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February 11, 1998

Chronic Fatigue Syndrome

Author Affiliations

Margaret A.WinkerMD, Senior EditorIndividualAuthorPhil B.FontanarosaMD, Senior EditorIndividualAuthor

JAMA. 1998;279(6):431-433. doi:10-1001/pubs.JAMA-ISSN-0098-7484-279-6-jac81007

To the Editor.—I was surprised that in the evaluation of a 56-year-old woman with chronic fatigue1 and in the discussion of the differential diagnosis that followed, no consideration was given to B12 deficiency. Fatigue, memory loss, weakness, changes in mood, and visual loss have all been reported to be associated with B12 deficiency in the absence of anemia and macrocytosis.2 B12 deficiency has also been reported to cause reversible white matter lesions on magnetic resonance imaging scan.3 Thus, determination of a serum B12 level and, in borderline cases, serum methylmalonic acid and homocysteine levels4 should be part of the routine evaluation of a patient with chronic fatigue. I would be interested to learn this patient's B12 level.