
    • Total extent of brain lesion correlate only moderately with locomotor disability
    • Clinically isolated syndrome on Brain stem better correlation
    • No of brain lesion in MR predicts progress to definite MS in next 1-5years, Poor correlation in next 5years (5-10)
  • Lesion site
    • Locomotor disability correlate with spinal and post fossa lesion
    • T2 lesion load in post fossa and spinal cord do not correlate with EDSS
    • Asymptomatic cord lesion with isolated optic neuritis in 40% cases
    • Extensive lesion in clinically eloquent pathway without functional consequence
  • Pathologic nature
    • Acute lesion
      • inflammation (perivascular lymphocytes, macrophage, infiltrate edema, active myelin breakdown and axonal damage)
    • Subacute lesion
      • Variable remyelination
    • Chronic lesion
      • Complete demyelination with marked astrocytic gliosis, and axonal loss
      • Inflammation at the edege
  • Acute lesion
    • Correlates with Gad enhancement in RR and SP MS for 2-6weeks
    • More common during relapse than remission
    • Most of them are asymptomatic
    • Cord lesion are symptomatic
    • Optic nerve lesion correlates with visual loss
  • Subacute lesions
    • Magnetizing transfer imaging
    • T1 hypointense lesion
    • MR spectroscopy
    • Measurement of atrophy
    • Diffusion tensor imaging
    • Myelin imaging by T2 decay analysis
  • Normal appearing White matter with microscopic changes
    • T1, T2 MT ratio and NAA
    • Clinical importance not clear
  • Cortical pathology and synaptic adaptation
    • Synaptic adaptation by functional MR
    • Cortical plaque not yet studied