In this female patient who presented with subarachnoid hemorrhage, CTA shows two aneurysms arising from anterior communicating artery and basilar artery tip.

Intracranial aneurysms are multiple in 10-30% of all cases.About 75% of these cases have 2 aneurysms, 15% have 3, and 10% have more than 3.

Multiple aneurysms can be bilaterally symmetric (mirror aneurysms) or located asymmetrically on different vessels. More than one aneurysm can be present on the same artery.

A strong female predilection is observed.
Predisposing diseases include:
– Polycystic kidney disease
– Fibromuscular dysplasia
– System lupus erythematosus
– Ehlers-Danlos syndrome
– Coarctation
– Cerebral AVM

References:
1. Emedicine; 2007 : Cerebral aneurysms.
2. Dahnert; 2003 : Radiology Review Manual, Lippincott, Williams & Wilkins.
3. Osborn 1994: Diagnostic Neuroradiology. Mosby.

Credit: Dr Ahmed Haroun