Arterial hypertension is regarded frequently as a manifestation of chronic nephritis. In recent years, however, there is a growing belief that hypertension alone is not necessarily evidence of nephritis. Allbutt1 was among the first to recognize from clinical observations that hypertension may be present without nephritis; this condition he termed "hyperpiesis." Under the title "primary hypertensive cardiovascular disease," Janeway2 described the same disorder, while more recently Mosenthal3 and others have suggested the term "benign or essential hypertension." Krehl4 observed hypertension in a number of patients with other clinical symptoms not supporting the diagnosis of chronic nephritis. Gross and microscopic examination of the kidneys of one of these patients failed to reveal abnormal changes.
Until renal function was estimated by the phenolsulphonephthalein test and by the quantitative determination of the nonprotein nitrogen constituents of the blood, the evidence of the kidney disease obtained was chiefly anatomical or clinical. Mosenthal observed essential
WILLIAMS JL. THE TOTAL NONPROTEIN NITROGEN CONSTITUENTS OF THE BLOOD IN ARTERIAL HYPERTENSION. Arch Intern Med (Chic). 1921;27(6):748–754. doi:10.1001/archinte.1921.00100120119008