The Pathogenesis of Malignant Hypertension

Whether hypertension follows the benign or the malignant course depends chiefly on the severity of the hypertension. Malignant hypertension may develop in hypertension due to any cause, provided it is sufficiently severe. The evidence for this hypothesis is as follows: 1. The characteristic finding in malignant hypertension during life is albuminuric retinitis (hypertensive neuroretinopathy) which differs from the retinitis of benign hypertension (arteriosclerotic retinitis) in the presence of neuroretinal edema. This neuroretinal edema is due to raised intracranial pressure, which in turn seems to be a consequence of the high level of diastolic arterial pressure. 2. The characteristic finding in malignant hypertension after death is acute arteriolar necrosis, the occurrence of which in the kidneys is chiefly responsible for the rapid renal failure which is so often the cause of death. Evidence from animal experiments suggest that the chief factor determining these arteriolar necroses is the high level of arterial pressure. 3. Albuminuric retinitis, rapid renal failure and acute arteriolar necroses may occur in essential hypertension, acute and chronic nephritis, pyelonephritis, polycystickidney, Cushing's syndrome and toxemia of pregnancy; these conditions may terminate therefore in the malignant phase. Alternatively, the hypertension may be stable, and, provided the underlying disease is stationary, the patient's condition may remain unchanged for many years; the hypertension may thus have the characteristics of the benign type. 4. In patients whose hypertension changes from the benign to the malignant phase, it is usual to find that the arterial pressure is higher in the malignant than in the benign phase. 5. It has been proved tha thypertension can be reversed from the malignant to the benign phase by measures which reduce the arterial pressure. It would therefore seem correct to speak of the malignant phase of hypertension and to relate this to the underlying malady whether this be essential hypertension, pyelonephritis or the like. The diagnosis of the malignant phase of hypertension carries a single and urgent therapeutic implication, namely, the prompt and persistent lowvering of arterialpressure.