Anemias & Case Study Practice

Anemia

• >10% decrease in

  • # of RBCs per unit volume

  • hematocrit

  • hemoglobin levels

Functional definition of Anemia

• decreased oxygen carrying capacity

Response to Sudden blood loss

• increased heart rate, respiratory rate, cardiac input → increases oxygenated blood flow

• blood flow from skin to essential organs

Response to Slowly Developing Anemia 

• increase in 2,3-BP → decrease in hemoglobin’s affinity of oxygen → more oxygen release to tissues

• increase in erythropoietin production by kidneys → release of more RBCs

Types of Iron deficiency anemias

• Pernicious anemia (B12)

• Aplastic anemia (bone marrow)

• Neoplasia (leukemia)

• Myelofibrosis (scarring in bone marrow)

• Renal disease

Blood Loss and Hemolysis

• hemorrhage

• menstrual flow

• gynecological disorders

• pregnancy

• parasitism

Decrease RBC Production

• Iron deficiency anemia

• Blood loss and hemolysis

Intrinsic Hemolytic Anemia

• thalassemia

• G6PD deficiency

• Sickle Cell Anemia

• Hereditary Spherocytosis

Extrinsic Hemolytic Anemia

• infections (malaria, mycoplasma)

• Lead poisoning

• Disseminated Intravascular Coagulation (DIC) 

Diagnosis of Anemia

• physical exam

• CBC count

• Bone marrow biopsy

• Fecal occult blood

• Iron metabolism

Macrocytic anemia

• High MCV (large RBCs)

• hyper segmented neutrophil

• some small spherocytes and teardrop cells

Microcytic anemia

Low MCV

Megaloblastic/Macrocytic Anemia

• lack of folic acid or B12

  • Folate (folic acid) + B12 interact → Thymidine synthesis (dTTP)

• Megaloblasts in bone marrow; macrocytes in peripheral blood

• Affects all proliferating cells: Skin, gut, and blood

Causes of Macrocytic Anemia

• lack of folate intake (alcoholics, teenagers, some infants)

• increased need - pregnancy, lactation, etc.

• Malabsorption

• Impaired metabolism

Causes of Iron Deficiency

• blood loss

• Increased iron usage (pregnancy, infancy, etc.)

• Malabsorption

• Dietary inadequacy

Lab Tests for iron

• Serum iron levels

• Unsaturated Iron Binding Capacity (UIBC)

• Total Iron Binding Capacity (TIBC) 

• Percent saturation

• Plasma ferritin

• serum transferrin receptor levels

• free erythrocyte protoporphyrin

• tissue iron

• sideroblasts (erythroblasts) and siderocytes (macrophages)

Identification of Iron Deficiency 

• Low MCV

• Low reticulocyte count

• High RDW

• Low Serum Ferritin 

• Transferrin (TIBC) increases

• Blood Smear - microcytic, hypochromic (pale RBCs); aniso- & poikilocytosis

Sideroblastic Anemia

• iron not incorporated into heme

• ringed sideroblasts

• iron in bone marrow

• treated with vitamin b6

Lead poisoning (Acquired sideroblastic anemia)

• inhibits ALA dehydratase and ferrochelatase

• ALA and iron accumulate

• High reticulocyte count and Free Erythrocyte Protoporphyrin (FEP) Test 

• increase of ALA in urine 

• Normocytic and normochromic; basophilic stippling (undegraded ribosomes)

Porphyria (Hereditary sideroblastic anemia)

• deficiencies in enzymes in heme synthesis

Types of porphyrias

• Cutaneous porphyria: affects skin; blisters; photosensitivity

• Acute porphyria: affects nervous system (mental disorders, muscle numbness, paralysis, cramping)

  • RBCs may fluoresce

Hereditary Hemochromatosis

• mutation in HFE (high iron) gene

  • HFE regulates hepcidin

• overload of iron (increased iron absorption and transportation)

Effects of Hemochromatosis 

• RBCs most affected 

• skin, liver, pancreas and heart also affected (bronze diabetes)

Diagnosis of Thalassemia

• CBC

  • Low: Hb, HCT, MCV, MCH, MCHC

  • High: Reticulocyte Count, ferritin + iron

Acquired Aplastic anemia

• normo- to macrocytic

• Low: reticulocyte count

• High: serum iron

• decrease in CD34+ (stem cells)

Iron Deficiency Lab Results

• Low:

  • Iron

  • Ferritin

• High:

  • TIBC

• microcytosis

Anemia of Chronic Disease Lab Results

• Low:

  • Iron

  • TIBC

• High or normal

  • Ferritin

Hemochromatosis Lab Results 

• Low: 

  • TIBC

• High:

  • Iron

  • Ferritin