Toxic leukoencephalopathy

Toxic leukoencephalopathy is an encephalopathy predominantly affecting white matter as a result of a toxic substance. The presentation can either be chronic or acute. In the acute phase, acute toxic leukoencephalopathy can have a characteristic and profound MR imaging appearance that is potentially reversible with therapy or removal of the offending agent.

The clinical presentation of toxic leukoencephalopathy is extremely variable, ranging from minor cognitive impairment, easily confused with psychiatric illnesses, to severe neurological dysfunction. The lack of imaging in patients with minimal or mild encephalopathic symptoms may account for why this entity may be underdiagnosed in the acute phase.

Aetiology

There are numerous agents implicated in toxic leukoencephalopathy. These include:

  • antineoplastic drugs
    • methotrexate (10% IV, 40% intrathecal): (C20H22N8O5)
    • carmustine
    • cisplatin
    • cytarabine
    • fluorouracil (5-FU)
    • thiotepa
    • interleukin-2 (IL-2)
    • interferon alpha (INF alpha)
  • immunosuppresive drugs
    • cyclosporin
    • tacrolimus
  • antimicrobial agents
    • amphotericin B
    • hexachlorophene
  • drugs of abuse
  • environmental toxins
  • cranial irradiation

The findings are potentially reversible therapy or removal of the offending agent in the early phase.

MRI
  • FLAIR: white matter abnormalities are typically confluent and symmetric, and may involve the corpus callosum as well, particularly the splenium
  • DWI: white matter abnormalities are similar to FLAIR, typically confluent and symmetric, and may involve the corpus callosum as well, particularly the splenium

Toxic and metabolic encephalopathies
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Article Information

rID: 4437
Section: Pathology
Synonyms or Alternate Spellings:
  • Toxic leukoencephalopathies

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Cases and Figures

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    Case 1: from methrotrexate and irradiation
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    Case 2: from narcotics
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    Case 3: from narcotics
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    Case 4
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