Neuro-Ophthalmologic Monitoring in the Management of Increased Intracranial Pressure From Leaking Arachnoid Cysts

Intracranial arachnoid cysts are common incidental imaging findings. They may rarely rupture, leading to the development of subdural hygromas and high intracranial pressure (ICP). Neurosurgical intervention has been advocated in the past, but recent evidence indicates that most cases resolve spontaneously. The role of neuro-ophthalmologic monitoring in identifying the few cases that have persisting vision-threatening papilledema that justifies intervention has not been emphasized. Retrospective review of 4 cases of leaking arachnoid cysts drawn from the files of the University of Michigan Medical Center (Michigan Medicine) between 2007 and 2018. In 1 case, surgery was avoidable as papilledema resolved over time despite lingering imaging features of mass effect. In 3 cases, papilledema persisted with the threat of permanent vision loss, prompting neurosurgical intervention. In one of those cases, the fluid collection was thinly but extensively spread across both hemispheres without brain shift; yet, papilledema was pronounced. Emergent evacuation led to rapid resolution of papilledema and encephalopathy, but with residual optic nerve damage. Because constitutional symptoms and even imaging are not always reliable indicators of high ICP in leaking arachnoid cysts, neuro-ophthalmologic monitoring of papilledema is valuable in identifying the cases when neurosurgical intervention is necessary.