[Pyoderma gangrenosum revealing Takayasu's arteritis]. / Pyoderma gangrenosum révélant une artérite de Takayasu.

BACKGROUND: Pyoderma gangrenosum is a form of neutrophilic dermatosis often associated with inflammatory disease or blood dyscrasias. We report a case of pyoderma gangrenosum revealing Takayasu's arteritis. OBSERVATION: A 26 year-old woman was followed since 2002 for pyoderma gangrenosum occurring during pregnancy and regressing under general corticosteroids. In January 2004, immediately after childbirth, she presented an extensive ulcerated lesion on the right forearm. Histological examination of a biopsy sample from this solution pointed towards pyoderma gangrenosum. Somatic examination showed reduced peripheral pulse on the right side, asymmetric blood pressure between the two arms and vascular murmur in the carotid, femoral and renal arteries. Based on laboratory and x-ray examinations, Takayasu's arteritis was diagnosed and chronic viral hepatitis B detected. Resumption of treatment with prednisone (1 mg/kg/d) resulted in resolution of the wounds within 1 month. DISCUSSION: Although pyoderma gangrenosum is a classic complication in Takayasu's arteritis in Japan, this combination is rare in Europe, North America and North Africa. This case was singular in terms of the occurrence of pyoderma gangrenosum with each pregnancy. However, a number of epidemiological and clinical features were consistent with those reported in the literature, namely presentation predominantly in female patients, young age and involvement of the limbs. In 60% of cases, pyoderma gangrenosum precedes Takayasu's arteritis. The recommended mode of treatment comprises oral corticosteroids as first-line therapy followed by cyclosporine as second-line treatment.

Non-linear analysis of the arterial pulsatile flow: assessment of a model allowing a non-invasive ultrasonic functional exploration.

Ultrasonic measurements and modelling of blood flow in large vessels allows non-invasive evaluation of clinically interesting hemodynamic variables. To this aim, a non-linear mathematical model for the pulsatile arterial flow is proposed using the approximation of "local flow" theory. The model requires only measurements of instantaneous radius and centre-line blood velocity, and the knowledge of the tube distensibility to calculate blood velocity profiles, pressure gradient and wall shear stress. Evaluation of the proposed model using experimental data obtained from the literature proved that it can provide reliable results. In addition, as shown by assessing significance of various non-linear terms, results did not significantly change when a linear pressure-radius relationship was used instead of a non-linear relationship. Also, the model was found to be moderately sensitive to arterial tapering. Thus, the proposed model is suitable for a non-invasive clinical arterial exploration since it only requires three measurements which can be easily and precisely obtained in vivo using ultrasonic methods: the instantaneous radius, the centre-line velocity and the mean pulse wave velocity, this last variable characterizing the tube distensibility when assuming a linear pressure-radius relationship.