Hematology Flashcards
Discuss the causes of decreased RBC production
- usually low reticulocyte count <2 Hormone Stimulation - decreased EPO from renal failure - hypothyroidism Bone Marrow Suppression - medication - chemotherapy - Radiation Bone Marrow Disorder - aplastic anemia - RBC dysplasia - marrow infiltration Lack of Nutrients - iron deficiency - vit B12 or folate deficiency Ineffective RBC erythropoiesis - megaloblastic anemia - alpha and beta thalassemia - myelodysplastic syndrome - sideroblastic anemia
Discuss the causes of increased RBC desctruction
- high reticulocyte count, LDH, bilirubin (jaundice) and low haptoglobin
Intravascular Hemolysis
- migroangiopathic hemolytic anemia: TTP, aortic stenosis, prosthetic valve
- transfusion reaction
- infection: malaria
- paroxysmal cold hemoglobinuria
Extravascular RBC Defects
- intrinsic RBC defects
- enzyme deficiency: G6PD, pyruvate kinase deficiency
- hemoglobinopathies: sickle cell anemia, thalassemia
- membrane defect: spherocytosis
- extrinsic RBC defect
- liver disease
- hypersplenism
- infection: malaria
- toxin: lead, copper
- autoimmune hemolytic anemia
Blood lossDiscuss the presentation and investigation for anemia
Presentation
- fatigue
- headache, syncope
- palpitation
- shortness of breath on exertion
- skin pallor
Investigations
- CBC for Hgb, MCV
- Reticulocyte count
- blood film
- iron: total iron binding capacity, transferrin, ferritin
- LDH, bilirubin, haptoglobin, Coomb's test (direct)
- anemia with reticulocytosis
- pancytopenia or blast cells require bone marrow biopsyDiscuss the differential for microcytic anemai
- MCV <80 TAILS - Thalassemia - Anemia of chronic disease - Iron deficiency - Lead poisoning - Sideroblastic anemia
Discuss the differential for macrocytic anemia
- MCV >100 BALDRAT - B12 and folate deficiency - Alcohol - Liver disease - Drugs (anti-metabolites) - Reticulocytosis - Aplastic anemia (AML, myelodysplastic) - Hypothyroid
List the differential for normocytic anemia
Low Reticulocyte Count
- anemia of chronic disease
- bone marrow failure
High Reticulocyte Count
- hemolytic anemia, inherited
- hemoglobinopathy: sickle cell, thalassemia
- membrane: spherocytosis
- metabolic: HMP shunt, glycolytic pathway
- hemolytic anemia, acquired
- immune: Coombs positive, drug related
- infection: malaria
- microangiopathic hemolytic anemia: DIC, TTP, HUS, HELLP
- drug related
- acute hemorrhage
- chronic renal failure
- endocrine dysfunction: hypothyroid, hypopituitarism
List the differential for primary hemostatic disorders
- inability form platelet plug
Thrombocytopenia
- decreased production
- folate or B12 deficiency
- liver disease or alcohol
- bone marrow failure: aplastic anemia, chemotherapy, drug induced, myelodysplasia
- congenital: Alport, Fanconi
- infection: HIV, HCV, EBV, mumps
- sequestration from splenomegaly
- liver disease, malignancy, myelodysplasia
- Increased destruction
- immune: ITP, SLE, HIT
- non-immune: DIC, TTP, HUS, HELLP, pre-eclampsia
- Dilution
Platelet Dysfunction
- hereditary: GPIb or GPIIb/IIa deficiency
- acquired: aspirin, NSAID, alcohol, CKD
Von willebrane Disease
Vascular
- hereditary
- connective tissue disorder
- acquired
- henoch-schonlein purpura
- Cushing's syndromeList the differential for secondary hemostatic disorders
- inability to form fibrin clot Hereditary - Factor 8 deficiency: Hemophilia A, vWD - Factor 9 deficiency: Hemophilia B - Factor 11 deficiency Acquired - liver disease - DIC - vitamin K deficiency
Discuss the approach to bleeding disorders
Low Platelets on CBC
- consider thrombocytopenia causes
Normal PT/INR and aPTT with normal platelet count
- differential: platelet dysfunction, vWD, factor 13 deficiency, vascular integrity disorder
- platelet function analysis (PFA-100) and blood film to assess for platelet dysfunction
- factor 8 activity level, vWF antigen and ristocetin cofactor for vWD (all low)
Prolonged aPTT only
- hereditarory: Hemophilia A, Hemophilia B, vWD, factor 11 or 12 deficiency
- acquired: heparin, direct thrombin inhibitor (dabigatran)
- factor 8, 9, 11 assay
Prolonged PT/INR Only
- hereditary: factor 7 deficiency
- acquired: warfarin, vit K deficiency, liver disease
- factor 7 assay if does not improve with vit K
Prolonged PT/INR and Prolonged aPTT
- hereditary: prothrombin deficiency, fibrinogen deficiency
- acquired: severe liver disease, excessive anticoagulation with Warfarin or Heparin, direct Xa inhibitor (Apixaban, Rivaroxaban), DIC
- assess fibrinogen and D-Dimer for DIC (low fibrinogen and high D-Dimer suggest DIC)
Differentiate between inflammatory and neoplastic lymph nodes
Consistency - rubbery in inflammatory - firm/hard in malignant Mobility - mobile in inflammatory - matted/immobile in malignant Tenderness - tender in inflammatory - non-tender in malignant Size - <2cm in inflammatory - >2cm in malignant Investigation - malignant require excision biopsy, core biopsy or fine needle biopsy
List the differential for generalized lymphadenopathy
Infection - bacterial: TB, Lyme, cat-scratch disease - viral: EBV, CMV, HIV - parasitic: toxoplasmosis - fungal: blastomycosis Inflammatory - rheumatologic: RA, SLE, vasculitis, Sjogren - Drug hypersensitivity - infiltrative: sarcoidosis, amyloidosis - serum sickness Neoplastic - blood: lymphoproliferative disorder, lymphoma - metastatic cancer - histocytosis X
Discuss the exam and investigations for splenomegaly
Exam - jaundice, stigmata of chronic liver disease - Petechiae for thrombocytopenia - palpation and percussion of spleen (Castell's sign) - palpation and percussion of liver - CHF Investigations - CBC, blood film, reticulocyte count - LDH, haptoglobin, LFT
List the differential for splenomegaly
Hematological - hemolysis - nutritional anemia - hemoglobinopathy - spherocytosis, elliptocytosis Infection - CMV - Bacterial endocarditis - TB - HIV/AIDS - EBV - Histoplasmosis Inflammatory - SLE - Felty syndrome - Still's disease Vascular - Splenic vein thrombosis - Portal vein obstruction - Portal vein hypertension Infiltrative - benign metaplasia - amyloidosis, sarcoidosis - lysosomal or glycogen storage diseasse Malignancy - Leukemia - Lymphoproliferative disorder - Hodgkin's lymphoma - Myeloproliferative disease - Metastatic
Discuss virchow’s triad
Stasis - bed rest - post-surgery - long leg cast - long flights Hypercoagulable State - Inherited thrombophilia: Factor V leiden, protein C/S deficiency, anti-phospholipid antibody syndrome - Active malignancy - Inflammatory disorder - Pregnancy, post-partum - Hormone replacement, OCP Endothelial injury - surgery - Venous catheter
Discuss the presentation and management of deep vein thrombosis
Presentation
- Pain and tenderness in thigh or calf
- unilateral swelling of leg with erythema and warmth
- Phlegmasia alba dolens: severe DVT with arterial spasm leading to cold, pale limb with weak pulse
- Phlegmasia cerulea dolens: total DVT causes severe edema, cyanosis, venous gangrene, compartment syndrome
- palpable cord
- pitting edema
- Homan’s sign: calf tenderness with forced dorsiflexion
Investigation
- D-dimer
- Compression ultrasound
Management
- Acute: LMWH Enoxaparin 1mg/kg/dose SC Q12H
- continue until warfarin INR 2-3
- Long term: NOAC or warfarin started on first day
- warfarin start at 2-5mg PO
- 3 months for provoked DVT
- 6 months or lifetime if unprovoked
