Question
| A. |
Not commonly caused by verocytogenic E coli |
| B. |
Causes mild to severe Coombs positive hemolytic anemia |
| C. |
Recurrences rare |
| D. |
Transient thrombocytopenia |
|
Correct Answer » B Explanation |
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Hemolytic Uremic Syndrome (HUS) is a form of thrombotic microangiopathy characterized by the classical triad:
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Microangiopathic hemolytic anemia
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Thrombocytopenia
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Acute kidney injury
It is most commonly seen in children following diarrheal illness.
Etiopathogenesis
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Most common cause: Verotoxin (Shiga-like toxin) producing Escherichia coli (E. coli O157:H7)
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The toxin causes:
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Endothelial injury (especially in renal vasculature)
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Platelet activation and aggregation
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Formation of microthrombi
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RBCs passing through these damaged vessels undergo mechanical fragmentation, leading to hemolysis.
Nature of Hemolysis
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Hemolysis in HUS is:
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Microangiopathic
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Coombs negative
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Peripheral smear shows:
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Schistocytes (helmet cells)
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