Marchiafava-Bignami disease

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Marchiafava-Bignami disease (MBD) is a rare CNS disorder usually seen in the context of alcoholism and malnutrition. The condition classically involves the corpus callosum with necrosis and demyelination.

Epidemiology

MBD is in most instances seen in chronic alcoholics, and as such the epidemiology reflects this demographic, with middle-aged to elderly male patients (40-60 years of age) being most commonly affected .

Clinical presentation

The clinical presentation of MBD can vary and patients often present with nonspecific clinical features such as motor or cognitive disturbances, a hemispheric disconnection syndrome (apraxia, hemialexia, dementia) and/or seizures.

Pathology

The disease is attributed to a deficiency of all eight types of vitamin B group and results in necrosis and demyelination of the corpus callosum. Some reports present cases of extension into the hemispheric white matter, internal capsule and middle cerebellar peduncle. Although rare, Morel laminar sclerosis can also be seen.

Histology

Histologically, the myelin loss may be striking and may be accompanied by axonal degeneration .

Radiographic features

Prior to the advent of cross-sectional imaging, the diagnosis was only limited to postmortem examination and only the acute variety was diagnosed.

Marchiafava-Bignami disease typically begins in the body of the corpus callosum and later involves the genu and then splenium . It classically involves the central layers with relative sparing of the dorsal and ventral extremes (which may be seen as a sandwich sign on sagittal MRI imaging).

CT

may typically show hypoattenuating regions in the corpus callosum
in exceptional situations of hemorrhage, these regions may turn into iso- or hyperattenuating

MRI

Corpus callosum may appear edematous in the acute phase and atrophic in the chronic phase.

T1: may show hypointense foci in the corpus callosum in the acute phase
T2
- acute phase: hyperintensities in the corpus callosum in the correct clinical setting may aid in the diagnosis
- subacute phase: may show hypointense focal lesions (likely as a result of hemosiderin)
- ears of the lynx sign may be seen.
MR spectroscopy: the NAA/Cr ratio may show a progressive decrease to a minimumlevel after the first few months followed by a partial recovery after around 11 months