KDR and Posterior Leukoencephalopathy Syndrome: In addition, hypertension caused by the anti-VEGFR drugs will damage the normal blood-brain barrier, resulting in extravasation of the fluid in to the brain parenchyma.[7,25] Cerebrovascular spasm may cause hypothalamic ischemia and hypoxia may also be another mechanism.[26] The mechanism that causes RPLS still needs further research.