Hematology Flashcards
What is the treatment for PE?
LMWH
What is the most common transfusion related infection
CMV
What is the confirmatory test for AIHA?
DAT
What is the treatment for AIHA?
Steroids
What does the buffy layer of blood contain?
WBC and platelets
What proteins make up normal adult hemloglobin?
Alpha and beta (and some delta)
α + β (A) = 97%; α + δ (A2) = 2%
What proteins make up normal fetal hemoglobin?
Alpha and gamma
α + γ (F)
At birth, what percentage of HbF do you have?
70%
30% HbA
At what age does the Hb pattern resemble that of an adult (HbF <2%)?
6 months
What is the composition of the following hemoglobins: HbF HbA HbA2 HbC HbS HbH HbBart
NORMAL HEMOGLOBINS
Hb F = α2γ2
Hb A = α2β2
Hb A2 = α2δ2 (normally up to 3% of adult Hb).
BETA CHAIN VARIANTS
Hb C = α2βC2 (a variant of the β chain).
Hb S = α2βS2 (a variant of the β chain).
Hb D and Hb E and HbOArab and 1000 others (other variants of the β chain).
TETRAMERS
Hb H = β4 (observed in α-thal)
Hb Bart = γ4 (observed in α-thal)
Where is an embryo, then fetus’ blood made?
Yolk sac then Liver
Yolk sac at 3 weeks
Migrates to the liver at 2 months
Bone marrow at 6 months.
What is a normal Hb range for men, women, newborns?
Men 140-180
Women 120-160
Newborns up to 200
When is the physiologic nadir for hemoglobin and why does it happen?
8-10 weeks for term babies
6-8 weeks for preterm babies
In utero there is hypoxemia, which results in upregulation of EPO and increased fetal Hb
When you are born, saturation goes up and EPO is suppressed
8-10 weeks represents fetal RBC life span
What is the best way to classify anemias?
1) Decreased production OR increased destruction
-CHECK RETICS
2) If decreased production
Microcytic, normocytic, macrocytic
3) If increased destruction
Bleed, hemolysis, splenomegaly
What is the differential diagnosis for microcytic anemia?
Cells are small because there is inadequate production of hemoglobin.
Iron deficiency anemia Thalassemia Sideroblastic anemia Lead Anemia of chronic disease (usually normocytic)
What is the differential diagnosis for normocytic anemia?
They are normal cells, just not enough
Usually due to something impairing adequate marrow synthesis.
Anemia of chronic disease
Chronic renal failure
Transient erythroblastopenia of childhood
Malignancy/marrow infiltration
Acute bleed (retic response can take 2-3 days)
Other: HIV, HLH
What is the differential diagnosis of macrocytic anemia?
Difficulty with DNA production. Cell division lags behind, cytoplasm continues to grow
Vitamin B12 deficiency
Folate deficiency
Marrow failure: Myelodysplasia, Diamond-Blackfan, Fanconi anemia, Aplastic anemia (These may be normocytic early on)
Massive reticulocytosis
Normal newborn
Hypothyroidism
Down syndrome
Chronic liver disease
Drugs (alcohol, AZT).
What is the differential diagnosis of hemolytic anemia?
Problem Intrinsic to the Red Cell
Membrane: hereditary spherocytosis, elliptocytosis
Enzymes: G6PD deficiency, PK deficiency
Hemoglobin: Hb SS, SC, S-βthal
Problem Extrinsic to the Red Cell
Non-immune hemolysis: HUS, TTP, DIC, Burns, Wilson, Vit E def, etc.
Immune hemolysis: autoimmune, iso-immune, drug-induced.
What are the three most important tests for anemia?
CBC
Retics
Peripheral blood smear
What are the following blood film findings associated with:
Target cells Pencil cells Howell-Jolly bodies Basophilic stippling Heinz bodies Hb H bodies
Target cells-iron deficiency, post splenectomy, liver disease, hemoglobinopathies
Pencil cell-iron deficiency
Howell-Jolly bodies-asplenia, megaloblastic anemia, hemolysis
Basophilic stippling- lead poisoning or thalassemia
Heinz bodies- denatured Hb seen in G6PD, thalassemia
Hb H bodies-β4 tetramers seen in Hb H disease.
What are the main causes of iron deficiency?
1) Inadequate iron endowment at birth
- Preterm
2) Insufficient iron in diet
- Only breastmilk after 6 months
3) Blood loss
- GI tract (cow milk, parasitic infection, varices, Meckel’s, polyp, ulcer, H pylori)
- Epsitaxis
- Menorrhagia
4) Malabsorption of iron
- Celiac disease
- Antacids
- Giardiasis
- IBD
- IRIDA.
Why is there an increased risk of Pb toxicity in iron deficiency?
Pica
What type of iron is better absorbed-heme iron or non-heme iron?
Heme iron
What is the typical pattern of lab results in iron deficiency anemia?
Inadequate retic response Low MCV High RDW High platelets Target cells, pencil cells Hypochromasia High transferrin/TIBC High soluble transferrin receptor (not affected by inflammation) Serum iron-not a good test because affected by diurnal variation, diet, stress, infection
What is the Mentzer index?
MCV/RBC <13=thal
MCV/RBC >13=iron deficiency
How do you treat IDA?
4-6 mg/kg/day elemental iron
Reduce cows milk to 16-24 oz
Use vitamin C/orange juice to improve absorption
Treat for 3 months
When will you see response to iron treatment?
Reticulocytosis within 3-7 days
Increased hemoglobin (usually 7 to 30 days): expect Hb increases by 10 in 4 weeks
Repletion of iron stores (usually by 3 months).
When do you use IV iron?
Malabsorption
If there is not an adequate response to iron therapy in IDA (e.g. no Hb response in 2 weeks), what are the possible explanations?
Non-compliance Wrong diagnosis Ongoing blood loss Infection Mal-absorption.
What are some features of iron deficiency anemia?
Pica
Koilonychia-spoon nails
Cheilosis-cracking at corners of mouth
Psychomotor retardation
What is thalassemia?
Group of anemia disorders due to diminished or absent normal globin chain production
What are the 4 different types of alpha thalassemia?
3 α genes:
- Silent carrier state
- Normal/mildly reduced Hb/MCV
- Hb electrophoresis normal
2 α genes:
- Alpha thal trait or minor
- Normal/mildly reduced Hb
- Low MCV
- Moderate anemia (Hb 70-100)
- Hypochromia
- Microcytosis
- Target cells
- Heinz bodies
- Splenomegaly
- Jaundice
1 α gene:
- Hb H disease
- 60-70% HbA, 30-40% HbH, 2-5% HbA2, 2-5% HbF
No alpha genes:
HbBart disease
All the gammas stick together γ4
Leads to hydrops
What is a normal Hb electrophoresis?
90-98% HbA
2-3% HbA2
2-3% HbF
What is the Hb electrophoresis patter in alpha thalassemia?
1) Alpha thalassemia carrier/trait (3 or 2 alpha genes)=NORMAL
There is a proprotional reduction in all types of Hb (HbA, HbA2, HbF) and therefore, the percentages stay the same
2) HbH disease (1 alpha gene): 60-70% HbA, 30-40% HbH, 2-5% HbA2, 2-5% HbF.
What are the differences between iron deficiency anemia and Alpha-thal trait?
1) In alpha thal, the iron studies (serum iron, TIBC, ferritin, and marrow stores) are normal.
2) In alpha thal, RDW is normal, in IDA it is high.
3) In alpha thal, the RBC count is increased, usually around 5, and the MCV is very low.
There are many small cells. The Mentzer’s index (MCV/RBC) is >13 in IDA, and under 13 in thal trait.
4) In IDA, platelets are often increased.
Why are patients from SE asia more likely than Africans to have children with HbH disease or HbBart?
Because SE asians have cis mutations (2 alpha deletions on one chromosome)
Africans have trans deletions (one on each chromosome)
What are the different types of beta thalassemia?
Beta gene defect can be B0 (absent production) or B+ (reduced production)
Type is determined by clinical phenotype!
Beta thalassemia minor (one defective gene)
Hypochromia Microcytosis Target cells Basophilic stippling Mild or no anemia.
Beta thalassemia intermedia (two defective genes B0/B+, B+/B+)
Severe hypochromic microcytic anemia with Hb 70-90
Hepatosplenomegaly
Bone changes-mastoid hyperplasia, frontal bossing
Iron overload
Some need for transfusions
Beta thalassemia major (B0/B+, B0/B0) Severe anemia (Hb <70) Abnormal growth Iron overload Need for transfusion.
Do you need to treat beta thal minor?
No
Offer genetic counseling
What is the typical hemoglobin electrophoresis in Beta thal minor?
Elevated HbA2 and HbF (the extra alpha chains combine with delta and gamma)
90-95% HbA
5-7% HbA2
2-10% Hb F
What is the hemoglobin electrophoresis pattern in betal thal intermedia?
20-40% HbA
5% Hb A2
60-80% HbF
What is the hemoglobin electrophoresis patter in beta thal major?
95% HbF
No Hb A
What is the treatment for B thal major?
Regular transfusions and iron chelation.
Monitoring for complications of iron overload (cardiomyopathy, endocrine, hepatitis)
Bone marrow transplantation
What are risk factors for lead poisoning?
Living in old home (before 1978)
Pica
What features do you see on blood smear with Pb poisoning?
Basophilic stippling
In Pb deficiency, what happens to zinc protophyrin?
High
How do you treat Pb toxicity?
Removal from exposure
Chelation
Correction of IDA
What are features of anemia of chronic disease?
Caused by inflammatory cytokines and hepcidin, which Inhibits intestinal absorption of iron
Ferritin is often high/normal, TIBC is low
What is Diamond Blackfan anemia?
Congenital pure RBC aplasia
What are the clinical features of Diamond Blackfan anemia?
Normocytic anemia that presents in first few months of life
Associated anomalies:
- Craniofacial malformations
- Thumb or upper limb abnormalities
- Cardiac defects
What are the laboratory and BM features of Diamond Blackfan Anemia?
Anemia
Normal wbc and plts
Low retics
Bone marrow with reduced erythroid precursors.
Are patients with Diamond Black Fan anemia at increased risk of cancer?
Yes, especially leukemia
How do you treat Diamond Black Fan ?
1/2 respond to long term steroid therapy
1/2 need chronic transfusions
In what group of children is transient eryhtroblastopenia of childhood most common?
Usually appears in otherwise healthy children (1-3 years)
Often after a viral trigger
Over what time period do children with TEC recover?
Recovery is spontaneous within 1-2 months
How do you differentiate between DBA and TEC and aplastic crisis?
DBA – younger than 1 year, elevated MCV (esp at recovery), increased Hb F and ADA. More severe anemia, 50% have congenital anomalies
TEC-recovers in 1-2 months, normal HbF (can be elevated in 20%)
Aplastic anemia-hemolytic disease, parvovirus B19, recover to baseline
What should you do if you are following a patient with TEC and their MCV or HbF remain elevated?
Refer to hematology to rule out DBA
What deficiencies cause megaloblastic anemia?
Folate or Vitamin B12
Both are required to make DNA
Results in continuing cell growth without division
What are risk factors for Vitamin B12 deficiency?
Strict vegetarian diet Picky eaters Prolonged breastfeeding if mom deficient Ileal resection (that is where B12 is absorbed) Abnormal intestinal transport Congenital IF (absorption requires IF) Gastrectomy (absence of IF) Malabsorption (celiac) Transcobalamin deficiency (transports B12)
What are risk factors for folate deficiency?
Decreased intake (excessive goat milk) Intestinal malabsorption (celiac, IBD, anticonvulsants, septra) Increased requirements (chronic hemolytic anemia, pregnancy).
What findings would you see on blood smear with megaloblastic anemia?
Megaloblastic changes
Howell-jolly bodies
Hypersegmentation of neutrophil nucleus
What features do you see in megaloblastic anemia?
Mild jaundice due to ineffective erthropoiesis
Glossitis
In B12 deficiency: peripheral neuropathy
What is the treatment for folate deficiency?
200-400 ug/day
What are dietary sources of folate?
Fruits, vegetables, milk, fortified bread/pasta/flour
What are dietary sources of vitamin B12?
Meat and dairy
What type of milk does not have folate in it?
Goat’s milk
What is the inheritance patter of hereditary spherocytosis?
Most AD
1/3 spontaneous mutation
What are the clinical features of hereditary spherocytosis?
Neonatal jaundice
Chronic hemolysis
Gall stones***most common complication
Splenomegaly
What investigations support a diagnosis of hereditary spherocytosis
Smear
DAT negative
High MCHC >350
Osmotic fragility rarely necessary
When should patients with HS get a splenectomy?
Moderate hemolysis, symptomatic disease
After age 5 to minimize risk of sepsis
G6PD is most common in which ethnicities?
Africa, Middle East, South Asia and the Mediterranean
What is the genetics of G6PD?
X-linked
What findings on smear are indicated of G6PD?
Blister cells-RBCs appear blistered and bitten (bite cells)
Heinz bodies
When is the G6PD assay falsely negative?
Patients who are actively hemolysing (because the older cells are dead)
What are the most common oxidants triggering hemolysis in G6PD?
Sulfas Nitrofurantoin Dapsone Naphthalene (moth balls) Anti-malarials-chloroquine Rasburicase Fava beans Infection.
Absent radius is found in which aplastic anemia?
Fanconi anemia
What are the 3 types of autoimmune hemolytic anemia?
1) Warm (IgG, extravascular hemolysis)-makes kids sick
2) Cold (IgM, called “cold agglutinin disease”)
3) Biphasic (Donath-Landsteiner IgG, called “paroxysmal cold hemoglobinuria”).
How do you diagnose autoimmune hemolytic anemia?
Positive DAT
What are some etiologies of AIHA?
Idiopathic Secondary to drugs Infection Lupus Immunodeficiency Lymphoproliferative diseases (lymphoma, ALPS)
Cold and biphasic AIHA are associated with which infections?
EBV, mycoplasma, CMV, HIV
How do you treat warm AIHA?
STEROIDS
Splenectomy
If need to, transfuse
How do you treat cold or biphasic AIHA
Supportive care
Transfusions
Plasmapheresis if severe