What is the role of subarachnoid hemorrhage (SAH) in the pathogenesis of hemorrhagic stroke?

Updated: Apr 22, 2019
  • Author: David S Liebeskind, MD, FAAN, FAHA, FANA; Chief Editor: Andrew K Chang, MD, MS  more...
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Answer

The pathologic effects of subarachnoid hemorrhage (SAH) on the brain are multifocal. SAH results in elevated intracranial pressure and impairs cerebral autoregulation. These effects can occur in combination with acute vasoconstriction, microvascular platelet aggregation, and loss of microvascular perfusion, resulting in profound reduction in blood flow and cerebral ischemia. [4] See the images below.

Noncontrast computed tomography (CT) scanning was Noncontrast computed tomography (CT) scanning was performed emergently in a 71-year-old man who presented with acute onset of severe headache and underwent rapid neurologic deterioration requiring intubation. The noncontrast CT scan (left image) demonstrates diffuse, high-density subarachnoid hemorrhage in the basilar cisterns and both Sylvian fissures. There is diffuse loss of gray-white differentiation. The fluid-attenuated inversion-recovery (FLAIR) image (right) demonstrates high signal throughout the cortical sulci and in the basilar cisterns, as well as in the dependent portions of the ventricles. FLAIR is highly sensitive to acute subarachnoid hemorrhage; the suppression of high cerebrospinal fluid signal aids in making subarachnoid hemorrhage more conspicuous than do conventional magnetic resonance imaging sequences.
Computed tomographic angiography examination and s Computed tomographic angiography examination and subsequent cerebral angiography were performed in 71-year-old man who presented with acute onset of severe headache and underwent rapid neurologic deterioration. Multiple aneurysms were identified, including a 9-mm aneurysm at the junction of the anterior cerebral and posterior communicating arteries seen on this lateral view of an internal carotid artery injection. Balloon-assisted coil embolization was performed.
Lateral view of a selective injection of the left Lateral view of a selective injection of the left internal carotid artery demonstrates a microcatheter passing distal to the aneurysm neck. This lateral view from an angiogram performed during balloon-assisted coil embolization demonstrates significantly diminished filling of the aneurysm.

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