Metachromatic leukodystrophy

Case contributed by Prof Mark Walterfang

Presentation

Progressive behavioral disinhibition and dysexecutive cognitive syndrome leading to termination of employment. Mental state examination revealed a cheerful, unconcerned and overfamiliar gentleman who was moderately restless and giggled during interview. His mood was elevated and affect expansive. Speech was generally coherent, but rapid, distractible and prone to abrupt changes of subject. Content was positive and excited, focused on past achievements. No evidence of delusions or hallucinations. Well oriented with poor insight and judgment.

Patient Data

Age: 30 years
Gender: Male

Bedside cognitive assessment

Diagram

Attention: 16

Visuoconstructional: 18

Memory: 15.5

Executive: 10.5

Language: 18.5

Total: 78.5

CT brain

CT

There is wide spread hypoattenuation of the supratentorial white matter with prominence of the lateral ventricles. 

MRI Brain

MRI

Extensive increased T2 signal seen in the periventricular white matter extending to the subcallosal white matter but sparing the subcortical u-fibers. This is associated with volume loss and ex-vacuo dilatation of the ventricles. There is a frontal lobe predominance, although the parietal and temporal periventricular white matter is also involved. The changes are confluent and involve the splenium. The corpus callosum is also thinned. Cerebral blood volume is decreased to the periventricular white matter. 

No diffusion restriction detected. No abnormal focus of susceptibility artefact. 

MR spectroscopy demonstrated elevation of myo-inositol and choline with relatively preserved NAA. 

SPECT

Nuclear medicine

Uptake is mildly reduced in the frontal lobes bilaterally and significantly reduced in the temporal lobes bilaterally. Uptake is also reduced in the left thalamus and right head of caudate.

No other significant abnormalities are seen.

The patient went on to have enzyme analysis which demonstrata a markedly deficient level of arylsulphatase A activity, indicating that he is affected by metachromatic leucodystrophy.

Case Discussion

This is a case of adult onset metachromatic leukodystrophy which, although uncommon, is one of the most common adult leukodystrophies. 

Of note, the MRS findings are atypical, in that choline is usually depressed. Myo-inositol elevation is characteristic 1-2

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