Acute renal failure

Study of kidney dysfunction in non-silicotic Egyptian workers

Occupational exposure to silica dust could lead to renal alterations in the glomeruli and proximal tubules. In the present study, occupational exposure to silica dust has been examined as a possible risk factor with respect to subclinical signs of kidney dysfunction. One-hundred forty eight exposed workers from a ceramic factory versus 121 controls of matched age, socioeconomic status and smoking habits were included. Data was collected through a questionnaire and clinical examination. There was a high prevalence of renal complaints in the ceramic workers specially the loin pain, dysuria. Crystalluria was significantly higher in the exposed group (12.2%) than the controls (5%). Renal urinary biomarkers including the high-molecular-weight protein albumin (U.Malb); the low-molecular-weight protein α1-microglobulin (α(1)M); the lysosomal enzyme N-acetyl-β-D-glucosaminidase (NAG) urinary excretion of copper (U.Cu) and zinc (U.Zn) have been investigated. Urinary levels of silica and creatinine (U.cr) were estimated. Data from the present study showed a high significant increase in the urinary excretion of all measured urinary parameters in the group of ceramic workers compared with control subjects. There were no significant differences in the means of U.Zn/U.cr, U.Malb/U.cr, and α(1)M/U.cr among the four investigated departments of ceramic factory. The significant difference was present mainly between the individual departments and the controls, while, there was significant differences in the means of U.Cu/U.cr, U.NAG/U.cr, and U.silica/U.cr among the four departments and the controls. Among the exposed workers, significant correlation was apparent between work duration and only U.Zn/U.cr (r=0.17, p<0.05), and U.Cu/U.cr (r=0.19, p<0.05), while all measured urinary parameters were significantly correlated with each other. On conclusion silica exposure leads to renal alterations which parallel the change in proteinuria and enzymuria, as well as the increased loss in urine of each of Zn and Cu. Measurement of the levels of urinary zinc and copper may serve as a sensitive indicator of the impaired renal function caused by silica exposure. The corresponding analytes could have potential value as indicators of renal function before the kidney is irreversibly injured and, thus could be suitable as monitoring tools for at-risk persons exposed to silica. Researches should assess whether the current occupational standards for silica adequately protect workers from renal disease or this established standard needs to be revised.

Renal failure secondary to acute tubular necrosis: epidemiology, diagnosis, and management

Acute tubular necrosis (ATN) is a form of acute renal failure (ARF) that is common in hospitalized patients. In critical care units, it accounts for about 76% of cases of ARF. Despite the introduction of hemodialysis > 30 years ago, the mortality rates from ATN in hospitalized and ICU patients are about 37.1% and 78.6%, respectively. The purpose of this review is to discuss briefly the cause, diagnosis, and epidemiology of ARF, and to review in depth the clinical trials performed to date that have examined the influence of growth factors, hormones, antioxidants, diuretics, and dialysis. In particular, the role of the dialysis modality, dialyzer characteristics, and dosing strategies are discussed.

Effects of smoking and lead exposure on proximal tubular integrity among Egyptian industrial workers

BACKGROUND

The hazards of occupational lead exposure are well documented. Tissue damage produced by lead is slow and progressive. The renal system is one of the systems primarily affected by lead. The present study aimed to evaluate renal proximal tubular functional and structural integrity among lead-exposed and cigarette-smoking male Egyptian workers. This study was extended to investigate the effect of lead exposure and cigarette smoking on urinary excretion of copper (Cu) and zinc (Zn).

METHODS

Participants included in the present study were 156 male workers grouped as follows: i) 75 lead non-exposed workers subgrouped into G1 that consisted of 36 non-smokers (age, 39.08+/-6.65 years) and G2, which included 39 smokers (age, 43.87+/-9.93 years); ii) 45 lead-exposed workers (work duration <20 years) subgrouped into G3 that consisted of 25 non-smokers (age, 37.40+/-3.76 years) and G4, which included 20 smokers (age, 38.40+/-4.95 years), and iii) 36 lead-exposed workers (work duration > or =20 years) subgrouped into G5 that consisted of 16 non-smokers (age, 45.94+/-4.19 years) and G6 which included 20 smokers (age, 45.70+/-2.25 years). Functional integrity of proximal tubules was studied by determining urinary level of low-molecular-weight protein alpha1-microglobulin (alpha1M), and structural integrity was investigated by measuring urinary activities of the lysosomal enzyme N-acetyl-beta-D-glucosaminidase (NAG) and the cytoplasmic enzyme glutathione S-transferase (GST). Urinary concentrations of Pb, Cu, Zn, and creatinine were also determined.

RESULTS

Data of the present investigation showed increased urinary excretion of all measured urinary parameters among lead-exposed workers in comparison with non-exposed workers whether they were non-smokers or smokers (G3 vs. G1, G5 vs. G1, G4 vs. G2, and G6 vs. G2), with greater elevation among lead-exposed smokers than among lead-exposed non-smokers (G4 vs. G3, G6 vs. G5). In addition, there was a greater increase in levels of all urinary parameters among workers with work duration > or =20 years than in those with <20 years' work duration (G6 vs. G4, G5 vs. G3).

CONCLUSIONS

Lead exposure in Egyptian workers causes damage to renal proximal tubules and results in its dysfunction. Cigarette smoking has a nephrotoxic effect and also is synergistic to lead nephrotoxicity on urinary excretion of GST and NAG, as well as Pb.

Does arterial hypotension due to cardiogenic shock in older patients lead to functional oliguria or to acute renal failure?

OBJECTIVES

Reports indicate some differences in the outcome of prolonged arterial hypotension due to cardiogenic shock: acute renal failure in older and more often functional oliguria in younger patients. The aim of the study is to analyze prolonged hypotension due to acute myocardial infarction in older and younger patients and to answer the question: does prolonged hypotension, due to acute myocardial infarction, lead to acute renal failure or to functional oliguria in older patients.

METHODS

During a 10-year observation, a study of 11 older (> 65 years) and 7 younger patients (< 65 years), suffering from acute myocardial infarction and cardiogenic shock, is presented: clinical data and laboratory: diuresis, sodium in urine, creatinine urine/plasma ratio, urine osmolality, osmolality urine/plasma ratio, renal failure index and fractional excretion of filtered sodium.

RESULTS

In 7 older and 5 younger patients, natriuresis indicated acute renal failure. The ratio of creatinine in urine and plasma in 3 older and 5 younger indicated functional oliguria; in 3 older and 1 younger, acute renal failure; and in 5 older and 1 younger, borderline values. In 7 older and 2 younger, the values of urine osmolality were in the range of functional oliguria and, in 4 older and 5 younger, borderline values between those two parameters, as the osmolality quotient in urine and plasma. The values of the renal failure index in all older and younger patients was lower than 3.0 (in 6 older and 3 younger, lower than 1.0) indicated functional oliguria, as the fractional excretion of filtered sodium Of 9 older patients who died, 5 were examined by autopsy, and 3 out of 4 younger who died. All had myocardial fibrosis and scars, apart from recent myocardial infarction and coronary atherosclerosis. In 2 older, acute tubular necrosis was found while in 2 no renal changes were found. In 2 younger, no renal changes were found and in 1 showed disseminated intravascular coagulation.

CONCLUSION

Acute renal failure due to cardiogenic shock in older patients is functional, or is rare renal.

Evaluation of renal functions--a computer programme

The authors describe the operational characteristics of a computer programme, which they developed and routinely use, to facilitate the evaluation of renal function tests data. Upon input of the necessary biochemical parameters the values of the various clearances, fractional excretions and other indices and ratios obtained from renal function tests are calculated. The computer programme provides an output of diagnostic commentaries in text format for further evaluation by the attending physician. The programme is written in FORTRAN IV language.

The lack of clinical value of laboratory parameters in predicting outcome in acute renal failure

In 55 patients with either the oliguric and nonoliguric form of acute renal failure, some laboratory parameters for the analysis of prerenal and intrinsic types of acute renal failure were examined. The parameters were analyzed within 7 days of the clinically known beginning of the illness. The parameters were analyzed as follows: sodium in urine, creatinine urine/plasma ratio, urine osmolality, osmolality urine/plasma ratio, renal failure index, and fractional excretion of filtered sodium. Hemodialysis was performed in 29 of the 55 patients. The oliguric form of acute renal failure was present in 49 of the 55 patients. In relation to renal failure index, prerenal acute renal failure was present in 7 patients and intrinsic acute renal failure in 48. It appears that in patients with a clinical diagnosis of prerenal acute renal failure, the urinary parameters do not separate them from those with acute tubular necrosis. It also appears that in patients with laboratory diagnosis of prerenal acute renal failure (i.e., a RFT less than 1.0), the response to treatment is unpredictable and in fact may have a worse prognosis than in those with a RFI greater than 1.0 (5/7 deaths vs 10/48 deaths).