19th February 2024

A 32-year-old female presents with a sudden headache that was worst along her occiput, associated with nausea and vomiting.

A 32-year-old female presents with a sudden headache that was worst along her occiput, associated with nausea and vomiting. She became progressively more confused while she was home. She is currently unable to provide a coherent history. She is agitated on examination, and anisocoria is noted. 

A CT brain has shown hyperdense regions within the basal cisterns and ventricular system enlargement.

Which structures have likely contributed to the ventricular system’s enlargement?