Cerebral oedema, or fluid accumulation in the cranial cavity occupied by the brain, becomes more of a risk at altitudes greater than 4,300m.

This generates excess fluid accumulation in the body.

Fluid accumulation interferes with gas exchange, and can cause the alveoli to fill with proteins and collapse due to edema and bleeding.

A blockage between the brain and the spinal cord prevents the fluid accumulation from leaking out.

Colloquialism for fluid accumulation around the knee joint.