Regina C. R. M. Abdulkader

Effect of acute kidney injury on weaning from mechanical ventilation in critically ill patients.

Objectives: Acute kidney injury (AKI) worsens outcome in various scenarios. We sought to investigate whether the occurrence of AKI has any effect on weaning from mechanical ventilation. Design and Setting: Observational, retrospective study in a 23‐bed medical/surgical intensive care unit (ICU) in a cancer hospital from January to December 2003. Patients: The inclusion criterion was invasive mechanical ventilation for ≥48 hrs. AKI was defined as at least one measurement of serum creatinine of ≥1.5 mg/dL during the ICU stay. Patients were then separated into AKI and non‐AKI patients (control group). The criterion for weaning was the combination of positive end‐expiratory pressure of ≤8 cm H2O, pressure support of ≤10 cm H2O, and Fio2 of ≤0.4, with spontaneous breathing. The primary end point was duration of weaning and the secondary end points were rate of weaning failure, total length of mechanical ventilation, length of stay in the ICU, and ICU mortality. Results: A total of 140 patients were studied: 93 with AKI and 47 controls. The groups were similar in regard to age, sex, and type of tumor. Diagnosis of acute lung injury/acute respiratory distress syndrome as cause of respiratory failure and Simplified Acute Physiology Score II at admission did not differ between groups. During ICU stay, AKI patients had markers of more severe disease: increased occurrence of severe sepsis or septic shock, higher number of antibiotics, and longer use of vasoactive drugs. The median (interquartile range) duration of mechanical ventilation (10 [6–17] vs. 7 [2–12] days, p = .017) and duration of weaning from mechanical ventilation (41 [16–97] vs. 21 [7–33.5] hrs, p = .018) were longer in AKI patients compared with control patients. Cox regression analysis demonstrated that a ≥85% increase in baseline serum creatinine (hazard rate, 2.30; 95% confidence interval, 1.30–4.08), oliguria (hazard rate, 2.51; 95% confidence interval, 1.24–5.08), and the number of antibiotics (hazard rate, 2.64; 95% confidence interval, 1.51–4.63) predicted longer duration of weaning. The length of ICU stay and ICU mortality rate were significantly greater in the AKI patients. After adjusting for Simplified Acute Physiology Score II, oliguria (odds ratio, 30.8; 95% confidence interval, 7.7–123.0) remained as a strong risk factor for mortality. Conclusion: This study shows that renal dysfunction has serious consequences in the duration of mechanical ventilation, weaning from mechanical ventilation, and mortality in critically ill cancer patients.

Leptospirosis severity may be associated with the intensity of humoral immune response

Leptospirosis severity may be increasing, with pulmonary involvement becoming more frequent. Does this increase result from an intense immune response to leptospire? Notice that renal failure, thrombocytopenia and pulmonary complications are found during the immune phase. Thirty-five hospitalized patients with Weils disease had 5 blood samples drawn, from the 15th day to the 12th month of symptoms, for ELISA-IgM, -IgG and -IgA specific antibody detection. According their 1st IgG titer, the patients were divided into: group 1 (n = 13) titer > 1:400 (positive) and group 2 (n = 22) titer < or =1:400 (negative). Early IgG antibodies in group 1 showed high avidity which may indicate reinfection. Group 1 was older, had worse pulmonary and renal function, and fever for a longer period than group 2. Throughout the study, IgG and IgA titers remained higher in group 1. In conclusion, the severity of Weils disease may be associated with the intensity of the humoral immune response to leptospire.

Long-Term Follow-Up of Patients after Acute Kidney Injury: Patterns of Renal Functional Recovery

Background and Objectives Patients who survive acute kidney injury (AKI), especially those with partial renal recovery, present a higher long-term mortality risk. However, there is no consensus on the best time to assess renal function after an episode of acute kidney injury or agreement on the definition of renal recovery. In addition, only limited data regarding predictors of recovery are available. Design, Setting, Participants, & Measurements From 1984 to 2009, 84 adult survivors of acute kidney injury were followed by the same nephrologist (RCRMA) for a median time of 4.1 years. Patients were seen at least once each year after discharge until end stage renal disease (ESRD) or death. In each consultation serum creatinine was measured and glomerular filtration rate estimated. Renal recovery was defined as a glomerular filtration rate value ≥60 mL/min/1.73 m2. A multiple logistic regression was performed to evaluate factors independently associated with renal recovery. Results The median length of follow-up was 50 months (30–90 months). All patients had stabilized their glomerular filtration rates by 18 months and 83% of them stabilized earlier: up to 12 months. Renal recovery occurred in 16 patients (19%) at discharge and in 54 (64%) by 18 months. Six patients died and four patients progressed to ESRD during the follow up period. Age (OR 1.09, p<0.0001) and serum creatinine at hospital discharge (OR 2.48, p = 0.007) were independent factors associated with non renal recovery. The acute kidney injury severity, evaluated by peak serum creatinine and need for dialysis, was not associated with non renal recovery. Conclusions Renal recovery must be evaluated no earlier than one year after an acute kidney injury episode. Nephrology referral should be considered mainly for older patients and those with elevated serum creatinine at hospital discharge.

Pattern of Renal Function Recovery after Leptospirosis Acute Renal Failure

Background: Although acute renal failure (ARF) is a frequent complication of severe leptospirosis, there are few studies on renal function recovery in the literature. The objective of the present study was to verify how and when renal function recovery occurs after leptospirosis ARF. Patients and Methods: 35 patients with leptospirosis ARF (plasma creatinine [Pcreat] ≧133 µmol/l at hospital admission) were prospectively studied during hospitalization, at discharge and 3 and 6 months after discharge. Creatinine clearance, fractional excretion of sodium and potassium, proteinuria and sodium proximal reabsorption were measured under normal sodium diet. Urinary pH and the ratio urinary to plasma osmolality (U/Posm) were measured 18 h after food and water withdrawal. All parameters were also measured in 18 healthy volunteers. Presence of laboratorial alterations usually found in leptospirosis were evaluated in the patients. Patients were divided in 2 groups according to their maximum Pcreat value during hospitalization: group 1 ( Pcreat >442 µmol/l, n = 21), and group 2 (Pcreat ≤442 µmol/l, n = 14). Results: All patients presented with jaundice, fever and myalgia. Bilirubin and creatine kinase were higher in group 1. Oliguria was observed in 11% of all patients and 49% required dialysis; all these patients were from group 1. All renal parameters were normal at the 6th month except U/Posm that remained lower than normal. The pattern of renal function recovery was similar in both groups except for urinary volume. Conclusion: After leptospirosis ARF, renal function recovery is fast and complete after 6 months, except for urinary concentration capacity.

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.

The kidney in leptospirosis

Leptospirosis is a worldwide zoonosis. Typically, patients are young men, although children can be affected. In children, this disease causes mainly alterations of sensorium. Acute renal failure and jaundice (Weil’s syndrome) are less common in children than in adults. The main renal histological findings are acute interstitial nephritis and acute tubular necrosis. Acute renal failure is characterized by hypokalemia and nonoliguria. Many factors are involved in its physiopathology: hypotension, hypovolemia, rhabdomyolysis, hyperbilirubinemia, and, primarily, the direct action of leptospiral proteins. Antibiotic administration (especially early administration) reduces length of hospitalization and leptospiruria. For children, even late antibiotic treatment has been shown to reduce the extent of acute renal failure and thrombocytopenia. Although the best method of dialysis is not yet established, early and intensive dialysis can decrease mortality. Mortality in patients with acute renal failure is ∼15–20% in association with the presence of oliguria, higher levels of creatinine, and older age. Functional recovery is fast and complete; however, abnormal urinary concentration can persist.

Nephrotoxicity of Insect and Spider Venoms in Latin America

One of the most important and lethal effects of animal venoms is nephrotoxicity. In Latin America, severe acute kidney injury has been reported after accidents with poisonous arthropods such as bees, caterpillars of the genus Lonomia, and spiders of the genus Loxosceles. In this article the characteristics of these venoms, their probable mechanisms of renal damage, and the clinical picture of the accidents are reviewed.

Rhabdomyolysis in presumed viscero-cutaneous loxoscelism: report of two cases

Until now, in viscero-cutaneous loxoscelism, discoloured urine has been attributed only to haemoglobinuria induced by the intravascular haemolysis caused by the venom. In this paper, 2 cases (in Brazil) of viscero-cutaneous loxoscelism with rhabdomyolysis and acute renal failure are described. Both patients presented with severe oedema, erythema and dermonecrosis at the bite site. Elevated creatine kinase levels were found in both cases (6841 and 1718 U/L) associated with severe acute renal failure (one required dialysis for 50 days). Therefore, in viscero-cutaneous loxoscelism, rhabdomyolysis secondary to intense local tissue damage can occur and should be considered as a contributing factor in acute renal failure. Creatine kinase should therefore be monitored in viscero-cutaneous loxoscelism to avoid acute renal failure and to reduce the severity of any renal damage.

Characteristics of Acute Kidney Injury in Patients Infected with the 2009 Influenza A (H1N1) Virus

BACKGROUND AND OBJECTIVES There have been few studies investigating acute kidney injury (AKI) in patients infected with the 2009 pandemic influenza A (H1N1) virus. Therefore, the objective of this study was to identify the factors associated with AKI in H1N1-infected patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This was a study of 47 consecutive critically ill adult patients with reverse transcriptase-PCR-confirmed H1N1 infection in Brazil. Outcome measures were AKI (as defined by the Risk, Injury, Failure, Loss, and End-stage renal failure [RIFLE] criteria) and in-hospital death. RESULTS AKI was identified in 25 (53%) of the 47 H1N1-infected patients. AKI was associated with vasopressor use, mechanical ventilation, high Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, and severe acidosis as well as with higher levels of C-reactive protein and lactic dehydrogenase upon intensive care unit (ICU) admission. A nephrology consultation was requested for 16 patients (64%), and 8 (50%) required dialysis. At ICU admission, 7 (15%) of the 25 AKI patients had not yet progressed to AKI. However, by 72 hours after ICU admission, no difference in RIFLE score was found between AKI survivors and nonsurvivors. Of the 47 patients, 9 (19%) died, all with AKI. Mortality was associated with mechanical ventilation, vasopressor use, dialysis, high APACHE II score, high bilirubin levels, and a low RIFLE score at ICU admission. CONCLUSIONS Among critically ill H1N1-infected patients, the incidence of AKI is high. In such patients, AKI is mainly attributable to shock.

Acute Renal Failure in Leptospirosis

Leptospirosis acute renal failure is reviewed: its prevalence, clinical characteristics, physiopathologic mechanisms, histology, mortality, follow-up, prophylaxis, and treatment.