The diagnosis essential hypertension

The prevalence of secondary and curable hypertension

The prevalence of secondary and curable hypertension was studied retrospectively in 1000 patients. The concept of "secondary hypertension" was used when hypertension was combined with a disease which may have affected the individual's blood pressure. When this definition was applied, 47 of the patients displayed some form of secondary hypertension: stenosis of the renal artery in 10, renoparenchymal disease in 21, hydronephrosis in 3, and endocrine hypertension in 13 (8 of the latter were using oral contraceptives). The blood pressure normalized in 11 and improved in 7 of these patients after operative treatment of the underlying disease or, when appropriate, discontinuance of intake of contraceptive pills. The incidence of secondary hypertension in this and other series is low, and the number of patients with curable hypertension is even lower. In the majority of cases, secondary hypertension can be diagnosed by anamnesis, physical examination and simple tests of blood and urine. If this basic investigation can be extended, the incidence of stenosis of the renal artery should be examined in the first place. Hypertension in young patient and in patients who are difficult to treat often justifies a more extensive investigation.

Secondary hypertension in a medical ward

The prevalence of secondary hypertension was evaluated by investigating 400 consecutive patients with arterial hypertension in a medical ward. They were classified into four groups according to the case history. Group A: 104 subjects with therapy-resistant hypertension, group B: 247 patients who had another concomitant disease as the primary reason for admission, group C: 34 patients referred to the ward for basic investigation due to recently diagnosed hypertension, group D: 15 patients with unwanted hypertension was 15.5% in the entire series, and 14.4%, 18.6%, 2.9% and 0% in groups A - D, respectively. Ten patients (2.5%) were operated on, nine of them from group A and one from group B. The findings demonstrate the importance of a careful examination of patients with therapy-resistant hypertension, since they might include subjects whose hypertension can be treated by surgery.

The frequency of secondary hypertension

In a series comprising 482 patients with hypertension requiring treatment 79 percent had to be classified as essential hypertension. Bilateral renal disease was found in 9 percent, unilateral renal disease in 3.3 percent, but only one patient underwent surgery. Renal artery stenosis was found in 24 patients (5 percent), but only 5 (1 percent) were operated on. Two cases of primary hyperaldosteronism and one of phaeochromocytoma were found; in all three surgical intervention was successful. Oral contraceptives had caused the elevated BP in 7 patients (1.5 percent). It is emphasized that the frequency of curable hypertension is still very low and this should be taken into account when routine examination of patients with hypertension requiring treatment is discussed.