Clinical Characteristics and Prognostic Factors of Hemolytic Uremic Syndrome in Korean Children

Hong, In Hee; Koo, Ja Hoon

Abstract

PURPOSE: Hemolytic uremic syndrome is one of the most frequent cause of acute renal failure in children and can lead to progressive deterioration of renal function. Present nationwide study was undertaken to determine the clinical characteristcs and prognostic factors of hemolytic uremic syndrome in korean children during past 10 years(1990-1999).
METHODS
Questionnaires(including clinical data, prodromal illness, lab data, treatment modality and prognosis) were mailed to all teaching hospitals in korea and 27 hospitals responded. During past 10 years, total 149 cases of HUS were diagnosed. Statistical analysis was done by chi-square test, using p<0.05 being "statistically significant".
RESULTS
Sex distribution showed slight female preponderance(female 84 vs male 65 cases) and "under 5 years of age" comprised 71.8%(107 cases). Yearly distribution showed increasing number of HUS cases during past 3-4 years and the majority of cases occurred during summer months. Diarrhea was the most common prodromal illness comprising 75.2 % followed by URI 18.2% and in 3.5% of cases no prodromal illness was noted. Lab data (mean+/-SD) showed Hb 7.3+/-2.1g/dL, platelet 49+/-32 X 103cells/mm3, BUN 74+/-36mg/dL, and creatinine 3.7+/-2.8mg/dL. Hypertension was seen in 32.9%, convulsion in 16.7%, mental change in 15.4% and renal replacement therapy(PD or HD) was done in 49.7% of cases. Clinical outcome showed complete recovery in 75.5%, persisting abnormal urinalysis without renal failure in 11.1%, chronic renal failure(including ESRD) in 6.7% and death in 6.7%(9 cases). Poor prognosis was associated with older patients age, higher serum creatinine level, existence of mental change and longer duration of oligoanuria. Out of these, duration of oligoanuria was the most closely associated factor leading to poor outcome. Out of 119 cases with "oligoanuria under 2 weeks", CRF and death were seen in 2 and 7 cases respectively. Compared to this, out of 12 cases with "oligoanuria over 2 weeks", CRF and death were seen in 4 and 2 cases respectively(p<0.0005).
CONCLUSION
The incidence of HUS is increasing recently in Korean children. And out of various prognostic factors(older age, higher serum creatinine, existence of mental change and duration of oligoanuria), duration of oligoanuria was the most significantly associated factor leading to poor outcome.