Maple syrup urine disease
Maple syrup urine disease (MSUD) is a very rare metabolic disorder. It is an inborn error of amino acid metabolism, which classically affects the brain tissue resulting in impairment or death if untreated.
Manifests itself in the first few days of life (12-24 hours) with the complex of symptoms which include.
- poor feeding
- a characteristic odour of maple syrup
It carries an autosomal recessive inheritance 1.
There is elevated plasma concentrations of branched-chain amino acids (BCAAs) (leucine, isoleucine, and valine) and allo-isoleucine,
MRI - brain
MRI may show diffuse swelling of the brain due to extensive oedema of the white matter.
- DWI - the posterior limbs of the internal capsules and optic radiations and the central corticospinal tracts within the cerebral hemispheres exhibit diffusion restriction, which represents myelin splitting oedema and is believed to be secondary to vacuolating myelinopathy.
- MR spectroscopy - single-voxel proton MR spectroscopy may show the presence of branched-chain amino acids (BCAA) and branched-chain alpha-keto acids (BCKA) resonating at 0.9 - 1.0 ppm, especially during a metabolic crisis 1-2
The structures in the posterior fossa exhibit prominent changes in signal intensity, swelling, and diffusion restriction of the already myelinated brain areas, such as the posterior brainstem tracks and the central cerebellar white matter.
- 1. Thomas B, Al dossary N, Widjaja E. MRI of childhood epilepsy due to inborn errors of metabolism. AJR Am J Roentgenol. 2010;194 (5): W367-74. doi:10.2214/AJR.09.2948 - Pubmed citation
- 2. Jan W, Zimmerman RA, Wang ZJ et-al. MR diffusion imaging and MR spectroscopy of maple syrup urine disease during acute metabolic decompensation. Neuroradiology. 2003;45 (6): 393-9. doi:10.1007/s00234-003-0955-7 - Pubmed citation
- 3. Morton DH, Strauss KA, Robinson DL et-al. Diagnosis and treatment of maple syrup disease: a study of 36 patients. Pediatrics. 2002;109 (6): 999-1008. doi:10.1542/peds.109.6.999 - Pubmed citation
- 4. Parmar H, Sitoh YY, Ho L. Maple syrup urine disease: diffusion-weighted and diffusion-tensor magnetic resonance imaging findings. J Comput Assist Tomogr. 28 (1): 93-7. J Comput Assist Tomogr (link) - Pubmed citation
Synonyms & Alternative Spellings
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