Effectiveness of therapeutic plasma exchange in the 1996 Lanarkshire Escherichia coli O157:H7 outbreak. Dundas S, Murphy J, Soutar RL, Jones GA, Hutchinson SJ, Todd WT. Lancet 1999;354(9187):1327-1330.

ABSTRACT:

The largest number of adult cases of hemolytic uremic syndrome (HUS)/thrombotic thrombocytopenic purpura (TTP) during an Escherichia coli O157 outbreak occurred in 1996 in central Scotland. The largest cohort within the outbreak overall was a group of elderly people who attended a church lunch. Adults who develop HUS/TTP induced by E. coli O157 tend to be elderly and have a historical mortality rate of almost 90% when treated conservatively. Therefore the decision was made to treat adults who developed HUS/TTP during this outbreak with therapeutic plasma exchange (TPE). This report describes the outcomes with this controversial treatment among the 22 adults who developed HUS/TTP. The mean age was 71 years. Sixteen cases received TPE. Six cases had contraindications to TPE or died before the procedure could be done. Ten of the 22 (45%) adults with HUS/TTP died. Causes of death associated with HUS/TTP were acute renal failure secondary to HUS, cardiac arrest, intracerebral hemorrhage, cerebral infarction, acute myocardial infarction, multiple organ failure, hepatorenal syndrome and septic shock. Five of the 16 (31%) TPE-treated cases died, four of eight aged over 70 years compared with one of eight aged less than 70 years. Premorbid illness, neurological features, treatment with ciprofloxacin or prostacyclin, and the laboratory severity of HUS/TTP were not associated with these deaths; the number of cases, however, was too small to allow for statistical conclusion. The mortality rate was high in adults who developed HUS/TTP induced by E. coli O157. TPE appears to be a promising treatment that was well tolerated in this elderly population. HUS/TTP used to be a rare disease in adults but the incidence has continued to rise since the first association with E. coli O157 was made. The authors recommended that a national register of adult cases of HUS/TTP induced by E. coli O157 should be established.