It is often overlooked and may cause several hematological, gastrointestinal, psychiatric and
neurological manifestations. Megaloblastic anemia is an early hematological sign, but neurological
symptoms may occur also in the absence of hematological abnormalities. SCD, peripheral neuropathy,
neuropsychiatric disorders and optic nerve atrophy are the most common neurologic manifestations.
The typical MRI finding in SCD is a symmetrical abnormally increased T2 signal intensity, commonly
confined to posterior or posterior and lateral columns in the cervical and thoracic spinal cord. Brain
involvement has also been reported in B12 deficiency patients with extensive areas of a high-intensity
signal in the periventricular white matter.