Headache persisting after aneurysmal subarachnoid hemorrhage: A narrative review of pathophysiology and therapeutic strategies

Objective: This narrative review of the literature concerns persistent headache attributed to past non-traumatic subarachnoid hemorrhage (SAH), based off demographic and clinical features, what are pathophysiologic mechanisms by which these headaches occur, which medical and interventional treatments have the most evidence for pain alleviation, and what pre-clinical evidence is there for emerging treatments for these patients.

Background: Following initial stabilization and treatment of spontaneous SAH, most commonly due to aneurysmal rupture, headache in the immediate inpatient setting and persisting after discharge are an important cause of morbidity. These headaches often receive heterogenous treatment of uncertain efficacy, and the risk factors and pathophysiology of their development has received little study.

Methods: A narrative review of current literature discussing post-SAH headache was conducted using a literature search in PubMed with search term combinations including "post subarachnoid hemorrhage pain", "subarachnoid hemorrhage headache", and "post subarachnoid hemorrhage headache". Clinical studies mentioning headache after SAH and/or treatment in the abstract/title were included through March, 2022.

Results and conclusion: Post-SAH headaches are shown to decrease quality of life, have a multi-modal pathophysiology in their occurrence, and only a select few medications (reviewed herein) have been demonstrated to have efficacy in alleviation of these headaches, while also harboring possible risks including vasospasm and re-bleeding. An effective treatment paradigm of these headaches will include trials of evidence-based therapeutics, rapid reduction of opioid medications if not effective, and consideration of multi-modal pain control strategies including nerve blocks.