Vitamin B12-responsive severe leukoencephalopathy and autonomic dysfunction in a patient with "normal" serum B12 levels

J. J. Graber, F. T. Sherman, H. Kaufmann, E. H. Kolodny, Swati Sathe

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23 Scopus citations

Abstract

Leukoencephalopathy and autonomic dysfunction have been described in individuals with very low serum B12 levels (<200 pg/ml), in addition to psychiatric changes, neuropathy, dementia and subacute combined degeneration. Elevated homocysteine and methylmalonic acid levels are considered more sensitive and specific for evaluating truly functional B12 deficiency. A previously healthy 62-year-old woman developed depression and cognitive deficits with autonomic dysfunction that progressed over the course of 5 years. The patient had progressive, severe leukoencephalopathy on multiple MRI scans over 5 years. Serum B12 levels ranged from 267 to 447 pg/ml. Homocysteine and methylmalonic acid levels were normal. Testing for antibody to intrinsic factor was positive, consistent with pernicious anaemia. After treatment with intramuscular B12 injections (1000 mg daily for 1 week, weekly for 6 weeks, then monthly), she made a remarkable clinical recovery but remained amnesic for major events of the last 5 years. Repeat MRI showed partial resolution of white matter changes. Serum B12, homocysteine and methylmalonic acid levels are unreliable predictors of B 12-responsive neurologic disorders, and should be thoroughly investigated and presumptively treated in patients with unexplained leukoencephalopathy because even long-standing deficits may be reversible.

Original languageEnglish (US)
Pages (from-to)1369-1371
Number of pages3
JournalJournal of Neurology, Neurosurgery and Psychiatry
Volume81
Issue number12
DOIs
StatePublished - Dec 1 2010

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ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology
  • Psychiatry and Mental health

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