Section Editor: Sandy Cheng-Yu Chen, M.D.
Taipei Medical University Hospital, Taipei, Taiwan
Figure Caption
Maple syrup urine disease (MSUD) is a rare autosomal-recessive disorder that affects the metabolism of branched-chain amino acids, resulting in diffuse white matter edema in the first few weeks of life after milk feeding. The cytotoxic-like white matter edema is distributed predominantly in the tegmentum of brain stem and corticospinal tracts (white arrows in A), middle cerebellar peduncle (yellow arrows in A), internal capsules (especially posterior limbs, red arrows in B), and centrum semiovales. The white matter edema may not be seen easily on T2WI due to the unmyelinated white matter in infant (C). Proton MR spectroscopy may show increased lactate, low NAA, and a methyl group peak at 0.9 ppm that can be reversed if the ketoacidosis is corrected.