RBC path Flashcards by Michael McMahan

\_\_\_\_ system
Blood cell forming system
Lymph tissue 
Bone Marrow
Red bone marrow 
Yellow bone marrow 
Circulating blood

Hematopoietic System

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Process in which red and white blood cells are
produced
Red bone marrow

Hematopoiesis

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 Erythropoiesis
 Regulated by kidneys
Erythropoietin
 1% of RBCs replaced daily
 Life span
120 days (4 months)

Erythrocytes

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 Immature red blood cells
 Reticular network of RNA in cytoplasm
 Normal range: 0.5% to 1.5%
 Indicator of bone marrow activity
 Reticulocytosis – elevated number of reticulocytes in blood
 Reticulocyte count should be appropriate to the clinical situation

Reticulocytes

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Heme – non-protein portion
Iron porphyrin - 4 pyrrole rings + iron
Globin – protein portion
HbA (Adult Hb) – 2 alpha, 2 beta
HbF (Fetal Hb) – 2 alpha, 2 gamma
Normal adult red cells contain mainly HbA

Hemoglobin

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 A reduction in the erythron – a reduction in the total red cell mass
below normal limits
 Reduction in the oxygen carrying capacity of the blood leading to
tissue hypoxia
 Usually diagnosed based on:
Inadequate numbers of erythrocytes (low hematocrit - the ratio
of packed red cells to total blood volume)
Inadequate level of hemoglobin – the hemoglobin concentration
of the blood

Anemia

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The lifespan of a red blood cell is about ____ days

120 days

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Increased RBC destruction
Decreased RBC production
Blood loss

Anemia

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Clinical Features of \_\_\_\_\_:
Pallor – pale skin and mucosa
Lethargy – lack of energy, fatigue, weakness
Dyspnea – labored breathing, SOB
Tachycardia, arrhythmia, chest pain
Koilonychia - spoon-shaped nails 
Atrophic glossitis 
Cognitive problems, dizziness
Cold extremities
Headache

Anemia

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 A hemoglobinopathy
 Inherited, mis-sense mutation of beta chain
 A single AA substitution of valine for glutamic acid
 Forms a new, abnormal hemoglobin, Hemoglobin S - HbS
 Sickle cell disease – homozygous HbS
 Sickle cell trait - heterozygous, a less serious condition

Sickle cell anemia

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 Individuals with sickle cell trait (heterozygous for HbS) have a survival
advantage in malaria-endemic areas
 Homozygous normal – increased mortality due to malaria
 Heterozygous – survival advantage
 Homozygous – increased mortality due to sickle cell disease
 About 8% of African Americans are heterozygous (sickle cell trait)
 1 in 600 African Americans are homozygous (sickle cell disease)

HbS

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Clinical Consequences of 
\_\_\_\_\_\_\_
Increased susceptibility to infection with 
encapsulated organisms
Pneumococcus pneumoniae
Hemophilus influenzae

Splenectomy

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“Mediterranean” anemia
Group of inherited diseases
Quantitative problem - too few globins synthesized
Underproduction of normal globin proteins due to 
mutations in regulatory genes
 Ineffective production of 
globin chains 
Alpha globin chains (α
Thalassemia)
Beta globin chains (β
Thalassemia)
 Regular transfusions – iron 
overload – organ damage
 Bone deformities – expansion 
of marrow space
 Splenomegaly - splenectomy
 Impaired growth 
 Bone marrow transplantation

Thalassemia

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Two genes involved in making beta chain (one from
each parent)
Severity depends on number of affected beta chain
genes
One gene – beta-thalassemia minor - beta-thalassemia
trait
Mild disease
Two genes – beta-thalassemia major (Cooley’s anemia)
Severe disease

Beta Thalassemia

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 Four genes involved in making alpha chain (two from each parent)
 Severity depends on number of affected alpha chain genes
 One gene – asymptomatic carrier
 Two genes – alpha-thalassemia minor - alpha-thalassemia trait
 Mild disease
 Three genes – hemoglobin H disease
 Moderate to severe disease
 Four genes – alpha-thalassemia major – (lethal)

Alpha Thalassemia

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ABO mismatch leads to _______

intravascular hemolysis

 Rh- mom
 Rh+ fetus
 Fetal RBCs cross the placenta and 
enter the maternal circulation 
during birth trauma
 Prophylactic anti-Rh (D) immune 
globulin (Rhogam) within 72 hours 
of delivery
 Rhogam lyses fetal RBCs in the 
maternal circulation – effectively 
removing any available antigen, 
so the mom doesn’t develop anti-
Rh antibodies

Erythroblastosis Fetalis:

1st Pregnancy at Delivery

2nd Pregnancy at Delivery  
 Rh- mom, with anti-Rh from prior 
pregnancy
 Rh+ fetus 
 Anamnestic response rapidly 
produces anti-Rh (IgG)
 Anti-Rh IgG crosses placenta 
and lyses fetal RBCs
 Rh-mediated hemolytic disease

Erythroblastosis Fetalis:

Immunoglobulin
Administered to Rh-negative women after pregnancies
in which they carried Rh-positive fetuses
Anti-D antibodies

Rhogam:

Rhesus Immune Globulin - RhIg

 Rh incompatibility
 Hemolytic anemia in utero
 Rh-negative mother develops antibodies against Rh-positive erythrocytes of
fetus
 Antibodies cross placenta and hemolyze fetal erythrocytes
 High levels of bilirubin and biliverdin
 Deposition in developing teeth
 Only primary teeth affected

Erythroblastosis Fetalis

Clinical Features of __________

 Anemia caused by immune destruction of erythrocytes
 Erythroblasts in peripheral blood
 Hyperbilirubinemia
 Kernicterus (bilirubin encephalopathy) if bilirubin reaches a high
levels
 Developmental dental defects reported

Erythroblastosis Fetalis

 X-linked disease; most common human enzyme defect (African-American male population)
 Most are asymptomatic; at risk for non-immune hemolytic anemia upon exposure to oxidative stress
 Oxidative stress: infections, drugs (aspirin)
 G6PD / NADPH / Glutathione pathway - maintains supply of reduced glutathione to scavenge free
radicals (anti-oxidant)
 Red cells sustain damage from oxidizing free radicals (phagocytosed in spleen)
 All individuals with Favism (hemolysis due to Broad Beans(fava)) are G6PD deficient
 Survival advantage in Malaria endemic environments

Glucose-6-Phosphate

Dehydrogenase Deficiency

Protozoal disease – primarily Plasmodium falciparum
Female Anopheles mosquito vector, human reservoir
Reproduction in red cells – showers of organisms
produce shaking, chills and fever
Hemolytic anemia
High morbidity, mortality

Malaria

 Most common anemia in US
 Lack of Fe most common nutritional 
deficiency in the world
 Microcytic, hypochromic
 Seen most often in females – more iron 
lost in menses than replaced by nutrition
 Treated with iron supplements
 When in males, suspect internal 
bleeding

Iron Deficiency Anemia

Dietary lack Impaired absorption Increased requirement Chronic blood loss

Iron deficiency

Iron Deficiency is Usually Caused by | ______ or ______

Dietary Lack or Blood Loss

``` Scandinavian, Northern European women Severe Fe-deficiency anemia Mucosal atrophy - atrophic glossitis Esophageal webs - dysphagia Increased risk for squamous cell carcinoma Esophagus Oropharynx Posterior Oral Cavity ```

Plummer-Vinson Syndrome

``` Absorption of _______ requires intrinsic factor, which is secreted by the parietal cells of the stomach ```

vitamin | B12

Autoimmune disease Not due to dietary deficiency of B12 A form of megaloblastic anemia caused by autoimmune gastritis and failure of intrinsic factor production leading to vitamin B12 deficiency Loss of ability to absorb Vitamin B12 Vitamin B12 (cobalamin) required for normal folate metabolism and DNA synthesis

Pernicious anemia

Megaloblastic anemia Dietary deficiency of folic acid Folate required for DNA synthesis

Folic acid deficiency

 Marrow aplasia secondary to supression of multipotent myeloid stem cells (erythrocyte, leukocyte and thrombocyte series), resulting in pancytopenia  May be caused by known myelotoxic agents (eg. whole body radiation)  Antineoplastic drugs (alkylating agents, antimetabolites)  Benzene  Chloramphenicol  Pathogenesis may involve T cell attack on myeloid stem cells  Prognosis unpredictable  Transfusion, bone marrow transplant

Aplastic Anemia

 An increase in the RBC mass  Relative polycythemia – dehydration – decreased plasma volume with normal red cell mass  Absolute polycythemia – a true increase in red cell mass  Primary polycythemia (polycythemia vera)  Erythropoietin-independent  Acquired, clonal stem cell disorder (a chronic myeloproliferative disorder)  Secondary polycythemia  Erythropoietin-dependent  Compensatory response to tissue hypoxia  Chronic lung disease  Cigarette smoking  Residence at high altitude  Paraneoplastic syndromes

Polycythemia (Erythrocytosis)