An MRI with T2/FLAIR hyperintensities in a symmetric, bilateral periventricular white matter distribution with T2-weighted hypointensities involving the basal ganglia and/or thalami is most consistent with the leukoencephalopathy associated with use of which of the following agents?
D. Carbon monoxide
Answer: B. Toluene Symmetric, bilateral periventricular white matter lesions typify many of the toxic leukoencephalopathies. Chronic use of toluene as an inhalant is associated with a characteristic leukoencephalopathy which typically presents with neurobehavioral abnormalities and marked cognitive impairment. Imaging often demonstrates the characteristic toxic leukoencephalopathy pattern. This is accompanied by symmetric, bilateral T2 hypointensities involving the thalami, basal ganglia and/or substantia nigra; the pathogenesis is unclear, and has been speculated to be secondary to iron deposition or toluene partitioning into neuronal membrane phospholipids. Methyl bromide (A) toxicity is associated with lesions involving the brainstem and cerebellum including the dorsal pons and dentate nuclei. The neurotoxicity associated with methotrexate (C) is more often associated with asymmetric lesions with prominent cortical involvement and restricted diffusion on DWI. The neurologic sequelae of carbon monoxide (D) toxicity features T2 hyperintense lesions of bilateral basal ganglia, particularly the globi pallidi. Levamisole (E) tends to produce scattered, asymmetric ovoid lesions with a predilection for the centrum semiovale.
1.de Oliveira A, Paulino M, Vieira A et al. Imaging Patterns of Toxic and Metabolic Brain Disorders. Radiographics. 2019;39(6):1672-95. <ahref=”https://doi.org/10.1148/rg.2019190016″>doi:10.1148/rg.2019190016</a> – <ahref=”https://www.ncbi.nlm.nih.gov/pubmed/31589567″>Pubmed</a> 2. Unger E, Alexander A, Fritz T, Rosenberg N, Dreisbach J. Toluene Abuse: Physical Basis for Hypointensity of the Basal Ganglia on T2-Weighted MR Images. Radiology. 1994;193(2):473-6. <ahref=”https://doi.org/10.1148/radiology.193.2.7972765″>doi:10.1148/radiology.193.2.7972765</a> – <a href=”https://www.ncbi.nlm.nih.gov/pubmed/7972765″>Pubmed</a> 3. Robert S. Hoffman, Lewis S. Nelson, MD, Lewis R. Goldfrank et al. Goldfrank’s Toxicologic Emergencies, Eleventh Edition. (2019) ISBN: 9781259859618 – <a href=”http://books.google.com/books?vid=ISBN9781259859618″>Google Books</a>
Contributed by: David Carroll, MD