2011/02/01 by L. Hannah Gould, John G. Jordan, John R. Dunn +4 · 5 citations
Biochemistry, Genetics and Molecular Biology · Medicine · Immunology and Microbiology · #Escherichia coli research studies #Iron Metabolism and Disorders #Complement system in diseases
paper · pdf · doi:10.1111/j.1532-5415.2011.03269.x
To the Editor: Hemolytic uremic syndrome (HUS) is the leading cause of acute renal failure in children in the United States. Most postdiarrheal HUS follows infection with Shiga toxin–producing Escherichia coli O157 (STEC O157).1 HUS and STEC infection are also serious illnesses in older adults, but little is known about the clinical characteristics and course of HUS in this population. Reports to the Foodborne Diseases Active Surveillance Network (FoodNet)2 of postdiarrheal HUS in persons aged 65 and older from 2000 through 2006 were reviewed. Surveillance was conducted in Connecticut, Georgia, Maryland, Minnesota, Oregon, and Tennessee and selected counties in California and New York. Cases were identified through passive and active surveillance and by reviewing hospital discharge data for International Classification of Diseases, Clinical Modification, Ninth Revision (ICD-9-CM) discharge diagnosis codes for HUS, acute renal failure, thrombotic thrombocytopenic purpura (TTP), or diarrhea caused by E. coli. Cases were validated using medical record review. Information on age, sex, hospitalization, death, and STEC O157 culture was collected. A case of postdiarrheal HUS was an illness that a physician diagnosed as HUS or TTP with diarrhea that began in the 21 days before HUS or TTP diagnosis. Confirmed cases met the following criteria: anemia (hemoglobin (Hb)<12.0 g/dL in women or <13 g/dL in men or hematocrit (Hct)<36% in women or <39% in men), platelet count less than 150,000/mm,3 acute renal impairment (serum creatinine level ≥1.5 mg/dL), and microangiopathic changes consistent with hemolysis on peripheral blood smear.1 Probable cases met all criteria, except microangiopathic changes were not recorded. All others were considered suspect cases. Twenty-seven cases of postdiarrheal HUS (17 confirmed, 10 probable, 4 suspect) in persons aged 65 and older were reported (0.83 cases per 1,000,000) (Table 1). At least one was reported from each site (range, 1 (OR, TN) to 8 (MN)). Twenty-two (82%) were in women. Women had a higher incidence than men (1.1 vs 0.4 cases per 1,000,000; P=.02). Thirteen cases were in persons aged 65 to 74 (0.77 per 1,000,000) and 14 in persons aged 75 to 84 (0.88 per 1,000,000; P=.01). HUS was diagnosed a median of 7 days after diarrhea began (range 2–17 days). Nineteen (70%) patients had bloody diarrhea. Eleven had other conditions in the 3 weeks before their HUS diagnosis, including urinary tract infection (n=4), immunocompromising condition or malignancy (n=3), kidney disease (n=2), and respiratory tract infection (n=1). Twenty-four (89%) were treated with an antimicrobial agent during the 3 weeks before HUS was diagnosed. Stool specimens from 22 (81%) were cultured for STEC O157, and it was isolated from 13 (59%). One of two patients whose stool did not yield STEC O157 and whose sera were tested had antibodies to O157 lipopolysaccharide. All patients were hospitalized; the median stay was 21 days (range, 4–101 days). Twenty-two patients (82%) received plasmapheresis, 18 (67%) red blood cell transfusion, 18 (67%) fresh frozen plasma, and six (22%) platelet transfusion. Fifteen (56%) required dialysis (14 hemodialysis, 1 peritoneal). Two (7%) underwent colectomy. Eight patients (30%) died: 15% of persons aged 65 to 74, 40% of persons aged 75 to 84, and 50% of four persons aged 85 and older. Six (26%) of the 19 who survived still required dialysis at discharge. Although rare, HUS is associated with high mortality and substantial morbidity in elderly persons. Most patients required more than 2 weeks of hospitalization, blood products, and dialysis, and one-quarter required dialysis after hospitalization. One-third died. Most cases occurred in women, similar to other studies,3–6 although the magnitude of female skew was much larger than in previous studies. The larger female population did not account for the female preponderance because the incidence of HUS was also higher in women. Rates of STEC infection in FoodNet are similar in men and women in this age group,3 so a higher infection rate in women cannot explain the finding. This study is one of the first to provide incidence estimates for postdiarrheal HUS in elderly patients. Limitations include incomplete clinical information needed to classify some patients and the limitations inherent in FoodNet surveillance.2 Early recognition and careful clinical management of STEC infection in elderly patients, including early treatment with parenteral volume expansion, might reduce progression to HUS.7 Stool culture for STEC O157 should be conducted early to aid in diagnosis and treatment, to encourage infection control precautions, and to help detect outbreaks.8,9 We thank Deborah Talkington and the Centers for Disease Control and Prevention Immunodiagnostics Laboratory for serological testing and for helpful feedback on this study. Conflict of Interest: The Centers for Disease Control and Prevention, the U.S. Department of Agriculture, and the U.S Food and Drug Administration provided funding for this report. Author Contributions: Study concept and design: LHG, PMG. Acquisition of data: JD, MA. Analysis and interpretation of data: LHG, JGJ. Preparation of manuscript: LHG, JGJ, PMG. Approval of final version of manuscript: all authors. Sponsor's Role: The findings and conclusions in this report are those of the authors and do not necessarily represent those of the funding agencies.