Acute renal failure due to nephrotoxins

Crush syndrome: a report of 2 cases and a review of the literature

The crush syndrome was first defined as a clinical entity in 1941. This paper reports 2 patients suffering from the syndrome as a result of being trapped for several hours during the Moorgate tube train disaster. An account of the initial course, management and complications is presented and discussed with reference to the available literature on the subject.

Normal renocortical blood flow in experimental acute renal failure

Renal cortical blood flow of rats with postischemic, myohemoglobinuric, and mercury-induced acute renal failure was measured by the hydrogen washout technique using implanted platinum electrodes. Total renal blood flow was determined by venous cannulation in separate series of rats. The values obtained with the two methods were in excellent qualitative agreement (r=0.99, P less than 0.001), although venous cannulation gave values that were constantly lower than those calculated for whole kidney from the cortical flow rate and assumed cortical mass. Myohemoglobinuria produced by glycerol injection caused cortical blood flow to fall from a control value of 7.37+/-0.23 (SEM) ml/min X g of cortex to approximately one-half that value for four hours after injection (P less than 0.001). Flow rates 12 and 24 hr after glycerol injection were 85% (P less than 0.001) and 90% (P less than 0.05) of control, respectively. Cortical flow was reduced to 5.49+/-0.39 (SEM) ml/min X g of cortex four hours after release of one hour's total bilateral renal arterial occlusion (P less than 0.001), but rose to normal within 24 hr. Poisoning with 4.7 mg/kg of body wt of mercuric chloride produced a cortical blood flow value that was 30% higher than control 24 hr after injection (P less than 0.01), while a 12 mg/kg of body wt dose gave a normal flow value. Inulin clearance was severely depressed in all models at all study times. Thus, in contrast to human acute renal failure, marked renal cortical ischemia is not an essential feature of these different forms of murine acute renal failure.

Intra- and extrarenal vascular changes in the acute renal failure of the rat caused by mercury chloride

Histologic evidence of intrarenal vasomotor changes were observed in the rat in the course of acute renal failure caused by the injection of HgCl2. Male Wistar rats injected s.c. with 2.5 or 4.7 mg HgCl2 per kg b. wt. developed fibrinoid damage in the media segments of preglomerular renal vessels, mostly in the arcuate and interlobular arteries. The lesions were patchy and irregularly scattered throughout the kidneys. 24 h post-injection the lesions were very rare and of only mild degree, whereas they were fully developed and regularly seen 48 h post-injection. A high percentage of similar changes was found in certain extrarenal vascular areas especially in the mesentery and pancreas. The damaged vascular segments were usually dilated. The results of various thichrome stains and histochemical reactions suggested edema of vascular smooth muscle cells and imbibition of the media by blood plasma substances, sometimes reaching the degree of fibrinoid necrosis. These findings were confirmed by electron microscopy. The imbibition of the smooth muscle cells by blood plasma material was clearly evidenced by the demonstration of intracellular fibrin precipitations. In connection with the degeneration of smooth muscle cells, accumulations of crystal-like fibrin formations could often be shown. Subendothelial fibrin formations were not observed. 96 h after the 2.5 mg injection the changes were already regressing, but edema of the vascular wall and signs of disturbed vasotonia persisted for several days. The maximum of the vascular changes usually coincided with the maximum of azotemia and the formation of debris cylinders in the renal tubules. However, no clear relationship was recognizable in individual cases between vascular damage, extent of tubular necrosis and renal function. The pathogenesis of the vascular changes is obscure, but neurogenic factors, increased release of catecholamines and/or vasoactive agents of renal origin in connection with other factors might play a decisive role. Arterial hypertension was absent. It is assumed that the structural damage of the vascular media is mainly brought about by prolonged or recurring vasospasms, or by alternating spasm and vasodilatation with local ischemia and increased tension of the vascular wall in the dilated segments. The altered function and structure of the vascular wall might, to a certain extent, contribute to renal insufficiency.

Renal hemodynamics in uranyl acetate-induced acute renal failure of rabbits

The role of renal hemodynamic alterations in the curtailment of renal function was studied in rabbits with uranyl acetate-induced acute renal failure. The day following the i.v. injection of uranyl acetate (2 mg/kg of body wt), renal blood flow (RBF) and clearance of creatinine (Ccr) decreased to approximately 60 and 20% of controls, respectively. Intracortical fractional flow distribution, estimated by radioactive microsphere method, did not change. The extraction ratio of para-aminohippurate (EPAH) decreased and the renal extraction of sodium (CNa/Ccr) increased, with minimal structural change in the kidney. Urine output increased to two to three times that of the control. After three days oliguria appeared despite complete recovery of RBF. The zonal flow redistributed toward the deep cortex. CCr and EPAH reached their minimums, concomitantly with tubular necrosis and intratubular casts. After seven days animals could be divided into the oliguric and diuretic groups. CCr and EPAH were higher in the diuretic group, while there was no significant difference in RBF and the flow distribution between groups. Regeneration of damagee tubular cells was found in the diuretic group but not in the oliguric group. The findings suggest the minor roles of RBF and the intracortical flow distribution, and a fundamental role of back leakage of filtrate across damaged tubular epithelium in the maintenance of reduced CCR and urine output during the oliguric stage in rabbits with uranyl acetate-induced renal failure.

Effects of transient hypotension on the structure and function of rat kidney

The immediate effects of renal structure and function of 60 or 90 min of hypotension and the effects of one to four days of recovery were studied in the rat. An initial diuresis occurred during the first day after hypotension, followed by decreased urine volumes. Along with the diuresis, the animals secreted a hypo-osmolar urine for two days following hypotension, which returned to a normal concentration at three days. Twenty four hour urine sodium excretion was depressed during the first and second days after hypotension while potassium excretion was no different from that of control animals. The morphologic alterations of tissue fixed immediately following 60 and 90 min of hypotension were greatest in the pars recta of the proximal tubule but were also seen focally in the pars convoluta. The cellular changes included dilated endoplasmic reticulum clumped nuclear chromatin, swollen mitochondria with small flocculent densities, and the formation of multivesicular bodies. One day after the hypotension, death cell and necrosis were observed extensively in the pars recta. This study describes an experimental model for the study of the renal effects of hypovolemic shock in rats.

Irreversible acute renal failure in idiopathic nephrotic syndrome

In five adult patients (aged 44 to 74 years) with idiopathic nephrotic syndrome, irreversible acute renal failure developed. Prior renal disease, associated systemic illness or occlusion of major renal vasculature was not present. All patients continued to excrete large amounts of proteins (8.6 to 15 g/24 hours) despite a minimal glomerular filtration rate and severe oliguria. One patient died after five months without recovering renal function. Four patients have required hemodialysis for a period of 12 to 58 months. The failure to recover renal function could not be explained by the light microscopic findings. It is suggested that the irreversibility of the renal failure may be related to either permanent alterations in renal blood flow or ultrastructural changes, or to both. Clinically, adult patients in whom acute renal failure develops during the course of idiopathic nephrotic syndrome seem to have a grave prognosis. Protracted oliguria or irreversible renal failure can be expected to occur.

Assessment of intrarenal perfusion with radioxenon: a critical review of analytical factors and their implications in man

Radioxenon has achieved wide use for assessing tissue perfusion. Here we review its application to the kidney for assessing mean blood flow and intrarenal perfusion rates. Correlation with alternative methods in animals suggests that the initial disappearance slope provides an adequate measure of mean renal blood flow despite the theoretical limitations of this approach. The stochastic method and compartmental analysis can also provide an acceptable measure fo mean renal blood flow, but only after the slowest flow components have been removed. Compartmental analysis does, however, provide an index of cortical perfusion not available from other methods. The evidence that the rapid component of xenon washout provides an index of cortical perfusion in man is reviewed, along with insights gained from the application of this approach to human disease.

Renal cortical blood flow in glycerol-induced acute renal failure in the rat

Renal hemodynamics and renal function were evaluated in rats at 3, 24, and 48 hours and at 7 days after the induction of acute renal failure (ARF) by glycerol injection. Three hours after induction of ARF, creatinine clearance was 0.04 ml/min/100 g; renal blood flow (RBF), 1.99 ml/min/100 g; and filtration fraction, 3.7%. All were abnormally low. Although the administration of isotonic saline (total dose, 3% of body weight) to rats 3 hours after glycerol injection significantly improved creatinine clearance (0.17 ml/min/100 g), RBF (2.54 ml/min/100 g), and filtration fraction (12.9%), these values still were significantly lower than those of controls (creatinine clearance = 0.50 ml. ml/min/100 g, RBF = 4.92 ml/min/100 g, filtration fraction = 20.0%, all P values less than 0.001). Serum creatinine concentrations were significantly elevated at 24 hours (3.72% gm/100 ml), 48 hours (4.69 mg/100 ml), and 7 days (0.66 mg/100 ml) after glycerol injection compared to control (0.46 mg/100 ml, all P less than 0.01). RBF during these phases was not different from normal (4.41 ml/min/100 g). RBF 3 hours after bilateral ureteral obstruction was measured to determine the effects of tubular obstruction on renal hemodynamics. The RBF of rats with ureteral obstruction (4.12 ml/min/100 g) was not significantly different from controls (4.41 ml/min/100 g), suggesting that tubular obstruction in this model of ARF is probably not the cause of decreased RBF. The depressed glomerular filtration, as reflected by the decreased creatinine clearance that occurs during glycerol-induced ARF, is probably related to altered intrarenal vascular resistance or to changes in glomerular capillary permeability, or both.

Angiography in epidemic nephropathy

Nephroangiography has been performed in 35 patients with epidemic nephropathy during the course of the renal lesion phase. In addition to enlarged kidney with thickened cortex, generalized renal vasodilatation was demonstrated in the majority of the cases, frequently combined with rapid circulation. Thus, contrary to previous assumptions, acute oliguric renal insufficiency may also occur in cases with peripheral renal vasodilatation. The angiographic appearance of epidemic nephropathy was characteristic and most evident in the oliguric and anuric phases. Nephroangiography in acute oliguric renal failure may thus be of value for the differential diagnosis and thereby influence the clinical management of the patient.

The mechanism of action of mercuric chloride on the isolated perfused rat kidney

Studies on 80 rat kidneys, perfused at constant flow, showed that mercuric chloride produced a marked increase in perfusion pressure within five minutes of administration. Adrenergic blocking agents (phentolamine and propranolol), angiotensin sensitivity depletion, bradykinin and low concentrations of mannitol had no effect on this increase in resistance. Perfusion of the kidney with 5 percent mannitol solution, however, significantly reduced the increase of vascular resistance induced by mercuric chloride. Evidence is presented that mercuric chloride may evoke an increase in vascular resistance by inducing endothelial cell swelling, an action antagonised by the hypertonic effect of mannitol. Other possible contributory mechanisms are also discussed.

Effect of intrarenal furosemide on renal function and intratenal hemodynamics in acute renal failure

The ability of short-term furosemide administration to alter intrarenal hemodynamics and to modify the clinical course of acute renal failure was assessed in six patients 2 to 9 days after the onset of acute renal failure. Following renal arterial catheterization, the intraarterial administration of furosemide at a dose of 9.6 mg/min for 30 minutes failed to improve renal function as assessed either by an increase in urine output or a decrease in serum creatinine during the 4 days after administration in the five oliguric patients. In a sixth patient with nonoliguric acute renal failure, urine volume increased with a gradual decrease in blood urea nitrogen and creatinine during the week after study. Furosemide failed to alter either mean renal blood flow or its intrarenal distribution as determined at intervals of 3 to 40 minutes after its infusion. These studies demonstrate that the short-term administration of furosemide in large doses does not improve renal hemodynamics or alter the clinical course of patients with established acute oliguric renal failure.

Renal blood flow in acute epidemic nephritis (nephropathia epidemica of Scandinavia)

Different haemodynamic and functional parameters were studied in 5 cases of acute epidemic nephritis with uraemia using nephroangiography and dye-dilution measurements combined with determination of extraction ratio and clearance for 51Cr-EDTA and PAH. In the acute phase, with greatly reduced renal function, increased vascular resistance was noted in spite of the vasodilatation observed in the renal artery out to and including the interlobular arteries. Moreover, angiography revealed enlarged kidneys with an increase in the thickness of the cortex and reduced cortical contrast accumulation. The renal blood flow, which was normal or slightly reduced initially, increased during convalescence, and renal function returned to normal. The investigation indicated that a primary vascular lesion in glomerular to postglomerular capillaries gives rise to pronounced interstitial oedema, which, probably as a result of secondary tubular compression, may be the cause of the rapidly developing renal failure.

Active and passive immunization to angiotensin in experimental acute renal failure

A number of studies support, and others fail to support, the concept that the renin-angiotensin system plays a key role in the pathogenesis of acute renal failure. This study, employing active and passive immunization against angiotensin II, was designed to examine the primacy of circulating angiotensin as a mediator of this syndrome. Neither mode of immunization significantly affected the degree of azotemia or the marked reduction of inulin clearance expected in rats subjected to glycerol-induced myohemoglobinuria. Twenty-four hours after challenge, inulin clearance (Cin) in actively immunized rats fell to 3.2% of control and that of unimmunized rats given the same dose of glycerol was 2.5% of control. Although there was some variation among groups of passively immunized rats, Cin of one group being 18% of control, Cin of the other groups was less than 3% of control. The dose and binding capacity of the immune globulin used here were essentially the same as those reported in another study in which immunization was thought to be of prophylactic value in rats subjected to s.c. administered glycerol injections. Technologic differences unrelated to immunization are suggested to have caused the difference in results in the two studies, and it seems doubtful that circulating angiotensin plays a key role in the pathogenesis of myohemoglobinuric acute renal failure in the rat.

Experimental acute renal failure induced by uranyl nitrate in the dog

The diminished glomerular filtration rate observed in previous studies of acute renal failure induced by uranyl nitrate has been ascribed to backflow of glomerular filtrate through necrotic tubular epithelium, since renal blood flow was essentially normal. Renal blood flow ( 133 xenon washout) and renal function were studied serially for 96 hours after the administration of uranyl nitrate (10 mg/kg, iv) in unanesthetized dogs with chronic renal artery catheters. Inulin clearance and total renal blood flow decreased to 25% and 52% of control, respectively, by 6 hours and remained depressed. By 3 hours, cortical flow decreased to 330±20 ml/min 100 g -1 (control 507±12 ml/min 100 g -1 ) and outer medullary flow increased to 147±8 ml/min 100 g -1 (control 97±18 ml/min 100 g -1 ), indicating intrarenal blood flow redistribution. From 6 hours on, these flow components were no longer separable. The ratio of flow in the outer two-thirds of the renal cortex to that in the whole cortex, determined using 85 strontium-labeled microspheres (15µ), decreased to 0.34±0.06 and 0.40±0.04 at 6 and 96 hours, respectively (control 2.21±0.12). Plasma renin activity was 1.8±0.6 ng/ml hour -1 at 3 hours and remained elevated (control 0.6±0.2 ng/ml hour -1 ). Histological examination revealed minimal tubular change at 6 hours and widespread disruption at 96 hours. The decrease in renal blood flow prior to any significant tubular pathology suggests that alterations in renal hemodynamics, which may be mediated by the renin-angiotensin system, are responsible for the diminished renal function observed in this model of acute renal failure.

Renal handling of phosphorus in oliguric and nonoliguric mercury-induced acute renal failure in rats

The renal handling of phosphorus was evaluated in rats with acute renal failure (ARF) induced by injection of mercuric chloride (HgCl(2)). Clearances of endogenous creatinine (Ccr) and of phosphorus (Cp) were measured in the following groups: 1. Intact animals (control); 2. Parathyroidectomized rats (PTX) with normal kidney function (PTX control); 3. Animals with mercury-induced acute renal failure (Hg-ARF); 4. PTX rats with Hg-ARF; 5. Rats with Hg-ARF maintained normophosphatemic with dietary phosphate restriction; 6. Animals with oliguric ARF following renal artery constriction; 7. Rats with unilateral Hg-ARF. In addition, radioinulin clearances were measured in 6 normal and in 14 azotemic animals and correlated with simultaneously recorded endogenous Ccr. Radioinulin clearance was also used as an estimate of GFR (glomerular filtration rate) in the animals of group 7. The Cp/GFR in the intact animals (group 1) was 0.25 +/-0.06 (mean +/-SD). PTX (group 2) caused a subsequent decrease in Cp/GFR to 0.11 +/-0.04 P < 0.0005. The ARF animals in group 3 were classified either as oliguric (U(vol) [urine volume] <2 ml/24 hr, Ccr 0.008 +/-0.005 ml/min) or nonoliguric (V(vol) >2 ml/24 hr, Ccr 0.136 +/-0.12). The Cp/GFR in the oliguric animals (0.16 +/-0.09) was lower than that in group 1, P < 0.0005, and failed to increase following administration of exogenous parathyroid hormone. The Cp/GFR in the oliguric animals in groups 5 and 7 was also lower than the clearance ratio in group 1, 0.030 +/-0.08 and 0.077 +/-0.006, respectively. In the nonoliguric ARF animals of group 3 the Cp/GFR (0.94 +/-0.29) was higher than that in group 1, P < 0.0005. In the nonoliguric ARF animals of group 4 the Cp/GFR 0.27 +/-0.08 did not differ from the clearance ratio in group 1, however it was higher than that in the PTX animals (group 2) P < 0.0005. Cp/GFR in the nonoliguric animals of group 5 was not different from that in the nonoliguric rats of group 3. In the animals with nonoliguric unilateral Hg-ARF Cp/GFR on the affected side 0.51 +/-0.16 was higher than that on the control (contralateral) side, 0.23 +/-0.07, P < 0.0005. These results indicate that the low Cp/GFR observed in the oliguric ARF animals was not related to the level of circulating parathyroid hormone nor to the presence or absence of azotemia but probably was due to a reduced renal cortical perfusion. The high Cp/GFR in the nonoliguric ARF animals could be explained by secondary hyperparathyroidism and impaired phosphorus reabsorption due to tubular injury.

Intrarenal hemodynamics in glycerol-induced myohemoglobinuric acute renal failure in the rat

A modified 138 Xe washout technique was used to study changes in intrarenal hemodynamics during glycerol-induced acute renal failure in the rat. Within 10 minutes after glycerol injection, the flow fraction supplied to component 1 of the washout curve ("cortex A") decreases, reaching minimum values 24 hours afer glycerol (31% of control conditions). Seven days thereafter five of the rats, still uremic, showed cortical flow fractions less than 50% of control values. Nine others had recovered. Twenty-four hours after glycerol, renal blood flow was 27% and increased to 86% of control conditions in the recovered rats 7 days after glycerol. 85 Kr autoradiographs and silicone rubber casts of the renal vasculature demonstrated a severe cortical hypoperfusion at the height of oliguria that gradually disappeared in parallel with the functional recovery of the kidney. These observations, in good agreement with micropuncture data, suggest that oliguria and renal insufficiency in this experimental model are the result of a primary decrease in glomerular filtration rate due to an increased preglomerular resistance.