How do you approach treatment and management of angiogram negative non-aneurysmal subarachnoid hemorrhage?

We repeat the catheter-based angiogram 7-10 days after the initial angiogram negative angiogram. MRI of the brain, including the spine, if SAH is predominantly in the posterior fossa.

If DSA is negative, we will typically obtain an MRI of the brain and cervical spine to rule out unusual causes such as cervical spinal AVM/AVF that can cause SAH. If that is also negative, depending on the patient's socioeconomic factors and likelihood of follow-up, we will repeat the angiogram in 7-10 days or in 3 months to rule out occult aneurysm/AVM. Once that is negative, the source of SAH is deemed non-arterial (likely venous), and no further follow-up is necessary.