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Samwel Mikaye Explains PNH: Cause, Key Clinical Features, Investigations and More
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.

Samwel Mikaye Explains PNH: Cause, Key Clinical Features, Investigations and More

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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