Idiopathic intracranial hypertension is consistently associated with venous outflow disturbances. Sinus venous stenosis are found at magnetic resonance venography in the large majority of IIH patients and may have various conformations, ranging from functional smooth narrowings of sinus segments associated or not with definite flow gaps, to segmental hypoplasia or aplasia of one or more central venous collectors. Stenosis are currently believed to be a consequence of a primary altered cerebrospinal fluid (CSF) pressure since it may normalize after CSF subtraction with lumbar puncture or shunting procedures. In this paper a "self-sustained venous collapse" is proposed as a crucial causative mechanism in predisposed subjects, leading to a self-sustained intracranial hypertension in presence of a wide range of triggering factors. The proposed mechanisms predict the long-term remission of IIH syndromes frequently observed after a single or few serial CSF subtractions by lumbar puncture.