Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BLISS > Microcytic, Macrocytic And Aplastic Anemias > Flashcards

Microcytic, Macrocytic And Aplastic Anemias Flashcards

1
Q

How is iron transported in plasma?

A

By a glycoprotein called transferrin synthesized in the liver

  • normally 1/3 saturated which makes average serum levels in men and women 120 and 100/dL respectively
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Ferritin

A

Protein-iron complex that is found in spleen, bone marrow and skeletal muscles via macrophages
Due to macrophages breaking down RBCs

High levels of ferritin in serum implies RBC damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How large is the normal zone of pallor in normal RBCs?

A

1/3 cell diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the 3 ways to classify anemia’s?

A
  • amount of hematocrit in the blood (%)
  • alterations in the RBC morphology/size
    (Normocytic, microcytic and macrocytic)
  • degree of reflective color (normochromic or hypochromic)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the most useful measurements for red blood cells?

A

Mean cell volume (MCV)
- normal = 82-96

Mean Cell Hemoglobin (MCH)
- normal = 27-33

Mean cell hemoglobin concentration
- normal = 33-37

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Microcytic hypochromic anemia’s

A

Caused by disorders of hemoglobin synthesis, usually due to iron deficiencies

Requires at least 1 of 3 components in sufficient amounts

  • iron
  • protoporphyrin
  • globin
  • decrease in any 3 causes microcytic anemia’s*

Most common form of anemia in hospitalized patients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Macrocytic anemia’s

A

Usually stem from abnormalities that impair Maturation of erythroid precursors in bone marrow
- usually folate or Vit B12 deficiencies

  • both folate and Vit. B12 are required for DNA synthesis and hemopoiesis by enabling methionine and thymidylate synthase enzymes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Normochromic, normocytic anemia’s

A

Diverse etiologies and have a wide variety of specific abnormalities to the share of RBCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Iron deficiency anemia

A
  • Deficiency of iron is the most common deficiency in the Underdeveloped world and the most common reason for anemia*
  • chronic blood loss it the most common cause of iron deficiency in the developed world*
  • it is assumed, until proven otherwise, that if a patient in the developed world has iron deficiency, it must be attributed to GI blood*

Can be caused by 1 of 4 causes

  • dietary lack
  • impaired absorption
  • increased requirement
  • chronic blood loss

ALWAYS PRODUCES HYPOCHROMIC MICROCYTIC ANEMIA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the recommended daily iron requirement for men and women?

A

7-10 mg =. Men

7-20 mg = women
- these values are due to only 10-15% of ingested iron is absorbed properly

  • at least 1 mg must be absorbed from the diet/day*
  • increased requirement in premenopausal/ pregnant women, growing infants and children*
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Organic vs inorganic iron

A

Red meat = organic form and is easily absorbed in diet (its in heme form)

Plant iron = inorganic form and is poorly absorbed in diet (in non heme form)

  • populations that eat more plants than meat are at risk for anemia*
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are possible causes of impaired absorption of iron

A

Spure

Chronic diarrhea

Gastrectomy

Celiac disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the most diagnostically significant finding for iron deficiency?

A

Disappearance of stainable iron in macrophages in the bone marrow

  • RBCs being destroyed dont have iron so the macrophages wont stain either in iron deficiencies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Poikilocytosis

A

Small elongated red blood cells that are also called “pencil cells”

  • seen in iron deficiencies and thalassemias
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Clinical features of acute iron deficient anemia

A

Weakness

Malaise

Easily fatiguable

Dyspnea

  • also present with symptoms based on the underlying causes of the anemia (i.e GI bleeds)*
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Clinical features of chronic iron deficiency anemia

A

Koilonychia (brittle concaved looking nails)

Alopecia (paleness)

Atrophied changes in tongue and gastric mucosa

Intestinal malabsorption

17
Q

Diagnostic criteria for iron deficiency anemias

A

Hypochromic and microcytic RBCs

Low MCV

Low serum ferritin

Low serum iron levels

Low transferrin saturation ( will lower before symptoms arise)

Elevated platelet count (not completely understood why)

responses to iron therapy

18
Q

Anemia’s of chronic disease

A 
Anemia’s that resemble iron deficiencies but are actually caused by suppression of erythropoiesis sue to systemic inflammation 
examples:
- chronic microbial infections 
- chronic immune disorders 
- neoplasms

Stem from high levels of plasma hepcidin (blocks transfer of iron to erythroid precursors by down regulating ferroportin in macrophages)
- this is caused due to high IL-6 levels seen in inflammatory states

  • Most common in hospitalized patients*
19
Q

Clinical features of anemias of chronic disease

A

Serum iron levels are low

Plasma hepcidin are high

RBCs slightly hypochromic and microcytic

Storage levels of iron in bone marrow and ferritin are high, but overall decrease in measured iron-binding capacity

  • treatment of anemia of chronic disease is commonly done via administration of erythropoietin, however the only way to reverse it is to cure the underlying cause*
20
Q

Megaloblastic anemia

A

Type of macrocytic anemia caused by a deficiency in thmidylate synthatase enzymes which lowers the free amount of thymidine and thymidylate (building block of DNA)

  • shows nuclear-cytoplasmic asynchrony disorder and causes premature apoptosis of RBCs in red bone marrow
    (Ineffective hematopoiesis)
21
Q

Clinical features of macrocytic anemias

A

Pancytopenia (low granulocyte and platelet precursors)

Hypercellular megaloblastic erythroid progenitors

RBCs appear ‘egg shaped”

Presence of hyper-segmented neutrophils in blood (5-6)

MCV = > 110 fL.

22
Q

Folate deficiency anemia

A

Almost always results from Inadequate dietary intake
- most common in elderly, vegans, Pregnant women

Can results from absorption/ metabolism dysfunction

  • high acidic foods in diets can causes an absorption disorder
  • Drugs can as well such as methotrexate and phenytoin
  • celiac disease and tropical sprue are the most common absorption issues
23
Q

Function of folate

A

Converts dihydrofolate -> tetrahydrofolate via dihydrofolate reductase

Tetrahydrofolate acts and an acceptor and donor for synthesis of dTMP
-dTMP is required to synthesize hemoglobin and membrane proteins in RBCs as well as DNA replication

24
Q

Clinical features of folate deficiency anemia

A

Insidious onset w/ weakness and easily fatigued

Often seen in alcoholics

GI symptoms (upset stomach, sore tongue/throat, diarrhea etc.)

  • NO neurological abnormalities occur (unlike Vit. B12 deficiencies*

Only way to really make the diagnosis is blood smears showing megaloblastic cells and measuring serum folate/ B12 levels.

25
Q

Vit B12 (cobalamin) deficiency anemia

A

Caused by Vit. B12 deficiencies usually via absorption/metabolic disorders
- almost never found in low dietary intake, except for vegans (avoiding milk and eggs)

Takes years form the beginning of onset to diagnose. (Due to very large stores of Vit B12 in the liver)

26
Q

Pernicious anemia

A

Most common cause of vitamin B12 deficiency anemia

Caused by an autoimmune attack on gastric mucosa that suppresses intrinsic factor production. ( assumed to be T-cell initiated)
- histologically shows chronic atrophic gastritis and a loss of parietal cells and marked increases in lymphocytes in the mucosa

Antibodies in the serum block binding of Vit B12 to intrinsic factor/ cubilin

27
Q

Vitamin B12 deficiency causes for malabsorption specifically

A

Gastrectomy

Ileal resection ( loss of intrinsic factor)

Chronic disease

Tropical sprue and whipped disease

Gastric atrophy

achlorhydria (low hydrochloride acid in the stomach)

28
Q

Function of Vit B12 in blood

A

Recycles tetrahydrofolate
( form that is needed for DNA synthesis)

deficiencies can show demyelination and degeneration of the posterior/lateral columns of the spinal cord

29
Q

Clinical features of Vit. B12 deficiencies

A

Pallor

Easy fatiguable

Dyspnea

red tongue

Symmetric numbness, tingling burning feet or hands

Unsteady gait/ loss of position of sense

30
Q

4 laboratory findings of vitamin B12 deficiencies

A

1) low serum, Vit B12 levels
2) normal/ slightly elevated serum folate levels
3) moderate to serve macrocytic anemia
4) leukopenia with hypersegmented granulocytes
* show pernicious anemia with serum antibodies to intrinsic factor*

31
Q

Normochromic/ normocytic anemia

A

Normal MCV

Increased reticulocyte counts for hemolytic anemia

Decrease reticulocyte counts for aplastic anemia

32
Q

Aplastic anemia

A

Multipotent myeloid stem cells are suppressed which leads to bone marrow failure and pancytopenia
- bone marrow has high levels of fat and low red bone marrow

Most aplastic anemia is idiopathic but drug induced is common when exposed to cancer chemo/whole body irradiation,or hypersensitivity reactions

Viral hepatitis is a rare cause but possible as well

33
Q

Specific inherited abnormalities that underlie aplastic aplasia

A

Fanconi anemia: rare autosomal disorder caused by defects in a multi-protein complex that is required for DNA repair

Marrow hypofunction: becomes evident early in life and is often seen via hypoplasia of kidney, spleen and bone marrow

Telomerase defects (always abnormally short telomeres in 510%)

34
Q

Two mechanisms possibly invoked during aplastic anemia

A

Extrinsic immune-mediated suppression of marrow progenitors

  • stem cells are first antigenically altered by drugs, infectious agents or environmental issues
  • promotes cellular immune response (TH1) that promotes IFN-y and TNF that suppress and kill hematopoietic progenitors
  • treated via immunosuppressive therapy against T cells

Intrinsic abnormality of stem cells with telomerase

  • 5-10% of patients
  • leads to premature senescence of hematopoietic stem cells
35
Q

Neoantigens

A

Genetically altered stem cells via intrinsic pathway in aplastic anemia release neoantigens which attach T cells and cause them to release TNF and IFN-y

shows connection between intrinsic and extrinsic pathways

36
Q

Clinical features of aplastic anemia

A

Can occur any age or any sex equally
- insidious onset

Pancytopenia and reticulocytopenia occurs with anemia induced weakness, pallor and dyspena

Thrombocytopenia induced petechiae and ecchymoses

Sudden random onset of chills and fevers

bone marrow biopsy is the only way to confirm

37
Q

Prognosis and treatment of aplastic anemia

A

Prognosis varies however all treatment usually requires bone marrow transplantation (75% survival)

Older patients or no donor = immunosuppressive therapy but this doesn’t cure, only prevents further damage

38
Q

Pure red cell aplasia

A

Only erythroid progenitors are completely absent from marrow

Often presents with cancers, autoimmune disorders and parvovirus B19 infections
- all of these will also produce autoimmune issues except parvovirus B19

39
Q

Parvovirus B19 in pure red cell aplasia

A

Initially attacks red cell progenitors, resulting in pure red cell aplasia.
- usually clears up within 1-2 weeks and because of this is temporary

Moderate to severe hemolytic anemias sickle cell anemia and hereditary spherocytosis will produce aplastic crisis
- if compounded with autoimmunity, will produce chronic red cell aplasia

BLISS (42 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions