Hematology #2 (Normocytic Anemias) Flashcards
MC type of normocytic anemia
Anemia of chronic disease: decreased RBC production in setting of chronic disease
There are three main factors that decrease serum iron in anemia of chronic disease. What are they?
1) Increased hepcidin: blocks release of iron from macrophages and reduces GI absorption of iron
2) Increased ferritin: sequesters iron into storage
3) Erythropoeitin inhibition via cytokines (Erythropoeitin stimulates RBC synthesis)
What does a CBC for anemia of chronic disease show?
How about iron studies?
Normocytic normochromic anemia
Decreased serum iron + increased ferritin + decreased TIBC
Treatment for anemia of chronic disease
How about if renal disease?
-Treat underlying disease to correct anemia
-Erythropoeitin-alpha
Explain how to differentiate the iron studies in the following anemias:
Iron deficiency
Anemia of Chronic Disease
Thalassemia
-Iron deficiency: decreased ferritin, increased TIBC
-Chronic Disease: increased ferritin, decreased TIBC
-Thalassemia: normal or increased serum iron
What is G6PD deficiency? What are some risk factors for it?
X-linked recessive disorder of RBC’s that causes episodic hemolytic anemia
Males, African Americans
What is the pathophysiology of G6PD deficiency and how does this affect RBC’s?
Normally, G6PD generates NADPH to protect the RBC’s from oxidative stress. In deficiency, methemoglobin is produced which leads to Heinz Bodies (clumps of damaged hemoglobin attached to RBC’s)
What are some exacerbating factors for G6PD deficiency?
-Infection (DKA) = MCC
-Fava Beans
-Meds (Dapsone, Nitrofurantoin, Chloroquine, Sulfa Drugs)
What are the symptoms of G6PD deficiency and what is unique about them?
-Asymptomatic until times of oxidative stress
-Episodic hemolytic anemia 2-4 days later
–back or abdominal pain, anemia
–jaundice (dark urine)
What is seen on peripheral smear and CBC in a patient with G6PD deficiency?
-Heinz bodies, schistocytes (bite cells)
-Normocytic hemolytic anemia during crisis
What other lab can you do for G6PD deficiency?
Enzyme assay for G6PD after episodes
Treatment for G6PD deficiency
-Avoid offending foods and drugs
-Iron and folic acid supplements
-Phototherapy if severe jaundice/neonatal
Sickle Cell Disease affects what part of the RBC?
Explain the pathophysiology of this.
-Beta-globin chain (RBCs sickle, cause hemolysis, and a vaso-occlusive crisis)
Point mutation where valine substitutes for glutamic acid in the beta chain. Sickle hemoglobin (HbS) has decreased solubility under hypoxic conditions, leading to sickling, vaso-occlusion, and hypoxia. Sickle cells are destroyed by the spleen (hemolytic anemia)
What is Sickle Cell Trait (Heterozygous AS)?
8% of African Americans
-Ususally asymptomatic unless exposed to extreme physical stress, extreme hypoxia, high altitudes, or dehydration.
-May develop episodic hematuria or isosthenuria (CKD, neither concentrated or dilute urine)
What is seen on hemoglobin electrophoresis in a patient with Sickle Cell Trait?
-Presence of both hemoglobin A (HbA) and Hemoglobin S (HbS) with A > S
Treatment for Sickle Cell Trait
Normally doesn’t need treatment
On the other hand, Sickle Cell Disease is….
-Homozygous sickle mutation (SS)
When do symptoms begin in patients with Sickle Cell Disease, why, and what is the MC initial presentation?
As early as 6 months (when HbSS replaces fetal hemoglobin)
Dactylitis MC initial presentation
-Others: Delayed growth, fever, infections
Explain increased risk of infections in patients with Sickle Cell.
-Functional asplenia and autosplenectomy (from repeated splenic infarctions) leads to increased risk of infections with encapsulated organisms (S. Pneumo, H. Flu, GABHS, etc.)
What organism should you be concerned about in a patient with Sickle Cell who gets Osteomyelitis?
Salmonella spp.
Asplastic crisis (bone marrow stops making RBC’s) is associated with what infection in those with Sickle Cell Disease
parvovirus B19 infections
What are some symptoms of a vaso-occlusive crisis in those with Sickle Cell Disease, or other symptoms they may be having?
-Acute splenomegaly and rapid decrease in Hgb (RBC pooling in spleen)
-Jaundice, Pigmented gallstones
-Acute chest syndrome, back, abdominal, bone pain
-Priapism **
-Avascular (ischemic) necrosis of bones (femoral or humeral head). H-shaped vertebrae
-Tibial skin ulcers
-Stroke**
Best initial test for Sickle Cell Disease. What is seen on it?
-Peripheral Smear: Target cells, sickled erythrocytes, decreased hemoglobin, decreased hematocrit
Howell-Jolly bodies (nuclear remnants) that indicate functional asplenia
What is seen on hemoglobin electrophoresis in those with Sickle Cell Disease?
-HbS, little to no HbA, increased HbF (it has better affinity for oxygen than HbA)
In Sickle Cell Trait, what is seen on electrophoresis?
HbS, decreased HbA
What is the definitive diagnostic for Sickle Cell Disease?
DNA analysis
What is the treatment for a patient in a Sickle Cell Crisis?
-Pain Control: IVF and oxygen (reverses and prevents sickling)
-Folic acid supplement (to promote RBC production)
-RBC transfusion may be needed
What is the only potentially curative treatment for Sickle Cell Disease, even though it has significant side effects?
Allogeneic stem cell transplant
In order to reduce episodes of Sickle Cell crisis, what medication can be used and what does it do?
Hydroxyurea: increases production of HbF (which does not sickle and has a higher affinity for oxygen) and reduces RBC sickling
Is Hydroxyurea used for acute episodes?
No, because it takes weeks to months to take effect
Because patients with Sickle Cell Disease are prone to more infections, what is given prophylactically to prevent complications?
Penicillin as early as 2-3 months until 5 years old to prevent complications
What vaccines should someone with Sickle Cell Disease FOR SURE get?
Pneumonia and Influenza Vaccinations
What does the word “Pancytopenia” mean?
Low WBC’s
Low Platelets
Low RBC’s
Low Hgb
What is aplastic anemia? (think about the name)
-Bone marrow hypocellularity (reduced number of hematopoietic cells) with pancytopenia (low number of RBC’s, platelets and WBC’s)
Etiologies of aplastic anemia
-Idiopathic MCC
-Radiation
-Infections: Parvovirus B19
-Meds: Sulfa drugs, Chloramphenicol, Anti-Epileptics (Carbamazepine, Phenytoin), NSAIDs, Anti-Thyroid Meds
What are some symptoms of pancytopenia
-Easy bruising, bleeding, frequent infections, fatigue
–Thrombocytopenia (low platelet count): mucocutaneous bleeding
–Anemia: weakness, fatigue, dyspnea
–Fever, Recurrent infections
What is seen on CBC with peripheral smear in aplastic anemia?
-At least 2 cytopenias: few or absent reticulocytes, thrombocytopenia (low platelets), neutropenia (few WBC’s), anemia (few RBC’s)
What’s the most accurate test for aplastic anemia? (Think about what is affected)
Bone marrow biopsy: hypo cellular, fatty bone marrow (T cells attack hematopoietic stem cells and bone marrow is replaced with fat)
Treatment for aplastic anemia
-Supportive (initial): Broad spectrum ABX, PRBC transfusion
-Severe in otherwise healthy patients < 50 y/o: Allogeneic hematopoietic stem cell transplant***
-Immunosuppresive therapy if > 50 years old or if not matched donor: Eltrombopag, Cyclosporine, Prednisone
