(Infected Related) Hemolytic Uremic Syndrome (HUS)

HUS is a thrombotic microangiopathy characterized by the presence of hemolytic anemia (destruction of red blood cells), low platelets, and organ damage due to the formation of microscopic blood clots in capillaries and small arteries, in this case especially acute kidney failure. Hemolytic uremic syndrome can lead to kidney failure, which can be life-threatening.

When categorized as typical, HUS is caused by Shiga toxin–producing Escherichia coli (STEC) gastrointestianl infection. Atypical HUS (aHUS), is associated primarily with mutations or autoantibodies leading to dysregulated complement activation. Secondary HUS relates to a coexisting disease.

Invasive Streptococcus pneumoniae infection continues to be an uncommon but important cause of HUS in children. Most cases can be confirmed or at least considered probable without performing a renal biopsy.

• Bloody diarrhea, usually a few days earlier
• Abdominal pain
• Vomiting
• Fatigue
• Pallor
• Reduced urine output
• Unexplained bruising or bleeding

A diagnosis of STEC HUS should be considered in any patient developing a thrombotic microangiopathy, particularly if it follows a diarrheal illness and is associated with acute kidney failure. As atypical forms of HUS also may be associated with diarrhea, therefore STEC infection should be confirmed.