6.5.2 Hemolytic Anemia Flashcards
1
Q
You suspect hemolytic anemia in your patient who presents with Hgb 6.3, recent fatigue, and increased __________________________, or evidence of _________________________________.
A
- You suspect hemolytic anemia in your patient who presents with Hgb 6.3, recent fatigue, and:
- increased reticulocyte count without evidence of bleeding or after correction of iron/nutritional deficiency, or
- evidence of RBC destruction with increased LDH and bilirubin, decreased haptoglobin, and alteration in RBC shape on peripheral smear
2
Q
Name the 5 categories of etiologies for hemolytic anemia
A
- Intracorpuscular vs extracorpuscular defects
- Inherited vs acquired defects
- Acute vs chronic
- Immune vs non-immune destruction
- Intravascular vs extravascular
3
Q
Describe the following:
- Intracorpuscular etiology of hemolytic anemia
- Mostly inherited or acquired?
- 5 main types of intracorpuscular causes
A
- Intracorpuscular etiology of hemolytic anemia
- Defects in the RBC itself that result in lysis
- Mostly inhereited
- Types of intracorpuscular causes
- Enzyme deficiencies
- G6PD or pyruvate kinase deficiency
- affect metabolic capacity including transport and recovery
- G6PD or pyruvate kinase deficiency
- Hemoglobinopathies
- Sickle cell disease
- Thalassemia
- Membrane defects
- Hereditary spherocytosis, elliptocytosis, tomatocytosis
- Alterations in RBC shape or membrane function
- Hereditary spherocytosis, elliptocytosis, tomatocytosis
- Paroxysmal nocturnal hemoglobinuria
- Acquired
- Alpha thalassemia
- Acquired d/t myelodysplasia
- Enzyme deficiencies
4
Q
Describe the following:
- Extracorpuscular etiology of hemolytic anemia
- Mostly inherited or acquired?
- 7 main causes of extracorpuscular HA
A
- Extracorpuscular etiology of hemolytic anemia
- Normal RBCs destroyed by mechanical, immunologic, infectious, or metabolic alterations
- Mostly acquired
- 7 main causes of extracorpuscular HA
- Antibodies directed at RBC membrane
- Autoimmune / alloimmune
- Transfusion rxn (acute/delayed)
- Drug-induced
- Mechanical stress
- Valve disease
- Device implants
- Platelet microthrombi in TTP/HUS/DITMA
- DIC: intravascular fibrin stranding
- Thermal burns
- Hypersplenism
- Causes trapping and destruction
- Infection
- Hereditary TTP
- Oxidant agents on metabolic defect
- Central toxins, venom, copper poisoning (Wilson’s dz)
- Antibodies directed at RBC membrane
5
Q
Your patient has an immune mediated hemolytic anemia. How is this caused?
How will you identify it?
A
- Immune mediated
- RBC destruction caused by antigen-antibody complexes and/or
- Complement proteins (membrane attack complexes)
- Direct or Indirect Coombs test
- Can detect presence of immune complexes directed against RBC globulins
- Causes
- Autoimmune hemolytic anemia, drug-induced hemolysis, hemolytic transfusion reaction, cold agglutinins dz
6
Q
Describe the following:
- Intravascular etiology of hemolytic anemia
- Examples of causes
- Signs/Dx
- Consequences
A
- Intravascular etiology of hemolytic anemia
- Occurs within the circulation, when there is significant membrane structural damage or when the RES is overwhelmed
- Examples of causes
- Trauma, shear stress
- Thermal burns
- Complement induced lysis
- Toxins
- Thrombotic microangiopathies
- Acute txfn rxn
- Rh immune globulin (used for tx ITP)
- Signs/Dx
- Free serum hgb or heme (products of hemolysis directly into bloodstream)
- Urinary hemoglobin, heme, hemodiserin
- Dark urine
- Oxyhemoglobin pink-tinged blood
- Mehemoglobin dark-tinged blood
- Consequences
- AKI, DIC, increased risk of thrombosis d/t free Hgb or heme
7
Q
Describe the following:
- Extravascular etiology of hemolytic anemia
- RES
- Consequences
A
- Extravascular etiology of hemolytic anemia
- Occurs via macrophages within the reticuloendothelial system
- RES
- Liver, spleen, bone marrow, lymph nodes
- Consequences
- Damaged RBCs
- RBCs coated in complement
- Alterations in RBC shape or reduced malleability (spherocytosis, sickle cells)
8
Q
Your patient has an anemia with elevated retics, and no clear source of bleeding or dietary deficiency. How will you proceed with dx workup?
A
- Treatment first if life-threatening anemia
- Transfusion for severe symptomatic anemia
- Plasmapheresis for TTP
- Hydration/diuresis for acute transfusion reaction
- H & P
- Onset of sx
- Recent transfusion? Last 4 wks (delayed onset?)
- New medication - esp if G6PD deficiency is suspected
- Hx of hemolytic anemia or fam hx of anemia
- Splenomegaly, hepatomegaly
- Presence of jaundice or scleral icterus
- Dark urine
- Lab tests
- If NO obvious cause based on presentation and initial symptoms:
- Start with direct antiglobin test (Coombs test)
- Will test for IgG or complement attached to RBC, will help distinguish btwn immune and non-immune mediated hemolysis
- Hgb, reticulocytes
- Lactate dehydrogenase (up)
- Haptoglobin (down)
- Increased unconjugated bilirubin
- Peripheral blood sphere
- Schistocytes, likely TMA
- Sphero, ellipto, stomatocytes: Inherited RBC dysmorphology
- Sickle cells or thalassemia
- If NO obvious cause based on presentation and initial symptoms:
- Other causes
- Direct parasitization (malaria, babesiosis, bartonellosis, leishmaniasis)
- Malaria can also cause hypersplenism causing an additional extravascular hemolysis
- Bactrerial infxn (clostridium, Haem B)
- Liver disease > splenomegaly d/t portal htn > RBC membrane alteration in target cells, spur cells, burr cells, stomatocytes
- Renal dz > fragmentation in microvasculature, uremic plasma, hemodialysis
- Direct parasitization (malaria, babesiosis, bartonellosis, leishmaniasis)