Spontaneous Intracranial Hypotension Masquerading as Headache from an Unruptured Middle Cerebral Artery Aneurysm

Spontaneous intracranial hypotension (SIH) is characterized by neurological symptoms resulting from cerebrospinal fluid leakage or volume depletion. Although orthostatic headache is the hallmark symptom, SIH can also present with nausea, vomiting, dizziness, tinnitus, and other neurological symptoms. In this case, a cerebral aneurysm identified during evaluation of the headache was initially considered a potential cause, prompting a decision to treat it. However, an orthostatic headache severe enough to interfere with standing or physical activity had been overlooked. After a pre-existing subdural effusion was identified, the evolving orthostatic features of the headache and the imaging findings raised suspicion of SIH. The headache resolved after a lumbar epidural blood patch. Although a cerebral aneurysm is a potential cause of headache, SIH may be difficult to recognize early. Careful history taking, particularly about the characteristics and postural nature of the headache, is therefore essential to appropriately evaluate patients with headache.