Hemolytic Uremic Syndrome (HUS) consists ofa triad of acquired hemolytic anemia, 
thrombocytopenia, and renal failure that occurs acutely in otherwise healthy 
individuals. HUS may be divided into two broad categories, typical, preceded by 
a diarrheal prodrome, and atypical. The clinical symptoms of HUS as well as its 
course, prognosis, and response to treatment appear to be significantly 
influenced by a number of factors, including age at onset, type and severity of 
underlying infections, and/or systemic diseases. A retrospective case series 
review of five patients diagnosed with Hemolytic Uremic Syndrome at the 
Pediatric University Hospital in Puerto Rico between 1997-2007 was performed. 
The study showed that the incidence of HUS in children in Puerto Rico is lower 
than other countries. However, the majority of cases have an atypical 
presentation, which places our patients at higher risk for life-threatening 
complications.