If the swelling is untreated, it causes death by brain herniation.The brain swelling is likely a result of vasogenic edema, the penetration of the blood–brain barrier by fluids. This process has been observed in MRI studies. Hypoxia increases extracellular fluid, which passes through the vasogenic endothelium in the brain. The leaking may be caused by increased pressure, or it may be caused by inflammation that makes the endothelium vulnerable to leaking. An MRI study found microhemorrhages in the corpus callosum of HACE patients, and hypoxia may also cause microvascular permeability. It has been hypothesized that vascular endothelial growth factor may cause the vascular permeability at the root of HACE. MRI scans of patients with HACE showed increased T2 in the corpus callosum, although grey matter was unchanged. This demonstrated that the blood-brain barrier was broken by cerebral blood vessels, thus interfering with white matter metabolism. Another study looked at the brains of people with HACE several months after their recovery; it showed hemosiderin deposits in the corpus callosum, evidence of vascular permeability.While there is strong evidence that vasogenic edema plays a major role in HACE, cytotoxic edema, cellular retention of fluids, may contribute as well. Cytotoxic edema may be caused by the failure of cellular ion pumps, which results from hypoxia. Then intracellular sodium and osmolarity increase, and there is an influx of water that causes cellular swelling. After the failure of the ATPase pumps, free radicals form and cause damage that complicates the edema.
Iridodonesis () is the vibration or agitated motion of the iris with eye movement. This may be caused by lens subluxation, the incomplete or partial dislocation of the lens; or by aphakia, the absence of a lens. The term originated from irido- (Latin: iris) + doneo (Greek: δονεο, to shake to and fro). See also
Phacodonesis

References
External links
An example of iridodonesis on YouTube