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Levamisole Leukoencephalopathy

•Background:
  • Levamisole is an adulterant that has been reported in 69% of cocaine entering the United States (Drug Enforcement Agency), and is also used for adjuvant chemotherapy or recurrent aphthous ulcer treatment.
  • Although the mechanism is unclear, it is hypothesized that levamisole may activate macrophages and lymphocytes, triggering a delayed hypersensitivity reaction that causes inflammation and demyelination.
•Clinical Presentation:
  • Variable, but may include confusion, aphasia/dysphasia, gait ataxia, hemiparesis, cognitive impairment, diplopia, facial palsy, incontinence, or parasthesia.
  • In this case, the patient presented with levamisole-induced leukoencephalopathy and cutaneous vasculopathy, along with a neuroleptic malignant syndrome-type appearance from cocaine use.
•Key Diagnostic Features:
  • Labs: Urine toxicology, CSF studies demonstrating lymphocytic pleocytosis +/- red blood cells or oligoclonal bands
  • Imaging: MRI with predominantly T2/FLAIR hyperintense, ovoid white matter lesions, often supratentorial in the periventricular or subcortical areas, along with corresponding T1 hypointensities, +/- restricted diffusion on DWI and ring enhancement. CT may initially be normal, but over time progressive hypodense lesions can be seen.
  • Brain biopsy: Demyelination with infiltration of macrophages and perivascular lymphocytes  
•Differential Diagnosis:
  • Multiple sclerosis: Periventricular and subcortical white matter lesions in perivenular distribution, with active lesions demonstrating a “leading edge” of incomplete peripheral enhancement and restricted diffusion. Optic nerve involvement is common.
  • Posterior reversible encephalopathy syndrome (PRES): Patchy subcortical white matter lesions commonly involve parietal and occipital lobes. Diffusion restriction on DWI is rare.
  • Acute disseminated encephalomyelitis: Postinfectious clinical course with self-resolving lesions. Usually deep and subcortical white matter is involved, while periventricular lesions are less common.
  • Progressive multifocal leukoencephalopathy: Seen in immunocompromised patients with JC virus reactivation. Patchy, asymmetric T2 hyperintense lesions typically in the parieto-occipital white matter with prominent subcortical U-fiber involvement. Usually non-enhancing, +/- surrounding punctate lesions (“Milky Way sign”) and corpus callosum involvement. Little to no mass effect.
  • CNS lymphoma: Hyperdense on CT  with solid enhancement on MRI and restricted diffusion.
  • Glioblastoma: Irregular mass lesion with vasogenic edema, and enhancement and restricted diffusion of solid component. Necrosis and hemorrhage are common. 
•Treatment:
  • Currently no definitive treatment.
  • Discontinuation of levamisole-containing cocaine and supportive care including steroids, plasmapheresis, and/or IVIG have been shown to improve clinical courses in case reports.
October 27, 2022

A 30-year-old man with 2 days of headaches and malaise, is found down by roommate. In the emergency department, he is found to have altered mental status, mutism, fever, tachycardia, hypertension, rigidity, hyperreflexia, and a purpuric rash.

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