Hypertension as cause and consequence of renal disease in the 19th century.

The pioneering work of Richard Bright, who introduced the concept of the renal origin of cardiovascular disease, initiated the continuous unfolding of knowledge on renal disease and its close interrelationship with arterial hypertension in the 19th century. Hypertension as a clinically and pathologically defined entity, however, was not established. The partial elucidation of the problem that the diseased kidney was sometimes the cause and sometimes the consequence of elevated blood pressure is not only fascinating but also remarkable, given the crude techniques available to physicians at that time. Subsequent workers came to regard 'Bright's disease' as consisting of several conditions differing in clinical manifestation and pathology. In particular, Johnson and Gull and Sutton drew attention to the small blood vessels in renal disease. Only the invention of a clinically applicable method of measuring blood pressure indirectly allowed Mahomed and Allbutt to show that hypertension may occur in the absence of renal disease. They paved the way for a clear separation of hypertensive renal disease from other forms of 'Bright's disease', culminating in the classification introduced by Fahr and Volhard.