Factors influencing the non-recovery of renal function after the relief of urinary tract obstruction in women with cancer of cervix.

OBJECTIVES: To identify factors associated with non-recovery of renal function after the relief of urinary tract obstruction in women with cancer of cervix. PATIENTS AND METHODS: Thirty-seven women with cancer of cervix and obstructive renal failure were prospectively studied. Patients were evaluated in the day before nephrostomy (D0); and in the 1st (D1), 7th (D7), and 30th day (D30) after unilateral nephrostomy. The following parameters were analyzed: age serum urea, and serum creatinine (S(creat)), in D0, D7, and D30. Renal cortical thickness was measured by ultrasonography in D0. During nephrostomy procedure, urine samples for urinalysis and culture were collected and renal biopsy was attempted. Patients were divided in two groups according to S(creat) in D30: patients with S(creat) < 1, 4mg/dL (R group) and those with S(creat) > or = 1, 4mg/dL (nR group). RESULTS: Ten patients died before D30 and were not studied. R group (n = 12) was younger (43 +/- 9 vs. 52 +/- 10 years, p < 0.05) than nR group (n = 15), and presented lower serum urea in D0 (134 +/- 67 vs. 212 +/- 51 mg/dL, p < 0.01) and in D7 (94 +/- 20 vs. 155 +/- 18 mg/dL, p < 0.05). Renal cortex was thicker in R group (17 +/- 1 vs. 13 +/- 1 mm, p < 0.05). Survival was higher in R group (11/12) than in nR group (0/15, p < 0.01). All urine samples showed leukocyturia but culture was positive in only two. In three out of nine biopsy attempts enough material was obtained. Light microscopy revealed interstitial fibrosis plus tubular atrophy, and partial glomerular fibrosis was present in two biopsies. CONCLUSIONS: The non-recovery of renal function after the relief of obstruction in human obstructive renal failure is associated with older age and decreased renal cortical thickness. The complete renal recovery improves patient survival despite malignancy.

Renal function changes after elective cardiac surgery with cardiopulmonary bypass.

Cardiac surgery can either induce acute renal failure or improve GFR by improving the cardiac performance. In order to study renal function changes after elective cardiac surgery (CS) with cardiopulmonary bypass (CPBP), 21 patients undergoing valvular CS (VCS) or coronary artery bypass (CAB) were prospectively evaluated in three time periods: before, 24 hours after surgery and 48 hours after surgery. Patients were divided in 2 groups according to the GFR percent change in comparison to the baseline value found 24 hours after CS (deltaGFR24): Group 1, deltaGFR24 decrease higher than 20% (n = 11) and Group 2, deltaGFR24 decrease < or = 20% or deltaGFR24 increase (n = 10). In Group 1, 73% of the patients underwent VCS (p = 0.05 vs. Group 2) and all of them had previous VCS in sharp contrast with Group 2, where none of the patients had previous CS (p = 0.006). Patients in Group I required more volume replacement than Group 2 during the first 24 hours after CS: 2,699+/-704 mL versus 217+/-603 mL respectively, p = 0.019. Despite similar baseline GFR, Group 1 presented lower GFR 24 hours after CS when compared to Group 2 (39+/-5 versus 75+/-8 mL/(min x 1.73m2), p = 0.001) and a significantly different deltaGFR 48 hours after CS as compared to Group 2 (-21+/-11 versus +88+/-36%, p<0.01). Baseline sodium fractional excretion (FENa) in Group 1 was lower than in Group 2 (0.27+/-0.04 versus 0.70+/-0.12%, p = 0.01). No changes were observed after CS in urinary osmolality (Uosm) and urinary pH (UpH) in both groups. The deltaGFR24 showed positive correlation with baseline FENa (r = 0.44 p = 0.04) and negative correlation with volume balance during the first 24h after CS (r = -0.63, p = 0.007). More patients in Group 1 required nitroprusside than in Group 2 (66% vs. 14%, p = 0.04). Anesthesia time was shorter in Group 1 as compared to Group 2: 323+/-21 vs. 395+/-26 min, p = 0.04. No significant hemolysis occurred during CS in either group. There were no differences in age, gender, CPBP time, need for dopamine and/or dobutamine between the two groups. In conclusion, patients who presented GFR decrease after CS underwent VCS more frequently, had more prevalence of previous CS, presented lower baseline FENa, required more volume infusion and more nitroprusside use. On the other hand, no tubular dysfunction was detected in the early follow-up of CS. These results suggest that the observed renal function changes should be the result of an appropriated renal response to a low effective blood volume. In fact, a low baseline FENa anticipated a GFR decrease in these patients. Consistently, CAB patients that usually improve their cardiac output after surgery showed a clear GFR improvement.

Risk factors for death and changing patterns in leptospirosis acute renal failure.

The risk factors for death and changes in clinical patterns in leptospirosis (Weil's disease) have not been well studied. We retrospectively studied 110 patients with Weil's disease hospitalized in Brazil between 1985 and 1996. Univariate statistical analysis showed that nonsurvivors were older than survivors, and had higher frequency of oliguria, cardiac arrhythmia, dyspnea, and pulmonary rales. Logistic regression showed that the only independent factor associated with death was oliguria (odds ratio [OR] = 8.98). The presence of arthralgia (OR = 4.71), dehydration (OR = 6.26), dyspnea (OR = 17.7), and pulmonary rales (OR = 9.91) increased after 1994. These data suggest that in Weil's disease the clinical patterns have changed and the presence of oliguria is a risk factor for death.

Acute bilateral renal artery occlusion due to granulomatous and necrotizing vasculitis.

A case of anuric acute renal failure due to bilateral renal artery obstruction in a 42 year-old man is presented. The obstruction was caused by bilateral thrombosis secondary to arteritis. Autopsy showed granulomatous and necrotizing vasculitis in both main renal arteries. Scarring and also necrotizing vasculitis were found from interlobular to arcuate renal arteries. The present case indicates that vasculitis should be considered when there is renal artery obstruction in young patients.

Prospective study of tetanus-induced acute renal dysfunction: role of adrenergic overactivity.

To assess the mechanisms related to tetanus-induced acute renal failure (ARF), 30 patients with tetanus had their renal function prospectively studied and factors possibly related to renal changes were evaluated during four weeks of hospitalization. Fifty percent of these patients had a glomerular filtration rate (GFR) < or = 50 ml/min in the first or second week of hospitalization (Group I) and 50% had a GFR > 50 ml/min throughout the entire hospitalization period (Group II). Age, gender, tetanus incubation time and tetanus onset time, hospitalization time, use of nephrotoxic drugs, need for mechanical ventilation with intermittent positive pressure, and presence of systemic infection were similar in both groups. None of the patients presented with oliguria. Autonomic nervous system (ANS) overactivity, characterized by intense variations in systolic and diastolic blood pressure, by increased heart rate and elevated urinary metanephrine excretion, was higher in Group I compared with Group II. Plasma renin activity, serum creatinephosphokinase levels, and myoglobinuria were not significantly different between the two groups. These results strongly suggest that tetanus-induced ARF has a high prevalence, is characterized by early onset, and is probably related to ANS overactivity.

Anuric acute renal failure caused by dextran 40 administration.

Dextran 40 is largely used in clinical medicine as a plasma substitute because of its beneficial effects on the microcirculation and antithrombogenic properties. An unusual adverse reaction of dextran administration is oligoanuric acute renal failure. We report two cases of anuric ARF induced by dextran 40. Diuresis and renal function were quickly resumed after plasma-pheresis treatment. Renal biopsy revealed normal kidneys except for swelling and vacuolation of renal tubules suggestive of osmotic nephrosis.

Severe acute renal failure induced by the venom of Lonomia caterpillars.

A case of a patient developing anuric acute renal failure and a hemorrhagic syndrome resembling disseminated intravascular coagulation after contact with Lonomia caterpillars is reported. Renal histology showed only mild changes consistent with renal ischemia, although the patient never was hypotensive. The mechanisms of renal injury were obscure and might be related to transient glomerular ischemia due to microcirculation fibrin deposition or to direct venom nephrotoxicity.

Peculiar electrolytic and hormonal abnormalities in acute renal failure due to leptospirosis.

Hypokalemia in leptospirosis acute renal failure (ARF) was studied in nine patients with severe leptospirosis ARF and five patients with moderate leptospirosis ARF and compared with five patients with severe acute tubular necrosis (ATN) and eight healthy individuals. Urinary volumes of both the severe and moderate leptospirosis groups were higher than those of the severe ATN group. Leptospirosis groups had serum potassium levels lower than those found in the healthy and severe ATN groups. Serum sodium levels were lower in the severe leptospirosis group than in the moderate leptospirosis, the severe ATN, and the healthy groups. There was a positive correlation between the fractional excretion of sodium and potassium in the severe leptospirosis group as well as between serum creatinine and potassium levels in the pooled leptospirosis groups. Urinary pH in the severe and moderate leptospirosis groups was lower than in the severe ATN group. Aldosterone levels were higher in the severe leptospirosis group than in the healthy individuals. Cortisol levels were higher in the leptospirosis groups than in the healthy subjects. These results strongly suggest that hypokalemia in leptospirosis ARF is due to renal potassium wasting potentialized by aldosterone and cortisol, requiring that special attention is given to potassium replacement as well as to volume repletion in the treatment of leptospirosis ARF.

Snakebite-induced acute renal failure: an experimental model.

Acute renal failure (ARF) has been frequently reported after bites from the Viperidae snake family. The lack of a reproducible animal model has hampered the study of renal damage mechanisms. Intravenous injection of rats with 0.4 mg/kg of Bothrops jararaca venom produced functional and morphologic changes similar to those observed in human snakebite-induced ARF. There was an acute and significant decrease in the glomerular filtration rate, diuresis, and renal plasma flow. Serum fibrinogen levels decreased significantly. There was intravascular hemolysis, as shown by a significant decrease in hematocrit, and an increase in plasma lactate dehydrogenase levels and free hemoglobin. Blood pressure and serum creatine phosphokinase levels were not affected. Light and electron microscopy showed massive fibrin deposition in glomerular capillaries, proximal and distal tubular necrosis, and hemolyzed red blood cell casts in renal tubules. Based on these findings, a model of snakebite-induced ARF was achieved. Ischemia related to glomerular coagulation and intravascular hemolysis were the most important pathogenic factors causing a decrease in the glomerular filtration rate, although a direct venom nephrotoxicity cannot be excluded.

Prolonged inhibition of angiotensin II attenuates glycerol-induced acute renal failure.

1. A lipophilic competitive angiotensin II antagonist (octanoyl-[8-leucine]-angiotensin II, OCTLEU A-II) was used to partially block the renin-angiotensin system in rats with glycerol-induced acute renal failure. The rats, which were maintained either on a normal or on a low-sodium diet, were dehydrated for 24 h before injection of glycerol. Daily intramuscular injections of OCTLEU A-II in peanut oil were started 48 h before glycerol administration to assure an angiotensin II blockade up to 48 h after glycerol administration. 2. In the low-sodium group (N = 23), acute renal failure was significantly attenuated in OCTLEU A-II-treated rats (N = 9) when compared with the controls (N = 14). The following values (means +/- 1 SD) for renal function parameters were obtained for the treated and control groups: urine volume, 15.2 +/- 11.7 vs 1.4 +/- 2.0 ml/24 h (P less than 0.01); plasma creatinine 5.5 +/- 1.3 vs 8.6 +/- 1.3 mg/dl (P less than 0.01); creatinine clearance 0.23 +/- 0.16 vs 0.03 +/- 0.03 ml min-1 kg-1 (P less than 0.01); plasma potassium 6.6 +/- 1.5 vs 10.1 +/- 1.9 mEq/1 (P less than 0.01); and sodium excretion fraction 3.0 +/- 4.0 vs 21.6 +/- 17.4% (P less than 0.02). Mean arterial blood pressure was 107 +/- 23 mmHg for the OCTLEU A-II-treated animals and 102 +/- 18 mmHg for the controls. 3. The rats on a normal sodium diet (N = 16) developed moderate non-oliguric renal insufficiency. The OCTLEU A-II-treated (N = 8) and control (N = 8) groups did not differ in any of the parameters measured. 4. The present results show that sodium restriction aggravates glycerol-induced acute renal failure and that the renin-angiotensin system participates, since its inhibition at the level of the angiotensin II receptor attenuates the extreme loss of renal function and prevents anuria.

Long-lasting inhibition of angiotensin response in rats by depot administration of octanoyl-[Leu8]-angiotensin II.

Depot administration of a lipophilic angiotensin II (AII) antagonist was tested for obtaining prolonged inhibition of the pressor response to AII in rats. Intramuscular injections of 1.5 or 5.0 mg of octanoyl-[Leu8]AII (oct-LAII), in oil solution produced the same degree of AII inhibition either 6 h or 24 h after the injection. The inhibition was comparable to that expected from the continuous intravenous infusion of oct-LAII at the rate of 1.2 microgram kg-1 min-1. The prolonged effect of intramuscular injections of oct-LAII in oil solution may be useful for chronic studies of physiopathological states involving the renin-angiotensin-aldosterone system.