Alexander Disease

Alexander disease is a rare, nonfamilial, leukoencephalopathy that is characterized by white matter abnormalities primarily in the frontal lobes.

Three clinical subtypes have been described:

• Neonatal: There is extremely rapid deterioration.
• Infantile: This is the most common. There is early onset macrocephaly and rapid deterioration.
• Adult: The least common and mildest subtype.

On CT, there is low attenuation within the frontal white matter, internal capsule, and caudate heads. There is intense enhancement in early disease in the periventricular rim, frontal lobe white matter, basal ganglia, thalami, brainstem (periaqueductal area), dentate nuclei, fornix, and optic chiasm. MRI shows white matter changes in the frontal white matter. The periventricular rim is high intensity on T1- and low intensity on T2-weighted images.