Normocytic Anemia Flashcards
What do reticulocytes (young RBCs) look like on blood smear?
- Large cells
- Blueish cytoplasm
Why does the reticulocyte look blue?
RNA within cytoplasm
What is the normal reticulocyte count?
1-2%
if the bone marrow is properly functioning what is the reticulocyte count in an anemia increased to?
> 3%
- Falsley elevated as this is a percentage of total RBC which will be lower
What is the normal reticulocyte level multiplied by to get the corrected reticulocye count?
Hct/45
How can hemolysis / peripheral RBC destruction also be divided into?
Extravascular and intravascular
What is the bone marrow response like in hemolysis or peripheral RBC destruction anemia?
Good bone marrow response
What destroys RBCs in an extravascular hemolysis?
Macrophages in reticuloendothelial system (in spleen, liver and lymph nodes)
What is globin broken down into?
Amino acids
What is protoporphyrin broken down into?
Unconjugated bilirubin
What is unconjugated billirubin bound to?
Serum albumin
What are the clinical and labratory findings in extravascular hemolysis?
- Anemia w splenomegaly (RE system)
- Jaundice due to unconjugated bilirubin
- Increased risk for bilirubin gallstones
- Marrow hyperplasia w corrected reticulocyte count >3%
What binds to free hemoglobin in the blood?
Haptoglobin
What are the levels of haptoglobin like in intravascular hemolysis?
Low as they are bound to hemoglobin
What are the clinical and labratory findings in intravascular hemolysis?
- Hemoglobinuria
- Hemoglobinuria
- Hemosiderinuria (tubular cells fall off - days later)
- Decreased serum haptoglobin
What kind of anemia is hereditary spherocytosis?
Normocytic anemia
- Extravascular hemolysis
What is affected in hereditary spherocytosis?
- Inherited defect of RBC cytoskeleton membrane tethering proteins
- Most commonly involves spectrin, ankyrin or band 3.1
What will be seen on blood smear in hereditary spherocytosis?
- Differing RBC sizes - High RDW - RBC distribution width
- Non biconcave (no central pallor)
How does Hereditart Spherocytosis result in anemia?
Spherocytes are less able to maneuver through speinic sinusoids
- Splenic macrophages then consume them creating an anemia
What are the labratory and clinical findings in HS?
- Spherocytes w loss of central pallor
- Increased RDW and MCHC
- Splenomegaly
- Jaundice (possible billirubin gallstones)
- Increased risk of aplastic crisis w. parvovirus B19 infection of erythroid precursors
What is MCHC?
Mean corpuscular hemoglobin concentration
- Average amount of hemoglobin per RBC relative to the size of the cell
- Hemoglobin / Hct
Increased in HS
What does parvovirus B19 affect?
Erythroid precursors
- Aplastic crisis possibility
How is HS (Herditary Spherocytosis) diagnosed?
Osmotic fragility test
- Increased fragility in hypotonic solution
- There is no extra membrane therefore it can’t expand as easily and will burst
How is HS treated?
Splenectomy
- Splenic macrophages are what is causing the condition
What will happen after splenectomy / what can be seen in Hereditary spherocytosis post-splenectomy?
- Anemia resolves
- Spherocytes persist
- Howell-Jolly bodies emerge on blood smear - Speen usually removes these DNA fragments
What do Howell-Jolly bodies look like on blood smear?
Small blue dots (DNA fragments)
What kind of anemia is sickle cell?
Normocytic hemolytic extravascular (mostly) anemia
- Also involves intravascular hemolysis resulting in decreased haptoglobin and target cells
What is affected in sickle cell?
Beta chain of hemoglobin
What is replaced in Sickle cell?
Normal glutamic acid (hydrophilic) replaced with valine (hydrophobic)
What happens to hemoglobin S when deoxygenated?
Poymerises
- Polymers aggregate into needle-like structures resulting in sickle cells
What causes an increased risk of sickling?
- Hypoxemia
- Dehydration
- Acidosis
What does hydroxyurea do?
Increases levels of HbF
- Used in sickle cell
What is massive erythroid hyperplasia?
Expansion of hematopoiesis into skull and facial bones (chipmunk)
- Extramedullary hematopoeisis w. hepatomegaly
- Risk of aplastic crisis w. parvovirus B19 infection of erythroid precursors
- Can occur in extravascular and intravascular hemolysis (sickle)
What is Dactylitis?
- Sign of sickle cell in infants
- Swollen hands and feet due to vaso-occlusive infarcts of bones
What is autosplenectomy?
- Shrunken, fibrotic spleen
- Associated w. sickle cell
- Howell-Jolly bodies will be seen on blood smear
What organism specifically may cause osteomyelitis in patients with sickle cell?
Salmonella paratyphi
- Autosplenectomy -> risk of encapulated organsim infection
What is the most common cause of death in sickle cell adults?
Acute chest syndrome
What is the most common cause of death in sickle cell children?
Encapsulated organism
What is acute chest syndrome?
- Vaso-occlusion in pulmonary microcirculation
- Presents with chest pain, SOB, and lung infiltrates; often precipitated by pneumonia
What is Renal papillary necrosis?
- Vaso-occlusive crisis of kidney
- Results in gross hematuria and proteinuria
What percentage of Africans carry sickle cell?
~ 10%
What is HbS?
Hb A (alpha2, Beta2) except the Beta chain is mutated with valine (hydrophobic) instead of glutamic acid
What can carriers of sickle cell be affected by?
Generally asymptomatic however can get microinfarctions in renal medulla
- Microscopic hematuria and eventually decreased ability to concentrate urine
What causes sickling?
Hypoxia and hypertonicity
What does the metabisulfite screening test diagnose?
Sickle cell disease and trait
What will electrophoresis show in sickle cell disease?
90% HbS, 8% HbF, 2% HbA2
- No HbA
What will sickle cell trait show on electrophoresis?
55% HbA, 43% HbS, 2% HbA2
How are sickle cell and Hemoglobin C disease inherited?
Aut Recessive
What is glutamic acid replaced by in Hemoglobin C disease?
Lysine
What is seen on blood smear in hemoglobin C disease?
Hemoglobin crystals
- Pnk/purple cylinder
