D59.5

HCC Category Mapping

What This Code Means

A rare blood disorder where red blood cells are destroyed in the bloodstream, particularly at night, leading to anemia and dark urine.

Coding Tips

• •This is a specific named condition (Marchiafava-Micheli disease); document any hemoglobinuria or thrombotic complications
• •Note any treatment with complement inhibitors or anticoagulation therapy

Clinical Significance

Paroxysmal nocturnal hemoglobinuria (Marchiafava-Micheli disease) is a rare acquired clonal stem cell disorder caused by somatic mutations in the PIGA gene, resulting in deficiency of glycosylphosphatidylinositol-anchored complement regulatory proteins (CD55 and CD59) on blood cell surfaces. This leaves red blood cells vulnerable to complement-mediated lysis, particularly during sleep when mild respiratory acidosis enhances complement activation. The disease triad includes intravascular hemolysis, bone marrow failure, and a strong predisposition to venous thrombosis, which is the leading cause of death.

Documentation Requirements

• ✓Document flow cytometry results showing deficiency of CD55 and CD59 (glycosylphosphatidylinositol-anchored proteins) on red blood cells and granulocytes.
• ✓Record hemoglobin levels, lactate dehydrogenase (often markedly elevated), reticulocyte count, haptoglobin (typically undetectable), and urinalysis showing hemoglobinuria.
• ✓Document any thrombotic events (Budd-Chiari syndrome, cerebral vein thrombosis, portal vein thrombosis).
• ✓Include treatment with complement inhibitors (eculizumab, ravulizumab) and anticoagulation status.

Commonly Confused Codes