Table of contents
- 1. Approach to Anemia
- 2. Microcytic Anemia
- 2.1. Thalassemia
- 3. Normocytic Anemia
- 4. Macrocytic Anemia
- 5. Multiple Myeloma
- 6. Pancytopenia
- 6.1. Causes
- 6.2. Aplastic Anemia
- 7. Notes
Approach to Anemia
- Pathologic state due to insufficient erythrocytes.
- Easiest way to classify:
- 2ndary to loss
- 2ndary to lack of production
- 2ndary to destruction
- Symptoms:
- Tachycardia, exertional dyspnea, pallor of nails/conjunctiva, fatigue, reduced exercise tolerance.
- Labs:
- CBC
- Pathology:
- To make RBC, require: Epo (Made in Kidney), Iron, Cobalamin, Vitamin B12, marrow microenvironment.
- Approach:
- Look at MCV (micro/normo/macrocytic)
- Peripheral blood smear (always look at smear).
- Reticulocyte Count: (tells you if the marrow is working).
- Typically a % of normal erythrocytes
- Now done with flow cytometry.
- Patients with anemia have LOW total erythrocytes
- Often corrected as reticulocyte index as bone marrow stress causes increased Epo production --> doubles of half-life of circulating reticulocytes (multiply by 0.5).
- Therefore, must correct to reticulocyte index = %retics * hematocrit (/45 *0.5)
- (last part is the correction factor for the doubling of retics)
- Absolute Retic Counts:
(some labs do FLOW cytometry, which reports Absolute Number--> eaier to use, less available)-
Retic Count Retic Index Interpretation 23,000-90,000/uL <2% Normal (Inappropriate Response to Anemia) > 100,000/uL >3% Appropriate Anemia Response
(Retic Index numbers: wikipedia, Retic count numbers: MKSAP 16)
-
- Mentzner index to distinguish thalassemia vs iron def anemia
- MCV/RBC -->
- <13 - talassemia (bone marrow still produces enough RBC)
- >13 - Iron def anemia (bone marrow cannot produce as many, so there are few RBCs and microcytic)
- MCV/RBC -->
Microcytic Anemia
DDx TAILS
- Thalassemia
- Anemia of Chronic Disease
- Iron Deficiency Anemia
- Lead Poisoning
- Sideroblastic Anemia
Standard Workup:
- Blood Film
- Ferritin
- Retics
- B12 (Folate low yield)
Can use RDW to help distinguish etiologies:
- Iron Deficiency: increased RDW (anisocytosis)
- Thalassemia minor: normal RDW (also expect high RBC count)
Thalassemia
- Risk factors:
- Thalassemia major --> only in kids
- B-thalassemia --> Mediterranian, Middle eastern.
- Labs:
- Microcytic anemia but Normal Ferritin.
- Persistently low MCV (MCV not changing if you trend it).
- Low RDW
- Hemoglobin electrophoresis
- If normal can still be alpha-thalassemia (B-thal will show up). Need to do genetic testing.
- Genetic testing = Definitive.
Normocytic Anemia
- Nutritional (Can be IDA, folate, B12, sick cell, methotrexate)
- Renal Failure (Often CKD stage 4) EPO deficiency. If giving Epo, ensure has iron too.
- Active Bleed
Macrocytic Anemia
- EtOH Use
- Myelodysplastic Syndrome
- Folate Deficiency
- B12 Deficiency (also glossitis, weight loss, macroovalocytes, hypersegmented PMNs, hemolysis, posteriour columns neuro deficits).
- etc...
Multiple Myeloma
- Pt may have history of fractures
- sPEP and uPEP (Serum Protein ElectroPhoresis, and urine Protein Electrophoresis)
- sPEP --> 80% sensitivity
- adding uPEP --> raises sensitivity to 80-95% sensitivity
- for uPEP they do spot urine for Bence Jones Proteins (even thought called uPEP)
- 5% of patients with MM will have normal sPEP and uPEP
Pancytopenia
Causes
- Primary BM Failure: (MDS, Aplastic Anemia)
- Malignancy: (Leukemia)
- Infiltrative Process (TB, Amyloidosis, Sarcoidosis)
- Drugs (Chemotherapy)
Aplastic Anemia
- Destruction of hematopoietic cells in BM leading to pancytopenia and hypocellular bone marrow.
- Etiology: (BROAD!)
- Congenital
- Fanconi's Anemia (genetic DNA repair problem, leads to leukemias and BM failure in Ashkenazi)
- Shwachman-Diamond Syndrome (BM failure and pancreatic insufficiency)
- Acquired
- Idiopathic (T-cell mediated - 1/3 to 2/3 of cases)
- Drugs (Chemotheraputic agents, and idiosyncratic rxns chloramphenicol, phenylbutazone)
- Toxins (Benzene, organic solvents, DDT, insecticides)
- Ionizing Radiation
- Post-Viral Infection (parvovirus B19, EBV, HDV, HEV, HHV6, HIV)
- Autoimmune (SLE) - rare
- Paroxysmal nocturnal hemoglobinuria (PNH) - associated with aplastic anemia, but not cause.
- Congenital
- Investigations:
- No LAD, can be acute or insidious
- Anemia, neutropenia, Thrombocytopenia +/- pancytopenia.
- Blood film (decreased number of RBC)
- Bone Marrow (Hypocellular, hypoplasia, fat replacement)
- Treatment:
- Remove Offending Agent
- Supportive care (transfusions, antibiotics)
- Immunosuppression (anti-thymocyte globulin - 50-60% respond, cyclosporine).
- Allogenic BM transplant.
Notes
- Bone Marrow Suppression causes 10 g/L/week loss of Hb. NOT MORE!
- High RDW associated with:
- Iron deficiency anemia, hemolytic anemias, myelofibrosis, blood transfusion
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