[Clinical vignettes. How to diagnose the cause of edema, a clinical approach].

Oedema is a frequent disorder and the easily detectable consequence of an increase of fluid located in the interstitial tissue. It could be localized or generalized and related either to a primary disturbance of hemodynamics at the capillary level, due to a modification of the Starling's law components with secondary water and saline retention, or to a primary retention of salt and water linked to a kidney abnormality. Generalized forms are pitting oedema, most often painless, white, bilateral and symmetric, distributed at the lower part of the body (localisation according to the gravitation law). They are different in their characteristics from localized oedema or lymphoedema which are tough. We propose a diagnostic approach based on medical history, clinical examination which allows a confident medical diagnosis and so an adapted therapy.