====== Traumatic subarachnoid hemorrhage diagnosis ======


It has been reported that patients with [[traumatic subarachnoid hemorrhage]] have increased [[leukocyte]] counts on hospital admission, which is an important parameter of severity of injury and an additional marker of neurological outcome in patients with [[severe traumatic brain injury]]
((Rovlias A, Kotsou S. The blood leukocyte count and
its prognostic significance in severe head injury. Surg
Neurol. 2001;55(4):190–196.)).

==== CT scan ====

[[Traumatic subarachnoid hemorrhage]], often a small amount of [[blood]] is seen filling a few [[sulci]], sometimes with an adjacent [[cerebral contusion]]. Small amounts of blood can also sometimes be appreciated pooling in the [[interpeduncular fossa]], appearing as a small hyperdense triangle, or within the [[occipital horn]]s of the [[lateral ventricle]]s.

Occasionally, and worrying for an underlying arterial dissection or an aneurysmal hemorrhage that preceded trauma, larger amounts of blood may be seen around the [[Circle of Willis]] and within the [[posterior fossa]]. 

When the history of trauma is not clear, an [[arteriogram]] may be indicated to R/O a ruptured aneurysm (possibly precipitating the trauma).