Pretruncal subarachnoid hemorrhage and high cerebral blood flow velocities with bevacizumab therapy.

We describe the case of a 55-year-old woman with metastatic colorectal cancer, treated with bevacizumab, who developed sudden occipital pain, with nausea, vomiting, mild confusion, and signs of meningeal irritation. Imaging studies (computed tomographic scan and magnetic resonance imaging) revealed a pretruncal subarachnoid hemorrhage without an underlying vascular malformation; transcranial Doppler carried out 24 hours after the clinical onset showed increased blood flow velocities, mainly in the right middle cerebral artery. The neurological and hemodynamic alterations resolved with medical treatment within 10 days. Bevacizumab is a humanized monoclonal antibody that inhibits the vascular endothelial growth factor. The potential role of anti-vascular endothelial growth factor treatment on the subarachnoid hemorrhage and increased cerebral blood flow velocities is discussed.