[Headache caused by endocranial hypotension secondary to sacrococcygeal trauma in a patient with a congenital arachnoid cyst].

Headache caused by intracranial hypotension after sacrococcygeal trauma, is a rare syndrome with very similar symptoms and physiopathology to post dural puncture headache. In both situations, cerebrospinal fluid (CSF) leaks through a dural tear, leading to a decrease in its pressure. A 13 year old patient presented a frontal and occipital positional headache, after undergoing sacrococcygeal trauma. In magnetic resonance images, the presence of a spinal arachnoid diverticulum (cyst) and CSF leak were confirmed. After the establishment of conservative medical treatment, complete clinical remission was observed. The diagnosis of intracranial hypotension headache syndrome is mainly clinical, once other possible headache etiologies have been discarded. Magnetic resonance imaging can be used to detect small CSF leaks, and in this case, magnetic resonance imaging clearly showed the existence of an arachnoid cyst. The presence of some meningeal diverticulums such as arachnoid cyst, constitute a risk to undergo this syndrome, due to the possibility of its rupture by minor traumatisms. The initial treatment should be conservative, as the dural tear seals spontaneously and the liquid is reabsorbed.