Patient selection: microangiopathic hemolytic anemia (MAHA)
Typical HUS is associated with Shiga-toxin which may be produced by Shiga-toxin-producing Escherichia coli (STEC) or STEC 0157:H7 (enterohemorrhagic EHEC).
Criteria for MAHA
(1) anemia
(2) schistocytosis (>= 2%)
(3) evidence of hemolysis (decreased to absent haptoglobin, elevated serum LDH, elevated serum indirect bilirbuin)
Reasons to consider typical HUS:
(1) microangiopathic hemolytic anemia
(2) thrombocytopenia
(3) elevated serum creatinine ("uremic")
(4) diarrhea
The diagnosis of typical HUS is made in the appropriate clinical setting plus evidence of Shiga toxin in the stool.
If Shiga toxin is absent then consider:
(1) an alternative diagnosis such as atypical HUS.
(2) false negative Shiga toxin test
A patient with typical HUS requires aggressive supportive care with or without dialysis. Eculizumab and plasma exchange have not proven to be effective in managing patients.
