Maculopathy associated with combination chemotherapy and osmotic opening of the blood-brain barrier

Eleven patients with intracranial malignant neoplasms underwent hyperosmotic opening of the blood-brain barrier by rapid mannitol infusion via the internal carotid or vertebral artery. Cyclophosphamide was administered intravenously preceding the mannitol infusion and methotrexate was infused after the mannitol via the same artery. Both the mannitol and methotrexate delivered via the carotid artery have direct access to the ipsilateral choroidal and retinal circulations. In these patients, retinal pigment epithelial changes eventually developed ipsilateral to the carotid infusions. The changes probably represent the toxicity of intraarterial methotrexate possibly potentiated by mannitol-induced opening of the blood-retinal barrier. Functional visual loss was minimal and was not a limiting factor with this therapeutic modality.