Venous hemodynamics in neurological disorders: an analytical review with hydrodynamic analysis.

Venous abnormalities contribute to the pathophysiology of several neurological conditions. This paper reviews the literature regarding venous abnormalities in multiple sclerosis (MS), leukoaraiosis, and normal-pressure hydrocephalus (NPH). The review is supplemented with hydrodynamic analysis to assess the effects on cerebrospinal fluid (CSF) dynamics and cerebral blood flow (CBF) of venous hypertension in general, and chronic cerebrospinal venous insufficiency (CCSVI) in particular.CCSVI-like venous anomalies seem unlikely to account for reduced CBF in patients with MS, thus other mechanisms must be at work, which increase the hydraulic resistance of the cerebral vascular bed in MS. Similarly, hydrodynamic changes appear to be responsible for reduced CBF in leukoaraiosis. The hydrodynamic properties of the periventricular veins make these vessels particularly vulnerable to ischemia and plaque formation.Venous hypertension in the dural sinuses can alter intracranial compliance. Consequently, venous hypertension may change the CSF dynamics, affecting the intracranial windkessel mechanism. MS and NPH appear to share some similar characteristics, with both conditions exhibiting increased CSF pulsatility in the aqueduct of Sylvius.CCSVI appears to be a real phenomenon associated with MS, which causes venous hypertension in the dural sinuses. However, the role of CCSVI in the pathophysiology of MS remains unclear

Prophylaxie post exposition au VIH: eligibilite des patients récemment infectés par voie sexuelle

QUESTION: Post-exposure prophylaxis (PEP) is effective in preventing HIV infection after professional exposure. PEP is also recommended after inadvertent sexual exposure if two conditions are met: the source person is known to be HIV infected, and exposure to this person occurred only once or is accidental. The objective of this study is to describe the circumstances of sexual exposure and determine how frequently these conditions were present among patients diagnosed during primary HIV infection. METHODS: Physicians of 35 patients diagnosed with primary HIV infection provided detailed information on the circumstances of infection as well as on the patients and source persons. RESULTS: Most patients were homosexual (71%), and 91% were male. Only one patient (3%) had a single exposure with a known HIV-infected person and was therefore eligible for PEP. Eight patients (23%) who did not know the HIV status of their partner would have been eligible considering single exposure as a sufficient criterion for PEP. Oro-genital contact appears to account for transmission in four instances. Eleven persons (31%) were infected after sexual contact with their stable partner, of whom 7 did not known his/her HIV status. Twelve patients (34%) were infected after multiple unprotected sexual contact with unknown partners. CONCLUSION: The direct impact of PEP in terms of HIV infections prevented is likely to be small. PEP will not make up for the failure of other prevention methods. It may, however, contribute to the disclosure and the discussion of risk situations and help physicians provide individual counselling taking into account the precise context of risk behavior

ADC mapping of the aging frontal lobes in mild cognitive impairment

Normal aging, leukoaraiosis (LA) and vascular disease particularly involve the human frontal lobes. We decided to investigate a population of elderly patients referred for neuroimaging because of progressive minor cognitive deficits but no dementia. They underwent conventional Magnetic resonance imaging (MRI) using axial T1 and T2-weighted imaging as well as coronal FLAIR sequences in addition to the axial diffusion-weighted MRI. MRI allowed us to differentiate patients with leukoaraïosis (LA+) from those without it (LA-) and mapping of the apparent diffusion coefficient (ADC) to investigate local tissular water motion. We observed an increase in the ADC in all investigated patients with increasing age (r=0.326, p=0.002). This increase was observed in both patients groups (LA+ and LA-). In addition, the LA+ group had significant higher ADC values than the LA- group after controlling for age (p<0.0001)