Subarachnoid hemorrhage
Greetings all! I haven't done an informative post for awhile and since I'm in a neuro/surgical ICU, I figured I discuss subarachnoid hemorrhage (SAH), particularly in a critical care context.
A SAH is a type of hemorrhage stroke. Bleeding occurs spontaneously or from a traumatic source within the subarachnoid space. As a quick reminder, the brain has tissue layers creating separate intracranial spaces where blood or CSF can collect. We name these bleeds often based on WHERE they occur.
Therefore, a SUBarachnoid hemorrhage occurs beneath the arachnoid mater but above the pia mater.
Background
Most SAH are spontaneous from a ruptured aneurysm, though around 20% of SAH do not have a defined cause. Less commonly people experience traumatic SAH (tSAH) from a fall or MVC. The management of a spontaneous SAH and tSAH are different.
Most common in patients >40 y/o, with dominance in woman. Most common cause is rupture of an aneurysm, 80% of which are berry aneurysms. Risk factors for aneurysm rupture are hypertension, smoking, hyperlipidemia, atherosclerosis, advanced age, and extreme emotional stress.
Diagnosis and ED Care
Symptoms: classically the "thunderclap" headache or "worst headache of my life" which progresses rapidly over several minutes. This is usually a constant headache that pain meds really can't touch. Patients can also have nausea or vomiting - beware if you see this as it is a sign of increasing intracranial pressures. Can also have photophobia, delirium. They do NOT have a focal neuro deficit.
Have a LOW threshold to scan this patient's head. Diagnosis is obtained from head imaging. Get a non-contrast head CT to identify the presence of intracranial blood. Of note, xanthochromia on LP is also diagnostic; however, this isn't helpful for surgical planning. On a non-contrast CT, blood will appear white.
Surgical & Critical Care Management
Emergency Surgery: At minimum people receive a ventriculostomy to drain the head of blood. Some people with significant swelling require a hemicraniectomy. Below is a general illustration of ventric placement (also called EVD - external ventricular drain).
After immediate drainage (or sometimes before), patients receive a CTA of the head to locate the aneurysm and if surgically repairable, the aneurysm will be coiled the next day in the neuro IR suite. These patients will also receive CT perfusion (at least once, sometimes twice) to check for vasospasm.
SAH precautions: apply to all patients at all times
HOB >30
Strict bedrest
Arterial line for precise BP measurement (you'll find disagreement among critical care providers about this since arterial lines have not been shown to improve patient mortality. However, that study was NOT in a neuro critical care population)
Continued ICP monitoring (via the ventric)
Antibiotics while the drain is in place (usually ancef)
Daily stool softeners to avoid straining with bowel movements
Low lights, quiet environment (no phone, little tv, etc)
Stat head CT for any acute neuro decline
Maintenance of euvolemia (SUPER important as hypovolemia can trigger vasospasm)
Seizure prophylaxis x 7 days (usually keppra 500 mg BID)
Vasospasm prophylaxis x 21 days (nimodipine 60 mg q4h)
No antiplatelets or blood thinners.
No dvt prophylaxis until bleeding has significantly decreased (usually after coiling- surgeon dependent)
Avoid hypercapnia, hyperglycemia, hyperthermia
Aggressive blood pressure control (usually SBP <140)
Sodium goals (patient dependent, higher goal if significant swelling present)
Worth noting that tSAH patients have SOME of these precautions but not all. Nimodipine is not indicated for vasospasm prevention in these patients. I've seen it used in special situations but most commonly not. Depending on size of tSAH, they may not need a ventric or seizure prophylaxis.
Prognosis
Prognosis has improved over the past 2 decades. Outcomes are multifactorial on age, size of bleed, overall health, and presence of rebleed or complication (vasospasm, ischemic stroke) etc. Roughly 1/3 of patients have a good outcome, meaning return to baseline functionality. 1/3 of patients will have a focal neuro deficit, usually due to vasospasm which caused an ischemic infarct. The remaining 1/3 of patients die from SAH.
At presentation you can use the Hunt and Hess Scale to help guide education for families about prognosis. Generally, the poorer the neuro exam at presentation, the worse the prognosis. There has been some criticism that it is observer dependent and distinguishing between Grade I and Grade II is moot. The important thing about this scale is that is does NOT include the CT imaging. I personally have seen HUGE bleeds that one would think would kill the patient but with prompt intervention they have a normal exam and good outcomes.
The most common complication is rebleeding of the aneurysm even if it has been repaired. This is usually due to poor blood pressure control, vasospasm, or head trauma after SAH recovery. Rebleeding is usually bad for most patients.
These patients stay in the ICU for at least 7 days for ICP and neuro monitoring. Some stay more if vasospasm is present. I do not get to interact with patients on neuro step down and don't have the privilege to see them in outpatient clinic. But if comorbidities that contributed to the stroke are well managed and the patient receives the necessary PT/OT and other support services, outcomes are good. It's still a horrible diagnosis to get but it's not as devastating as it used to be.
If you work in neurology/neurosurgery and see these patients in clinic, please reblog and comment. I think a lot of ICU providers (myself included) get jaded with the horrible stuff we see and don't have a good grasp of longer term recovery.















