Chapter 14-RBCs And Bleeding Disorders Flashcards
What is the major difference regarding the spleen between intravascular and extravascular hemolysis
Splenomegaly is not seen in intravascular hemolysis
What is the antibody present in cold hemolysin antibodies
IgG
In addition to a mutation in the Beta chain, which event in the alpha chain further worsens the prognosis
Gaining an Alpha chain chromosome, leading to further imbalance and alpha chain deposition
How does acute blood loss affect white cells
- massive decreased in blood pressure results in increased levels of adrenergic hormones
- mobilizes granulocytes and Increased leukocytosis
Which type of Von Willebrand disease is quantitative
Type 1 and 3
What is the significance of HgH
Such a high affinity for Oxygen that it can be let go and used normally
What are the histological appearances during megablastic anemia
- macrocyclic and oval that lack the central pallor of normal RBCs and appear hyperchromic, but no rise in MCHC
- Low reticulocyte count
- Neutrophils show nuclear hypersegmentation 6 lobules
What is the pathogenesis of hemolytic uremic syndrome (HUS)
- Infection with E Coli O157:H7 which contains the Shiga like toxin
- Creates endothelial defects that cause the accumulation of platelets
What is the mechanism that HIV induced thrombocytopenia
Megakaryocytes possess the receptors CD4 and CXCR4, which allows for infection
-Furthermore, can cause B cell hyperplasia and lead to production of alloantibodies to the platelets
What are the numbers and locations of the hemoglobin components
- 2 alphas from an identical pair on chromosome 16
- 2 betas on a single gene on chromosome 11
What is Kasabach-Merritt syndrome
associated with DIC:
-giant hematomas as a result of thrombi forming within the neoplasm because of stasis and recurrent trauma to the blood vessels
Which form of hemolysis is seen in G6PD deficiency
Extravascular and intravascular hemolysis
What is the method of pathogenesis is cold antibody anemia
Temperature falls, IgM binds to RBCs and fixes complement, C3b deposits, temperature warms up and allowed to flood, the C3b binds to phagocytes and is removed
What are the lab test values seen in thrombotic microangiopathies
Aka TTP and HUS
-PT and PTT are normal
What is the amino acid substitution in the cause of HbC
Lysine for glutamate
What is the mechanisms of disease in the case of atypical hemolytic uremic syndome (HUS)
Defects in complement protein H, CD46, or factor I
*All inhibit the activation of the alternative pathways
What is the role of OCs in avitaminatosis
-Decreased absorption
Following blood loss, how long does it take for the CFU-Es to mature and appear as newly released RBCs (reticulocytes) in the Peripheral blood
5 days
What is the treatment for hereditary spherocytosis
Splenectomy, which solves the problem of anemia as they are not removed by macrophages
In those patients with hereditary spherocytosis (HS) what is the underlying cause of an aplastic crisis
Infection of the parvovirus, which infects and kills the progenitors in the bone marrow
What is the cause of chronic immune thrombocytopenia purpura (ITP)
Autoantibody destruction of platlets
What are the characteristics clinical findings in hemophilia A
- Easy bruising
- Massive Bleeding felling procedures
- spontaneous hemorrhages in trauma locations
*Patechiae are absent
What is occuring during myelophthisic anemia
There is morrow failure as a result of displacement by a space occupying lesion
What are the secondary clinical features seen in Beta thalassemia major
- Splenomegaly (extramedulary site)
- cardiac disease usually cause of death (hemochromatosis)
What is the most common cause of B0 thalassemias
Chain terminator mutations
What is the target of cold hemolysin antibodies and what is the mechanism of action
1) IgG binds to the P group on RBCs in cold regions of the body.
2) Lysis occurs when those cells reach warmer areas
3) Causes intravascular hemolysis and hemogloburia
What is the cause of absolute primary polycythemia
-Intrinsic abnormality of hematopoietic precursors
What are the levels of inorganic iron uptake Decreased by
Tannates (in tea)
Carbonates
Oxalates
Phosphates
Why does hydrops fetalis only start to emerge during the third trimester of pregnancy
In early development, there is gamma and delta chains that are functional, however later in development there is need to the alpha chains
What is the most common inherited bleeding disorder of humans
Von Willebrand disease
What is the difference in presentation between acquired and congenital TTP thrombotic thrombocytopenia purpura
Acquired- tends to be alloantibodies to ADAMS13 that inhibit its activity
Congenital- tends to show in adolescence and episodic
What is the mechanism of action in the case of TMPRSS6 and its role anemia
Mutation in the protein that normally suppresses the level of hepcidin at low iron levels. Therefore, even at low levels of iron, there is high levels of hepcidin
What are the clinical presentations of aplastic anemia
Progressive:
- weakness, pallor, dyspnea,
- thrombocytopenia (petechiae and ecchymosis)
- neutropenia (minor infections or onset of chills and fever
What is the process flowing acute blood loss to replace the loss products
1) Blood volume is restored by the intravascular shift of water from the interstitial fluid compartment
2) Results in hemodilation and lowering of the hematocrit
3) Signals for the increased production of erythropoietin
4) proliferation of committed erythropoietin progenitors (CFU-E)
What is the inheritability of paraoxysmal nocturnal hemoglobinuria (PNH)
X linked, but only inheriting one is sufficient to cause disease
What are morphological changes seen in pernicious anemia
- Fundic gland atrophy
- tongue becomes shiny, glazed, and “beefy” aka atrophic glossitis
- demyelination of the dorsal and lateral spinal
How is PNH diagnosed
Flow cytometry
What will folate treat and not treat in respect to vitamin B12 deficiency
Will treat the B12 anemia, but will not the neurological issues that arise
Where is the prevalence of hereditary soherocytosis more prevalent
Northern Europe
How is iron 2+ transported across the apical membrane of duodenum
DMT1
What is the defect in Glanzmann thrombasthenia
Platelets fail to aggregate in response to ADP, collagen, epi, thrombin due to:
-Defect in IIb-IIIa, which is the bridge formation via binding to fibrinogen
What is the pathogenesis of thrombotic thrombocytopenia purpura
Deficiency of ADAMTS13 aka vWF metalloprotease
What is the tendency for sickle cells to form when deoxygenated
Polymerizes to form stacks of cells
What complication can be seen in the Gi tract with cases of Extreme hemolysis
Pigment gallstones
Which infections have seen to cause aplastic anemia
-viral hepatitis of the Non-A, Non-B, non-C and non-G
What is the most common cause of primary polycythemia
Polycythemia Vera
What are the three categories that bleeding disorders due to defective platelet functions are divided into
1) Defects in adhesion
2) Defects in aggregation
3) Defects in secretion
What is aplastic anemia a disorder that is characterized by
-syndrome of chronic hematopoietic failure and CYYTOPENIA
Which factor is affected in hemophilia A
Factor VIII
What are the features that hemolytic anemias share
- shortened red cell life span
- elevated erythropoietin levels
- accumulation of hemoglobin degradation products that accumulate as a result of the hemolysis
The most severe forms of hemophilia A are seen in which mutation
Inversion involving the X chromosome where there is entire elimination of Factor VIII production
What are the morphological features seen in pernicious anemia
Chronic strophic gastritis:
- loss of parietal cells
- prominent infiltrate of lymphocytesand plasma cells
- megaloblastic changes in mucosal cells
What are the principal clinical features of extravascular hemolysis
- Anemia
- splenomegaly
- jaundice
What are the histological findings in the cause of trauma induced hemolytic anemia
- Shisctocytes (red cell fragments)
- Burr cells (pointy cells)
- Triangle cells
What are the clinical features that can be seen in severe iron deficiency
-Koilonychia (spoon nails)
-alopecia
-atrophic changes to tongue and gastric mucosa leading to intestinal malabsorption
-pica
Plummer Vinson syndrome
What is a good plasma value that correlates with the total body storage levels of iron
-plasma ferritin
What are the variants that cause the most severe disease of G6PD issues
G6PD-
G6PD Mediterranean
What is the lifespan of the RBCs in the cause of hereditary spherocytosis (HS)
10 to 20 days as opposed to 120 days
Which patients population is at a higher risk for alpha thalassemia
Asian
What is the product leading to anemia in chronic diseases and what are the other common values
IL-6 causes the increased levels of hepcidin:
- Low serum iron
- Low binding capacity
- high stores of iron in macrophages and ferritin levels
What are the classic signs of avitamintosis
- cheilosis
- Glossitis
- Dermatisis
What are the histological features in G6PD deficient cells
- Heinz bodies
- Bite cells (where a portion containing the Heinz body was removed by a macrophage)
What are the mutations in hereditary spherocytosis (HS)
Ankyrin, band 3, spectrin, band 4.2
What is the cause of hydrops fetalis
-Most severe alpha thalassemia, with deletions of all four chains
What are the antibodies in immune thrombocytopenia purpura (ITP) against
IgG against gp IIb-IIIa or Ib-IX
What is the cause of secondary absolute polycythemia
-Red progenitors are responding to an increased level of erythropoietin
What are the complications that arise in Beta-thalassemia as a result of the increased levels of erythropoietin
Extra-medullary sites, as well as hyperplasia in the marrow leading to:
- erosion of the bony cortex
- Impairment of bone growth
- skeletal abnormalities
- Cachexia
Which two conditions are classified under thrombi microangiopathy
TTP- thrombotic thrombocytopenia purpura
HUS- Hemolytic-uremic syndrome
What is hereditary hemorrhagic telangiectasia (aka Weber-Oiler-Rendu syndrome)
Autosomal dominant condition that causes modulation to TGF-Beta, leading to dilated, tortuous blood vessels with thin walls. This is very prone to bleeding
How does bleeding into tissues differ from bleeding into the gut or out of the body
Iron is not recaptured, so if its not into the tissue, there is the risk of iron deficiency
How is iron transported in the blood
transferrin
Where does the majority hemolytic anemias have premature destruction of RBCs
Within macrophages located in the spleen, also known as extravascular hemolysis
How does the treatment of pure red cell aplasia differ with regards to the presence and abscence of a thymoma
With thymoma: resection leads to improvement
Without: immunosuppressive therapy
What are the main two causes of megablastic anemia
Vitamin B12 and Folate deficiency
In newborns with alpha thalassemia, what is found in their blood with regards to parts of hemoglobin
-Excess gamma globulin forming gamma tetramers known as hemoglobin Barts
What is the location of action for type 3 antibodies in pernicious anemia
Present in 85-90% or patients and are recognizing the alpha and beta subunits of the proton pump of the gastric parietal cells
What is iron stored and bound to
IN the parenchymal cells of the liver, especially ferritin
-Macrophages in other tissues
What is the level of hepcidin in Beta-thalassemia and what is its effect
Decreased, leading to excess iron absorption due to mechanism:
- erythropoietin suppresses hepcidin, which decreases iron absorption
- Iron becomes excess and can lead to secondary hemochromatosis
In general, wha is the cause of marcocytic anemias
-abnormalities that impair the maturation of erythropoietin precursors in the bone marrow
As free haptoglobin decreases during intravascular hemolysis, what happens to the remaining free hemoglobin
Oxidizes to methemoglobin, which is brown
How do the majority of the clotting factor related defects present
- Large postraumatic ecchymoses or hematomas
- prolonged bleeding after a laceration of surgical procedure
“Patients presented with excessive bleeding following a dentist procedure”
What is the mechanism of hemolysis in paroxysmal nocturnal hemoglobinuria
Intravascular as the RBCs are prone to hemolysis via the MAC complex due to the lack of GPI proteins
Which population is shown to have cold hemolysis type anemia
Children following a viral infection
What is the most common nutritional disorder in the world
Iron leading to decreased hemoglobin synthesis
IN those patients that survive beta thalassemia major, what is the effect seen in the bones of the patients
- Have the “crew cut” in the skull
- cheekbones and other prominences are enlarged and distorted
What is the relation and mechanism of telomerase defects in the causation of aplastic anemia
Telomerase is responsible for keeping the DNA long in order to allow for long term replication. Without it, the stem cells will undergo hematopoietic cell exhaustion
What is the mechanism that thrombotic thrombocytopenia purpura (TPP) causes disease
1) Missing ADAMTS13 does not degrade vWF
2) vWF is allowed to accumulate and activate platelets
What is occurring during pure red cell aplasia
Primary marrow disorder in which only erythropoietin progenitors are suppressed or absent
What is the result of a splicing event causing beta thalassemia
-Production of abnormal and normal RNA, so there is still some normal Beta-globin present
In the case of immune thrombocytopenia purpura (ITP), what is the effect of a splenomegaly
Hrombocytopenia is markedly improved
What are some of the clinical signs of DIC
- Thombi in microvasculatrue
- microangiopathic hemolytic anemia
- bilateral renal cortical necrosis
- Waterhouse-Friderichsen Syndrome
- Giant hematomas (Kasabach-Merritt syndrome)
When are microangiopathic diseases seen
DIC TTP HUS Malignant hypertension SLE Cancers
What is the most significant trauma caused hemolysis
- Cardiac valve prosthesis
- Microangiopatic diseases
Once within the ileum pal cells, how does the B12 reach the blood
Binds to transccobalamin 2
What is the survival of a fetus and child with hydrops fetalis dependant on
Blood transfusions for life, with a stem cell transplant having some effect
What are the other lab and blood findings in the case of myelophthisic anemia
Displacement causes:
- abnormal release of nucleated erythroid precursors and immaterial granulocytic from into the blood (leukoerythroblastosis)
- tear drop shaped RBCs
What is the result of a chain terminator mutations in the production of beta thalassemias
B0
- Insertion of a stop codon
- Insertion or deletions that shift the reading frame
*Both result in the cessation of normal Beta globin
What is Henoch-Schonlein purpura
Systemic immune disorder that is characterized by:
- purpuric rash
- colicky abdominal pain
- ployarthralgia
- acute glomerulonephritis (immune complex deposition)
What are the changes in blood levels in folic acid from B12
- The respective level will be decreased
- Increased Serum homocysteine
- methylmalonate levels are normal in folate
- No Neurological changes
What is the heritability of Von Willebrand disease
Autosomal dominant
What does the RBC look like in the cause of Beta-thalassemia
Underhemoglobinized
-hypochromic, microcytic red cells with diminished survival of the RBC and oxygen carrying capacity
What are the lab values in the case of chronic immune thrombocytopenia purpura (ITP)
- low platelet count
- normal or increased megakaryocytes in bone marrow
- large platelets
- Normal PT and PTT