From the Guidelines
Non-aneurysmal subarachnoid hemorrhage (NASAH) has a recurrence rate of approximately 2-5% over 5 years, which is significantly lower than aneurysmal SAH. For patients with NASAH, I recommend follow-up imaging at 3-6 months after the initial event using CT angiography or MR angiography to ensure no previously undetected aneurysms are present.
- Blood pressure control is essential, with a target of <140/90 mmHg using medications like ACE inhibitors (e.g., lisinopril 10-40 mg daily), ARBs (e.g., losartan 25-100 mg daily), or calcium channel blockers (e.g., amlodipine 5-10 mg daily) 1.
- Lifestyle modifications are also crucial, including smoking cessation, limiting alcohol intake to less than 2 drinks per day, regular exercise, and maintaining a healthy weight.
- Patients should avoid activities that cause sudden increases in blood pressure, such as heavy lifting or straining, for at least 4-6 weeks after the initial hemorrhage.
- Headache monitoring is important - any sudden, severe headache ("thunderclap headache") warrants immediate medical attention as it could indicate recurrence. The lower recurrence rate in NASAH compared to aneurysmal SAH is likely due to the absence of a persistent vascular abnormality, though some cases may be caused by small aneurysms that thrombosed or were not detected on initial imaging 1. The management of NASAH should prioritize blood pressure control, lifestyle modifications, and close monitoring for recurrence, as the risk of recurrence is relatively low but still present.
From the Research
Risk of Recurrence of Non-Aneurysmal Subarachnoid Hemorrhage (SAH)
- The risk of recurrence of non-aneurysmal SAH is a significant concern, with studies suggesting that patients with non-perimesencephalic SAH have an increased risk of a worse neurological outcome 2.
- A study published in 2018 found that only one patient (1.4%) with non-perimesencephalic SAH had a repeat digital subtraction angiography (DSA) that revealed a small saccular anterior choroidal artery aneurysm, considered to be the source of hemorrhage 3.
- Another study published in 2014 found that patients with non-aneurysmal SAH have a better prognosis compared to aneurysm-related SAH, but poor admission status was the only independent predictor of unfavorable outcome in the multivariate analysis 2.
- A study published in 2015 found that nonaneurysmal SAH is associated with the potential for vasospasm, with higher rates in the diffuse versus perimesencephalic SAH patterns 4.
- A systematic review published in 2018 found that intrathecal nicardipine has shown potential benefits and safety in the treatment of cerebral vasospasm, but limited studies on the use of intrathecal nicardipine following non-traumatic subarachnoid hemorrhage demonstrate the need for more research in this field 5.
- A recent study published in 2023 found that non-aneurysmal SAH seems to have a good prognosis for the majority of patients, especially for patients with a perimesencephalic bleeding pattern SAH, but non-aneurysmal SAH patients are however affected by vasospasm and hydrocephalus and have similar risk factors for poor outcome as patients with aneurysmal SAH 6.
Factors Associated with Unfavorable Outcome
- Loss of consciousness (LOC) and Fisher grade 4 bleeding pattern have been associated with increased risk for unfavorable outcome in patients with non-aneurysmal SAH 6.
- Poor admission status has also been identified as an independent predictor of unfavorable outcome in patients with non-aneurysmal SAH 2.
- Vasospasm and hydrocephalus are common complications in patients with non-aneurysmal SAH, and can contribute to unfavorable outcomes 4, 6.