Hemo 2 Flashcards
Hematopoietic System
– cell forming system
Blood
Hematopoietic System
Blood cell forming system
(3)
Lymph tissue
Bone Marrow
-Red bone marrow
-Yellow bone marrow
Circulating blood
Hematopoiesis
(2)
Process in which red and white blood cells are
produced
Red bone marrow
Hematopoietic Bone
Marrow in the Adult
(4)
Vertebrae
Ribs
Sternum
Ilia
Erythrocytes
(3)
Erythropoiesis
Regulated by kidneys- Erythropoietin
1% of RBCs replaced daily
Erythrocytes
Life span
120 days (4 months)
Reticulocytes
(3)
Immature red blood cells
Reticular network of RNA in cytoplasm
Indicator of bone marrow activity
Reticulocytes
Normal range:
0.5% to 1.5%
Reticulocytosis -
elevated number of reticulocytes in blood
-reticulocyte count should be appropriate to the clinical situation
Peripheral Blood Examination:
Phlebotomy (Venipuncture)
Normal Peripheral Blood Values
Erythrocytes –
Thrombocytes –
Leukocytes –
4.0 – 5.5 million / mm3
150 - 400 thousand / mm3
5 – 10 thousand / mm3
Peripheral Blood Smear - RBCs
(2)
Biconcave disks – central pallor
7-8 microns diameter
Hematocrit - percent
Males
Females
40 - 54%
37 - 47%
Hemoglobin – grams per deciliter (100ml)
Males
Females
14 - 18
12 - 16
Serum =
Plasma – Clotting Factors
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
Erythrocytes –
anemia, erythropenia
(Leukocytes –
leukopenia)
(Thrombocytes -
thrombocytopenia)
Cell size
(3)
Normocytic
Macrocytic – B12, Folate deficiency
Microcytic – Iron deficiency
Hemoglobin content
(2)
Normochromic
Hypochromic
A reduction in the erythron –
a reduction in the total red cell mass
below normal limits
Anemia
Reduction in the oxygen carrying capacity of the blood leading to
tissue hypoxia
Anemia
Usually diagnosed based on:
Inadequate numbers of erythrocytes (low hematocrit -
Inadequate level of hemoglobin –
the ratio of packed red cells to total blood volume)
the hemoglobin concentration of the blood
AnemiasThe lifespan of a red blood cell is about — days
Each day, must replace
120
Anemia
Increased
Decreased
— loss
RBC destruction
RBC production
Blood
Clinical Features of Anemia
(9)
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
Clinical Symptoms of Anemia
(7)
Fatigue
Increased heart rate
Shortness of breath / increased respiratory rate
Low blood pressure
Pale Skin
Central nervous system
Cardiac failure can develop and compound the tissue hypoxia caused by the deficiency of O2 in the blood
Fatigue –
a person with a low hematocrit cannot carry enough oxygen in the blood to meet energy demands.
Weakness, malaise, and easy fatigability.
Increased heart rate -
compensates for the low oxygen carrying capacity of the blood
Shortness of breath / increased respiratory rate –
compensates for the poor delivery of oxygen to the tissues.
Dyspnea on mild exertion.
Low blood pressure –
a decrease in blood viscosity directly lowers total peripheral resistance to the flow of
blood, thus lowering mean arterial blood pressure
Pale Skin -
hemoglobin is bright red when oxygenated and less red when deoxygenated. Because the redness
of skin is due to the redness of blood, the skin of an anemic person (who has less oxygen in the blood) will be
less red (paler) than the average person
Central nervous system -
hypoxia can cause headache, dimness of vision, and faintness
Anemias of Increased Blood Destruction
(8)
Anemias of Increased Blood Destruction
Sickle cell anemia
Thalassemia
Erythroblastosis fetalis
Hereditary spherocytosis
G6PD deficiency
Paroxysmal nocturnal
hemoglobinuria
Autoimmune hemolytic
anemia
Mechanical trauma to
red cells
Malaria
Sickle Cell Anemia
(6)
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
HbS
(3)
Individuals with sickle cell trait (heterozygous for HbS) have a survival
advantage in malaria-endemic areas
About 8% of African Americans are heterozygous (sickle cell trait)
1 in 600 African Americans are homozygous (sickle cell disease)
Homozygous normal -
increased mortality due to malaria
Heterozygous HbS –
survival advantage
Homozygous HbS –
increased mortality due to sickle cell disease
Behavior of HbS in
Hypoxic Conditions
(4)
HbS molecules polymerize when deoxygenated, forming HbS aggregates
Cytosol changes from a freely-flowing liquid to a viscous gel
With continued deoxygenation, HbS aggregates form long, needle-like fibers
that distort the red cell shape
Sickle cell trait
Sickle cell trait –
HbA interferes with HbS polymerization in the heterozygous
condition
Red cells do not sickle except under conditions of profound hypoxia
Clinical Effects of Sickling
in Sickle Cell Anemia
(5)
Hemolytic anemia
Microvascular occlusions
Vaso-occlusive crises (pain crises)
Commonly involved sites: bone, lung, liver, brain, spleen
Autosplenectomy
Hemolytic anemia -
chronic hemolysis – and jaundice – phagocytosis in
spleen
Microvascular occlusions -
sickle cells becone arrested during transit
through the microvasculature
Vaso-occlusive crises (pain crises) –
episodes of hypoxic injury and
infarction that cause severe pain in the affected region
Clinical Consequences of
Splenectomy
(3)
Increased susceptibility to infection with
encapsulated organisms
Pneumococcus pneumoniae
Hemophilus influenzae
Thalassemia
(5)
Thalassos = sea
“Mediterranean” anemia
Group of inherited diseases
Quantitative problem - too few globins synthesized
Underproduction of normal globin proteins due to
mutations in regulatory genes
Thalassemia
(6)
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
Beta Thalassemia
(4)
Two genes involved in making beta chain (one from
each parent)
Severity depends on number of affected beta chain
genes
One gene
Two genes
Beta Thalassemia
One gene –
beta-thalassemia minor - beta-thalassemia
trait
Mild disease
Beta Thalassemia
Two genes –
beta-thalassemia major (Cooley’s anemia)
Severe disease
Alpha Thalassemia
(2)
Four genes involved in making alpha chain (two from each parent)
Severity depends on number of affected alpha chain genes
Alpha Thalassemia
One gene –
Two genes –
Three genes –
Four genes –
asymptomatic carrier
alpha-thalassemia minor - alpha-thalassemia trait
- Mild disease
hemoglobin H disease
-Moderate to severe disease
alpha-thalassemia major – (lethal)
Blood Transfusion Reactions: ABO Blood Group Incompatibility
(2)
ABO mismatch leads to intravascular hemolysis
Antibody-coated erythrocytes destroyed by
both complement-mediated lysis and by
phagocytosis in spleen
ABO blood groups
Type O –
Type A –
Type B –
Type AB –
45%
42%
10%
3%
Rh antigen
Positive -
Negative -
85%
15%
Hemolytic Blood Rh-Mediated
Hemolytic Disease of the Newborn
Antigens on surface of red cells
ABO antigens –
Rh antigen (Rhesus factor) –
A, B, AB, O
Rh+, Rh-
Classification of blood types:
A pos, A neg, etc.
Erythroblastosis Fetalis:
1st Pregnancy at Delivery
(5)
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:
2nd Pregnancy at Delivery
(5)
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
Rhogam:
Rhesus Immune Globulin - RhIg
(3)
Immunoglobulin
Administered to Rh-negative women after pregnancies
in which they carried Rh-positive fetuses
Anti-D antibodies
Erythroblastosis Fetalis
(7)
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
Clinical Features:
Erythroblastosis Fetalis
(5)
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 - Atasu M, Genc A, Ercalik S,
Enamel hypoplasia and essential staining of teeth from
erythroblastosis fetalis, J Clin Pediatr Dent., 22(3):249-52, 1998
Glucose-6-Phosphate
Dehydrogenase Deficiency
(7)
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
Malaria
(5)
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
Anemias of Decreased
Red Blood Cell Destruction
(4)
Iron deficiency anemia -
microcytic, hypochromic
Anemia of chronic
disease
Sideroblastic anemia
Pernicious anemia (B12
deficiency) - macrocytic
Folic acid deficiency
anemia - macrocytic
Aplastic anemia
Myelophthisic anemia
Iron Deficiency Anemia
(6)
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
Middle-aged female with
profound anemia
Hb =
6.2 (nl: 12-16 g/dl)
Iron Deficiency
(4)
Dietary lack
Impaired absorption
Increased requirement
Chronic blood loss
Iron Deficiency is Usually Caused by
Dietary Lack or Blood Loss
Infants –
breast feeding
Iron Deficiency is Usually Caused by
Dietary Lack or Blood Loss
Children
poor diet
Iron Deficiency is Usually Caused by
Dietary Lack or Blood Loss
Adults
M/F
Males - peptic ulcer
disease
Females - menorrhagia or
pregnancy
Iron Deficiency is Usually Caused by
Dietary Lack or Blood Loss
Elderly
(2)
Colonic polyps / colon
adenocarcinoma in
Western world
Hookworm infection in
developing world
Iron Deficiency is Usually Caused by
Dietary Lack or Blood Loss
(3)
Malnutrition, malabsorption,
gastrectomy
Serum ferritin –
reflects iron stores in bone marrow
macrophages and liver
Total iron binding capacity (TIBC) –
measure of transferrin
molecules in blood
% saturation –
percent of transferrin molecules bound by
iron (nl = 33%)
Serum iron –
measure of iron in the blood
Plummer-Vinson Syndrome
(5)
Scandinavian, Northern European women
Severe Fe-deficiency anemia
Mucosal atrophy - atrophic glossitis
Esophageal webs - dysphagia
Increased risk for squamous cell carcinoma
increased risk for squamous cell carcinoma
(3)
Esophagus
Oropharynx
Posterior Oral Cavity
Macrocytic Anemia
macrocytic
(2)
Pernicious anemia (B12 deficiency)
Folic acid deficiency anemia
Absorption of vitamin
B12 requires
intrinsic
factor, which is
secreted by the
parietal cells of the
stomach
Cobalamin –
Intrinsic
Factor complex
absorbed in the ileum
Vitamin B12 Deficiency Anemia:
Pernicious Anemia
(5)
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
Folic Acid Deficiency
(3)
Megaloblastic anemia
Dietary deficiency of folic acid
Folate required for DNA synthesis
Aplastic Anemia
(5)
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)
Pathogenesis may involve T cell attack on myeloid stem cells
Prognosis unpredictable
Transfusion, bone marrow transplant
May be caused by known myelotoxic agents (eg. whole body
radiation)
(3)
Antineoplastic drugs (alkylating agents, antimetabolites)
Benzene
Chloramphenicol
Anemias of Blood Loss
(5)
Gastrointestinal bleeding
Hemoptysis (coughing up blood)
Epistaxis (nosebleed)
Hematuria (blood in urine)
Menstrual blood loss
Gastrointestinal bleeding
(3)
Hematemasis (vomiting blood)
Melena (black stool)
Hematochezia (red blood in feces).
Menstrual blood loss
(2)
Menorrhagia (excessive bleeding)
Metrorrhagia (irregular bleeding).
Fecal Occult Blood Test – Stool Guaiac
Screening test for occult bleeding in GI tract
Polycythemia (Erythrocytosis)
(3)
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
Absolute polycythemia – a true increase in red cell mass
Primary polycythemia (polycythemia vera)
(2)
Erythropoietin-independent
Acquired, clonal stem cell disorder (a chronic myeloproliferative disorder)
Secondary polycythemia
(2)
Erythropoietin-dependent
Compensatory response to tissue hypoxia