Sentinel headache can be seen in up to 60% of patients preceding spontaneous aneurysmal subarachnoid hemorrhage (aSAH) by days or weeks. Consensus opinion is that structural changes in the aneurysm wall or minor bleeding may be implicated in the symptoms resulting in the sentinel event. Sentinel headache is associated with different features from usual or common headaches. These headaches develop rapidly, achieve maximum intensity within minutes and may last hours to days. They are not always associated with the classic signs of spontaneous aSAH such as altered level of consciousness, neck stiffness and focal neurological signs. The differential diagnosis of new onset severe atypical headache includes cerebral venous thrombosis, arterial dissection, reversible cerebral vasospasm syndrome, vasculitis, and aSAH. Typically, the rupture or leakage of a brain aneurysm produces hemorrhage into the subarachnoid space which can clinically present as meningeal irritation signs including pain with eye movement.
Aside from the clinical presentation, the imaging studies are required to assess aSAH. Ruptured cerebral aneurysms present with subarachnoid hemorrhage (SAH) with or without intracerebral and/or intraventricular extension. On rare occasions, an aneurysmal rupture may present with isolated intracerebral hemorrhage (ICH) and/or intraventricular hemorrhage (IVH) without overt blood products in the subarachnoid space thus posing potential diagnostic challenges.
Other causes of intraparenchymal hemorrhage include hypertensive parenchymal bleeding or bleeding from vascular malformations. Typically, these result in focal neurological complaints or deficits depending on the bleed site but may have a similar clinical presentation as this case. Subarachnoid blood may be readily identified by diagnostic tests including non-contrast head CT scan and lumbar puncture, though angiography may be warranted based on the history.