Usera: RBC 2 Flashcards by Megan Foggia

What is the range of MCV for normocytic anemias?

80-100

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List five causes of normocytic anemias

acute blood loss
early iron deficiency and anemia of chronic disease
aplastic anemia
chronic renal failure
malignancy

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Normocytic anemia can be caused by intrinsic or extrinsic defects. List 3 intrinsic defects and 2 extrinsic defects.

Intrinsic: membrane defect, abnormal Hb, enzyme deficiency

Extrinsic: truama, immune destruction

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Normocytic anemia can be caused by (blank) hemolysis when splenic and hepatic macrophages phagocytose (blank). The (blank) become bound by IgG with or without the deposition of C3b. The red cells can then take on an abnormal shape such as (blank) or (blank)

extravascular; RBCs; RBCs; spherocytosis; sickling

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Two laboratory findings in extravascular hemolysis?

increased unconjugated bilirubin (too much RBC destruction)

increased serum LDH

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Normocytic anemia can be caused by (blank) hemolysis, which occurs when RBC phagocytosis by splenic/hepatic macrophages occurs within (blank).

intravascular; blood vessels

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3 reasons why RBC hemolysis would occur within blood vessels?

enzyme deficiency (G6PD)
mechanical trauma
complement/immune destruction

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4 lab findings in intravascular hemolysis?

increased unconjugated bilirubin
increased serum LDH
decreased serum haptoglobin
hemosiderinuria (brown urine)

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This is an acute phase reactant that complexes with hemoglobin… the complex then binds to macrophages and is phagocytosed.

haptoglobin

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Why is serum haptoglobin DECREASED in normocytic anemias?

Hb is released from RBCs in excess and complexes w haptoglobin, causing the free haptoglobin levels to decrease

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Hereditary spherocytosis is most commonly due to a mutation in (blank), which causes the RBCs to become (blank) instead of biconcave. It can also be due to mutations in the following…

ankyrin; spherical;

band 3, spectrins, protein 4.2

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Hereditary spherocytosis is autosomal (blank) and prevents with what 4 symptoms?

dominant; jaundice (chronic hemolysis), gallstones, splenomegaly, aplastic crisis in children

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What makes up the gallstones in hereditary spherocytosis?

calcium bilirubinate

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What happens to the following in hereditary spherocytosis?

MCHC?
Osmotic fragility?
LDH and bilirubin?

Increased MCHC (>conc of Hb)
Increased osmotic fragility (hyper-permeability to sodium) can lead to rupture in a hypotonic solution
increased LDH and bilirubin

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Are all spherocytes due to genetic disease?

no, anything that affects the surface area of the red cell membrane can cause spherocytes

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Hereditary elliptocytosis is an autosomal (blank) disease due to a defect in (blank).

dominant; spectrin tetramers or 4.1

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Two clinical findings in hereditary elliptocytosis?

mild anemia

splenomegaly

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What causes sickle cell anemia on a genetic level?

recessive missense mutation; Valine instead of Glutamic acid in beta-globin chain

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If you are heterozygous for sickle cell trait, do you have anemia? What is this called?

no anemia; HBAS

**occurs in 10% of blacks

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If you are homozygous for sickle cell trait, what type of hemoglobin do you make? What percentage of this type is the threshold for disease?

HBSS; 60% HBS is threshold for disease

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In people heterozygous for HgbS (carriers of sickling hemoglobin), the polymerisation problems are (blank), because the normal allele is able to produce over 50% of the haemoglobin. In people homozygous for HgbS, the presence of long-chain polymers of HbS distort the (blank) of the red blood cell from a smooth doughnut-like shape to ragged, making it fragile and susceptible to breaking within capillaries.

minor; shape

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What type of hemolysis occurs in sickle cell anemia?

predominantly extravascular hemolysis

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What are three triggers for HBS molecules to polymerize?

low pH (acidosis)
low O2 (hypoxia)
volume depletion (dehydration)

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Why are newborns with sickle cell anemia protected from sickling for 5-6 months?

they have HBF (two alpha, two gamma chains)

**treatment w hydroxyurea can increase levels of HbF

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List as many clinical findings in sickle cell anemia that you can... What is the most common cause of death in sickle cell patients?

``` dactylitis (pain in hands and fingers) acute chest syndrome**most common cause of death stoke gallstones (calcium bilirubinate) priapism aspetic necrosis of femoral head aplastic crisi autosplenectomy ```

Sickle cell anemia causes susceptibility to infections by (blank), due to a dysfunctional (blank). It can also cause osteomyelitis by (blank)

encapsulated organsims, like strep. pneumoniae and H. influenzae; spleen; Salmonella paratyphi

What does sickle cell anemia do to the kidneys?

can occur in peritubular capillaries and cause microhematuria (collection of RBCs in the tubules) and renal papillary necrosis

How can you treat sickle cell anemia? When should you give a transfusion?

infectious prophylaxis or pain management; only give transfusion if acute chest syndrome or aplastic crisis

G6PD deficiency is a recessive (blank) disease; it affects 22% of (blank); (blank) are asymptomatic; (blank) RBCs are usually affected while (blank) RBCs have are normal or near-normal

X-linked; blacks; females; old; young

What is the problem pathophysiologically with having G6PD deficiency?

you aren't converting NADP+ to NADPH, which is required for glutathione to be reduced - reduced glutathione protects RBCs from oxidative damage and hemolysis

3 inciting causes of G6PD deficiency?

infection drugs: primaquine, sulfas fava beans

This is a more severe variant of G6PD deficiency; decreased enzyme activity throughout life span of RBCs

Mediterranean G6PD

In G6PD Mediterranean, (blank) accumulates and injures RBCs via hemolysis. Oxidized hemoglobin precipitates to form (blank). Macrophages will take a "bite" from RBCs with damaged membranes, forming (blank)

H202; heinz bodies; bite cells

Clinical findings in G6PD Mediterranean?

``` heinz bodies (blue dots in yellow stained RBCs) bite cells ```

What are Heinz bodies?

precipitates of hemoglobin that can be seen in G6PD mediterranean

3 clinical findings in G6PD deficiency?

normocytic anemia sudden onset of back pain and delayed hemoglobinuria susceptibility to infections (impaired MPO - NO NADPH in oxidative burst)

When should you do an RBC enzyme analysis in patients with G6PD deficiency?

after their hemolytic episode has resolved **G6PD levels will be near normal in reticulocytes and young cells

5 types of immunohemolytic anemia?

``` warm agglutinins cold agglutinins complement drug induced paroxysmal cold hemogloninuria ```

This is the most common hemolytic anemia - it is extravascular

warm agglutinins

What immunoglobulin is involved in warm agglutinins?

IgG

What happens in warm agglutinins?

IgG coats RBCs and they are phagocytosed by splenic macrophages

What is the cause of nearly 50% of warm agglutinin cases?

idiopathic

What immunoglobulin is involved in cold agglutinins?

IgM

What is the cause of cold agglutinins?

mycoplasma pneumoniae infectious mononucleosis **Raynaud's phenomenon is common

Immunohemolytic anemia can also be (blank) mediated, in which RBCs are either coated by (blank) and phagocytosed by liver macs, or coated by (blank) which prompts formation of the membrane attack complex

complement; C3b (extravascular); C5-C9 (intravascular)

3 clinical findings in immune hemolytic anemia?

jaundice hepatosplenomegaly Raynaud's phenomenon

Lab findings in immune hemolytic anemia?

Positive DAT (Direct Coombs test: tests for antibodies bound to RBC surface) Positive indirect Coombs: test for antibodies present in the bloodstream Unconjugated hyperbilirubinemia Hemoglobinuria Decreased haptoglobin normocytic anemia RBC agglutination (IgM is a big pentamer)

What happens in a drug-induced immune hemolytic anemia? What drug is commonly involved in such a reaction?

antibody (IgG) to a drug binds to RBC membranes and causes extravascular hemolysis; penicillin

What types of drugs will cause a drug-induced immune hemolytic anemia?

quinidine quinine isoniazid sulfonamides

How do you treat drug-induced IHA?

discontinue offending drug give corticosteroids to suppress immune system splenectomy IVIG (immunoglobulin coats macrophages and saturates them so they are unavailable to bind/phagocytose RBCs)

This is an acquired membrane defect in myeloid stem cells due to a mutation in PIG-A gene

Paroxysmal nocturnal hemoglobinuria

The mutation in the (blank) gene in paroxysmal nocturnal hemoglobinuria results in loss of (blank), which normally destabilizes C3 and C5 to inhibit formation of the membrane attack complex. So, when (blank) is nonfunctional, this will result in intravascular (blank)

PIG-A; Decay accelerating factor (DAF); DAF; complement mediated lysis

Paroxysmal nocturnal hemoglobinuria can lead to episodic (blank), (blank) deficiency, increased risk of both (blank) and (blank)

hemoglobinuria; iron; thrombosis (platelet fragments); AML

3 lab findings with paroxysmal nocturnal hemoglobinuria

normocytic anemia decreased haptoglobin increased serum/urine Hb

What are the different cell fragments seen in traumatic hemolysis?

schistocytes burr cells helmet cells

Traumatic hemolysis can be caused by (blank)

Disseminated intravascular coagulation (RBCs are damaged by fibrin buildup or clots in small vessels)

2 other causes of traumatic hemolysis?

long distance running | artificial heart valves (rough flow of blood through these plastic tubes)

What are these? ``` hypersplenism microangiopathic hemolytic anemia microorgansims like malaria and clostridium perfringens snake venom chemical physical ```

causes of non-immunologic hemolytic anemia

What is alloimmune hemolytic anemia?

occurs after a transfusion reaction, when a recipient makes antibodies to the antigens on the donor's RBCs - results in intra and/or extravascular hemolysis

Lab findings in alloimmune hemolytic anemia?

``` DAT + anemia depending on severity total and indirect bilirubin increased haptoglobin increased LDH increased ```

Anemia and hyperbilirubinemia that occur as a result of maternal anitbodies to a baby's RBCs; will present with positive DAT (Coomb's test), increased total and indirect bilirubin, increased LDH

Hemolytic disease of the newborn

Anemia can be associated with systemic disease. It is usually normochromic and normocytic anemia. Give one example.

renal disease

What cell type will be seen in anemia associated with systemic disease?

burr cells

Anemia can also occur with (blank), and is usually normochromic and normocytic unless there is blood loss, hemorrhage, or a myelophthisic process (having to do w the bone marrow)

neoplasia

Hemolytic anemia can be associated with infection. Name two of the most common pathogens.

Clostridium perfringens | Malaria

Macrocytic anemias can be divided into what two categories?

megaloblastic (characterized by B12 or folate deficiency) or nonmegaloblastic (alcoholism)

In macrocytic anemias, the MCV is (blank)

>100

What can cause B12 deficiency?

pernicious anemia pure vegan diet (B12 is in animal products) malnutrition malabsorption (decreased intrinsic factor, decreased gastric acid, decreased intestinal absorption)

Parietal cells synthesis (blank) and (blank). HCl frees (blank). free (blank) binds to R-binders. Pancreatic enzymes cleave R-binders from b12 in duodenum. Then b12 binds to (blank). Both reabsorbed in (blank). Stored in liver 6-9 years

HCl and intrinsic factor; B12; B12; intrinsic factor; terminal ileum

Reasons for folate deficiency? | 3 general categories

Decreased intake: malnutrition, ETOH, goat milk, infants/elderly Malabsorption: celiac, bacterial overgrowth Drug inhibition: 5-fluorouracil, MTX, TPM-SFX, phenytoid, birth control, ETOH

Where is iron absorbed? Folate? B12?

duodenum; jejunum; terminal ileum

In megaloblastic anemia, there is delayed (blank) maturation. What cells does it affect?

nuclear (nuclei will be way too large); affects all rapidly dividing cells

Elevated homocysteine can cause damage to (blank)

vascular endothelial cells **associated with vascular disease

What type of reaction is occuring in pernicious anemia? What is the body making autoantibodies to?

type II hypersensitivity; autoimmune destruction of parietal cells or antibodies that block B12/intrinsic factor from binding

In what population does pernicious anemia occur in?

Those with blood group A

3 symptoms of pernicious anemia

smooth/sore tongue peripheral neuropathy (due to B12 deficiency) dementia

What is one way to differentiate B12 deficiency from folate deficiency?

B12 deficiency will cause peripheral neuropathy, while folate deficiency will not; hit em with a tuning fork

What is the best way to test for folate deficiency?

decreased serum and RBC folate

Treatment for Vit B12 deficiency? Folate deficiency?

IM injections of B12; | oral admin of monoglutamic folic acid

What is the most common cause of nonmegaloblastic (no problem w bone marrow) macrocytosis? What else can cause it?

ETOH; liver disease due to increased cholesterol (makes RBC membranes larger)

What type of cells will be present in nonmegaloblastic macrocytosis?

target cells

What type of immune cells will be seen in Vit B12 and/or folate deficiency?

hypersegmented neutrophils