Hematology #1 (Microcytic Anemias) Flashcards
MCC of anemia worldwide
Iron Deficiency Anemia
Etiologies of iron deficiency
-In US
-In World
US: Chronic blood loss (menstruation, colon cancer, parasitic hookworms)
World: Diet (Celiac, H. Pylori, Bariatric surgery)
What are some risk factors for iron deficiency anemia? (Think of states that have increased metabolic requirements)
-Children, pregnant, lactating women
-Cow milk ingestion younger than 1 year of age
What is the pathophysiology of iron deficiency anemia?
Decreased production of RBC’s due to lack of iron and decreased iron stores (ferritin)
Symptoms of iron deficiency anemia
-Fatigue, weakness, dyspnea
-Pasophagia (ice craving)
-Pica (crave clay, starch)
-Koilonychia (spooning of nails)
-Angular cheilitis
-Glossitis (smooth tongue)
-Leg cramps climbing stairs
What is shown on a CBC for iron deficiency anemia?
Iron studies show…
CBC: microcytic hypochromic anemia
–reduced iron stores halt production of hemoglobin = hypo chromic (not red)
–Reduced RDW (red cell distribution width) = mix of small and large cells
Iron Studies: decreased ferritin (iron stores), increased TIBC (transferrin = delivers iron, decreased transferrin saturation (serum iron/iron binding capacity), decreased serum iron
However, what is the definitive diagnostic for iron deficiency anemia?
Bone marrow biopsy: absent iron stores
Treatment for iron deficiency anemia
-iron replacement (corrects anemia in 6-8 months)
–Ex: Ferrous sulfate 325 mg PO daily
-If severe, red blood cell transfusion
Recommendations for taking iron supplements
-Take iron supplement with Vitamin C (ascorbic acid), with water or juice, on an empty stomach
-Take 2 hours before or 4 hours after antacids
What is a normal MCV?
What is the MCV in iron deficiency anemia?
Normal: 80-100
Iron Deficiency: Microcytic <80
Explain the pathophysiology of lead poisoning anemia (plumbism)
-Lead poisons enzymes, causing cell death, shortens the lifespan of RBC’s, and inhibits enzymes needed for heme synthesis –> acquired sideroblastic anemia
Risk Factors for lead poisoning anemia
-Who is it MC in?
-What is the MCC?
-MC in children due to increased permeability of blood-brain barrier and iron deficiency (increases lead absorption)
-MCC is ingestion or inhalation of environmental lead (paint chips or lead dust)
Symptoms of lead poisoning anemia
-Neuro symptoms: ataxia, fatigue, learning disabilities, difficulty concentrating, hearing loss, developmental delays
-Peripheral neuropathy: wrist or foot drop
-Intermittent abdominal pain, loss of appetite, constipation
-Burton’s Line: thin, blue black line at base of gums near the teeth
What is the initial diagnostic done for lead poisoning anemia?
Capillary fingerstick sample: Serum lead level > 10 mcg/dL
What is seen on peripheral smear for lead poisoning anemia?
Microcytic hypo chromic anemia with basophilic stippling (dots of denatured RNA in RBC’s)
However, what is seen on bone marrow biopsy for lead poisoning anemia?
Ringed sideroblasts
–immature RBC surrounded by rings of iron. Storing iron instead of using it.
What is a unique finding on radiographs in lead poisoning?
Lead lines: linear hyper densities at the metaphyseal plates in children
Treatment for lead poisoning anemia
-First option:
-Mild 44 mcg/dL or lower:
-Moderate (45-69):
-Severe (70 or higher):
Removal of source of lead is most important component of treatment
Mild: outpatient follow up and lifestyle modifications
Moderate: Succimer (combines with lead in the bloodstream and is removed by kidneys)
Severe: Succimer + Calcium disodium edetate
What exactly is thalassemia?
What are some risk factors?
Decreased production of globin chains
Runs in families, SE Asians, Mediterraneans
When should you suspect a thalassemia (what is shown on labs that would lead you to this?)
-Microcytic anemia with normal/increased Iron or no response to Iron treatment
Explain what happens in beta thalassemia
What is one RF that you should remember with this condition?
Decreased production of beta-globin chains leading to excess alpha chains
Mediterranean (Greek, Italians)
How many alpha and beta globin chains are in a normal adult HgbA cell?
2 alphas and 2 betas
Explain beta thalassemia minor vs major (Cooley’s Anemia
-Minor: only one gene is defective. MC type! Usually asymptomatic
Major (Cooley’s Anemia): both beta genes mutated. Ineffective erythropoeisis and shortened RBC lifespan
When do symptoms occur in beta thalassemia major and why?
What are some of the symptoms?
-After 6 months of life, when fetal hemoglobin begins to diminish
-Pallor, irritability, dyspnea, mental delays
-Hemolytic anemia: jaundice, splenomegaly
-Osteoporosis by age 10, compression fractures, disc degeneration (red marrow replaced by inactive yellow)
-Hypogonadism, DM, growth failure
-Cardiac dysfunction: heart failure
-Enlarged kidneys
-Bony abnormalities, hair on end appearance of skull
Explain what is seen on hemoglobin electrophoresis in beta-thalassemia in both types.
-Minor: decreased HgbA, increased Hgb F
-Major: Little to no HgbA, very high Hgb F
What is one advantage of Hgb F in comparison to the other types?
It has a stronger affinity for oxygen, so those with thalassemia have higher amounts of it to make up for the lack of HgbA
What is seen on CBC and peripheral smear with beta-thalassemia major (think size, shape, etc.)
-Microcytic hypo chromic anemia
-Normal or increased serum Fe
Peripheral smear: target cells , teardrop cells, basophilic stippling
Explain the significance of target cells
-Centrally located disc of hemoglobin surrounded by abundance of cell membrane (due to lack of globin chains)
What is seen on skull radiographs in beta-thalassemia?
Hair on end appearance: due to extramedually hematopoeisis
What is the treatment for beta thalassemia major?
-Frequent transfusions
-Iron chelating agents (Deferoxamine) to remove excess iron from chronic transfusions.
-Vitamin C and folate supplementation (substrates for RBC production)
-Splenectomy in some cases (stops RBC destruction)
Explain the pathophysiology of Alpha Thalassemia
-3/4 gene deletions cause decreased alpha chain production and excess beta chains. The beta chains form insoluble beta chain tetramers (Heinz bodies) with no oxygen carrying capacity in the RBC’s. They are then destroyed by the spleen (hemolytic anemia).
Symptoms of alpha thalassemia
-Symptomatic at birth (unlike beta thalassemia)
-Anemia, jaundice
-Hepatosplenomegaly
-Gallstones
-Increased bone marrow hematopoesis: frontal bossing, maxilla overgrowth
Hemoglobin H Disease (Alpha Thalassemia Intermedia) is characterized by ______ gene deletions and the presence of _______.
3/4 gene deletions
Heinz Bodies (HbH - beta chain tetramer)
On the other hand, Hydrops Fetalis is characterized by _______ gene deletions and the presence of _________. This is associated with stillbirth or death shortly after birth.
4/4 gene deletions
HgB Barts: gamma tetramers
What is seen on CBC and peripheral smear in alpha thalassemia (Hemoglobin H Disease)?
-Microcytic Hemolytic Anemia (schistocytes, tear drop cells, increased reticulocytes –immature RBC’s). Target cells, increased RBC count
-Heinz Bodies
-Normal or increased serum iron
-Hemoglobin electrophoresis: HbH (beta chain tetramer)
Treatment for alpha thalassemia (same as beta)
-Frequent blood transfusions
-Iron chelating agents (Deferoxamine) to remove excess iron
-Splenectomy in some cases (stops RBC destruction)
-Bone marrow transplantation definitive in MAJOR
What is one way to differentiate Alpha from Beta Thalassemia with labs?
Alpha will have normal Hb ratios in adults, whereas Beta will be decreased.
What is one thing to avoid as treatment in patients with thalassemia?
Avoid iron supplementation: they are already in iron overload
