Cerebral Cavernous Malformation Bleeding Following Cerebrospinal Fluid Diversion Surgery: A Case Report and Literature Review.

Cavernous malformations (CM) are rare intracerebral vascular lesions occurring in the brain, or less commonly in the spine, with an annual bleeding risk of up to 1.1%. These lesions can be occult or present to signs and symptoms based on location or, more frequently, are a result of hemorrhagic events. The most challenging aspect of managing these cases is weighing the risks and benefits of surgical treatment and intervening before the onset of a devastating hemorrhagic event. Here, we present the second case of CM haemorrhage following the cerebrospinal fluid (CSF) diversion procedure with a literature review of theories explaining this phenomenon. We present a 37-year-old female who has a known case of brainstem cavernoma and underwent left sub-temporal resection with stable residual since 2011, then was managed conservatively due to patient preference till she had a deterioration in December 2021 manifested as confusion, diplopia, dysarthria, and significant left sided weakness leaving her wheelchair bound. CT showed supratentorial hydrocephalus with extensive periventricular transependymal edema and no clear haemorrhage. A ventriculoperitoneal (VP) shunt was inserted, with no intraoperative complications. A few hours post-VP shunt insertion, she experienced a worsening in her mental status, hemiparesis, and dysarthria. Subsequent imaging found evidence of acute haemorrhage in the location of the previously noted residual. She was managed by supportive care. Causative factors of CM haemorrhage are poorly understood, and current data only suggest that prior haemorrhage and CM location could increase bleeding risk. Only one case of CM bleeding post-shunt insertion was reported; however, studies on other types of intracranial vascular lesions suggest that alterations in transmural pressure (including cerebrospinal fluid diversion procedures) can increase the risk of haemorrhage by changing the hemodynamic flow in these abnormally formed and weak vascular structures.