{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T13:09:01Z","timestamp":1780664941413,"version":"3.54.1"},"reference-count":20,"publisher":"BMJ","issue":"6","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2026,5,5]]},"published-print":{"date-parts":[[2026,6]]},"abstract":"<jats:p>Blood blister-like aneurysms (BBAs) are rare, fragile vascular lesions most commonly arising from non-branching segments of the internal carotid artery. Basilar artery BBAs are exceptionally uncommon and present significant diagnostic and management challenges. We report the case of a woman in her late 50s who presented with sudden-onset occipital headache, neck stiffness, and subarachnoid haemorrhage. Digital subtraction angiography identified a 3 mm blister-like aneurysm in the basilar artery, considered the presumed culprit lesion, along with an incidental basilar artery fenestration. Endovascular flow-diversion was recommended; however, the patient declined intervention after informed counselling and was managed conservatively with intensive neurocritical monitoring. The patient recovered without residual neurological deficit. This case highlights the diagnostic overlap between aneurysmal and perimesencephalic subarachnoid haemorrhage, the importance of careful vascular imaging, and the management challenges posed by rare posterior circulation BBAs and associated vascular variants.<\/jats:p>","DOI":"10.1136\/bcr-2025-268504","type":"journal-article","created":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T12:25:11Z","timestamp":1780662311000},"page":"e268504","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Basilar artery blister aneurysm presenting with subarachnoid hemorrhage: management challenges in the context of basilar artery duplication"],"prefix":"10.1136","volume":"19","author":[{"given":"Insha","family":"Aleena","sequence":"first","affiliation":[{"name":"Department of Neurology, Apollo Multispeciality Hospitals Kolkata, Kolkata, West Bengal, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7606-6135","authenticated-orcid":false,"given":"Venkata Sai Bhargav Pradeep","family":"Konakanchi","sequence":"additional","affiliation":[{"name":"Acute Internal Medicine, Sandwell and West Birmingham Hospitals NHS Trust, Birmingham, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sakshi","family":"Puri","sequence":"additional","affiliation":[{"name":"Department of Neurology, Apollo Multispeciality Hospitals Kolkata, Kolkata, West Bengal, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Manoj","family":"Mahata","sequence":"additional","affiliation":[{"name":"Department of Neurology, Apollo Multispeciality Hospitals Kolkata, Kolkata, West Bengal, India"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,6,5]]},"reference":[{"key":"2026060505250793000_19.6.e268504.1","doi-asserted-by":"publisher","DOI":"10.3171\/JNS\/2008\/108\/4\/0662"},{"key":"2026060505250793000_19.6.e268504.2","doi-asserted-by":"publisher","DOI":"10.3174\/ajnr.A4606"},{"key":"2026060505250793000_19.6.e268504.3","doi-asserted-by":"crossref","first-page":"387","DOI":"10.1016\/j.radcr.2020.01.009","article-title":"Basilar trunk artery aneurysm presenting with brainstem stroke","volume":"15","author":"Kavak","year":"2020","journal-title":"Radiol Case Rep"},{"key":"2026060505250793000_19.6.e268504.4","doi-asserted-by":"crossref","first-page":"1747","DOI":"10.3174\/ajnr.A0654","article-title":"Aneurysms of the vertebrobasilar junction: incidence, clinical presentation, and outcome of endovascular treatment","volume":"28","author":"Peluso","year":"2007","journal-title":"AJNR Am J Neuroradiol"},{"key":"2026060505250793000_19.6.e268504.5","first-page":"163","article-title":"Basilar trunk perforator artery aneurysms","volume":"36","author":"Gross","year":"2013","journal-title":"Case Report and Literature Review Neurosurg Rev"},{"key":"2026060505250793000_19.6.e268504.6","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejrad.2013.09.017"},{"key":"2026060505250793000_19.6.e268504.7","doi-asserted-by":"crossref","DOI":"10.1186\/s41016-021-00245-1","article-title":"The formation mechanism of acute dissection of blood blister-like aneurysm and its implication of endovascular treatment","volume":"7","author":"Ye","year":"2021","journal-title":"Chin Neurosurg J"},{"key":"2026060505250793000_19.6.e268504.8","doi-asserted-by":"crossref","first-page":"595","DOI":"10.1016\/j.wneu.2017.09.054","article-title":"Characteristics of Blood Blister-Like Aneurysms with a Saccular-Shape Appearance","volume":"108","author":"Nishikawa","year":"2017","journal-title":"World Neurosurg"},{"key":"2026060505250793000_19.6.e268504.9","doi-asserted-by":"crossref","unstructured":"Raz E , Koneru S , Nossek E , et al . Basilar artery perforator rupture as the cause of perimesencephalic subarachnoid hemorrhage. J Neurosurg 2026;1\u20137. doi:10.3171\/2025.8.JNS251169","DOI":"10.3171\/2025.8.JNS251169"},{"key":"2026060505250793000_19.6.e268504.10","unstructured":"Adigun OO , Reddy V , Sevensma KE . Anatomy, head and neck: basilar artery. In: StatPearls. 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