Noncontrast Brain Computed Tomography Findings of Spontaneous Intracranial Hypotension in the Emergency Department Setting.

Background: Spontaneous intracranial hypotension (SIH) is a difficult diagnosis, especially in an emergency department (ED) setting where magnetic resonance imaging (MRI) is usually not available.

Objective: To emphasize the presence of a very frequent but unnoticed tentorial subdural hygroma among a number of recognized noncontrast brain computed tomography (CT) findings in patients with spontaneous intracranial hypotension.

Methods: This is a case series study of 7 consecutive patients with orthostatic headache who were admitted to the ED and finally diagnosed as SIH, and of 11 women who underwent brain CT due to very severe orthostatic headache after epidural anesthesia. We evaluated the CT findings of patients with SIH and further compared each patient's CT findings with their respective MRI and with the brain CT of women with postepidural anesthesia orthostatic headache.

Results: Noncontrast brain CT was abnormal in five out of seven (71%) SIH cases: tentorial subdural hygroma was found in four (57%) cases; supratentorial subdural hygroma and cervical spinal venous engorgement were found in two (29%) cases, and subdural hematoma was found in one case. All women with severe orthostatic headache after epidural anesthesia had CT findings similar to those of spontaneous intracranial hypotension patients.

Conclusions: The presence of a tentorial subdural hygroma on brain CT in a patient with orthostatic headache may strongly suggest the diagnosis of intracranial hypotension. This finding can be of high clinical significance in an emergency setting, avoiding additional invasive or expensive procedures.