Patient selection: microangiopathic hemolytic anemia (MAHA)
Criteria for MAHA
(1) anemia
(2) schistocytosis (>= 2%)
(3) evidence of hemolysis (decreased to absent haptoglobin, elevated serum LDH, elevated serum indirect bilirbuin)
A patient with MAHA should have testing done for ADAMTS13.
Indications for emergent plasma exchangte:
(1) platelet count < 30,000 per µL
(2) serum creatinine < 2.0 mg/dL
(3) Plasmic score >= 5
A person who does not meet these indications can be started on plasma exchange if clinically indicated.
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ADAMTS13
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Diagnosis
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Management
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< 10%
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TTP
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daily plasma exchange, immunosuppressive drugs
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>= 10%
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atypical HUS
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discontinue plasma exchange, start eculizumab, monitor renal function
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Problems in diagnosis:
(1) red blood cell changes in iron deficiency may be mistaken for hemolytic schistocytosis
(2) pre-existing elevation of INR and/or serum creatinine can result in a low Plasmic score in the presence of TTP
