Clinical question: Does intravenous volume expansion during diarrheal illness mitigate the nephrotoxic effects of hemolytic uremic syndrome (HUS)?
Background: HUS often results in significant morbidity, particularly when oligoanuria is also present. Shiga-toxin-producing bacteria, notoriously Escherichia coli O157:H7 in the context of a diarrheal illness, are the most common cause, and worldwide outbreaks have been increasingly described. One prior report suggests that early IV fluid administration results in improved outcomes.
Study design: Prospective cohort study.
Setting: Eleven pediatric hospitals in the U.S. and Scotland.
Synopsis: Fifty children with diarrhea-associated HUS were enrolled and received clinical care at the discretion of the local provider, independent of the study. A family questionnaire (to define initial illness) and chart review were subsequently performed. Oligoanuria, defined as a urine output of less than 0.5 mL/kg/hr for at least one calendar day after HUS onset, was present in 34 (68%) patients. Oligoanuric and nonoligoanuric patients were similar at baseline; however, there was a significant association between less fluid administration in the first four days of illness and oligoanuria. Specifically, lack of IV fluids portended a 1.6 times higher likelihood of oligoanuria (95% confidence interval, 1.1-2.4; P=0.02).
The authors also suggest a dose-response relationship to their findings, which potentially strengthens their findings. However, the practical applicability of these findings appears limited. Many of the patients who did not receive IV fluids early on were also not admitted to a hospital, likely signifying mild illness without notable dehydration. Replicability of the benefits of early volume expansion in HUS will depend on the ability to accurately identify patients with Shiga-toxin-producing diarrheal illnesses at presentation. If this is feasible, it would be interesting to examine the details of oral hydration as well, particularly in those who are not dehydrated enough to require hospitalization.
Bottom line: Early IV fluids might be nephroprotective in diarrhea-associated HUS.
Citation: Hickey CA, Beattie J, Cowieson J, et al. Early volume expansion during diarrhea and relative nephroprotection during subsequent hemolytic uremic syndrome. Arch Pediatr Adolesc Med. 2011;165:884-889.
Reviewed by Pediatric Editor Mark Shen, MD, FHM, medical director of hospital medicine at Dell Children’s Medical Center, Austin, Texas.