Microangiopathic Anemia

Epidemiology and Etiology:

• Caused by physical disruption of RBC’s by fibrin strands in the microcirculation
• DIC
• Severe burns
• Snake bites
• Septicemia
• Drugs
• Thrombotic thrombocytopenic purpura (TTP)
• Also associated with large vessel disease (heart and aorta)

Common sites:

Gross features:

Histologic features:

• Poikilocytes (RBCs with an abnormal shape):
• Helmet cells
• Pre-karatocyte
• Eccentric pseudovacuole
• Keratocyte (horn cell)
• Like helmet cell but with two horns
• Irregular fragments (schistocytes)
• spherocytes

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

Other features:

• haptoglobin goes down (binds to free hemoglobin)

References:

• CAP Color Atlas of Hematology, 1998