Diffuse Angiogram-Negative Subarachnoid Hemorrhage is Associated with an Intermediate Clinical Course

Area of Science:

• Neurology
• Neurosurgery
• Critical Care Medicine

Background:

• Nontraumatic subarachnoid hemorrhage (SAH) can be angiogram-negative in 15-20% of cases.
• These angiogram-negative cases include perimesencephalic SAH and diffuse SAH.
• Perimesencephalic SAH is generally considered to have a better prognosis than diffuse SAH.

Purpose of the Study:

• To compare the clinical course and functional outcomes of perimesencephalic SAH, diffuse SAH, and aneurysmal SAH.
• To better characterize the prognostic implications of each SAH subtype.

Main Methods:

• Retrospective cohort study of nontraumatic SAH patients admitted between 2012 and 2017.
• Patients were categorized into perimesencephalic SAH, diffuse SAH, and aneurysmal SAH groups based on radiographic bleed patterns.
• Demographics, complications, and clinical outcomes were analyzed and compared across the three groups.

Main Results:

• Aneurysmal SAH patients were more likely to be female, White, and active smokers.
• Critical care complications like hypotension, shock, and endotracheal intubation were significantly higher in diffuse SAH and aneurysmal SAH groups compared to perimesencephalic SAH.
• Diffuse SAH patients experienced intermediate functional outcomes, with higher rates of nonhome discharge and poor functional status than perimesencephalic SAH, but lower than aneurysmal SAH.

Conclusions:

• Perimesencephalic SAH is associated with a benign clinical course.
• Diffuse SAH confers an intermediate prognosis, more severe than perimesencephalic SAH but less so than aneurysmal SAH.
• Vigilant acute care and high-acuity observation are crucial for patients with diffuse SAH to mitigate morbidity and neurologic compromise.