Subarachnoid Hemorrhage

Burst Water Balloon in a Sealed Box

Imagine a garden hose (brain artery) running through a sealed cardboard box (skull) that's cushioned inside with bubble wrap soaked in water (cerebrospinal fluid in the subarachnoid space). The hose has a weak balloon bulge (aneurysm) from years of water pressure pushing on it. When the balloon finally pops, water sprays everywhere inside the box — the bubble wrap gets soaked and irritated, the box's internal pressure skyrockets because there's nowhere for the water to go, and the pressure crushes the cushioning material and everything inside. Meanwhile, the water's minerals start corroding the metal pipes (vasospasm from blood breakdown products), making them squeeze shut and choke off flow. The box's drainage holes (CSF pathways) get clogged with debris, trapping even more fluid inside and driving pressure higher until the whole system fails.