Master Paroxysmal Nocturnal Hemoglobinuria (PNH) with Picmonic for Medicine

With Picmonic, facts become pictures. We've taken what the science shows - image mnemonics work - but we've boosted the effectiveness by building and associating memorable characters, interesting audio stories, and built-in quizzing.

Paroxysmal Nocturnal Hemoglobinuria (PNH)

Pirate of the Night He-man-globe-urinates
Picmonic

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, chronic, life-threatening, hemolytic anemia caused by an acquired intrinsic defect in the cell membrane of RBCs, WBCs and platelets.  It is a clonal stem cell defect disease caused by complement-mediated destruction of these cells. It presents with a triad of Coombs-negative hemolytic anemia, pancytopenia, and venous thrombosis.

9 KEY FACTS
PATHOPHYSIOLOGY
Defective PIG-A Gene
Defective PIG with Apple

RBCs in patients with PNH are either missing or have a mutated phosphatidylinositol glycan class A (PIG-A) gene, resulting in a mutated PIG-A protein.  Without PIG-A, important proteins cannot connect to the cell The PIG-A gene codes for a protein that ultimately results in the production of a GPI anchor.

Deficiency of DAF (Decay Accelerating Factor CD55)
Deficient DAF-Daffy with CD55 guns

Decay accelerating factor (DAF) is a glycosylphosphatidylinositol (GPI) anchored protein to RBC's that is also known as CD55. The decreased expression of DAF (CD55) leads to an inability to adequately protect RBC's from hemolysis because of increased activation of C3. C3 accumulation on RBC's opsonizes them for destruction.

SYMPTOMS
Dark Urine in the Morning
Dark Urine with Morning-sun

Also termed “cola-colored” urine. Breathing slowly at night causes retention of carbon dioxide.  This slight increase in CO2 during sleep leads to respiratory acidosis which enhances complement attachment to RBCs, neutrophils and platelets leading to hemolysis and thrombosis formation.

Intravascular Hemolysis
Hemolysing-rbc

Intravascular complement-mediated lysis or destruction of RBCs, neutrophils and platelets can lead to pancytopenia, aplastic anemia, or acute leukemia.  These patients are coombs negative.

Thrombosis
Thrombosis in vessel

Formation of small blood clots are formed within veins. This is the most common cause of death.

DIAGNOSIS
Decreased CD55 and CD59
Down-arrow CD 55 guns and 59 gun and hook

Flow cytometry will show a decrease in CD55 (Decay Accelerating Factor) and CD59 on RBCs and granulocytes.  For RBCs, the lack of CD55 and CD59, which are both GPI-linked, leads to the inability to inhibit complement and therefore lysis of RBCs. The Ham’s test (acidified serum lysis) and Sugar water test (sucrose lysis test) are abandoned diagnostic tests that are no longer used as diagnostic tools.

TREATMENT
RBC Transfusion
Blood Transfusion

Severe anemia in patients with hemolytic disease are often administered transfusions including RBC’s at a hemoglobin less than 7 g/dL.  Washed RBC transfusions to reduce ABO incompatibilities and reactions are not required in patients with PNH.

Eculizumab
Eco-lizard-mob

A humanized monoclonal antibody that is a terminal complement inhibitor.  Eculizumab specifically binds to the complement protein C5 and inhibits its cleavage to C5a and C5b.  Inhibiting cleavage of C5 prevents the generation of the terminal complement complex C5b-9 and therefore prevents the cell from being lysed.  The -li- in eculizumab indicates that this drug targets part of the immune system, -zu- indicates that it is humanized, and the ending -mab indicates this is a monoclonal antibody.

Bone Marrow Transplant is Curative
Bone Arrow Transplant

Allogenic (from same species) bone marrow transplant is the only known cure.  Bone marrow transplant is offered to patients with severe disease (life-threatening thrombosis and/or very low blood counts) because the procedure has a 15-20% chance of death.   

Unlock all 9 facts & definitions with Picmonic Free!

JOIN FREE

Take the Paroxysmal Nocturnal Hemoglobinuria (PNH) Quiz

Picmonic's rapid review multiple-choice quiz allows you to assess your knowledge.

START QUIZ NOW

It's worth every penny

Our Story Mnemonics Increase Mastery and Retention

Memorize facts with phonetic mnemonics

Unforgettable characters with concise but impactful videos (2-4 min each)

Ace Your Medical (MD/DO) Classes & Exams with Picmonic:

Over 870,000 students use Picmonic’s picture mnemonics to improve knowledge, retention, and exam performance.

Choose the #1 Medical (MD/DO) student study app.

Picmonic for Medicine (MD/DO) covers information that is relevant to your entire Medical (MD/DO) education. Whether you’re studying for your classes or getting ready to conquer the USMLE Step 1, USMLE Step 2 CK, COMLEX Level 1, or COMLEX Level 2, we’re here to help.

Works better than traditional Medical (MD/DO) flashcards.

Research shows that students who use Picmonic see a 331% improvement in memory retention and a 50% improvement in test scores.