HemeOnc Flashcards
When is a physiological drop in H&H expected by?
2-3 month of life (8-10 weeks) in term infants
How low of a Hgb can be normal for a term infant who is 8-10 weeks?
9
What is done for asymptomatic physiologic anemia of infancy?
No further laboratory evaluation
In a premature infant, when can the physiologic nadir of H&H happen?
1-2 months (7-8 weeks)
What is the etiology of physiological anemia in newborns?
Low erythropoietin production
What is the equation for normal MCV?
Roughly 70 + 2(age in years)
What is the first thing you should do with a question concerning anemias?
Figure out whether it is micro-, macro-, or normocytic
What is normal MCV for children?
70-90 (adults is 80-100)
What is the MCV in a microcytic anemia?
Under 70
What are the 3 main considerations for a microcytic anemia?
- Thalassemia
- Too little iron
- Too much lead
What are the 3 usual hemoglobins?
- F (2 alpha/2 gamma)
- A (2 alpha/2 beta)
- A2 (2 alpha/2 delta)
What are thalassemias caused by?
Defects in genes that code for hemoglobin chains- proper quantities aren’t produced
What are hemoglobinopathies caused by?
Errors in sequencing of hemoglobin chains (quality)
Which patients will eventually get iron overload?
Anyone undergoing regular transfusion therapy (thalassemia, sickle cell, aplastic anemia)
What is done to remove excess iron in the body?
Chelation therapy
What happens if iron builds up in the body?
Toxic buildup in liver (hemosiderosis) and hearts
What is a significant cause of morbidity and mortality in chronically transfused patients?
Toxic buildup of iron in the liver and heart
Where are the 2 alpha globin genes located?
Chromosome 16
4 alleles (aa/aa)
What causes alpha thalassemia?
Mutations in one to all 4 of the alpha globin alleles
What happens if only one or two alpha alleles (alpha globin gene) are defective?
Children are typically asymptomatic and it is picked up on routine screening
What do labs show for kids with 1 or 2 defective alpha alleles (alpha globin gene)?
Microcytic hypochromic anemia with normal iron and lead studies
What is it called when one alpha allele is defective?
“Silent trait”
What is it called when two alpha alleles are defective?
“Alpha thalassemia trait”
How is alpha thalassemia diagnosed?
Hemoglobin electrophoresis
If hemoglobin electrophoresis is done in the neonatal period, what does the electrophoresis show?
Hemoglobin Bart (gamma chains banding togther)
For alpha thalassemia with silent trait or alpha thalassemia trait, what is the treatment?
No treatment
What happens when there are 3 defective alpha globin genes?
Hemoglobin H disease
What does Hemoglobin H disease lead to?
Hemolysis and hepatomegaly
What can Hemoglobin H disease be treated with?
- Transfusions
2. Usually a splenectomy
What does 4 defective alpha globin genes cause?
Hydrops fetalis
What does hydrops fetalis result in?
Still birth or death soon after birth
If a hydrops fetalis survives, what do they require?
Transfusions for life
How are thalassemias diagnosed?
Hemoglobin electrophoresis
What is elevated in thalassemias?
Hemoglobin F
What is caused by a defect in one of the beta globin gene alleles?
Thalassemia minor or thalassemia trait
True or False: Patients with thalassemia minor or thalassemia trait are asymptomatic?
True
How is thalassemia minor or thalassemia trait diagnosed?
When a mild microcytic anemia is noted on incidental testing
What results from severe deficiency of beta globin due to a mutation in both beta globin gene alleles?
Thalassemia Major/Cooley’s anemia
-Can’t make hemoglobin A1, so body makes A2 (delta) or F (gamma)
Small for age Greek child with anemia and an enlarged liver/spleen?
Thalassemia major
How do patients with thalassemia major present?
- 1st year of life
- Profound microcytic, hypochromic anemia
What physical exam findings is seen in Thalassemia major?
Hepatosplenomegaly
What is seen on XR in Thalassemia major?
- Thickened bone
2. Skull has “hair-on-end” appearance
What causes the “hair-on-end” appearance in skull XR for thalassemia major?
Extramedullary hematopoiesis
What is the treatment for Thalassemia major?
Chronic transfusion therapy
What are the 2 long term complications with beta thalassemia major?
- Cholelithiasis
2. Hemosiderosis (iron deposition in heart, liver, pancreas)
What are the findings for sickle cell anemia on hemoglobin electrophoresis?
Hemoglobin F
Hemoglobin S
What are the findings for beta thalassemia on hemoglobin electrophoresis?
Low/No Hemoglobin A1
Elevated hemoglobin A2
Hemoglobin F
10 week old infant of Mediterranean descent with hemoglobin of 9.0 and MCV of 89… diagnosis?
Physiologic anemia of infancy… this is a normocytic anemia, don’t be fooled by ethnicity of Mediterranean
When does the risk for iron deficiency anemia in infants begin?
After 4 months
Who is the risk for iron deficiency anemia higher in, breast fed or formula fed infants?
Breast fed
When does the risk for iron deficiency anemia happen in preterm infants?
Earlier than 4 months (as in term infants) especially with no iron supplementation
Why are infants who are given cow’s milk (versus formula or breast milk) before 12 months of age at increased risk for iron deficiency anemia?
Because of low amount of iron absorbed
True or False: Iron deficiency anemia is typically completely asymptomatic?
True
18 month old with pallor and tachycardia?
Iron deficiency anemia
Low hemoglobin (<6) and low MCV (<60)?
Iron deficiency anemia
Child with a history of drinking lots and lots and lots of cows milk (probably still on the bottle)?
Iron deficiency anemia
What else does low iron cause besides anemia?
Mild delays in cognitive development (even without frank anemia)
You find a microcytic anemia in a kid drinking too much milk, what do you do?
Trial of iron
If anemia improves after a one month trial of iron, what do you do?
Continue the iron treatment (it was probably iron deficiency anemia)
If anemia doesn’t improve after a one month trial of iron, what do you do?
Investigate for other causes of microcytic anemia (lead toxicity or thalassemia) or of chronic iron deficiency (celiac)
How is iron deficiency anemia treated?
Ferrous sulfate (until 2 months after Hgb levels normalized- replenishes iron stores), improve diet (limit milk), get them off the bottle
When is parenteral iron administration given?
Rarely- only if cannot take PO iron or in extreme social circumstances
What is the most common environmental illness in kids?
Lead poisoning
What does lead poisoning affect?
Production of heme (interferes with a variety of enzyme systems)
Microcytic anemia with a high RDW?
- Iron deficiency anemia
2. Lead toxicity
Microcytic anemia with a normal RDW?
Thalassemia
Microcytic anemia with a low RDW?
Nothing
Choice of 2 microcytic anemias, one with lower RDW likely due to?
Thalassemia (vs. Iron deficiency)
When is FEP (free erythrocyte protoporphyrin) elevated?
- Lead poisoning
2. Iron deficiency anemia
When is FEP (free erythrocyte protoporphyrin) normal?
Thalassemia
What typically coexists with lead poisoning and enhances lead absorption?
Iron deficiency
What is the gold standard test for lead poisoning?
Whole blood lead level (not fingerstick)
What is an immature RBC with iron-bloated mitochondria surrounding the nucleus?
Ringed sideroblast
What is a ringed sideroblast evidence of?
- Lead poisoning
2. Sideoblastic anemia
What is the MCV in macrocytic anemia?
> 100 (often around 110)
What is B12 frequently due to?
Poor absorption of B12 (often from GI disorder like Crohn’s disease)
Name 4 things B12 deficiency can be due to?
- Intrinsic factor deficiency (pernicious anemia)
- Bacterial overgrowth
- Following a bowel resection
- Vegetarian diet
Compromised gut + Heme question?
B12 deficiency
3 B’s of B12 deficiency?
B12 Deficiency:
- Bacterial overgrowth
- Bowel resection
- HLS-B27 (Crohn’s)
Goat’s milk?
Macrocytic anemia from folic acid deficiency
What 2 deficiencies often coexist?
B12 and folate
What happens if you treat someone with a folate deficiency, but don’t correct the B12?
CBC will look better, but this can lead to irreversible neurologic damage
What 3 things should you think of with a normocytic anemia?
- Patient is bleeding
- Patient has chronic disease
- Hemolytic process
What are 3 reasons that a red cell might be destroyed?
- Enzyme problems (G6PD)
- Structural problem (HS)
- Weird shape (Sickle Cell)
When a red cell breaks open, where do you find the remnants and in what form?
Urine, hemosiderin/bilirubin
Is serum haptoglobin low or high in hemolytic anemia?
Low- Used up in transporting released hemoglobin from RBCs
What results in an elecated retic count?
Hemolytic anemia
What is a normal retic count?
1%
What is the one exception of a hemolytic anemia not causing an elevated retic count?
Parvovirus (if it causes aplastic crisis in someone with a chronic hemolytic anemia- Sickle cell or Hereditary spherocytosis)
What is a sign that a hemolytic process in immune-mediated?
Positive Coombs test
What does the direct Coombs test identify?
Antibodies on the surface of the red cell
What protects a red cell from oxidative stress (which can lead to hemolysis)?
G6PD
What are small, purple granules in the red cell that form as a result of damage to the hemoglobin molecule?
Heinz bodies
What condition do you see Heinz bodies in?
G6PD
African American or Mediterranean boy with dark urine who is jaundiced and anemic
G6PD
Sudden onset of pallor and anemia in an otherwise healthy child?
G6PD
What are 5 things that can cause oxidative stress leading to issues in someone with G6PD?
- Sulfa-containing antibiotic (Bactrim)
- Nitrofurantoin
- Moth Balls
- Antimalarial meds
- Fava beans
True or False: Hepatomegaly is seen in G6PD
False: There is NO hepatomegaly or splenomegaly in G6PD
How is G6PD inherited?
X-linked
When should testing for G6PD deficiency be done?
Several weeks after an episode
-Testing right after or during an episode isn’t reliable because reticulocytes have a large amount of G6PD and can lead to false negative test
If you have a negative test for G6PD, does it rule this out?
Not necessarily. If the negative test was right after an episode, it could be a false negative test.
What is treatment for G6PD?
- Hemodynamic support (Fluid +/- RBCs)
2. Remove the oxidant stressor
What might newborns with G6PD require?
Phototherapy and/or exchange transfusion (to help resolve the indirect hyperbilirubinemia)
What is the most common inherited cause of hemolytic anemia?
Hereditary Spherocytosis
What is caused by defects in the surface of red cells resulting in loss of erythrocyte surface area?
Hereditary Spherocytosis
How is hereditary spherocytosis inherited?
Autosomal dominant (most common… an autosomal recessive form can also occur)
What is the main feature of hereditary spherocytosis?
Chronic hemolysis
How does hereditary spherocytosis present?
- Mild/Mod anemia
- Splenomegaly
- Intermittent jaundice
- Gallstones
Is the mean corpuscular hemoglobin concentration (MCHC) decreased or increased in Hereditary Spherocytosis?
Increased- More hemoglobin per volume (smaller cell with same amount of Hgb)
How is hereditary spherocytosis diagnosed?
Osmotic fragility test- Cells break open more easily
What results from a spectrin deficiency or spectrin mutation?
Hereditary Spherocytosis
Ankyrin deficiency can also case HS, but spectrin is better choice
In hereditary spherocytosis when can you monitor until recovery?
If hemolysis isn’t severe (Hgb >5-6)
What can be curative for Hereditary Spherocytosis?
Splenectomy
What is the most common cause of aplastic crisis in children with hereditary spherocytosis?
Parvovirus B19
What is the most common reason for children with hereditary spherocytosis to require a blood transfusion?
Aplastic crisis due to Parvovirus B19
Are defects of structure typically dominant or recessive?
Dominant
Are enzyme defects typically dominant or recessive?
Recessive
What is the mutation in Sickle Cell?
Substitution at amino acid 6 of the beta globin chain (valine is substituted for a glutamic acid)
Which type of anemia is a result of an amino acid substitution?
Sickle Cell
When does sickle cell anemia typically present clinically?
Not until after 6 months of age
When are children typically diagnosed with sickle cell disease?
When their newborn screens come back abnormal
How does vasoocclusive crisis present?
Acute pain secondary to ischemia and infarction
How is a vasoocculsive crisis treated?
Rehydration and pain control
What is dactylitis?
Pain and swelling of the hands and feet, typically seen in infants with sickle cell
How is dactylitis treated?
Aggressive pain control
How does sequestration crisis present?
Shock
What causes a sequestration crisis?
Pooling of blood in the liver and spleen- usually in response to an infection
True or False: Sequestration is considered a medical emergency?
True- Requires hospitalization and transfusion
When do you typically do a splenectomy in a sickle cell patient?
After the 2nd or 3rd sequestration episode
What typically causes aplastic crisis in sickle cell patients?
Parvovirus infection (people with sickle cell or HS need high retic counts to keep up with increased red cell destruction…if this isn’t working, Hgb decreases)
How are aplastic crises treated?
Blood transfusions as needed
What should make you think of a hyperhemolytic crisis?
History of sickle cell with a recent infection
What often precedes an aplastic crisis or sequestration crisis?
Hyperhemolytic crisis
When do you see priapism?
Sickle cell
True or False: Antibiotic prophylaxis with penicillin is recommended for all children with sickle cell disease through age 5?
True
What extra vaccination should children with sickle cell disease receive?
Pneumococcal
Why do older children with sickle cell get antibiotics and a septic workup for fevers?
Because they are considered to be asplenic
What does the spleen remove from red cells?
Howell-Jolly bodies (you will see these nuclear particles once asplenic)
Howell-Jolly Bodies?
Sickle Cell
Heinz Bodies?
G6PD
True or False: Most states screen newborns for sickle cell disease?
True
Consider if child newly emigrated from developing country
By what age do children with sickle cell have functional asplenia?
5
What is typical of the abdominal exam for a child with sickle cell after age 5?
Small, hard, non-palpable spleen
If you have an older child with a palpable spleen, what should you think?
Either hemoglobin SC or sickle trait and thalassemia together (Hemoglobin-S, Beta-thal)
Children with sickle cell and thalassemia are resistant to what?
Malaria (thought how these two genes remained in gene pool)
What are the 3 features of acute chest?
- Chest pain
- Infiltrate on CXR
- Hypoxia
Sickle cell patient with chest pain, infiltrate on CXR, and hypoxia, what do you do next?
Get an ABG to confirm the hypoxia (O2 sats usually not good enough for diagnosis)
What can resolve chronic hemolysis in patients with hemolytic anemias?
Partial or total splenectomy
What must you do a few weeks before a splenectomy in a kid with a hemolytic anemia?
Vaccinate against H. Flu, S. Pneumo, and N. Meningitidis
What 3 bacteria are post-splenectomy patients at risk for after surgery?
- H. Flu
- S. Pneumo
- N. Meningitidis
True or False: Children with splenectomies should have antibiotic prophylaxis until adolescence?
True- this should be a consideration
If you have a post-splenectomy patient with fever, what do you do?
CBC, blood cultures, IV ceftriaxone
What is the treatment for ACS?
Transfusion
When transfusing someone for ACS, what do you have to consider?
Starting Hct… if it is low, simple transfusion is fine. If it is high, they may require an exchange transfusion
Which two problems is chest pain in a child with sickle cell difficult to distinguish between?
Pneumonia v. Pulmonary infarct
If you have a child with sickle cell disease who presents with fever, cough, and chest pain, what do you treat for?
Both pneumonia and pulmonary infarct (hard to tell difference between two)
African American child with stroke symptoms, what do you do?
Transfusion then MRI (treat before diagnose)
Child with symptoms of stroke, new to US, how do you diagnose the underlying disorder?
Hemoglobin electrophoresis (sickle cell is underlying disorder)
How to diagnose the problem would be MRI
What type of hematologic disease is cholelithiasis associated with?
Sickle cell disease
Child with sickle cell disease presents with right upper quadrant tenderness- what do you do?
Abdominal US (cholelithiasis)
What are anemias due to suppression of the red cell line in the bone marrow?
Hypoplastic and aplastic anemias
What can aplastic anemia present similarly to?
Acute leukemia
What are some features of acute leukemia that help to differentiate it from aplastic anemia?
- Hepatosplenomegaly
- Lymphadenopathy
- Depression of WBC or Plt counts
- High LDH
- High uric acid
- Fevers
- Bone pain
- Blasts
How is diagnosis for either aplastic anemia or acute leukemia confirmed?
Bone marrow biopsy
What drug is responsible for an aplastic crisis?
Chloramphenicol
What type of anemia is Fanconi’s anemia?
Aplastic anemia
When does Fanconi’s anemia present?
Later in childhood (usually after age 3)
Does Fanconi’s anemia present with macrocytic or microcytic anemia?
Macrocytic
What type of hemoglobin is elevated in Fanconi’s anemia?
Fetal hemoglobin
Name 4 physical characteristics associated with Fanconi’s anemia?
- Abnormal skin pigmentation
- Growth retardation (short stature)
- Renal abnormalities (urinary retention)
- Absent or hypoplastic thumb
What type of anemias are Fanconi and Diamond-Blackfan?
Macrocytic
How is Fanconi’s anemia inherited?
Recessive
Which type of anemia puts children at risk for transformation to AML or myelodyslpastic syndrome?
Fanconi’s
What will patients with Fanconi’s anemia require?
Transfusion of RBCs and platelets
What is the cure for Fanconi’s anemia?
Bone marrow transplant
What can lead to a prolonged remission in Fanconi’s anemia?
- Immunosuppressants
2. Androgens (less common)
Which two conditions are profound isolated red cell anemias that present in infancy/toddlerhood?
Diamond-Blackfan Anemia
Transient Erythroblastopenia of Childhood
What anemia is due to an arrest in the maturation of red cells?
Diamond-Blackfan Anemia
What anemia is a consequence of a suppression of erythroid production?
Transient Eryhtroblastopenia of Childhood
What are shared features of DBA and TEC?
- Low Hgb and retic count
- Gradual onsent
- Relatively asymptomatic
Which often presents with anemia at birth, DBA or TEC?
DBA
Which 2 anemias affect the red cell line exclusively?
- TEC
2. DBA
If you see a 2 or 3 year old with an anemia exclusively affecting the red cell line, what is it?
Probably TEC (will not be DBA because this affects infants)
What is the difference in time-course between DBA and TEC?
DBA is chronic
TEC is transient
Kid with severe anemia who has thumb abnormalities, urogenital defects, or craniofacial problems?
DBA
Mnemonic for DBA
DBA:
Dysmorphic facies
Babies
Anemia
What is the median age of onset for TEC?
18-26 months (T for Toddler)
What is median age of onset for DBA?
2-3 months (BA for baby)
Which type of anemia, TEC or DBA, almost always has a spontaneous recovery?
TEC (DBA rarely has a spontaneous recovery)
Which type of anemia, TEC or DBA, is more likely to have dysmorphology?
DBA (uncommon in TEC)
What type of anemia, TEC or DBA is less likely to require transfusions?
TEC (Transfusions are common in DBA)
Which type of anemia, DBA or TEC, are steroids helpful?
DBA (Steroids aren’t indicated for TEC)
Which has a higher incidence, DBA or TEC?
TEC is common (DBA is extremely rare)
Child with severe anemia (Hgb 3-5) who has a reticulocytosis (retic count 5-10%), recent viral illness… what is the cause?
Probably TEC (now in recovery phase)
What is the typical course for TEC?
Usually resolves spontaneously within several months…transfusion is rarely needed.
True or False: Steroids are used in TEC
False: Steroids are used with DBA
What 3 things are blood donations typically tested for?
- Hep B
- Hep C
- HIV
What is the MCV in DBA versus TEC?
- DBA is macrocytic
- TEC usually normal (unless patient is recovering with a reticulocytosis and MCV may be slightly elevated)
If you get a question with dark urine or a positive Coombs test (DAT), what type of anemia should you think?
Hemolytic anemia (look for signs of hemolysis)