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Biomedical subjects

M Hermier

Publications and source records attributed to M Hermier.

At least 19 recordsLinked to original sources

[Neurological aspects of Fabry's disease].

Fabry disease is a rare X-linked disorder caused by deficient activity of the lysosomal enzyme alpha-galactosidase A. Progressive accumulation in lysosomes of the undegraded glycosphingolipids leads to a multi-system disease with dermatological, ocular, renal, cardiac, and neurological manifestations. Peripheral nerve involvement, neuropathic pain and chronic acroparesthesiae, are frequent and early-onset signs revealing the disease. They are due to the involvement of small nerve fiber, thus explaining the normality of electroneuromyography. Cochleo-vestibular and autonomic nervous system involvement is frequent. Besides rare aseptic meningitis, central nervous system involvement is essentially represented by cerebrovascular events (stroke, transient ischemic attack). Affecting essentially the posterior circulation, their etiologies have to be clarified: progressive stenosis of small vessels with globotriasocylceramide deposits, arterial remodeling, endothelial dysfunction, pro-thrombotic state, cerebral hypoperfusion consecutive to dysautonaumy, cardiac embolism. MRI shows numerous silent lesions, increasing with age, mainly in small perforant arteries (periventricular white matter, brainstem, cerebellum, basal ganglia). Pulvinar calcifications, due to an increase in cerebral hyperperfusion, could be specific of Fabry disease. Positon tomography analysis shows a reduced cerebral flow velocity and impaired cerebral autoregulation, secondary to the glycosphingolipid storage in vascular endothelial cells. Enzyme replacement therapy has to be carefully monitored.

Brain↗

[Reversible acute postpartum cerebral angiopathy].

Acute cerebral angiopathy is a rare neuro-vascular complication in postpartum. In this setting, the implication of vasoconstrictive drugs used for lactation or deliverance hemorrhage inhibition has been established. This review aimed 1) to describe, epidemiologic, clinical and diagnostic features of this pathological condition. 2) To put in perspective this condition within the scope of neurovascular clinical syndrome of pregnancy.

Cerebral Arterial Diseases↗

[Diffusion and perfusion MR imaging in cerebral lymphomas].

Because of the increasing incidence of cerebral lymphoma, it is critical for patient management to recognize the MR features of this disease. We present the characteristic morphological and functional MRI features of this tumor. The findings on MRI studies, including morphological, diffusion and perfusion imaging, performed in 9 biopsy-proven cases of cerebral lymphoma with 13 lesions are presented and analyzed, and are discussed in comparison with published literature data. All patients underwent diffusion-weighted imaging with a single shot echo-planar pulse sequence. Dynamic susceptibility-contrast MRI was performed using a T2*-weighted gradient-echo echo-planar sequence after intravenous injection of chelates of gadolinium at the rate of 6 ml/s and a temporal resolution of 1 second. All cases of cerebral lymphoma appeared hypointense or isointense on T1-weighted images and in 75% of cases iso- or hypointense on T2-weighted images. All lesions enhanced except one in a patient receiving steroid therapy. On diffusion-weighted images, tumours were hyperintense with normal or decreased ADC values (0.717+/-0.152.10-3 mm2/sec, range: 0.550-1.014) and an ADC ratio tumour/normal white matter of 0.974+/-0.190 (range: 0.768-1.410). On perfusion, the signal intensity-time curve of each tumour showed a characteristic type of curve with a significant increase of the signal intensity above the baseline and a low maximum relative cerebral blood volume ratio (rCVBmax) of 1.43+/-0.64 (0.55-2.62). Due to their higher cellularity, the lack of neoangiogenesis, and the increased permeability of the blood-brain barrier related to the infiltration of blood vessels wall by lymphomatous cells, cerebral lymphoma presents characteristic diffusion and perfusion MRI features that should be useful for diagnosis and patient follow-up.

Adult↗

Hyperthyroidism and cerebral venous thrombosis.

The demonstration of an underlying prothrombotic condition in cerebral venous thrombosis (CVT) may have important practical consequences in terms of prevention. Thyrotoxicosis through a hypercoagulable state may be a predisposing factor for CVT. The authors present the cases of 4 patients who developed CVT and hyperthyroidism. At the acute stage, hyperthyroidism was associated with an increase in factor VIII (FVIII). At follow-up, FVIII level remained increased in 2 patients. Hyperthyroidism may have an impact on FVIII level. Accordingly in patients with hyperthyroidism and neurological symptoms, the diagnosis of CVT should be considered and an exhaustive coagulation screening may be appropriate.

Factor VIII↗

Acute hypertensive encephalopathy with widespread small-vessel disease at MRI in a diabetic patient: pathogenetic hypotheses.

We report unusual magnetic resonance imaging (MRI) findings in a diabetic patient with neglected hypertension and hyperglycemia, presenting with seizures and coma. Outcome was fatal despite intensive care. The MRI findings included bilateral insular and temporo-occipital grey and white matter involvement, and numerous, scattered, lacunar-like lesions involving the peripheral and deep white matter, basal ganglia grey matter, and brainstem. Lesions had a low apparent diffusion coefficient, and some enhanced following contrast injection. Hypertensive encephalopathy with widespread and severe acute small-vessel disease was considered. Pathophysiology is discussed.

Acute Disease↗

Craniopharyngiomas: our experience in Lyon.

OBJECTIVE: We reviewed our experience in surgical treatment of craniopharyngiomas. Surgical treatment of craniopharyngiomas in children represents a challenge for neurosurgeons because it presents a different set of surgical problems. Results are controversial and debates concerning strategies to ameliorate the rate of success and to decrease the rate of morbidity and mortality are ongoing. Post-surgical quality of life is related to the anatomical relationship between the hypothalamic region, vascular structures and optic pathways. DISCUSSION: From 1985 to 2004, 60 children (age range, 4 months to 18 years) were treated in our institution. Since 1987, all patients were studied with pre- and postoperative MRI. Two groups of patients were distinguished: a group of 36 patients treated with surgical direct surgery; a second group of 24 patients treated only with intracystic chemotherapy with bleomycin (18 patients) or associated with surgery (six patients). In the first group, the removal of lesion was total in 74% of cases. Two patients died in the early postoperative period and two more died later (early mortality of 5% and late mortality of 11%). All patients presented ante-pituitary insufficiency and diabetes insipidus, which required substitutive treatment. Twenty-two patients presented with visual problems, including amaurosis in two cases. In the group treated with bleomycin, 18 patients presented a primary cystic or a mixed form of craniopharyngioma and six patients showed a cystic recurrence. Eighteen patients were treated with bleomycin only. The dose used varied from 30 mg to a maximal dose of 150 mg, with a middle dose of 60 mg in the large majority of cases. In this group, the cyst disappeared in 12 patients and reduced to 30% of its initial volume, and stabilization of the lesion was achieved in the other six patients. Only 11 patients presented partial endocrine insufficiency. Of the 18 patients, 16 were of school age, 14 of whom were following a normal educational program and two an assisted program. No mortality was reported. CONCLUSION: Our experience showed that in the group treated with intracystic chemotherapy alone, results were better with a low rate of morbidity and mortality. Endocrinological, visual and neuropsychological evaluations were also correlated with better outcome. In cases of cystic craniopharyngiomas, we considered bleomycin as the treatment of choice. For solid forms or for cases resistant to intracystic chemotherapy with bleomycin, direct surgery has to be proposed.

Adolescent↗

Clinical and imaging predictors of intracerebral haemorrhage in stroke patients treated with intravenous tissue plasminogen activator.

OBJECTIVE: To evaluate clinical, biological, and pretreatment imaging variables for predictors of tissue plasminogen activator (tPA) related intracerebral haemorrhage (ICH) in stroke patients. METHODS: 48 consecutive patients with hemispheric stroke were given intravenous tPA within seven hours of symptom onset, after computed tomography (CT) and magnetic resonance imaging (MRI) of the brain. Baseline diffusion weighted (DWI) and perfusion weighted (PWI) imaging volumes, time to peak, mean transit time, regional cerebral blood flow index, and regional cerebral blood volume were evaluated. The distribution of apparent diffusion coefficient (ADC) values was determined within each DWI lesion. RESULTS: The symptomatic ICH rate was 8.3% (four of 48); the rate for any ICH was 43.8% (21 of 48). Univariate analysis showed that age, weight, history of hyperlipidaemia, baseline NIHSS score, glucose level, red blood cell count, and lacunar state on MRI were associated with ICH. However, mean 24 hour systolic blood pressure and a hyperdense artery sign on pretreatment CT were the only independent predictors of ICH. Patients with a hyperdense artery sign had larger pretreatment PWI and DWI lesion volumes and a higher NIHSS score. Analysis of the distribution of ADC values within DWI lesions showed that a greater percentage of pixels had lower ADCs (< 400 x 10(-6) mm(2)/s) in patients who experienced ICH than in those who did not. CONCLUSION: Key clinical and biological variables, pretreatment CT signs, and MRI indices are associated with tPA related intracerebral haemorrhage.

Adult↗

Influence of the site of arterial occlusion on multiple baseline hemodynamic MRI parameters and post-thrombolytic recanalization in acute stroke.

In this prospective MRI study, we evaluated the impact of the site of occlusion on multiple baseline perfusion parameters and subsequent recanalization in 49 stroke patients who were given intravenous tissue plasminogen activator (tPA). Pretreatment magnetic resonance angiography (MRA) revealed an arterial occlusion in 47 patients: (1) internal carotid artery (ICA) + M1 middle cerebral artery (MCA) occlusion (n=12); (2) M1 MCA occlusion (n=19); (3) M2 MCA, distal branches of the MCA and anterior cerebral artery (ACA) occlusion (n=16). Patients with ICA occlusion had significantly larger DWI, PWI and mismatch lesion volume on pretreatment MRI compared to patients with other sites of occlusion. The differences in cerebral blood flow (CBF) and peak height were significantly higher in patients with ICA occlusion compared to patients with other sites of occlusion (P=0.03 and P=0.04, respectively). Day 1 MRA showed recanalization in 28 patients (60%). The rate of recanalization was significantly different depending on the site of occlusion: 33% in ICA + M1 MCA occlusion, 63% in M1 MCA occlusion and 81% in either M2 MCA, distal branches of the MCA or ACA occlusion (P=0.002). Our data suggest that CBF and peak height are the most relevant MRI parameters to assess the severity of hemodynamic impairment in regard to the site of occlusion.

Adult↗

[Gastroparesis on a gastric ulcer].

INTRODUCTION: Gastroparesis is the failure of the stomach to empty because of decreased gastric motility. It's a fairly frequent medical problem. Diabetes is the most common known cause. OBSERVATION: The first case report is that of an 82 year-old woman, in whom acute gastric distension occurred, evoking a gastric volvulus on the scan. Upper endoscopy revealed gastric ulcers. All symptoms disappeared with medical treatment. The second case report concerns a 37 year-old man who was admitted with signs of occlusion. CT scans revealed acute gastric distension. Emergency surgery revealed no gastric volvulus. Upper endoscopy revealed gastritis and numerous ulcers. The signs regressed with medical treatment. DISCUSSION: Our observations are original in their -pseudo-surgical discovery. Acute gastric distension is rare, but must be recognised because of the risk of perforation and rupture of the stomach walls. These case reports are also original in their aetiology. Gastric ulcers are rarely described in this situation. CONCLUSION; Gastroparesis is a frequent situation but potentially severe. A review of the principle signs, aetiology and treatment is made.

Acute Disease↗

Intravenous r-TPA in vertebrobasilar acute infarcts.

Presented are the clinical data of 18 consecutive patients who were treated by IV recombinant tissue plasminogen activator (r-TPA) for suspected vertebrobasilar (VB) acute ischemia within 7 hours. The mean delay for treatment was 5 +/- 3.6 hours. Mean baseline NIH Stroke Scale score was 17 +/- 4. At 3 months, 10 patients were independent (modified Rankin Scale [mRS] score = 0 to 2), whereas 8 patients showed a poor outcome (mRs = 3 to 6). IV r-TPA in VB ischemia in a 7-hour window may be safe and efficient.

Aged↗

[Delayed post-anoxic leukoencephalopathy].

INTRODUCTION: The onset of post-anoxic encephalopathies can be delayed after the acute hypoxic injury. CASE REPORT: We present the case of a 45-year-old woman who achieved complete recovery from an episode of hypoxia related to a suicide attempt (ingestion of benzodiazepine). Three weeks later she developed a confusional state with akinetic mutism and parkinsonism. Brain CT-scan showed bilateral hemispheric white matter hypodensities. MRI showed extensive bilateral hyperintensities on T2-weighted and Flair sequences within the hemispheric white matter and the globus pallidus. EEG showed diffuse slow activity. All investigations for leukodystrophies were negative. Brain biopsy showed normal cortex and widespread demyelination with axonal sparing in the underlying white matter. The patient experienced a partial clinical recovery. CONCLUSION: The clinical course and the results of paraclinic investigations were consistent with the diagnosis of delayed post-anoxic leukoencephalopathy.

Female↗