Acute disseminated encephalomyelitis (ADEM)

Case contributed by Radiopaedia admin


Admitted with torticollis and fever. Associated abnormal posturing. Working diagnoses - ?encephalitis ?demyelination ?tumor.

Patient Data

Age: 9 months
Gender: Female

There are multiple abnormal areas of low attenuation within both hemispheres which are irregular, some quite confluent, which appear to preferentially affect the white matter. These lesions do not appreciably enhance post-contrast. The sulci, basal cisterns and ventricles appear normal. No bulging of the fontanelles. No shift of midline structures or brain herniation. Normal venous sinuses. No acute intracranial hemorrhage or extra-axial collection. Normal appearance of the mastoid air spaces. No destructive bone lesion.

There are widespread areas of T2 hyperintense signal abnormality involving the subcortical white matter in the parasagittal medial parietal lobes, left temporal operculum and occipital subcortical white matter. Further deep grey matter involvement in both thalami is noted along with diffuse pontine signal alteration with extension into the cerebellar peduncles.
There is patchy diffusion restriction around the margin of particularly the left temporal focus.

There is no pathological intracranial enhancement following contrast administration.

There is a longitudinal central T2 hyperintense non-enhancing cord lesion spanning C3-5. No other cord lesion or pathological spinal enhancement identified. Prominent jugular chain lymph nodes (likely reactive) noted.

Case Discussion

In the acute presentation, non-enhancing intra-axial lesions, preferentially affecting the subcortical white matter/deep grey matter and exerting no appreciable mass effect along with an associated spinal cord lesion are features most consistent with ADEM

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