Heme Flashcards
Hemophilia
X-linked recessive inheritance clotting factor disorder
- Hemophilia A: factor VIII decrease → “Aight”
- Hemophilia B: decreased clotting factor IX
- Normal Factor Activity: 50-150%
- mild: 6-49% (Bleeding during surgery)
- moderate: 1-5% (occasional bleeding)
- Severe: <1% (spontaneous bleeding)
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S/sxs:
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hemarthrosis (bleeding in joint)
- main sxs = excessive bleeding
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hemarthrosis (bleeding in joint)
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Diagnosis: increased PTT, normal PT, normal platelets and function
- → corrected with mixing study
- if PTT is NOT corrected with mixing studies = indication of lupus anticoagulant or factor inhibitor
- most specific test: functional assay for factor VIII or IX
- → corrected with mixing study
-
Tx: replacement for depleted factors
- avoid situations that cause bleeding
- avoid certain drugs that interfere with platelet function (NSAIDs and aspirin)
Von Willebrand Disease
Autosomal Dominant → most common genetic bleeding disorder clotting factor disorder
- missing protein for platelet function (usually hangs out in the endothelium of the blood vessels and is important for factor VIII transport → platelets cannot adhere to vessel at site of injury → bleeding doesn’t stop as quickly as it should
- hormonal changes, stress, pregnancy, inflammation, and infection can stimulate vWF production
- S/sxs: hx and family hx of bleeding, bruising easily, increased menstrual bleeding, no hemarthrosis, petechiae, bleeding with minor injury
-
Dx:
- decreased vWF and decreased Factor VIII
- normal CBC, normal platelet count, and increased bleeding time
- → normal or prolonged PTT with normal PT
-
Tx: DDVAP (desmopressin)
- if excessive bleeding → transfusion of concentrated blood clotting factors containing vWF
Vitamin K Deficiency
Clotting Factor Disorder
Vitamin K does not cross the placenta and it is a fat soluble vitamin for bone calcification and activation of coagulation factors
- Vitamin K activates: factors II, VII (half-life = 4-6 hours), IX, X, Protein C and Protein S
- prolonged PT
- causes: malnutrition, abx, fat malabsorption, hemorrhagic disease of the newborn
-
S/sxs:
- bleeding, mucosal bleeding, epistaxis, GI hemorrhage, menorrhagia, and hematuria
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Dx:
- prolonged PT or elevated INR that improves with phytonadione (generic name for vitamin K1)
- Tx: Oral or SQ phytonadione
What causes a high aPTT?
activated partial thromboplastin time
measures the intrinsic pathway (slower)
- Intrinsic Pathway Factors: XII, XI, IX, VIII
- aPTT is the time in seconds for a fibrin clot to form: measures the function of factors VIII, IX, and XI
-
Causes of a high aPTT:
- heparin
- decreased factor (VIII, IX, XI), vitamin K, liver disease
- consumption: inhibitor, DIC
What causes a high PT?
Prothrombin Time: measured in INR
measures the extrinsic pathway (faster pathway)
-
PT is the time in seconds for the fibrin clot to form: measures the function of tissue factor and Factor VII
- Warfarin
- NOACS
- decreased factors: VII, liver disease, Vitamin K
- overconsumption: DIC
Heparin-Induced Thrombocytopenia
hypercoagulable state
- ≥ 50% reduction in platelet count within 7-10 days of exposure to heparin; results in global thrombocytopenia and thromboembolism due to immune rxn with platelet factor
- S/sxs: hx of multiple DVTs, CBC is normal, PT and PTT is normal
- Dx: HIT assay
-
Tx:
- to prevent thrombotic stroke or MI use antiplatelet therapy: aspirin, clopidogrel, prasugrel or dipyridamole/aspirin combo
- stop the heparin but still need an anticoagulant → must use a direct thrombin inhibitor (dabigatran)
Antiphospholipid Syndrome
Hypercoagulable State
Dx & Tx trick: CardiB goes to War → Cardiolipin, anti-beta 2, tx with warfarin
certain membrane phospholipids are normally prevented from activating the coagulation cascade by binding to circulating phospholipid-binding proteins; antibodies to these binding proteins block this protective measure and predispose the pt to thrombosis → associated with lupus and PREVIOUS MISCARRIAGES
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S/sxs:
- hx of multiple DVTs
- CBC is normal, PT and PTT are normal
- hx of multiple DVTs
-
Dx: ANA and CRP in SLE
- Russell’s Viper Venom time is specific to detect lupus anticoagulant
- (+) anticardiolipin antibody
- (+) anti-beta 2 glycoprotein I ELISA
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Tx:
- Prednisone (for Lupus) and Warfarin
Factor V Leiden Mutation
Most common genetic hypercoagulable state
mutations in factor V (of the common pathway) make it resistant to normal inactivation by activated protein C and predispose the pt to venous thrombosis
- have high suspicion in pts with recurrent thromboembolic events, thromboembolism in young pts, or in pts with NO risk factors; previous miscarriages
- S/sxs: hx of multiple DVTs, CBC is normal, PT and PTT are normal
-
Dx:
- Factor V leiden Assay
- Protein CC
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Tx: anticoagulation
- antiplatelet therapy: aspirin, clopidogrel, prasugrel or dipyridamole/aspirin
- oral anticoagulant: Vitamin K antagonist, warfarin, direct thrombin inhibitor (dabigatran) or factor Xa blocker (rivaroxaban)
Normal Platelet Range
130-400K
Idiopathic Thrombocytopenic Purpura
aka immune thrombocytic purpura
- Epidemiology: autoimmune rxn to platelets usually after a viral illness → splenic platelet destruction often after an acute infx
- Caused by: viral infx, SLE, lymphoma, medications
-
s/sxs:
- mucosal bleeding, purpura, rashes, easy ecchymosis, petechial rashes
- chronic in adults, self-limiting in children (usually)
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dx:
- diagnosis of exclusion (clinical diagnosis)
- isolated thrombocytopenia (very low) with a normal CBC and normal peripheral blood smear
- (+) Direct Coombs Test
- Normal PT and aPTT
- Primary ITP: isolated thrombocytopenia (<100K) without a known cause
- Secondary ITP: isolated thrombocytopenia (<100K) with an underlying condition (e.g. HIV)
-
Tx:
- steroids (prednisone) → blocks production of antibody
- IVIG (IV Immune globulin)
- Rituxan (Rituximab) → thrombopoietin receptor agonist
- Splenectomy → reserved for pts with severe thrombocytopenia (<15K)
Thrombotic Thrombocytopenic Purpura
acute febrile disease with multi-organ thrombosis
-
caused by: deficiency or inhibition of metalloproteinase ADAMTS13 → most commonly disabled by autoantibody
- ADAMTS13 normally degrades (cuts up) vWF multimers; so with deficiency have increased platelet adhesion → platelet thrombosis = damages brain and kidneys
- Triggers: after drugs: quinidine, cyclosporine, clopidogrel, ticlopidine
- Risk Factors: female, AA, use of desmopressin (DDVAP), pregnancy
- Hemolytic uremic syndrome
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S/sxs:
- adults = purpura and FAT RN → Fever, anemia, thrombocytopenia, renal failure, neurological symptoms
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Dx: CBC = normal, except LOW platelets
- schistocytes (RBC fragments on the smear)
- (-) Direct Coombs Test
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Tx:
- plasmapheresis (plasma exchange) = tx of choice → done daily until evidence of subsiding disease and is indicated by a normal platelet count
- corticosteroids + Rituximab (thrombopoietin receptor agonist)
Disseminated Intravascular Coagulation
abnormal activation of the coagulation sequence lead to the formation of microthrombi through the microcirculation → causes increased consumption of platelets, fibrin, and coagulation factor
-
S/sxs: bleeding and thrombosis occur simultaneously
- bleeding and oozing at catheter sites, mucosal surfaces, petechiae, and ecchymosis, hypotension, and tachycardia
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Dx:
-
decreased platelets (slightly), increased bleeding time, increased PT and aPTT, (+) D-Dimer
- SCHISTOCYTES
- Fibrinogen = decreased
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decreased platelets (slightly), increased bleeding time, increased PT and aPTT, (+) D-Dimer
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Tx:
- supportive care: cryoprecipitate, FFP, platelet transfusions if <10K, heparin for thrombosis, tx the cause
Schistocyte
Microcytic Anemia
Low MCV (<80): a Tic is small (microcytic)
- Thalassemia
- Iron Deficiency
- Chronic Disease
- Lead poisoning
Iron Deficiency Anemia Pathophys, Etiology, & Risk Factors
Microcytic Anemia: most common cause of anemia worldwide
- Pathophys: decreased RBC production due of lack of iron and decreased iron stores (ferritin) normally stored in the bone marrow, liver and spleen
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Etiology:
- chronic blood loss = most common cause in the US, excessive menstruation, occult GI blood loss, decreased absorption: diet, celiac, bariatric surgery, H.pylori
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Risk Factors:
- increased metabolic requirements → children, pregnant and lactating women
- → cow milk ingestion in young children: infants fed cow’s milk <1 yr of age, toddlers fed large quantities of cow’s milk
Iron Deficiency Anemia S/sxs, PE, Dx, & Tx
Microcytic (<80) anemia
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S/sxs: weakness, fatigue, exercise intolerance, dyspnea
- pagophagia→ craving for ice
- Pica: appetite for non-foods (clay, starch)
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PE: koilonychia: spooning of the nails
- angular cheilitis : inflammation of the corner of the mouth
- tachycardia, glossitis (smooth tongue), signs of anemia (pallor)
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Dx:
- CBC: microcytic hypochromic anemia = CLASSIC
- Increased RDW, decreased reticulocytes
- Iron Studies: decreased ferritin (pathognomonic), increased TIBC (transferrin), decreased transferrin saturation
- CBC: microcytic hypochromic anemia = CLASSIC
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Tx: iron replacement: results in increased reticulocytes (within 5-10days), correction of anemia (6-8weeks), repletion of iron stores (1-3 months)
- increased absorption: take iron replacement with vitamin C (ascorbic acid) with water or orange juice on an empty stomach
- severe life threatening anemia tx: rbc transfusion (e.g.myocardial ischemia)
Intrinsic vs Extrinsic Hemolytic Anemia
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Intrinsic: (inherited Disorders)
- sickle cell anemia, thalassemia (microcytic), G6PD deficiency, hereditary spherocytosis
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Extrinsic: (Acquired Disorders)
- autoimmune hemolytic anemia, DIC, TTP, HUS, paroxysmal nocturnal hemoglobinuria, hypersplenism
Hemolytic Anemia S/sxs & Dx
- acute onset of pallor from anemia
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splenomegaly
- jaundice with high indirect bilirubin → too much RBC breakdown for the liver to keep up with
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splenomegaly
- increased LDH: hemolytic anemias will have increased LDH b/c it is part of the RBC membrane
- increased reticulocytes
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Dx:
- positive Coombs test if autoimmune etiology
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G6PD deficiency:
- episodic hemolytic anemia associated with sulfa drugs, fava beans, infx
- HEINZ BODIES
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Hereditary Spherocytosis:
- (+) osmotic fragility test: mixes RBCs with varying saline, abnormally shaped RBCs will be fragile and fall apart
- Thalassemia: very low MCV + normal TIBC and ferritin
- Sickle Cell Anemia: very high reticulocyte count + pain
Autoimmune Hemolytic Anemia Tx
1st line = steroids; more severe and persistent may need a splenectomy and/or blood transfusions
Hereditary Spherocytosis Tx
Hemolytic anemia
splenectomy after appropriate IZs
Two types of Autoimmune Hemolytic Anemia
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warm antibody type: autoantibodies attach to and destroy RBCs at temperatures equal to or in excess of normal body temp
- medications: penicillins, cephalosporins, rifampin
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Cold antibody Type: autoantibodies become most active and attack RBCs only at temperatures below normal body temp
- IgM antibodies
Anemia of Chronic Disease Etiology &
Pathophys
Microcytic or Normocytic Anemia
due to decreased RBC production in setting of chronic disease
- Etiology: chronic infection, inflammation, autoimmune disorders, malignancy
-
Pathophys: 3 main factors that decrease serum iron:
- increased hepcidin: acute phase reactant that blocks the release of iron from macrophages, blunts EPO, and reduces GI absorption
- increased ferritin: acute phase reactant that sequesters iron into storage
- erythropoietin inhibition via cytokines
Anemia of Chronic Disease common causes, Dx, & Tx
Microcytic or Normocytic Anemia
-
Most common causes:
- CKD (stage 4 and 5), anemia from connective tissue disorders, other diseases → RA, SLE, HIV, CA, cirrhosis, chronic infx
-
Dx: normocytic or decreased MCV
- decreased TIBC, and normal or increased ferritin
- CBC, serum iron, ferritin, transferrin
-
Tx:
- tx the underlying disorder
- recombinant EPO and iron supplements if HGB <10gm/dl → need to stop once hgb >11 gm/dl due to increased risk of MI and stroke
Aplastic Anemia
Normocytic, normochromic anemia
- only anemia where all 3 cell lines are decreased: decreased WBCs, decreased RBCs, decreased platelets
- ***will have normal MCV, decreased reticulocytes***
-
Etiology:
- often idiopathic but can be caused by chemicals, drugs, or radiation → ACE inhibitors, sulfonamides, phenytoin, chloramphenicol, chemo, methimazole, and radiation
-
PE: severe pallor, petechiae, ecchymosis, mucosal bleeding
- → severe infx with decreased RBCs, WBCs, and platelets but no reticulocytosis
-
Dx: suspect in pts with pancytopenia (WBC < 1500, ****platelets <50K****)
- decreased reticulocytes (helps to differentiate aplastic anemia in sickle cell patients who usually have a high baseline reticulocyte count)
- serum iron = elevated
- Most accurate test = bone marrow biopsy → normal cell morphology, hypocellular bone marrow with fatty infiltrate
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Tx:
- d/c offending drug, RBC transfusion
- curative = bone marrow transplant (for pts <50 yo)
- immunosuppression agents for pts >50 yo or with comorbidities
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Filgrastim (hematopoietic growth factor: G-CSF)
- reduces infx but does not change the course of the disease