Toxic demyelination from methotrexate therapy
Image #1 8-18-2000 T2 axials - show diffuse confluent white
matter high signal
Image #2 11-12-2000 T2 axials - white matter high signal which
is vastly improved
Image #3 11-12-2000 T1 axials - normal appearance
Toxic demyelination can be caused by various endogenous or
exogenous toxins which can result in temporary or permanent damage.
Endogenous toxins result from inborn errors of metabolism.
Exogenous toxins are usually from various drugs. Some toxins like
methotrexate and XRT affect mainly the myelin and white matter
causing toxic demyelination. This patient had leukemia and received
methotrexate thereapy. The first MRI shows extensive high signal in
the white matter on the T2 images which vastly improve on the
follow-up study 3 months later.
Causes of toxic demyelination:
Chronic alcoholism (common)
Radiation therapy (uncommon)
Differential considerations: Dysmyelinating disease , ADEM
(usually patchy), MS, PML(immunosuppresed, XRT/drug toxicity,
Discussion of Multiple Choice Question:
MBD is an uncommon disease originally described in poorly
nourished Italian men who drank excessive crude red wine. Corpus
callosum demyelination and necrosis is the characteristic
pathologic finding which causes focal cystic areas to form in the
corpus callosum (genu, body, splenium).
Diagnostic Neuroradiology, Osborn