What triad defines Hemolytic Uremic Syndrome?

What triad defines Hemolytic Uremic Syndrome?

• A. Thrombocytopenia, microangiopathic hemolytic anemia, and kidney failure
• B. Leukocytosis, anemia, and liver failure
• C. Hyperglycemia and ketosis
• D. Nephrotic-range proteinuria and edema

Answer: (A)

Hemolytic Uremic Syndrome is defined by a triad of findings from a small-vessel thrombotic process: thrombocytopenia, microangiopathic hemolytic anemia, and acute kidney injury. The microangiopathy causes red blood cell destruction as they pass through narrowed, thrombus-filled vessels, leading to schistocytes on smear and elevated LDH with low haptoglobin. Platelets are consumed in those same clots, producing low platelet counts. The kidneys take a hit because the same microthrombi form in renal microvasculature, leading to reduced filtration and acute kidney injury. This combination—low platelets, MAHA, and renal failure—is what makes the correct option the best answer. The other sets describe features that don’t match HUS (for example, unrelated metabolic states, liver involvement, or nephrotic-range symptoms), so they don’t fit the characteristic pattern of HUS.

Hemolytic Uremic Syndrome is defined by a triad of findings from a small-vessel thrombotic process: thrombocytopenia, microangiopathic hemolytic anemia, and acute kidney injury. The microangiopathy causes red blood cell destruction as they pass through narrowed, thrombus-filled vessels, leading to schistocytes on smear and elevated LDH with low haptoglobin. Platelets are consumed in those same clots, producing low platelet counts. The kidneys take a hit because the same microthrombi form in renal microvasculature, leading to reduced filtration and acute kidney injury.

This combination—low platelets, MAHA, and renal failure—is what makes the correct option the best answer. The other sets describe features that don’t match HUS (for example, unrelated metabolic states, liver involvement, or nephrotic-range symptoms), so they don’t fit the characteristic pattern of HUS.