Dr. S.0 MIKAYE/LinkedIn
Dec 23, 2025, 08:57
Samwel Mikaye Explains PNH: Cause, Key Clinical Features, Investigations and More
Samwel Mikaye, CEO of SaMik Medical Center, posted on LinkedIn:
“Paroxysmal Nocturnal Hemoglobinuria (PNH) is a rare acquired hematologic disorder characterized by intravascular hemolysis, bone marrow failure, and thrombosis.

Cause / Pathophysiology
- Caused by a somatic mutation in the PIGA gene
- Leads to deficiency of GPI-anchored proteins on blood cells
- Key missing protective proteins:
- CD55 (DAF)
- CD59
- Without these, red blood cells are destroyed by complement
Key clinical features
- Hemoglobinuria, often noticed in the morning
- Anemia (fatigue, pallor)
- Jaundice
- Abdominal pain
- Dysphagia
- Erectile dysfunction
- Venous thrombosis (unusual sites: hepatic, portal, cerebral veins)
- May be associated with aplastic anemia
Investigations
- Flow cytometry: absence or reduction of CD55 and CD59 (diagnostic test)
- Low hemoglobin
- Raised LDH
- Low haptoglobin
- Negative Coombs test
- Possible pancytopenia
Management
- Eculizumab or Ravulizumab (complement inhibitors)
- Folic acid supplementation
- Blood transfusions if needed
- Anticoagulation for thrombosis
- Bone marrow transplant in severe cases
Complications
- Life-threatening thrombosis
- Chronic kidney disease
- Progression to aplastic anemia or acute leukemia
- Acquired (not inherited)
- Intravascular hemolysis
- Negative direct Coombs test
- Flow cytometry is diagnostic”
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