Idiopathic intracranial hypertension - IIH (synonymous old terms: benign intracranial hypertension - BIH, pseudotumor-cerebri - PTC) it’s a syndrome, related to elevated intracranial pressure, of unknown cause, sometimes cerebral emergency, occuring in all age groups, especially in children and young obese womans, in the absence of an underlying expansive intracranial lesion, despite extensive investigations. Although initial symptoms can resolve, IIH displays a high risk of recurrence several months or years later, even if initial symptoms resolved. Results: A 20-year-old male, obese since two years (body mass index 30, 9), was admitted for three months intense headache, vomiting, diplopia, progressive visual acuity loss. Neurologic examination confirmed diplopia by left abducens nerve palsy, papilledema right > left. At admission, cerebral CT scan and cerebral MRI with angio MRI 3DTOF and 2D venous TOF was normal. Despite treatment with acetazolamide (Diamox), corticosteroid, antidepressants (Amitriptyline), anticonvulsivants (Topiramate) three weeks later headache, diplopia persist and vision become worse, confirmed by visual field assessment, visual evoked potential (VEP). A cerebral arteriography demonstrate filling defect of the superior sagittal sinus in the 1/3 proximal part and very week filling of the transverse right sinus on venous time. Trombophylic profile has revealed a heterozygote V factor Leyden mutation, a homozygote MTHFR and PAI mutation justifying an anticoagulant treatment initiated to the patient. The MRI showed a superior sagittal sinus, right transverse and sigmoid sinus thrombosis, dilatation and buckling of the optic nerve sheaths with increased perineural fluid especially retrobulbar, discrete flattening of the posterior segment of the eyeballs, spinal MRI showed posterior epidural space with dilated venous branches, with mass effect on the spinal cord, that occurs pushed anterior on sagittal T1/T2 sequences cervical and thoracic. The opening pression of lumbar puncture, done with the patient in the lateral decubitus position, was 60 cm H2O, the cytochemical CSF study were normal. The patient was operated: a lombo-peritoneal with a variable pressure valve was inserted. Two months after the patient general condition improved: he was without headache, abducens palsy and the visual field assessment, ocular motility examination, ophthalmoscopy were normal. Conclusion: IHH is rare, variable in evolution, and in many cases it disappears on its own within 6 months without affecting life expectancy. Weight loss, fluid or salt restriction, in conjunction with medical treatment, angioplasty and venous stenting across the sinus stenosis under general anesthesia and surgical treatment (shunting, optic nerve sheath decompression and fenestration, gastric by-pass surgery) are treatment alternatives. Such disorder should be closed monitored because 10 to 25% of cases could be affected by recurrencies or by permanent vision loss to those patients with resistant papilledema despite treatment.