[Secondary blepharospasm, analysis and pathophysiology of blepharospasm. French translation of the article]

PURPOSE

To localize the brain structures involved in blepharospasm.

MATERIALS AND METHODS

This is a retrospective consecutive series of brain MRI's of patients with secondary blepharospasm whose immediate past medical history included cerebrovascular accident or head trauma.

RESULTS

Six patients, including 4 with CVA with ischemic or hemorrhagic lesions of the thalamus and caudate nuclei and 2 with head trauma with contusive sequellae to the tectal plate and frontal cortical and cerebellar atrophy.

CONCLUSION

According to the literature, brain lesions associated with blepharospasm involve mainly the thalamus, head of the caudate nucleus, corpus striatum, globus pallidus, internal capsule, cerebral cortex and cerebellum. This study demonstrates that blepharospasm is associated with a lesion of a complex neural network - cortex-thalamus-globus pallidus-cortex - and does not correspond to a single, unique lesion. This network is connected with ascending and descending sensory-motor pathways and motor nuclei.

[Rare localization of lipoma in the parotid region: about a case]

La localisation des lipomes au niveau parotidien est très rare. Nous rapportons un nouveau cas avec une revue de littérature concernant un patient de 55 ans, qui a consulté pour une masse au niveau de la région parotidienne évoluant depuis quatre ans. À la palpation nous avons trouvé une formation de consistance molle, mobile et indolore. Le patient a bénéficié par la suite d'une imagerie (échographie et IRM), d'où le diagnostic final d'un lipome parotidien a été retenu ; le traitement était conservateur sur le choix du patient.

[Pyogenic brain abscesses in adults]

Pyogenic brain abscesses (BA) are rare and their diagnosis may be difficult because of the absence of specific clinical or biological signs. However, the use of diffusion-weighted brain MRI sequences has modified the management of BA, as they are highly sensitive and specific to differentiate pyogenic brain abscesses from necrotic tumors, which are the most frequent differential diagnosis in case of ring-enhancing lesions on CT scan. This new tool allows for a rapid diagnosis and should be followed by a CT-guided aspiration of BA. This safe procedure should be performed if possible before starting antibiotics in order to optimize microbiological diagnosis. Recent epidemiological changes include an increase in the numbers of immunocompromised patients and a decrease in the traditional causes of BA (direct inoculation, ear nose and throat infections, etc.). In consequence, a wider range of bacterial species may be involved, making it all the more necessary to obtain a microbiological diagnosis. Many uncertainties remain in terms of the duration of antibiotic treatment, the optimal radiological follow-up and the place for associated treatments such as corticosteroids and anticonvulsive therapy. BA remain severe infections with high mortality and morbidity rates; the factor most regularly associated with a poor prognosis is the patients neurological status at diagnosis.

[Aspect of brain MRI in mitochondrial respiratory chain deficiency. A diagnostic algorithm of the most common mitochondrial genetic mutations]

Mitochondrial diseases are due to deficiency of the respiratory chain and are characterized by a broad clinical and genetic heterogeneity that makes diagnosis difficult. Some clinical presentations are highly suggestive of given gene mutations, allowing rapid genetic diagnosis. However, owing to the wide pattern of symptoms in mitochondrial disorders and the constantly growing number of disease genes, their genetic diagnosis is frequently difficult and genotype/phenotype correlations remain elusive. For this reason, brain MRI appears as a useful tool for genotype/phenotype correlations. Here, we report the most frequent neuroradiological signs in mitochondrial respiratory chain deficiency and we propose a diagnostic algorithm based on neuroimaging features, so as to direct molecular genetic tests in patients at risk of mitochondrial respiratory chain deficiency. This algorithm is based on the careful analysis of five areas on brain MRI: (1) basal ganglia (hyperintensities on T2 or calcifications); (2) cerebellum (hyperintensities on T2 or atrophy); (3) brainstem (hyperintensities on T2 or atrophy); (4) white matter (leukoencephalopathy); (5) cortex (sub-tentorial atrophy); (6) stroke-like episodes. We believe that the combination of brain MRI features is of value to support respiratory chain deficiency and direct molecular genetic tests.