Types of Arterial Hypertension and Their Recognition
Although the most common cause of a consistent elevation in blood pressure is essential hypertension, there are a number of other pathologic states which are regularly attended by increased arterial pressure. Certain of these states are an established part of general medical knowledge; others are decidedly unusual, and one has been set aside as a distinct clinical entity only within recent years. Needless to say, it is of considerable importance that the hypertension of all these conditions be differentiated from the common type of elevated blood pressure. Fortunately, differential diagnosis usually is a simple matter, although in certain instances it may be impossible to arrive at a definite conclusion even after the most detailed clinical and laboratory studies. It will be our purpose in this communication to review the various causes of hypertension with particular reference to those features which are of value in distinguishing one type from another.
Essential hypertension is characterized by a continuous, though often variable, elevation of blood pressure in the absence of glomerulonephritis and other conditions known to cause increased arterial tension. The term must still be interpreted to indicate a symptom complex rather than a disease entity, and it is probable that as medical knowledge increases, distinct types of cases will be separated from the main group on the basis of specific etiologic factors. In essential hypertension both the systolic and diastolic blood pressure are increased. Tests of renal function, in the early stages, give normal results, but as time passes, a. . .