title: Infratentorial and supratentorial leukoencephalopathy associated with vitamin B12 deficiency.
abstract: BACKGROUND
  Striking cerebral white matter abnormalities involving supratentorial regions seen on magnetic resonance imaging (MRI) scans have been described in patients with vitamin B12 deficiency. Severe involvement of infratentorial structures with partial reversibility has not been previously documented.
  
  
  METHODS
  A 54-year-old man experienced severe weight loss, associated with dementia and focal deficits. Laboratory analysis showed a severe vitamin B12 deficiency and elevated serum homocysteine. MRI scans showed a severe and diffuse white matter abnormal signal involving both the supra- and infratentorial compartments. Vitamin B12 supplementation resulted in a mild improvement in cognitive deficits and a marked resolution of imaging abnormalities.
  
  
  CONCLUSIONS
  Leukoencephalopathy and dementia should raise the suspicion of a vitamin B12 deficiency because vitamin B12 supplementation may result in at least partial clinical improvement.
authors: Department of Neurology Long Island Jewish Medical Center, Long Island Campus for Albert Einstein College of Medicine, New Hyde Park, NY 11042, USA.
authors: S
authors: S
authors: Su
authors: R B
authors: RB
authors: Libman
authors: A
authors: A
authors: Diamond
authors: S
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authors: Sharfstein