Background and purpose People with one or more first degree relative affected (FDRA) by aneurysmal subarachnoid haemorrhage (aSAH) are at a higher lifetime risk of an aSAH than those without a family history. Screening may be worthwhile for people with two or more FDRA by aSAH. Little is known about the characteristics of people with a family history of aSAH who undergo screening in clinical practice.

Methods Observational analysis of consecutive attendances at an intracranial aneurysm screening clinic.

Results Of 96 adults seen, 19 did not have a family history of aSAH and 77 had one or more FDRA by aSAH: 35 had two or more FDRA, 21 had one FDRA plus one or more affected second degree relative and 21 had one FDRA only. In these three respective groups, 29 (83%), 15 (71%) and five (24%) adults underwent screening, of whom six (21%), two (13%) and one (20%) had an aneurysm detected (p=0.5). Of the nine patients with aneurysms, four underwent treatment. Considering other risk factors, adults with two or more FDRA were more likely to be hypertensive (OR 3.3, 95% CI 1.0 to 10.8; p=0.046) but were no more likely to smoke or drink to excess than adults with one FDRA. Adults who underwent screening were more likely to be hypertensive and drink alcohol to excess (both p=0.03), but were no more likely to smoke than those who were not screened.

Conclusions In clinical practice, people undergoing intracranial aneurysm screening had stronger family histories of aSAH and they were also more likely to have modifiable risk factors for aSAH.