A 50-year-old female comes to the ED with a headache. The room is dark as I enter and she is holding her head with her hands. She reports that the pain started suddenly while driving and was instantly the worst headache she ever had. The pain hasn’t changed at all.  There was no trauma. She isn’t on blood thinners. She has a history of migraines that usually have photophobia, but this headache started faster than usual and is worse. It has only been 5 hours since the headache started. Given the concerning history, the patient was sent for an emergent CT head.  Radiology calls, and reports there is a bleed. My patient has a subarachnoid hemorrhage. 

Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is one of the “Can’t miss headache diagnoses” of Emergency Medicine. It is a life-threatening emergency with a mortality rate of 50% and a significant amount of morbidity in those that do survive. Quick identification and proper management are essential for good outcomes. Most SAH’s occur spontaneously due to aneurysm rupture which may have been triggered by a strenuous activity like weight lifting or intercourse.  A past medical history of a connective tissue disorder is also a risk factor.  

History

Be concerned about sudden onset headaches/thunderclap headaches (max pain within 1 hour of onset), neck pain/stiffness/meningeal signs (remember blood is irritating to meninges), headache then LOC, headache onset during exertion, trauma, blood thinner use, personal or family history of aneurysm/comorbidity associated with aneurysms. 

Diagnosis

Once you have a concerning history, CT head is the initial study of choice. Studies have shown if performed within 6 hours of headache onset the CT head approaches 100% sensitivity. There is debate on the next best test if you are outside of the 6 hour window. Some literature states that a CTA may be sufficient to rule out SAH, however the standard of care currently still remains to perform an LP after the CT if suspicion is high. On the LP, there unfortunately is not well validated criteria to completely rule out SAH. Xanthochromia theoretically should be a concerning finding, but lack of xanthochromia does not completely rule out SAH. If a traumatic tap, the degree of RBC drop from tube 1 to 4 also does not completely rule out SAH. If the CSF is not definitively negative and the history is concerning, a neurosurgical consultation is warranted. 

There are some risk stratification scores that are in the pipeline, but they are not ready for prime time/have not become standard of care yet. 

Treatment

Blood pressure control

SAH is one of the intracranial bleeds that does have evidence for blood pressure control. Depending on your consulting neurosurgeon, BP goals can be anywhere from <140 systolic to <160 systolic. In the ED, a good choice for BP control is nicardipine. It is rapidly reversible and easily titratable. Nitroprusside and nitroglycerin are contraindicated in SAH. Consider putting in an arterial line to ensure you are achieving goal BP’s and not overshooting (avoiding hypotension is essential). 

Reverse blood thinners

If the patient is on anticoagulation, it should be reversed (unless there is a compelling reason to not reverse). PCC is the mainstay of anticoagulation reversal, but if there is a reversal agent specifically for your patient’s anticoagulant, consider using that instead. 

Anti-platelet agents

If the patient is on an anti-platelet agent, do not give platelets in an attempt to replace inhibited platelets/reverse the anti-platelet agent. Studies have shown an increase in mortality if platelets are given in an attempt to reverse antiplatelet agents. If the patient has severe thrombocytopenia, platelet transfusion may be indicated, but do not give platelets just because the patient is on an anti-platelet agent. An exception to this is if there is planned neurosurgical intervention and your neurosurgeon specifically requests 1 unit of platelets prior to intervention, it is okay to transfuse. You can also consider giving desmopressin.

Pain control

Aggressive pain control should be pursued as some element of hypertension may be related to pain. Treating the patient’s pain aggressively may allow you to use lower doses of anti hypertensive agents or potentially avoid them all together. 

Prevent vasospasm

If the SAH is non traumatic, give nimodipine to prevent vasospasm. Non traumatic SAH is associated with stroke secondary to a delayed vasospasm that occurs. Nimodipine is given in an attempt to prevent this delayed stroke that can occur in your patient. It is not indicated in traumatic SAH. 

Once you have the Neurosurgeon on the phone you will need to discuss if this patient needs to be transferred or if additional imaging is required.  In atraumatic bleeding they will want to know where the location of the bleeding is and a CT angiogram is indicated.  Depending on logistics of travel, this might serve the patient better to be performed at the accepting facility.  Lastly, you can ask the neurosurgeon if they have a preference on seizure prophylaxis.   

 Summary

• Know the must ask questions while taking a history to screen for risk of SAH
• CT head approaches near 100% sensitivity if performed within 6 hours of headache onset, but if after 6 hours the standard of care is still to perform an LP
• Control BP with nicardipine with goal BP <140 or 160 systolic
• Reverse anticoagulation. Do not transfuses platelets just for antiplatelet agent use
• Give nimodipine for non traumatic SAH to prevent stroke caused by vasospasm

Authors:
Dan Loughran, MD
Peer reviewed and edited by:
Timothy Stokes, MD