A case of multiple intracranial aneurysms with unruptured associated aneurysms and newly developed ruptured aneurysm.

SUMMARY: We report a case of mirror aneurysms at the middle cerebral artery bifurcation with rupture on the left side. After six years, the patient had subarachnoid haemorrhage from a de novo aneurysm which developed separate from but adjacent to the already present aneurysm on the right side. The mechanism of development of multiple aneurysms, especially of the mirror-image type cannot be explained based only on haemodynamic factors and congenital segmental arterial vulnerability which is generalised than focal is highly likely. The sequence of development of aneurysms in this patient along with existing knowledge regarding rupture of aneurysms in conditions like polycystic kidney disease raise questions about the current trend of treating all patients with coincidental, unruptured aneurysms as they may never bleed from such aneurysms but could still be at risk of SAH from newly developing aneurysms.