Pyelonephritis as a cause of hypertension.

E VIDENCE that pyelonephritis is a remote if not a proximal cause of hypertension is very great. This conclusion is based upon observations which can be listed in six general categories. 1. The emergence of hypertension during the clinical course of pyelonephritis.‘-3 2. The frequency of hypertension in the pyelonephritic population.3s4*13 3. The frequency of pyelonephritis in the hypertensive population.4*5 4. The precipitation of hypertension in pregnancy by pyelonephritis and its reversal by treatment of the pyelonephritis6 5. The disappearance of hypertension following removal of a unilaterally pyelonephritic kidney.7 6. The unusual but occasionally reported amelioration of hypertension following medical treatment of pyelonephritis. Lacking in this chain of evidence is the ability to produce hypertension in animals in whom pyelonephritis has been deliberately induced.” Most observers reporting studies of this sort feel that the interstitial nephritis and other histologic manifestations of human pyelonephritis are quite easily reproduced, but characteristically animals do not become hypertensive.3 It is also widely appreciated that many patients with pyelonephritis may come to autopsy in uremia without having been significantly hypertensive.i7 Hypertension During Clinical Course of Pyelonephritis: Perhaps the best description of the emergence of hypertensive disease during the clinical course of pyelonephritis is in the original reports of Weiss and ParkerIe in which the importance of the relationship was clearly described. They present two casts of normotensive individuals developing hypertension over many years. They also stress how the manifestations of hypertensive disease supercede those of chronic urinary tract infection as the clinical course of the two diseases unfolds. This observation helps explain why pyelonephritis may be occult in many hypertensive persons. In women, particularly, minor episodes of bladder irritation are taken so much as a matter of course that infection may establish itself in the urinary system without impressing its presence upon the patient. The recent demonstration that eight of thirty traced patients who had been treated for acute pyelonephritis had bacteriuria, and that five of the eight were asymptomati? gives one insight into the origin of those instances of silent pyelonephritis in patient who present with preterminally severe hypertension. In the hypertensive phase of the illness the pyelonephritis often is silent. In an unpublished study of renal biopsies in patients with hacteriuria and pyelonephritis, twelve of twentyfive patients with bacteriuria who also had hypertensive disease showed definite evidence of histologic pyelonephritis upon kidney biopsy.‘O In ten of these twelve the bacteriuria was asymptomatic. Seven of twenty-six biopsies from normotensive patients with Ijacteriuria showed histologic evidence of pyelonephritis, and of these seven only two were asymptomatic. Because percutaneous renal biopsy retrieves a random sample of kidney-, this suggests that the pyelonephritic process is more widespread and less focal in those patients with hypertension than in the normotensive. Thus the appearance of hypertension in the usual pyelonephritic patient is indicative of fairly widespread and diffuse involvement of the kidney. From the data of Grieble and .Jackson4 comes the inference that without great reduction of renal mass one cannot conclude that a given patient’s pyelonephritis is the cause of his hypertension. Hypertension in Pyelonephritic Population: From almost all studies of large series of cases of pyelonephritis emerges the fact that hypertensive disease is a major clinical manifestation of this form of renal disease.3t4a’3 Brod13 found 60 per cent of one hundred and thirty-two