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Heme and Lymph Midterm > Chapter 14: Anemias > Flashcards

Chapter 14: Anemias Flashcards

1
Q

What is anemia defined as?

A

reduction of the total circulating red cell mass below normal limits

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2
Q

Acute blood loss

A

-loss of intravascular volume
-cardiovascular collapse, shock, and death
-EPO will stimulate committed erythroid progenitors in the marrow
-

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3
Q

Chronic blood loss

A
  • rate of loss exceeds the regenerative capacity of the marrow or when iron reserves are depleted
  • iron deficiency anemia appears
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4
Q

Hemolytic anemias

A
  • shortened lifespan of RBC
  • elevated EPO
  • accumulation of Hbg degradation products
  • within phagocytes=extravascular hemolysis
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5
Q

Hereditary spherocytosis

A
  • inherited disorder cause by intrinsic defects in the red cell membrane skeleton that render the red cells spheroid, less deformable, and vulnerable to splenic sequestration and destruction
  • northern europe
  • Spectrin is a problem
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6
Q

Pathogenic mutations in HS

A
  • Ankyrin
  • band 3
  • spectrin
  • band 4.2
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7
Q

What helps HS

A

a splenectomy

-the spleen is an asshole and keeps eating all of the abnormally shaped cells

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8
Q

Clinical features of HS

A

osmotic lysis

  • HS red cells have increased MCHC (mean cell hemoglobin concentration, due to dehydration caused by the loss of K+ and H20
  • anemia, splenomegaly, and jaundice*
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9
Q

What will cause an aplastic crisis in HS patients?

A

Parvovirus B19 infection

-they don’t have the reserves to deal with this

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10
Q

Glucose-6-Phosphate Dehydrogenase deficiency

A
  • red cells can’t protect themselves against oxidative injuries and leads to hemolysis
  • G6PD reduces NADP to NADPH,
  • We need that NADPH in order to use glutathione to neutralize H202
  • recessive X-linked trait
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11
Q

Which G6PD deficiency variant is the most clinically significant?

A

the mediterranean variant

-they eat a lot of fava beans which can cause it

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12
Q

What are Heinz bodies?

A

-high levels of oxidants causes cross-linking of reactive sulfhydryl groups on globin chains, which become denatured and form membrane-bound precipitates… that’s what they are

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13
Q

Sickle cell disease

A
  • point mutation in B-globin that promotes the polymerization of deoxygenated hemoglobin
  • red cell distortion, hemolytic anemia, microvascular obstruction, and ischemic tissue damage
  • Glu to Val mutation
  • HbS
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14
Q

What does Hbs protect against?

A

falciparum malaria

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15
Q

Why do infants not become symptomatic for sickle cell disease until 5-6 months?

A

HbF inhibits the polymerization of HbS even more than HbA

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16
Q

What is HbC variant of sickle cell disease

A

Val to LySINE (Seeeeeeeen=C)

-

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17
Q

What facitilitates sickling?

A

a higher Mean cell hemoglobin concentration (MCHC)

  • decrease in intracellular pH
  • transit time of red cells through microvascular beds
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18
Q

What is a wierd way that sickle cell patients can have a milder form of the disease?

A

if they also have an alpha thalassemia

-no Hemoglobin can get made… so it doesn’t matter if it’s screwed up or not

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19
Q

Why do ppl with sickle cell disease get microvascular occlusions?

A
  • free hbg released from lysed sickle red cells can bind and inactivate NO
  • NO is a potent vasodilator and inhibitor of platelet aggregation
  • thrombosis
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20
Q

What are howell-jolly bodies?

A

small nuclear remnants

  • seen in sickle cell disease
  • also in asplenia
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21
Q

What morphologic changes are seen in sickle cell?

A
  • new bone formation (crewcut and cheekbones)
  • increased breakdown of Hgb leads to pigment gallstones… hyperbilirubinemia (unconjugated)
  • autosplenectomy can happen (shrinkage
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22
Q

Clinical features of sickle cell?

A
  • commonly involve bones, lungs, liver, brain, spleen, and PENIS
  • children get the hand-foot syndrome or dactylitis of the bones of the hands or feet or both
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23
Q

What is acute chest syndrome

A

dangerous type of vaso occlusive crisis involving the lungs

  • fever, cough, chest pain, and pulm infiltrates
  • inflammation causes slow blood flow
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24
Q

What is priapism

A

-with sickle cell disease, 45% of males have hypoxic damage and erectile dysfunction

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25
Q

What 2 factors contribute to stroke in Sickle cell disease?

A
  • adhesion of sickle red cells to arterial vascular endothelium
  • vasoconstriction caused by the depletion of NO by free hemoglobin
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26
Q

Where do aplastic crises with sickle cell disease stem from

A

Parvovirus B19 infection of red cell progenitors

-transient cessation of erythropoiesis

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27
Q

What are we at risk for infection with if we have sickle cell disease (because of the altered splenic function)

A

Pneumococcus pneumonia
Haemophilus influenzae
meningitis

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28
Q

What can we use to diagnose sickle cell disease?

A

metabisulfite

  • an oxygen consuming reagent
  • if there is any HbS at all, it will sickle when we apply this
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29
Q

B thalassemias

A

caused by mutations that diminish the synthesis of B globin chains

  • chromsoome 11
  • mutations that diminish synthesis of B-globin chains
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30
Q

What kind of mutations are the most common cause of B null thalassemia?

A

chain terminator mutations

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31
Q

What is HbA,

A

2 alpha globulins and 2 Beta

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32
Q

What is the main result of B thalassemia?

A

diminished survival of RBCs and their precursors

-ineffective erythropoiesis

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33
Q

What is another serious comlication of ineffective erythropoiesis?

A

excessive absorption of dietary iron

  • ineffective erythropoiesis suppresses hepcidin, a critival negative regulator of iron absorption
  • iron accumulation
  • secondary hemochromatosis
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34
Q

Where is B thalassemia major most common?

A

Mediterranean countries

35
Q

What does the anemia manifest in infants?

A

6-9 months after birth

-because of the HbF with is 2 alpha 2 gamma.. there’s no B globin needed at that time

36
Q

What kind of cells will we find in B thalassemia?

A

Target cells

-elevated reticulocyte count

37
Q

Morphology of B-thalassemia Major?

A
  • target cells
  • crewcut and chipmunk facies
  • phagocyte hyperplasia and extramedullary hematopoiesis…. enlargement of spleen
38
Q

B-Thalassemia Minor

A

heterozygous carriers of a B+ or B null allele

  • basophilic stippling and target cells
  • much more common than major
  • asymptomatic
  • has implications for genetic counseling
  • HbA2 is diagnostically helpful (alpha2 and delta 2)
39
Q

alpha thalassemia

A
  • inherited DELETIONS that result in reduced or absent synthesis of alpha-globin chains
  • gamma tetramers=Barts…. that happens in newborns
  • B4 tetramers are HbH
40
Q

Alpha thalassemia trait

A
  • there’s 4 genes for this
  • 2 of them are (-) trait
  • if on the same chromosome, watch out for genetic purposes (especially in asians)
41
Q

Hemoglobin H disease

A
  • caused by deletion of 3 alpha globin genes
  • most common in Asian populations because of that weird chromosome thing they do
  • HbH has high affinity for oxygen… useless for O2 delivery
  • moderately severe anemia resembling B-thalassemia intermedia
42
Q

Hydrops Fetalis

A

most severe form of alpha thalassemia

  • deletion of all 4 genes
  • Barts
  • high affinity for oxygen, so baby doesnt get any
  • other squiggly letter forms up with excess B to be functionall
43
Q

Paraxysmal nocturnal hemoglobinuria (PNH)

A

results from acquired mutation sin the phosphatidylinositol glycan complementation group A gene (PIGA)

  • essential for the synthesis of certain membrane-associated complement regulatory proteins
  • the only hemolytic anemia caused by an acquired genetic defect
  • GPI linked propteins are deficient because of inactive PIGA
  • basically, red cells become more susceptible to lysis by complement (intravascular hemolysis)
44
Q

What 3 GPI-linked proteins that regulate complement activity are deficient in PNH?

A
  • decay accelerating factor (DAF)=CD55
  • membrane inhibitor of reactive lysis (MIRL)= CD59 (most important): inhibitor of C3 convertase… prevents spontaneous activation of the alternative complement pathway
  • C8 binding protein
45
Q

What happens in PNH?

A
  • we sleep
  • shallow breaths
  • decrease in pH increases activity of complement
  • hemosiderinuria
  • eventually leads to iron deficiency
46
Q

leading cause of death in PNH?

A

thrombosis

47
Q

What is the only cure for PNH?

A

stem cell transplantation

48
Q

Immunohemolytic anemias

A

caused by antibodies that bind to red cells, leading to their premature destruction

49
Q

direct coombs tests

A

sees if the patients red cells has Ig or complement on them

50
Q

Indirect coombs test

A

patients serum is tested for its ability to agglutinate commercially available red cells bearing particular defined antigens

51
Q

Warm antibody type

A

most common form of immunohemolytic anemai

  • IgG class
  • that binds Fc receptors… partial phagocytosis
  • leads to spherocytes
  • moderate splenomegaly due to hyperplasia of splenic phagocytes is usually seen
52
Q

Cold agglutinin typ

A
  • IgM antibodies
  • bind RBCs avidly at low temperatures
  • happens in fingers and toes
  • transient interaction with IgM is good enough to deposit sublytic C3b… good opsonin
  • removal of RBCs by phagocytes in spleen and liver and bone marrow
  • Raynaud phenomenon
53
Q

Cold hemolysin type

A

IgGs that bind to P blood group antigen on the red cell surface in cool, peripheral regions of the body
-children following viral infections

54
Q

hemolytic anemia resuting from trauma to red cells

A
  • cardiac valve prostheses and microangiopathic disorders
  • microvascular lesion that results in luminal narrowing… often due to the deposition of fibrin and platelets
  • schistocytes, helmet cells, triangle cells
55
Q

name the hemolytic anemias

A

-hereditary spherocytosis
-G6PD deficiency
-sickle cell disease
-thalassemias
-PNH
Immunohemolytic anemia
-hemolytic anemia from trauma

56
Q

name the anemias of diminished erythropoiesis

A
  • megaloblastic anemias
  • anemia of folate deficiency
  • iron deficiency anemia
  • anemia of chronic disease
  • aplastic anemia
  • pure red cell aplasia
  • marrow failure
57
Q

Megaloblastic anemias

A
  • impairment of DNA synthesis
  • leads to ineffective hematopoiesis and distinctive morphologic changes, including abnormally large erythroid precursors and red cells
  • Pernicious anemia= B12 deficiency
  • Folate deficiency
58
Q

Morphology with megaloblastic anemias

A

nuclear hypersegmentations

  • big ass cells (>100)
  • giant metamyelocytes and band forms
59
Q

Pernicious anemia

A
  • B12 deficiency
  • autoimmune gastritis
  • impairs production of intrinsic factor (secreted by parietal cells of the fundic mucosa) which is required for B12 uptake from the gut (ileum)
  • B12 will take methyl group from THF (makes Thymidine) and give methyl group to homocystein to make methionine
  • this doesn’t get better with folate administration
  • B12 is also good for methymalonic acid to succinyl CoA
60
Q

What kind of antibodies will we likely see in pernicious anemia?

A

Type 3: 85-90%…. they get the alpha nd B subunits of the gastric proton pump
-leads to chronic atrophic gastritis

61
Q

What other organism can compete with us for B12 and can induce a deficiency state?

A

raw fish tapeworms… diphyllobothrium latum

62
Q

Morphology of pernicious anemia

A

fundic gland atrophy

  • intestinalization
  • atrophic glossitis
  • demyelination fot eh dorsal and lateral spinal tracts
  • spastic paraparesis and sensory ataxia
  • severe paresthesias in the lower limbs
63
Q

clinical lab values for pernicious anemia

A
  • leukopenia with ypersegmented granulocytes
  • low serum B12 (duh)
  • elevated levels of homocystein and methylmalonic acid
64
Q

How is diagnosis of pernicious anemia confirmed?

A

by an outpouring of reticulocytes and a rise in hematocrit levels begginning about 5 days after parenteral administration of vitamin B12

65
Q

What are people who have pernicious anemia at risk for?

A

gastric carcinoma

66
Q

Anemia of folate deficiency

A
  • look a hell of a lot like B12 deficiency!
  • BUT THERE’S NO NEURO CHANGES
  • suppressed synth of DNA is the immediate cause of megaloblastosis
  • we are entirely dependent on diet for folic acid
  • absorbed in proximal jejunum
67
Q

What drug inhibits dihydrofolate reductase and lead to a deficiency of FH4?

A

methotrexate

68
Q

How can the diagnosis of folate deficiency be made?

A

low folate in serum or red cells

  • the methylmalonate concentrations are normal
  • so neruo changes do not occur
  • remember that in B12 deficiency, folate will not prevent those neuro deficits
69
Q

Iron deficiency anemia

A
  • most common nurtitional disorder in the world
  • inadequate hemoglobin synthesis
  • transferrin binds it up in the plasma 1/3 saturation
  • Ferritin binds it up in cells
  • absorbed int he proximal duodenum
70
Q

What regulates iron absorption?

A

hepcidin

  • released by liver in response to increases in intrahepatic iron levels
  • binds ferroportin and causes it to be endocytosed and degraded
  • then, not as much iron is absorbed
  • ineffective erythropoiesis suppresses hepatic hepcidin production
71
Q

What are the 4 main causes of iron deficiency?

A
  • dietary lack
  • impaired absorption
  • increased requirement
  • chronic blood loss
72
Q

what kind of anemia does iron deficiency produce?

A

hypochromic microcytic anemia

73
Q

morphology of iron deficiency anema

A

dissappearance of stainable iron from macrophages in the bone marrow

  • microcytic and hypochromic cells
  • poikilocytosis: small elongated red cells (pencil cells)
74
Q

Clinical features of iron deficiency anemia

A

Plummer vinson syndrome: glossitis, esophageal web, microcytic hypochromic anemia

  • serum iron and ferritin are low,
  • total plasma iron binding capacity (TIBC) is high
75
Q

What are the stages of iron deficiency

A
  • storage iron is depleted- ferritin is low and TIBC is high
  • serum iron is depleted- serum iron is low and the is low % saturation (>33%)
  • normocytic anemia: bone marrow makes fewer, but normal-sized, RBCs
  • microcytic, hypochromic anemia: bone marrow makes smaller and fewer RBCs
76
Q

Anemia of Chronic Disease

A

Impaired red cell production associated with chronic diseases that produce systtemic inflammation

  • most common cause of anemia among hospitalized patients
  • IL-6 stimulates increase in hepcidin…. ferroportin is gone,,,, no iron… damn
  • reduction in EPO some some godforsaken reason… maybe to fend off certain types of infection… like bacteria
  • “iron sequestration in the setting of inflammation”
77
Q

Aplastic Anemia

A

syndrome of chronic primary hematopoietic failure and attendant pancytopenia

  • most common cause is chemo drugs that cause marrow suppression
  • chloramphenicol and gold salts
  • most cases are idiopathic
  • hypocellular bone marrow… there’s just fat there and fibrous stroma
  • dry tap on bone marrow
78
Q

Clinical features of aplastic anemia

A
  • Splenomegaly is characteristically absent*
  • red cells are slightly macrocytic and normochromic
  • reticulocytopenia is the rule
79
Q

Pure Red cell aplasia

A

a primary marrow disorder in which only erythroid progenitors are suppressed

  • Parvovirus B19 preferentially infects and destroys red cell progenitors
  • this could lead to an aplastic crisis in anyone who has a moderate to severe hemolytic anemia
  • if someone is immunosuppressed, an ineffective immune response can let the infection persist… leading to chronic red cell aplasia and a moderate to severe anemia
80
Q

Myelophthisic anemia

A

a form of marrow failure in which space-occupying lesions replace normal marrow elements

  • the commonest cause is metastatic cancer
  • teardrop-shaped cells… believed to be deformed because of their tortuous escape from the fibrotic bone marrow
81
Q

Chronic renal failure

A

whatever its cause, it is almost invariably associated with an anemia that tends to be roughly proportional to the severity of the uremia
-the dominant cause of anemia in renal failure is the diminished synthesis of EPO by the damaged kidneys, which leads to inadequate red cell production

82
Q

hepatocellular liver disease

A

erythroid progenitors are preferentially affected

-macrocytic due to lipid abnormalities with liver failure…. cuase RBC membranes to acquire phopholipid and cholesterol

83
Q

Endocrine disorders

A

hypothyroidism

-may be associated with a mild normochromic, normocytic anemia

Heme and Lymph Midterm (11 decks)

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