Norman M. Simon

Hemodynamic Studies in Chronic Uremia

Hemodynamic functions and blood volume were observed in patients with chronic uremia. Thirty-one patients had clinical features of circulatory congestion and 37 did not. The degree of anemia and acidosis was comparable in both groups. However, creatinine clearance was significantly lower in patients with circulatory congestion. Both groups of patients had greater blood pressure, heart rate, plasma volume, and total peripheral resistance than normal. Resting cardiac output was abnormally decreased in 19% of the patients with circulatory congestion and in 14% of patients without features of circulatory congestion. There was no correlation between blood volume and blood pressure. Intravenous digitalization of seven of the patients with circulatory congestion produced clinical and hemodynamic improvement in only two. Hemodialysis effected an increase in cardiac output and a decrease in total peripheral resistance in six patients with congestion. In seven patients without circulatory congestion after dialysis there was a fall in plasma and blood volume, associated with a slight decrease in cardiac output. It is suggested that congestion of the circulation in chronic uremia results from a variety of hemodynamic, myocardial, and metabolic alterations, rather than from any single abnormality.

Renal-Pressor Hypertension Secondary to Unilateral Hydronephrosis

Abstract In a patient with hypertension temporally related to unilateral hydronephrosis the kidney disorder appeared to be a complication of abdominal pregnancy. Renal arterial disease and urinary-tract infection were excluded as contributing causes for the hypertension. Renal-vein catheterization demonstrated greatly increased activity of the renin-angiotensin system in the kidney affected by hydronephrosis. Corrective ureteral surgery resulted in cure of hypertension, with restoration of normal renal pressor activity. Early diagnosis and treatment are common factors shared by this case with the few reported cases in which hypertension associated with hydronephrosis has been alleviated by surgery.

Persistent Nephrogenic Diabetes Insipidus after Lithium Carbonate

Excerpt Lithium salts are effective in the management of manicdepressive psychosis. The margin of safety with their use is low so that significant side-effects may occur even when blood levels are ...

Thrombelastography of blood from subjects with chronic renal failure.

Blood samples from 23 subjects with chronic renal failure and 19 controls were tested using thrombelastography and other hematologic tests. The uremic subjects were divided into two groups, those who had not yet begun maintenance hemodialysis treatments (12 subjects) and those who had (11 subjects). Compared to those from control subjects, the thrombelastograms from the uremic subjects consistently indicate normal clotting times but significantly elevated amplitudes. The increased amplitudes correlate positively in the dialyzed uremic group with both platelet count and fibrinogen concentration and correlate negatively in both uremic groups with hematocrit. Thrombelastography demonstrates a hypercoagulability in these samples in vitro, despite the prolonged bleeding time that commonly occurs in uremic subjects.

Streptococcal infections and epidemic acute glomerulonephritis in South Trinidad

Streptococcal cultures and antibody studies of patients during an epidemic of nephritis in Trinidad, W. I., provided evidence of a streptococcal etiology associated with impetiginous sores. Similar studies of “well” schoolchildren throughout the year revealed high incidences of sores and of streptococci in areas both with and without nephritis. The relation of these infections to antibody responses and to renal disease is considered but not completely defined.

Kidney Function after Renal Revascularization for Hypertension

Kidney function was evaluated in 53 patients with renal arterial hypertension before and after renal revascularization and was correlated with changes in blood pressure. Data were derived from an analysis of personal observations and of findings reported by others.Revascularization produced a significant decrease in blood urea nitrogen and serum creatinine in 13 azotemic patients. It did not significantly affect glomerular filtration rate when normal in 20 patients, but caused a rise in renal blood flow in three patients. Improvement in renal function was more closely correlated with preoperative functional status than with cure of hypertension.Glomerular filtration rate and renal blood flow increased significantly in the revascularized kidney, but decreased in the contralateral kidney. Urine flow and sodium concentration in the revascularized kidney rose to levels equal to, or greater than, those in the contralateral kidney. The preoperative disparity in urine osmolality between kidneys was narrowed, whereas the concentration of nonresorbable urine solute became equal to, or lower than, that of its mate postoperatively. In most cases, the Howard test reverted to negative. The tubular rejection fraction ratio of sodium became normal or suggested contralateral renal arterial disease. The only functional differences between patients whose hypertension was cured and those whose blood pressure failed to respond to revascularization related to glomerular filtration rate and the Howard test.Impairment of function of the contralateral uninvolved kidney was rarely observed after surgery. The revascularized kidney frequently exhibited excessive natriuresis and diuresis, independent of changes in systemic blood pressure or glomerular filtration rate.

Serum Renin Activity in Human Renal Homotransplantation

Serial determinations of serum renin activity (RA) have been made in 19 patients recipient of 21 allografts. Five patients received kidneys from 4 related and from 1 unrelated living donors; 13 patients received allografts from 15 adult cadavers, and 1 from an anencephalic newborn. During the first post transplant month observations were made in 18 recipients. RA was found increased transiently in 7 and persistently in 10 recipients. The increase in RA was associated with acute tubular necrosis, 5; occlusive vascular lesions of the graft artery or its branches and infarction of the graft, 4; cortical necrosis, 2; and acute rejection, 3. In 2 recipients no apparent cause for the rise in RA could be found, and in 1 the increase was probably related to diuretic therapy. During the late post transplant period, from 2 months to 2 years and 8 months, observations were made in 10 recipients. RA remained increased in 2 recipients with occlusive vascular lesions and rejection of the allograft, respectively. In 6 other recipients RA increased in association with rejection, 4; development of graft artery stenosis, 1; and diuretic therapy, 1. In 2 recipients with uneventful course RA remained normal. There was no statistically significant correlation between changes in RA and endogenous creatinine clearance, or body weight. However, there was a significant negative correlation between RA and sodium excretion, and a small positive correlation between RA and diastolic blood pressure.

Pressor Response to Angiotensin II in Hypertension Correlation with Plasma Renin Activity and Response to Norepinephrine and Metaraminol

Abstract The pressor response to angiotensin II infused intravenously was studied in 8 normal subjects and 44 patients with primary and secondary hypertension. The mean dose of angiotensin II required to increase diastolic blood pressure by 20 mm. Hg was significantly lower in 24 patients with essential hypertension than in control subjects and 11 patients with renovascular hypertension. Mean plasma renin activity in peripheral venous blood was similar in control subjects and patients with essential hypertension and significantly higher in patients with renovascular hypertension. The pressor dose of angiotensin II was directly correlated with peripheral plasma renin activity. However, norrnotensive control subjects and patients with essential hypertension with similar values of plasma renin activity exhibited markedly different sensitivity to angiotensin II. Further, the pressor response to norepinephrine and metaraminol paralleled that to angiotensin both in patient groups and in individual cases. The results suggest that the pressor response to angiotensin II in hypertensive patients is related not only to the level of circulating endogenous angiotensin but also to nonspecific hyperreactivity in essential hypertension and nonspecific hyporeactivity in renovascular hypertension.

Maintenance dialysis for diabetic nephropathy with uremia.

Abstract Fourteen patients, aged 28–61 yr, with diabetic nephropathy and uremia were observed on maintenance dialysis for a total of 156.5 dialysis patient months (range: 1.5–30 months per patient). Clinical course on dialysis was eventful in most cases, though nitrogen retention and acidosis were readily controlled. Bouts of circulatory congestion and severe fluid retention were frequent in nine patients, six of whom died of acute myocardial infarction or intractable heart failure. Septic complications and hepatitis caused or contributed to the demise of four patients, and thromboembolic complications to that of one patient. Rehabilitation on dialysis was limited in nine cases, and five remained disabled. Retinopathy was not improved. Emotional problems were common in nine patients, five of whom required psychiatric care. Ten patients died between 1.5 and 21 months after the start of dialysis, and only one survived over 30 months. Three patients underwent renal transplantation 6 to 18 months after inception of dialysis. They all died 10 days to 3 months after surgery of overwhelming septic complications. Survival rate on maintenance dialysis for the whole group was 54.8 per cent at 1 yr, and 16.4 per cent at 2 yr.

Proximal Renal Tubular Dysfunction in Severe Burns

Proximal renal tubular function was studied in 11 patients with severe burn injury. Creatinine clearance was normal or increased in ten patients. Fractional excretion of sodium was less than 1% in ten. Fractional excretion of uric acid and amylase were increased in all but four and two cases, respectively, while absolute clearances of lysozyme and beta 2-microglobulin were increased in all but one patient. Renal threshold phosphate concentration was reduced in four patients. Twenty-four-hour urine glucose excretion exceeded 1 g in five patients, aminoaciduria was noted in eight, and proteinuria, predominantly globulinuria, was present consistently. Metabolic acidosis was seen in one patient, and transient hypokalemia occurred in two. Abnormalities of proximal tubular function were more marked in the five patients with the greatest extent of third-degree burns who died. The cause of proximal tubular dysfunction is not clear and may be related to an adaptive response to severe injury.