[MRI in the diagnostic and evolutive control of subacute combined degeneration. A case report]

A deficit of vitamin B12, generally resulting from pernicious anaemia, can give rise to disorders of the spinal cord, brain, optic and peripheral nerves. The principal neurological syndrome is subacute combined degeneration of the spinal cord (SCD), which can cause progressive motor and/or sensitive alterations, instability and incontinency, due to the demyelination of the posterior horn of the spinal cord. The identification by magnetic resonance (MR) of signal hyperintensity in T2 weighted sequences at the level of the posterior horns of the spinal and/or cervical cord can be of great use in diagnosising the patient with SCD, above all when the symptoms are mild or nonspecific, and the patient does not have haematological or gastrointestinal alterations. Besides, the evolution of the altered signal of the posterior horns in MR can be of use in evaluating the efficacy of treatment, since their normalization is related to clinical improvement.

The impact of silent vascular brain burden in cognitive impairment in Parkinson's disease

BACKGROUND AND PURPOSE

White matter hyperintensities (WMHs) detected by magnetic resonance imaging (MRI) of the brain are associated with dementia and cognitive impairment in the general population and in Alzheimer's disease. Their effect in cognitive decline and dementia associated with Parkinson's disease (PD) is still unclear.

METHODS

We studied the relationship between WMHs and cognitive state in 111 patients with PD classified as cognitively normal (n = 39), with a mild cognitive impairment (MCI) (n = 46) or dementia (n = 26), in a cross-sectional and follow-up study. Cognitive state was evaluated with a comprehensive neuropsychological battery, and WMHs were identified in FLAIR and T2-weighted MRI. The burden of WMHs was rated using the Scheltens scale.

RESULTS

No differences in WMHs were found between the three groups in the cross-sectional study. A negative correlation was observed between semantic fluency and the subscore for WMHs in the frontal lobe. Of the 36 non-demented patients re-evaluated after a mean follow-up of 30 months, three patients converted into MCI and 5 into dementia. Progression of periventricular WMHs was associated with an increased conversion to dementia. A marginal association between the increase in total WMHs burden and worsening in the Mini Mental State Examination was encountered.

CONCLUSIONS

White matter hyperintensities do not influence the cognitive status of patients with PD. Frontal WMHs have a negative impact on semantic fluency. Brain vascular burden may have an effect on cognitive impairment in patients with PD as WMHs increase overtime might increase the risk of conversion to dementia. This finding needs further confirmation in larger prospective studies.

[Neuroradiologic findings of glutaric aciduria type I]

Glutaric aciduria type I is a rare disorder of organic acid metabolism caused by deficiency of glutaryl-CoA dehydrogenase, a mitochondrial enzyme. Improper degeneration of amino acids: tryptophan, lysine, and hydroxylysine, results in increased levels of glutaric acid, which typically becomes clinically manifest as an acute dystonic crisis in young children. Accumulation of glutaric acid causes neurotoxicity in the basal ganglia and fronto-temporal cortex which can lead to progressive dystonia, hypotonia, permanently impaired speech and seizures. Because dietary and drug therapy may alter the natural history of the disease, early diagnosis of such patients is critical. We report the magnetic resonance (MR) imaging findings in a 16 year-old girl with this disorder who presented with a chronic dystonic syndrome and previously diagnosed of brain paralysis. MR imaging demonstrated bilateral involvement of the putamina and periventricular white matter, and bilateral temporal atrophy and widened Silvian fissures.