Spontaneous intracranial hypotension (SIH) is an infrequent disease, related to a leak of cerebrospinal fluid. There are not controlled studies for this treatment.The main of this study is to demonstrate the superiority of the Trendelenburg position compared to supine position during 24 hours after an epidural blood patch for a spontaneous intracranial hypotension

Various treatments have been used for patient with spontaneous intracranial hypotension, but there is not definite approach. Some patients, fortunately, improve spontaneously. Bed rest and increased fluid intake have been advocate. The effectiveness of the caffeine has been shown in some studies, but durable beneficial effect is doubtful. The efficacy of steroids has not been established. However, although there have been no controlled studies, autologous epidural blood patch (EBP) can be considered the treatment of choice for patients. The success rate of EBP for a post lumbar puncture headache is about 90%, but for SIH, is very less about 50% after the first one and 77% after the second. The amount of blood injected must be sufficient. On the other hand, the leak is usually located on dorsal, above the prolonged rest must be respected. One study, have demonstrated, without randomization, a success rate of 90% with a prolonged Trendelenburg after EBP. We decided to do this study, to confirm a superiority of a 24 hours prolonged Trendelenburg position.

It's a monocentric study of parallel randomized open blind groups. Patients will be recruited by investigators in our headache emergency room. If the diagnose of SIH is confirmed (orthostatic headache from more than 5 days and less than 28 days with a normal MRI or with sign of SIH) study will be proposed.

After a signed information, the patients will be randomized in 2 groups, the investigator is blind of the randomized arm of patient

1. EBP with 24 hours bed rest
2. EBP with 24 hours Trendelenburg position

V1: inclusion V2 : 24 hours before EBP (headache, associated symptoms, HIT6) V3 : randomization and EBP V4 : first evaluation 30 minutes after standing (headaches, associated symptoms) V5 : phone evaluation (safety) D7 V6 : Evaluation at D15 (headache, associated symptoms, safety) V7 : Evaluation at D30 (headache, associated symptoms, control cerebral MRI, HIT6, safety) V8 : last evaluation D60 (headache, associated symptoms,HIT6 safety)

Collection of 2nd EBP, 3rd EBP, 4th EBP throughout the study up to J 92 maximum

Inclusion Criteria:

• 18 years or more
• No contraindication for BPE
• Severe or moderate headache within 15 min standing, mild or no headache after 15 min bed rest
• Headache from 5 to 28 days
• Normal or evidence of low CSF on MRI
• Signed informed consent

Exclusion Criteria:

• Known dural leak in the previous 2 months the onset of headache
• Abnormal MRI
• First BPE for SIH
• The patient has participated in another clinical trial than can interact with the evaluation
• Contraindication of Trendelenburg position