Abstract:

This video explains Paroxysmal Nocturnal Hemoglobinuria (PNH), a rare acquired hemolytic anemia. It covers the introduction, pathogenesis (including the role of GPI, CD55, and CD59), clinical features (hemolysis, pancytopenia, thrombosis), lab diagnosis (Ham's test and flow cytometry), and relevant MCQs. PNH is characterized by a mutation in the GPI gene, leading to a deficiency of CD55 and CD59 proteins on blood cells. This deficiency causes complement-mediated lysis of RBCs, WBCs, and platelets, particularly at night when physiological acidosis activates the complement system.

Understanding Paroxysmal Nocturnal Hemoglobinuria (PNH): A Concise Summary

• 0:00:46 Introduction to PNH: Defined as an acquired hemolytic anemia resulting from a cell membrane defect in RBCs.
• 0:01:01 Genetic Basis: The defect involves a mutation in the GPI (glycosylphosphatidylinositol) gene.
• 0:02:58 Role of CD55 and CD59: Normally, CD55 (DAF - Decay Accelerating Factor) and CD59 (MIRL - Membrane Inhibitor of Reactive Lysis) protect blood cells from complement-mediated lysis.
• 0:04:15 Pathogenesis: In PNH, mutated GPI leads to a deficiency of CD55 and CD59, rendering blood cells susceptible to complement activation during nocturnal acidosis, causing intravascular hemolysis and pancytopenia.
• 0:05:21 Paroxysmal Nocturnal Hemoglobinuria (PNH) Terminology Explained:
  • Paroxysmal: Attacks, not continuous anemia.
  • Nocturnal: During the night.
  • Hemoglobinuria: Red colored urine.
• 0:08:50 Clinical Features:
  • Hemolysis (paroxysmal, nocturnal)
  • Pancytopenia (anemia, leukopenia, thrombocytopenia)
  • Thrombosis
• 0:09:45 Typical Triad of PNH: Hemolysis, pancytopenia, and thrombosis.
• 0:10:50 Lab Findings: Hemoglobinemia, hemoglobinuria, methemoglobinemia, methemoglobinuria, hemosiderinuria, mild jaundice, mild anemia, reticulocytosis.
• 0:10:52 Screening Test (Ham's Test): Artificially acidifying serum and observing RBC hemolysis.
• 0:11:48 Confirmatory Test (Flow Cytometry): Demonstrating the absence or reduction of CD55 and CD59 on blood cells. A bimodal distribution of RBCs indicates the presence of both normal cells (with CD55/CD59) and affected cells (lacking CD55/CD59).
• 0:14:40 MCQs: Sample questions related to PNH pathogenesis and diagnosis.
• 0:16:54 Additional Resources: Information on accessing notes from the session and connecting via social media for further educational content.
• 0:17:35 WhatsApp Support: Inquiries about the topic taught in the session can be sent to the support number provided.