Atypical hemolytic uremic syndrome: a clinical conundrum.

BACKGROUND: Patients negative for Shiga toxin-producing E. coli (STEC) are categorized as having atypical hemolytic uremic syndrome (HUS) and are associated with an increased risk for complement mutations and poorer prognosis compared with typical HUS. However, STEC identification is limited by the natural history of HUS. METHODS: The current study is aimed at identifying HUS patients with poor outcomes based on the presence or absence of diarrhea (D) or Shiga toxin (S). A single-center retrospective review (2003-2012) of 42 HUS patients (follow-up 31.3 ± 38.7 months) was carried out. HUS was managed clinically with supportive treatments such as dialysis, plasma therapy, and eculizumab. RESULTS: There was no significant difference in the D+S+ (31 %), D+S- (50 %) and D-S- (19 %) groups in the outcome variables of chronic kidney disease stages I-II (100 % vs 81 % vs 67 %) and proteinuria at follow-up (20 % vs 12.5 % vs 33.3 %), hospitalization duration (16.0 ± 8.7 vs 18.1 ± 9.5 vs 23.7 ± 12.9 days); dialysis requirement (50 % vs 81 % vs 66.7 %), and dialysis duration (10.2 ± 1.9 vs 33.3 ± 72.8 vs 10.3 ± 8.1 days). There was no significant difference in study outcomes in STEC+ (59 %) versus STEC- (41 %) groups. Genetic testing was performed in 12 % of HUS patients based on age, recurrent HUS, familial HUS, persistently low C3, or prolonged dialysis, and 80 % of the patients tested were positive for genetic mutations. CONCLUSIONS: Our study does not show poorer outcomes in STEC- HUS. Indications and the cost-effectiveness of genetic testing, eculizumab, and plasmapheresis in STEC- HUS need to be evaluated further.

Mitral valve diseases in Williams syndrome-case report and review of the literature.

Williams syndrome is a genetic syndrome involving an unusual facies, short stature, developmental delay and heart defects. There is a genetic marker for this disease. Williams syndrome is frequently associated with congenital heart defects. The most common cardiac diagnoses are supravalve aortic stenosis, supravalve pulmonic stenosis, and arterial hypertension. In contrast, the association of mitral valve prolapse with Williams syndrome is less well defined. We present a case of a 15-year-old girl with Williams syndrome who underwent successful mitral valve repair. Review of the echocardiographic database of our institution over a 10-year period identified 26 other patients with Williams syndrome. Overall, 10 of the 27 children with Williams syndrome had mitral valve disease (37%) including 9 patients with mitral valve prolapse and one with mitral insufficiency. In conclusion, patients with Williams syndrome should be examined for mitral valve disease. Mitral valve repair is feasible and may be considered in the growing child with Williams syndrome.