Hemolysis Flashcards
General Features of Hemolytic Anemia
- Jaundice/Scleral icterus (excess bilirubin from free Hb degradation)
- Dark Urine
- Pigmented gallstones (excess bilirubin from free Hb degradation)
- Ankle Ulcers
- Splenomegaly
- Aplastic Crises assoc. with Parvovirus B19
- Increased Folate requirement
Functions of Spleen
- Antibody factory
- Blood quality control (macrophages)
- WBC and platelet repository
Post Splenectomy Findings
- Howell-Jolly Bodies
- Target Cells
- Acanthocytes
- Schistocytes
- Nucleated Red Cells (NRBCS) in plasma
Parvovirus B19
- Non-encapsulated DNA virus
- lyses RBCs in bone marrow
- Not a problem for normal people because effects seen 7-10 days post exposure and normal RBC lifespan ~120 d
- In hemolytic anemia patients, RBC life span is much shorter –> plumetting Hb values because current RBCs are lysing
Extravascular Hemolysis
Macrophages in Spleen, Liver, Marrow remove damaged or antibody coated cells
Intravascular Hemolysis
- RBCs rupture inside vasculature
- Release free Hb into circulation
- Could potentially cause iron overload, other general features of hemolysis
Lab Features of Hemolytic Anemias
- Increased RBC Production
- Blood
- Increased Rct (shows as polychromasia in smear)
- Increased MCV (Rct larger than RBCs)
- Circulating NRBCs
- Increased RDW
- Bone Marrow
- Erythroid hyperplasia (increased prod. of RBC precursors)
- Decreased M:E
- Bone
- Marow space expansion due to increased erythropoeisis
- Frontal Bossing** **
- Blood
- Increased RBC Destruction
- Decreased RBC lifespan
- Increased LDH Levels
- Increased unconj. bilirubin
- Decreased serum Haptoglobin
- Hemoglobinemia
- Hemoglobinuria
- Hemosiderinuria
- Decreased RBC lifespan
Peripheral Smear Artifacts due to Hemolysis
- Schistocytes
- Sphereocytes
- Bite/Blsiter cells
- indicates Heinz Body hemolysis from oxidative damage
- seen in G6PD deficiency
- indicates Heinz Body hemolysis from oxidative damage
Classification of Hemolytic Anemias by Etiology
- Congenital - membrane defects
- Hereditary Spherocytosis
- Enzymatic Defects
- Immune Mediated Hemolysis
- Warm Antibody HA
- Drug Induced
- Cold Antibody HA
- Warm Antibody HA
- Non-Immune Hemolytic Anemia
Hereditary Sphereocytosis
- Congenital
- Autosomal Dominant
- Defect with Spectrin & Ankyrin - membrane skeleton proteins
- lipid blebs @ surface from skeleton, pinched by macrophages inside splenic sinusoids
- Over time = extravascular hemolysis
- Clinical Features
- Splenomegaly
- Ankle Ulcers
- Increased Osmotic fragility
- Treatment
- Folate
- Splenectomy
- will stop extravascular hemolysis, but spherocytes will remain
G6PD Deficiency
- Shutdown of Aerobic glycolysis –> no energy for RBC to maintain biconcave shape
- increases RBC susceptibility to ox. damage
- anything that causes ox stress will percipitate hemolysis
- No G6PD, nothing to stop Hb–>methemoglobin –> heinz bodies from methemoglobin percipitation –> bite cells
- X-linked
- Cells destroyed mainly by extravascular hemolysis
- Clinical Features
- Hemolysis
- **Drugs that cause it **
- Sulfa drugs
- Dapsone
- Vitamin K
- Quinine
- Cholorquinine
Ways Immune Mediated Hemolysis work
- Ig coated RBCs interact with Fc Receptors on macrophages (extravascular hemolys)
-
C3 Coated RBCs
- interact with C3 receptors on macrophages (extravascular hemolys)
- complete complement cascade –> lysis (intravascular hemolys)
Hallmark of Autoimmune Hemolytic Anemias
Coomb’s Test
Coomb’s Test
- Direct
- looks for IgG OR C3 directly bound to RBC
- Indirect
- Looks for IgG ONLY in serum
Warm Antibody Hemolytic Anemia/Autoimmune Hemolytic Anemia (AIHA)
- Antibodies react with RBCs at 37 degrees C
- Do not agglutinate RBCs
- IgG antibodies formed (indirect Coomb’s positive) and bind RBCs (direct Coomb’s positive) with or without completment deposition
- both direct AND indirect Coomb’s will be positive
- IgG will be +, C3 may or may not be positive
- Associated with immune platelet destruction = Evan’s Syndrome
- Clinical Features
- Splenomegaly
- Jaundice
- Lab
- Increased Rct
- Increased Billirubin
- Increased LDH
- Coomb’s (direct & indirect)
- **Spherocytes **on peri. smear
- Treatment
- Immune suppression
- Corticosteroids (prednisone)
- Splenectomy
- Rituximab
- Folate
- Immune suppression
Methods of Immune Suppression in Autoimmune Mediated Hemolyses
- Corticosteroids (Prednisone)
- Splenectomy
- make sure to immunize against encapsulated organisms before doing this
- Rituximab (immune suppression drug)
General Mechanisms for Drug Induced Hemolyses
- Innocent Bystander
- Ab made against drug
- Ab-drug complex form
- Complexes deposit on RBC surface
- Hemolysis
- Hapten Mechanism
- Drugs bind RBC
- Ab form against Ab-RBC
- Hemolysis
- Ex: Penicillins & Cephalosporins
- True Autoimmune Mechanism
- Some drugs cause Ab to form against RBCs
- once started, Abs form without drug present
- Ex: alpha-methyldoa, L-Dopa, Procaindamide
Cold Agglutinin Disease
- Pathogenic bodies are usually IgM
- DOES cause RBC agglutination
- Fix complement for SURE
-
IgM falls off when RBCs return to warmer areas, but **complement stays on **
- can cause **intravascular hemolysis **
- OR can complete complement cascade in liver –> extravascular cascade
- Treatment
- Mycoplasma or Mononucleosis both associated with IgM
- lymphoproliferative diseases
- Keep patient warm
- Immunosuppressors (Rituximab, chemo)
- _***Steroids and Splenectomies are INEFFECTIVE_
Non-Immune Hemolytic Anemia causes
- Mechanical Traume to RBCs
- Heart & large vessel abnormalities
- March Hemoglobinuria
- Infections
- Drugs, Chemicals, Venom
Microangiopathic Hemolytic Anemia (MAHA)
- Shear damage do RBCs due to them passing by areas of endothelial damage
- Schistocytes are hallmark
- Etiologies
- TTP/HUS
- DIC
- Hypertension
- Vasculities