Anemia Flashcards

1
Q

Etiology of Anemia

A
  • Blood loss
    • Acute
      • Loss of blood volume
    • Chronic
      • Only when regenerative capacity exceeded by blood loss or iron reserves depleted
  • Deficiency of Hb building blocks
    • Fe ⇒ iron deficiency
    • Porphyrin ⇒ sideroblastic
    • Globin ⇒ Thalassemias
  • Deficiency of DNA buidling blocks
    • Vit B12/Folate
  • Marrow failure
    • Primary failure
      • Aplasia, neoplasia, toxic suppression, infiltration
    • Secondary failure
      • Renal, endocrine, chronic inflammation, hepatic, drugs and poisons, infections, cancer
    • Excess destruction ⇒ hemolytic anemia
      • Congenital ⇒ mutation in RBC membrane, Hb, or RBC enzymes
      • Acquired
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2
Q

Hypochromic Microcytic Anemias

A
  • Anemia with low MCV
  • Failure of marrow precursors to make Hb
    • Fe, porphyrin, globin
  • Differential dx
    • Iron deficiency
    • Thalassemias
    • Sideroblastic anemia
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3
Q

Iron Deficiency Anemia

Pathogenesis

A
  • Dec. Fe ⇒ marrow can’t make Hb ⇒ anemia
  • Causes ⇒ blood loss > nutritional lack
  • Who
    • Infants ⇒ Fe deficient diet
    • Adolescent girls/Premenopausal women ⇒ Menses/pregnancy
    • Post-menopausal women and all men ⇒ GI blood loss
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4
Q

Iron Deficiency Anemia

Dx

A
  • CBC
  • Blood smear ⇒ paler/smaller, central clearing larger, anisocytosis
  • Iron studies ⇒ Fe low, TIBC high, Ferritin low, RDW high
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5
Q

Thalassemias

A
  • Hypochromic, microcytic anemia
  • Dec or absent synthesis of alpha or beta globin chains
    • Alpha ⇒ Africa and SE Asia
    • Beta ⇒ Mediterranean region
  • Thalassemia trait ⇒ mild anemia w/ hypochromic microcytic RBC
  • Thalassemia major ⇒ severe anemia in childhood, hepatosplenomegaly, jaundice, marked bone changes
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6
Q

Beta-Thalassemia Minor

Dx

A
  • Hb 10-13
  • RBC slightly elevated
  • MCV 60-70
  • Smear ⇒ microcytosis, hypochromia, target cells, RBC with basophilic stippling
  • Hb electrophoresis ⇒ slight dec Heb A, Inc. Hgb A2, Hgb F normal or slightly elevated
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7
Q

Beta-Thalassemia Major

Dx

A
  • Severe anemia in childhood ⇒ Hb 3
  • Smear
    • Markedly hypochromic with marked anisocytosis
    • Poikilocytosis
    • Stippled cells
    • Target cells
    • Ellipitcal cells
    • Tear drop calls
    • Hypochromic cells with polychormatophilic rims
    • Nucleated RBCs
  • Hb electrophoresis
    • Absent or small amount of Hgb A
    • Slighrly increased Hgb A2
    • Rest Hgb F
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8
Q

β-Thalassemia Major

Pathogenesis

A
  • Dec. B-globin ⇒ excess A-globin ⇒ insoluble aggregates in erythroblasts
  • Anemia d/t ineffective erythropoiesis & extravascular hemolysis
  • Systemic iron overload
  • Skeletal deformities ⇒ inc. EPO and bone marrow expansion
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9
Q

Alpha Thalassemia

A
  • Results from alpha gene deletion
    • Single ⇒ silent
    • 2 ⇒ trait
    • 3 ⇒ Hb H disease
    • All 4 ⇒ Hydrops fetalis
      • Hb electrophoresis only Hgb Barts
  • Mild microcytic anemia w/ normal to elevated RBC
  • MCV 60-70
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10
Q

Sideroblastic Anemia

A
  • Porphyrin impairment ⇒ abnormal RBC iron metabolism
  • Causes
    • Hereditary
    • Acquired ⇒ lead poisoning, ETOH, drugs
    • Neoplasia ⇒ refractory sideroblastic anemia, sign of myelodysplastic syndromes
  • Clinical findings
    • Inc. Fe, Normal TIBC, Inc. ferritin
    • Ringed sideroblasts in bone marrow
  • Treatment ⇒ remove offending agent if possible, treat myelodysplasias
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11
Q

Macrocytic Anemias

A

Anemia w/ high MCV

Pathophysiology ⇒ megaloblastic vs nonmegaloblastic

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12
Q

Megalobastic Anemia

A
  • Failure of DNA synthesis ⇒ async. maturation of nucleus and cytoplasm
  • Caused by Vit B12 or folate deficiency
  • See macrocytosis w/ low retic count
  • Severe
    • Neutropenia
    • Thrombocytopenia
    • Hypersegmented neutrophils
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13
Q

Vit B12 Deficiency

Pathogenesis

A
  • Cofactor for homocysteine ⇒ met
  • Liver stores lasts 3+ years
  • From fish and meat
  • Absorbed bound to IF in terminal ileum
  • Clinical Features
    • Macrocytic megaloblastic anemia
    • Glossitis
    • Neuropathy
      • Loss of position/vibratory sensation in LE, ataxia, UMN signs
      • Urinary/fecal incontinence
      • Impotence
      • Dementia
    • Neutropenia/thrombocytopenia
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14
Q

Vit B12 Deficiency

Etiology

A
  • Pernicious anemia
  • Total gastrectomy
  • Malabsorption disease
  • Terminal ileum disease or removal
  • Pancreatic insufficiency
  • Drug induced malabsorption
  • Food malabsorption
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15
Q

Vit B12 Deficiency

Dx

A
  • Peripheral smear
    • Macrocytic RBC w/ MCV > 100
    • Hypersegmented polys
  • Serum B12 levels low
  • Serum MMA high
  • Serum homocysteine high
  • Schillings test
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16
Q

Folate Deficiency

A
  • Mainly from green vegetables
  • Takes only a few months to develop
    • ETOH, nutritional failure, malabsorption, anticonvulsant therapy, pregnancy, hemolytic anemias, antifolate drugs
  • Same as Vit B12 def. except no neurological sx
  • Dx ⇒ peripheral smear / serum folate
  • Tx ⇒ daily oral folate
17
Q

Normochromic Normocytic Anemias

A
  • Anemia w/ normal MCV and MCHC
  • Path ⇒ most from marrow failure, some d/t hemolysis
  • Check corrected reticulocyte count (CRC)
    • CRC = pt’s retic x pt’s Hct/nl Hct
    • CRC <4% ⇒ Marrow failure
  • Differentials
    • Anemia of chronic disease
    • Primary blood dyscrasias
    • Hemolytic Anemias
18
Q

Hypoproliferative Normocytic Anemia

Etiologies

A

Marrow failure

  • Primary bone marrow stem cell d/o
    • Aplastic anemia
    • Myelodisplasia
    • Leukemia
  • Marrow failure due to disease in the body
    • Autoimmune d/o
    • Chronic infections
    • Neoplasms
    • Renal disease
    • Endocrine d/o
19
Q

Anemia of Chronic Disease

A
  • Pathogenesis
    • Chronic inflammation/infection ⇒ cytokines ⇒ liver makes Hepcidin ⇒ poor Fe absorption ⇒ anemia
  • Most common anemia in hospitalized pts
  • Diagnosis
    • Fe low / TIBC low / >10% Sat / Ferritin NOT LOW
  • Tx ⇒ treat underlying condition, EPO not that effective
20
Q

Hemolytic Anemias

A
  • Anemia d/t shortened RBC survival
    • Marrow compensation ⇒ high retics
    • MCV normal or high depending on % retics
  • Classification
    • Based on site of hemolysis
      • Intravscular vs extravascular
    • Based on mech
      • Acquired vs inherited
  • Morphological features
    • Marked inc. in normoblasts
    • High EPO ⇒ High erythropoiesis
    • Accum. Hb breakdown byproducts
    • Reticulocytosis
    • Cholelithiasis
    • Hemosiderosis
21
Q

Hemolytic Anemias

Dx

A
  • History and Clinical Findings
    • Signs and sx of aenmia
    • Fhx
    • Dark urine
    • Jaundice
    • Hx of gallstones
    • Hepatosplenomegaly
    • Lymphadenopathy
  • Tests
    • Anemia w/ high retic count
    • Check Smear for ⇒ sickled RBCs, schistocytes/helmet cells
    • Dec. haptoglobin ⇒ if intravascular
    • Inc. LDH
    • Inc. unconjugated bilirubin
    • Direct Coombs test
22
Q

Immune Hemolysis

A
  • RBC coated w/ Ab or complement
    • IgG ⇒ warm Ab
      • Idipathic, autoimmune, lymphoproliferative, drugs
      • Spherocytes seen on smear
    • IgM ⇒ cold Ab
      • Usu. post-infectious
  • Direct Coombs’ test positive
23
Q

Non-Immune Hemolysis

A
  • Microangiopathic Hemolysis
    • RBCs destroyed as they pass through small vessels
    • Causes ⇒ Thrombocytic thrombocytopenic purpura (TTP), hemolytic-uremic syndrome (HUS), pregnancy, drugs, metastatic cancers
    • See schistocytes on smear
  • Mechanical hemolysis
  • Infection ⇒ malaria, babesiosis, etc
  • Hypersplenism / Trauma
24
Q

Hereditary Hemolytic Anemias

A
  • Hemoglobinopathies
    • Thalassemias
    • Hgb S, Hgb C, Hgb S-Hgb-C
  • Enzyme deficiencies
    • Pyruvate kinase or G6PD
  • Membrane defects
    • Hereditary spherocytosis/elliptocytosis/stomatocytosis
25
Q

Sickle Cell Anemia

Overview

A
  • Autosomal recessive
    • Point mutation ⇒ glu to val sub
    • Heterozygotes asymptomatic
  • Dx ⇒ Hgb electrophresis for Hgb S
26
Q

Sickle Cell Anemia

Clinical Issues

A
  • Severe hemolytic anemia
  • Jaundice
  • Inc. sickling w/ dehydration, hypoxia, acidosis, fever, infection
  • Most acute complications are vaso-occlusion
  • Chronic hyperbilirubinemia
27
Q

Sickle Cell Anemia

Acute Complications

A
  • Vaso-occlusive crises
    • Painful crisis due to hypoxic injury and infarction
    • Bones, lungs, liver, spleen, brain, penis can be affected
    • Acute chest syndrome ⇒ pumonary vasculature involvement
  • Aplastic crises ⇒ parvovirus B19
  • CVA
  • Splenic sequestration ⇒ occurs in childhood, later functionally asplenic
28
Q

Sickle Cell Anemia

Chronic Complications

A
  • Infection w/ encapsulated organisms
  • Renal disease
  • Pulmonary disease
  • Retinopathy
  • Avascular necrosis of bone
  • Skin ulcers
  • Pigmented gallstones
  • Hepatitis
  • Heart ⇒ tachy, flow murmurs
  • CNS ⇒ inc risk of stroke
29
Q

Sickle Cell

Pathology

A
  • Bone marrow ⇒ erythroid hyperplasia
  • Extramedullary hematopoiesis can occur
  • Erythrostasis in sleen ⇒ thrombosis, infarction, autosplenectomy
  • Infarction 2/2 vascular occlusion and anoxia
30
Q

Sickle Cell

Lab Findings

A
  • Hb 5-11%
  • Inc bilirubin
  • Inc. retic count
  • Nucleated RBCs
  • Howell-Jolly bodies
  • Leukocytosis and throbocytosis
  • Hb electrophoresis
    • Hgb S 75-95%
    • No Hb A
    • Nomral Hb A2 and Hb F
31
Q

Sickle Cell Trait

Dx

A
  • Normal CBC
  • No sickled cells on smear
  • Dithionate test ⇒ inc. turbidity of RBC
  • Sickle Cell preparation ⇒ see sickles after sodium metabisulfite
  • Hb electrophoresis ⇒ gold standard
    • 60-70% Hb A
    • 30-40% Hb S
32
Q

G6PD Deficiency

A
  • Abnormal HMP shunt or glutathione metabolism
  • X-linked recessive ⇒ almost always in men
  • RBCs sensitive to oxidateive stress ⇒ hemolysis
    • Infection, drugs, fava beans
  • Clinical issues
    • Jaundice
    • Dark urine
    • Episodic hemolysis associated w/ meds
      • Sulfa, nitrofurantoin, primaquine
  • Smear
    • Heinz bodies ⇒ abnormal Hgb precipiates in RBC
    • Bite cells
33
Q

Hereditary Spherocytosis

A
  • Intrinsic defect in spectrin ⇒ abnl RBC membrane
  • Autosomal dominant
  • See spherical RBCs
    • Increased osmotic fragility
    • Extravascular hemolysis
  • Clinical issues
    • Hemolytic anemia
    • Splenomegaly
    • Jaundice
    • Pigmented gallstones
    • Hemolytic crises
  • Dx
    • Inc retics / inc. MCHC / neg direct Coombs
    • Spherocytes on smear
    • Osmotic fragility test positive
  • Treatment ⇒ splenectomy