GI: RBC Disorders Flashcards
- Due to decreased production of Hemoglobin
- RBC progenitor cells in the Bone marrow divide multiple times to achieve the correct MCV: 80 -100
- Microcytosis is due to an “Extra division” –> Too small
- Macrocytic anemia is due to “One less” division –> Too big
- Hemoglobin = Heme + Globin
Microcytic Anemia
Microcytic Anemia Diseases?
Microcytic Anemia Diseases?
- Iron Deficiency (Late)
- Anemia of Chronic Disease
- Thalassemias
- Lead Poisoning
- Sideroblastic Anemia
Macrocytic Anemia Diseases?
Macrocytic Anemia Diseases?
- Megaloblastic
- Folate Deficiency
- B12 Deficiency
- Orotic Aciduria
- Non-Megaloblastic
- Liver Disease
- Alcoholism
- Reticulocytosis
Non-Hemolytic Normocytic Anemia Diseases?
Non-Hemolytic Normocytic Anemia Diseases?
- Iron Deficiency (Early)
- Anemia of Chronic Disease
- Aplastic Anemia
- Chronic Kidney Disease
Hemolytic Normocytic Anemia Diseases?
Hemolytic Normocytic Anemia Diseases?
- Intrinsic
- RBC membrane defect: Hereditary Spherocytosis
- RBC Enzyme Deficiency
- G6PD
- Pyruvate Kinase
- HbC defect
- Paroxysmal Nocturnal Hemoglobinuria
- Sickle Cell Enemia
- Extrinsic
- Autoimmune
- Microangiopathic
- Macroangiopathic
- Infections
- Decreased Levels of Fe2+
- -> decreased Heme –> decreased Hemoglobin —> Microcytic anemia
- Most common type of Anemia
- Nutritional deficiency (1/3 world)
- Meat and non-meat consumption
- Absorption occurs in the Duodenum
- Enterocytes have Heme and non-Heme (DMT1) transporters
- Transport Fe2+ across the Cell membrane via Ferroportin
- Transferrin transports Fe2+ to Liver and Bone marrow Macrophages
- Intracellular Fe2+ is bound to Ferritin
Iron Deficiency Anemia (Microcytic Anemia)
- Serum Iron = measure of Iron in the Blood
- Total Iron-binding Capacity = measurement of Transferrin molecules in the Blood
- % Saturation = % Transferrin- Fe2+ complexes
- Serum Ferritin = Fe2+ stores in Macrophages and Liver
Laboratory Measurements of Iron Status
- Infants – Breast feeding (Human milk is low in Fe2+)
- Children – Poor diet
- Adults (20 – 50) – Peptic ulcer disease in Males / Menorrhagia or Pregnancy in Females
- Elderly – Colon polyps / Carcinoma in Western world; Hookworm (Ancylostoma duodenale and Necator americanus) in the Developing world
- Other – Malnutrition, Malabsorption, Gastrectomy (acid state)
Iron Deficiency Typical
- Storage of Iron is depleted –> Decreased Ferritin; Increased TIBC
- Serum Iron is depleted –> Decreased Iron, Decreased % Saturation
- Normocytic anemia – BM makes fewer but normal sized
- Microcytic Hypochromatic anemia – BM makes smaller, and Fewer
Stages of Iron Deficiency
Clinical Features of Iron Deficiency
- Anemia w/ Conjunctival pallor
- Microcytic Hypochromatic
- Increased RDW
- Decreased Ferritin, Serum Fe2+, % Saturation
- Increased TIBC, Increased Free Erythrocytic Protoporphyrin (FEP)
- Pica
- Koilonychia – spoon nails
Plummer-Vinson Syndrome (Microcytic Anemia)
- Fe2+ deficiency anemia w/
- -> Microcytic Hypochromatic anemia
- Esophageal web –> Dysphagia
- Atrophic Glossitis –> Beefy-red tongue
- A/w Chronic Inflammation or Cancer
- Most common in Hospitilized pts.
- Production of Acute phase reactants from the Liver; Including Hepcidin
- Inflammation –> Hepcidin (Liver) – sequesters Fe2+ in Storage sites, binds Ferroportin to Intestinal mucosal cells and Macrophages, inhibit transport
- Limiting Fe2+ transfer from Macrophages or Erythroid precursors
- Suppressing EPO production –> Prevents Bacterial growth
- Increased Ferritin, Free Erythrocyte Protoporphyrin (FEP)
- Decreased TIBC, Serum Fe2+, % Saturation
Anemia of Chronic Disease
(Microcytic / Normocytic Anemia)
- Defective Protoporphyrin (Heme) synthesis
- Protoporphyrin is synthesized via a series of RXNs
- Ferrochelatase attaches Protoporphyrin to Fe2+ to make Heme
- Final RXN occurs in the Mitochondria
- Fe2+ is transferred to Erythroid Precursors and Enters the Mitochondria to form Heme –> If Protoporphyrin is def. –> Fe2+ trapped in Mitochondria
- Fe2+ laden Mitochondria –> Ring around the Nucleus of Erythroid precursors –> ‘Ringed Sideroblasts’ Mito. In Bone marrow
- Congenital: Aminolevulinic acid synthesis def. (ALA Synthase def.)
- Acquired: Alcoholism – Mito. Poison, Lead Poisoning inhibits ALAD and Ferrochelatase, Vit. B6 def. – cofactor for ALAS – TB treatment (Isoniazid Tx)
- Increased Ferritin, Serum Iron, % Saturation
- Decreased TIBC
- Tx: Pyridoxine (B6) cofactor for ALA synthase
Sideroblastic Anemia
(Microcytic Anemia)
- Decreased Synthesis of the Globin Chains of Hemoglobin
- Inherited mutation
- Protected against Plasmodium falciparum malaria
- Alpha and Beta variant chains
- Normal Hemoglobin are HbF(alpha2, gamma2), HbA(alpha2,beta2), HbA2(alpha2,delta2)
Thalassemia
(Microcytic Anemia)
- 4 Alpha genes are normally present
- One gene – Asymptomatic
-
Two genes – Mild anemia w/ Increased RBC count
- Cis deletion – Asians (worse)
- Trans deletion – African Americans
- Three genes – Severe anemia –> Beta chains form Tetramers (HbH) that damage RBCs –> HbH seen on Electrophoresis
- Four genes – Not compatible w/ Life –> Hydrops Fetalis –> Gamma cahins form Tetamers –> Hb Barts syndrome seen on Electrophoresis
Alpha-Thalassemia
(Microcytic Anemia)
- Point mutations in Promoter or Splicing sites
- Mediterranean and African
- Two genes – present on Chrom 11 –> Absent Beta0 or Diminsed Beta+
Beta-Thalassemia
(Microcytic Anemia)
- Mildest form of disease and is Asymptomatic w/ increased RBC count
- Beta chain underproduced (Heterozygote)
- Microcytic Hypochromatic RBCs and Target cells on Blood smear
- Hemoglobin Electrophoresis shows:
- Slightly Decreased HbA w/ Increased HbA2 (5%, normal 2.5%) and HbF (2%, normal 1%)
Beta-Thalassemia minor
(Beta/Beta+)
- Most severe form of the disease and Severe anemia
- Few months after birth - Homozygote
- High HbF (alpha2gamma2) at birth –> Temporarily protective
- Unpaired alpha chains precipitate –> Dmg RBC membrane –> Ineffective erythropoiesis and Extravascular hemolysis (Removal of circulating RBCs by Spleen)
- Massive Erythroid Hyperplasia –> Expansion of Hematopoiesis into the Skull –> ‘Crewcut’ and ‘Chipmunk face’
- Extramedullary Hematopoiesis w/ Hepatosplenomegaly
- Risk of Aplastic crisis w/ Parvovirus B19 inf. Of Erythroid precursors
- Tx: Chronic transfusions –> Hemochromatosis (Tx: Deforaxamine)
- Microcytic Hypochromic RBCs w/ Target cells and Nucleated RBCs
- Electrophoresis shows HbA2 and HbF w/ little/none HbA
Beta-Thalassemia major
(Beta0/Beta0)