Effects of septic shock on renal function in humans

Urinary Biochemistry and Microscopy in Septic Acute Renal Failure: A Systematic Review

BACKGROUND

Biochemistry and microscopy of urine are widely published diagnostic activities in patients with acute renal failure (ARF). However, their scientific basis in patients with septic ARF has not been assessed systematically.

METHODS

We performed a systematic review of MEDLINE, EMBASE, CINHAL, and PubMed databases and bibliographies of retrieved articles for all studies describing urinary biochemistry, indices, and microscopy in patients with septic ARF.

RESULTS

We identified 27 articles (1,432 patients). Because of substantial heterogeneity, no formal quantitative analysis could be performed. Urinary biochemistry or derived indices were reported in 24 articles (89%), and microscopy, in 7 articles (26%). The majority were small single-center reports and had serious limitations. For example, only 52% of patients were septic, only 54% of patients had ARF, many studies failed to include a control group, time from diagnosis of sepsis or ARF to measure of urinary tests was variable, and there were numerous potential confounders. Urinary sodium, fractional excretion of sodium, urinary-plasma creatinine ratio, urinary osmolality, urinary-plasma osmolality ratio, and serum urea-creatinine ratio showed variable and inconsistent results. Low-molecular-weight proteinuria was described in only 22% of articles. A few reports of urinary microscopy described muddy brown/epithelial cell casts and renal tubular cells in patients with septic ARF, whereas others described normal urinary sediment.

CONCLUSION

The scientific basis for the use of urinary biochemistry, indices, and microscopy in patients with septic ARF is weak. More research is required to describe their accuracy, pattern, and time course in patients with septic ARF.

Renal and liver function tests in surgical septicemia

The prognostic value of conventional renal and liver function tests was evaluated during surgical septicemia. Changes in renal function variables were associated with the development of septic shock. Creatinine clearance was the most sensitive variable in predicting the outcome of septic shock, but serum creatinine and urine output were also of some value in this respect. Significantly lower creatinine clearance and urine output values, as well as significantly higher serum creatinine concentrations, were thus observed during septic shock with fatal outcome compared to non-fatal septic shock. In septicemia not complicated with shock, the variables of renal function remained in the normal range irrespective of final outcome. Among the liver function tests, serum albumin and total protein concentration revealed significant differences in behaviour between survivors and patients dying with persistent septicemia. However, due to the small differences and considerable overlap observed between the two groups of patients during the first 2 weeks of septicemia, these two variables are of limited practical value as prognostic predictors. The other liver function tests gave no information as regards the outcome of septicemia in the present study.

Bacteremia and fungemia complicating neoplastic disease. A study of 364 cases

During a 14 month period there were 364 episodes of bacteremia and fungemia at Memorial Sloan-Kettering Cancer Center. The first nine months of the study were retrospective, and the next five prospective. In patients with leukemia or lymphoma (group 1), Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus were the most frequently isolated organisms. The mortality in this group was 40.5 per cent. In the patients with solid tumor (group 2), Esch. coli, Staph. aureus, Bacteroides sp. and Candida sp. were most frequent. Mortality was 27.8 per cent. The source of infection in both groups was often indeterminate. High mortality was associated with pulmonary and intraabdominal infection and with Ps. aeruginosa, K. pneumoniae or polymicrobic sepsis. Factors of prognostic significance were the causative microorganism, source of infection and shock. Although mortality was higher in patients with leukopenia than in those with normal leukocyte counts, the differences were not significant. The mortality in this series was low considering the severity of the underlying diseases and the immunosuppressed state of many of the patients. In a prospective, randomly controlled study, mortality was further diminished by infectious disease consultation at the time the positive blood culture was reported. Severe fungal superinfection, predominantly aspergillosis and candidiasis, was found in 52 per cent of the autopsy patients with leukemia or lymphoma (group 1), but in only 8 per cent of those with solid tumors (group 2).

Hypophosphataemia in septicaemia: higher incidence in gram-negative than in gram-positive infections

Phosphataemia has been investigated in 54 patients with Gram-negative septicaemias; either absolute (serum phosphate <2 mg./100 ml.) or relative (P./B.U.N. 0.04) hypophosphataemia was found in 69% of all determinations. In 37 patients with Gram-positive septicaemias hypophosphataemia was present in only 24%, many of whom had additional Gram-negative bacteriuria and possible Gram-negative septicaemia suppressed by antibiotics. The mechanism of this phenomenon is not known. This new sign of Gram-negative septicaemia has some diagnostic importance.