Hypertensive encephalopathy is a neurological dysfunction induced by malignant hypertension. The term "hypertensive encephalopathy" was introduced to describe this type of encephalopathy by Oppenheimer and Fishberg in 1928. It describes cerebral conditions, typically reversible, caused by sudden and sustained severe elevation of blood pressure. Hypertensive encephalopathy occurs in eclampsia, acute nephritis and crises in essential hypertension. Symptoms of hypertensive encephalopathy include headache, restlessness, nausea, disturbances of consciousness, seizures,  bleeding in the retina, and papilledema. Focal brain lesions may be associated with specific neurological symptoms. These neurological impairments may culminate in a coma. The condition is treated by drugs that decrease blood pressure.