Hematology Flashcards

1
Q

What are the symptoms of anemia?

A

there is a progression from dyspnea and fatigue to lightheadedness, syncope, and chest pain

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2
Q

Whaat is cryoprecipitate?

A

a blood product used to replace fibrinogen and provides high amounts of clotting factors

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3
Q

When do we transfuse platelets?

A
  • less than 10K in an asymptomatic patient

- less than 50K in a bleeding patient

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4
Q

Describe the etiology, symptoms, labs, and treatment of iron deficiency anemia.

A
  • most often due to chronic blood loss or dietary deficiency, particularly with unsupplemented breast milk
  • presents with koilonychia, pica, and anemia
  • labs demonstrate a microcytic anemia with low ferritin, high TIBC, low saturation, and low serum iron; RDW is elevated
  • treat with iron replacement
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5
Q

Describe the pathogenesis and labs suggestive of anemia of chronic disease.

A
  • chronic inflammation upregulates IL-6 and thus hepcidin, which lowers iron availability
  • presents with a microcytic anemia, increased ferritin, reduced TIBC, low serum iron, and low % saturation
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6
Q

Compare the iron studies for iron deficiency anemia and anemia of chronic disease.

A
  • IDA: low serum iron, low ferritin, elevated TIBC, low % sat
  • AOCD: low serum iron, high ferritin, low TIBC, low % sat
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7
Q

Describe the pathophysiology, etiology, and labs consistent with sideroblastic anemia.

A
  • a defect in protoporphyrin synthesis that results in formation of ringed sideroblasts present on blood smear
  • causes include X-linked defect in ALA synthase, alcohol’s suppressive effect on bone marrow, lead poisoning, and isoniazid or vitamin B6 deficiency
  • labs demonstrate a microcytic anemia with iron overload and sideroblastic rings, which are iron-laden mitochondria around the nuclei
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8
Q

What is the difference between sideroblastic anemia and porphyria?

A

both are defects in heme synthesis, but porphyrias do not present with ringed sideroblasts on blood smear

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9
Q

What is the difference between a ringed sideroblast and basophilic stippling?

A
  • ringed sideroblasts are caused by iron-lade mitochondria and seen in the bone marrow for sideroblastic anemias
  • basophilic stippling is an aggregation of residual ribosomes seen in sideroblastic anemias and thalassemias but on a peripheral smear
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10
Q

Target cells on a peripheral smear are indicative of what diseases?

A

HALT:

  • HbC
  • Asplenia
  • Liver disease
  • Thalassemia
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11
Q

Describe the of pathophysiology, labs, and diagnosis of alpha-thalassemia.

A
  • due to a deletion of one or more alpha-globin genes, which produces a microcytic anemia
  • 1 is asymptomatic, 2 produces a mild anemia, 3 produces HbH (B4 tetrads), and 4 produces HbBarts (y4 tetrads) with hydrops fetalis and in utero death
  • importantly, 3 deletions is the only microcytic anemia that is associated with an increased reticulocyte and erythrocyte count
  • diagnosis is made with hemoglobin electrophoresis and genetic testing
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12
Q

Describe the pathophysiology and labs of B-thalassemia minor.

A
  • a microcytic anemia caused by the deletion of one beta-globin gene, typically in Mediterraneans or Africans
  • labs demonstrate a microcytic anemia, elevated HbA2 and HbF levels, and target cells
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13
Q

Describe the pathophysiology, presentation, lab findings, and treatment of B-thalassemia major.

A
  • a microcytic anemia caused by the mutation of two beta-globing genes, which results in unpaired alpha chains
  • these alpha chains damage RBC membranes, contributing to ineffective hematopoiesis and extravascular hemolysis
  • presents with hepatosplenomegaly and crew cut sign after birth since HbF is protective
  • labs demonstrate a microcytic anemia, elevated HbA2 and HbF levels, and target cells
  • requires chronic transfusions
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14
Q

What are the etiologies and common features of all megaloblastic anemias?

A
  • caused by folate or B12 deficiency, orotic acuduria, and Diamond-Blackfan anemia
  • all are caused by impaired DNA synthesis
  • they all present with macrocytic anemia, hyper-segmented neutrophils, and glossitis
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15
Q

Describe the pathophysiology and presentation of Diamond-Blackfan anemia.

A
  • a megaloblastic anemia with rapid-onset in the first year of life
  • due to an intrinsic defect in erythroid progenitor cells
  • presents with elevated HbF, short stature, craniofacial abnormalities, and upper extremity malformations (e.g. triphalangeal thumbs)
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16
Q

Describe the etiology, pathophysiology, and labs consistent with folate deficiency anemia.

A
  • commonly due to dietary deficiency or the use of folate antagonists like methotrexate
  • impaired DNA synthesis leads to a megaloblastic, macrocytic anemia
  • labs demonstrate an elevated homocysteine level but normal MMA level
17
Q

Describe the etiology, pathophysiology, and labs consistent with B12 deficiency anemia.

A
  • due to dietary deficiency, pernicious anemia, pancreatic insufficiency, any damage to the terminal ileum, and occasionally metformin use
  • impaired DNA synthesis leads to a megaloblastic, macrocytic anemia as well as posterior column dysfunction
  • labs reveal elevated homocysteine and methylmalonic acid
18
Q

Describe the pathogenesis, presentation, diagnosis, and treatment of sickle cell disease.

A
  • an autosomal recessive Glu to Val mutation in the beta chain leads to sickling, particularly with hypoxia, dehydration, fever, and cold temperatures
  • leads to predominately extravascular hemolysis but some intravascular hemolysis as well
  • presents with bilirubin gallstones, infection following autosplenectomy, osteomyelitis from Salmonella, stroke, avascular necrosis, and renal papillary necrosis
  • the best initial test is a peripheral smear while the most accurate is hemoglobin electrophoresis
  • treat with oxygen, hydration, and analgesia PRN; chronic folic acid replacement; early pneumococcal and meningococcal vaccination; hydroxyuria; daily penicillin prophylaxis; and ceftriaxone or fluoroquinolones for fever
19
Q

What preventative care is indicated for patients with sickle cell disease?

A
  • hydroxyurea to increase HbF
  • daily oral penicillin prophylaxis to decrease the risk of S. pneumoniae sepsis
  • daily folic acid
  • the PCV23 polysaccharide vaccine at 2 and 5 years old; MCV at 2 with a booster 3-5 years later
  • serial transcranial Doppler ultrasound beginning at 2 years of age to identify those are risk for stroke
20
Q

Describe the pathogenesis, presentation, labs, diagnosis, and treatment of hereditary spherocytosis.

A
  • a cytoskeleton defect leads to an abnormal shape and loss of flexibility, which causes extravascular hemolysis in the spleen
  • presents the symptoms of extravascular hemolytic anemia: splenomegaly, gallstones, and jaundice
  • labs demonstrate microcytosis, elevated MCHC, elevated RDW, and a negative Coombs test
  • the most accurate test is eosin-5-maleimide flow cytometry which is more accurate than osmotic fragility
  • treat with folate replacement and splenectomy
21
Q

Describe the pathophysiology, etiology, diagnosis, and treatment of autoimmune hemolysis.

A
  • IgG binds RBCs in the central body at warm temperatures and induce an extravascular hemolysis, leaving spherocytes
  • associated with SLE, CLL, penicillin, and cephalosporins
  • labs show an elevated MCHC and, in contrast to hereditary spherocytosis, a positive Coombs test
  • treat with steroids, IVIG, rituximab, and splenectomy
22
Q

Describe the pathogenesis, etiology, diagnosis, and treatment of cold agglutinin disease.

A
  • due to IgM antibodies that bind RBCs and fix complement at cold temperatures in the extremities, producing extravascular hemolysis and spherocytes
  • due to EBV, Waldenstrom macroglobulinemia, and Mycoplasma pneumoniae
  • a direct Coombs test is positive only for complement and the cold agglutinin titer is most accurate
  • treat with rituximab and plasmapheresis (steroids and splenectomy don’t help)
23
Q

Describe the pathogenesis, etiology, and diagnosis of G6PDH deficiency.

A
  • due to an X-linked recessive mutation inhibiting production of glutathione reductase
  • infection, dapsone, quinidine, sulfa drugs, primaquine, nitrofurantoin, and fava beans then induce hemolysis
  • the best initial test is blood smear for Heinz bodies and bite cells; the most accurate is a G6PDH level months after the acute episode
  • treatment is avoidance
24
Q

What are Heinz bodies?

A

hemoglobin precipitants seen on the periphery of blood cells in those with G6PDH deficiency and eventually removed, forming bite cells

25
Q

Describe the pathogenesis, presentation, diagnosis, and treatment of paroxysmal nocturnal hemoglobinuria.

A
  • CD55, CD59, or PIGA deficiency, which lead to over activation of the complement system, intravascular hemolysis, and thrombosis
  • presents with pancytopenia, hematuria, and thrombosis
  • may be complicated by iron deficiency anemia or AML
  • the diagnosis is made with flow cytometry
  • treat with steroids, eculizumab, and HSCT
26
Q

Describe the pathophysiology, presentation, diagnosis, and treatment of polycythemia vera.

A
  • a proliferation of mature myeloid cells, particularly erythrocytes but also granulocytes and platelets, due to a JAK2 mutation
  • presents with hyperviscosity symptoms including headache, blurry vision, flushing, venous thrombosis, and itching after bathing
  • labs demonstrate normal oxygen levels and an appropriately depressed EPO
  • treat with phlebotomy, aspirin, hydroxyurea, allopurinol and rasburicase, and ruxolitinib, a JAK inhibitor
27
Q

Describe the pathophysiology, presentation, and treatment of essential thrombocytosis.

A
  • a proliferation of mature myeloid cells, particularly platelets, due to a JAK2 mutation
  • symptoms are derived from the increased risk of bleeding and/or thrombosis
  • very few complications (no risk of malignancy or hyperuricemia) but if treatment is needed, the initial therapy is hydroxyurea
28
Q

What are acute leukemias?

A
  • those characterized by the accumulation of >20% blasts in the bone marrow, which crowds out normal hematopoiesis
  • causes thrombocytopenia, anemia and neutropenia but a high white count as blasts enter circulation
  • tends to present with infection due to the loss of functioning white blood cells
29
Q

Describe the pathophysiology, presentation, feared complication, and treatment of acute promyelocytic leukemia.

A
  • a subtype of AML characterized by a t(15;17) translocation which disrupts the retinoic acid receptor (RAR)
  • presents with signs of pancytopenia including bleeding and infection despite a normal or elevated WBC
  • a risk for DIC given the presence of Auer rods
  • treat with ATRA which causes the blasts to mature and die off
30
Q

Chronic Myelogenous Leukemia

A
  • a proliferation of mature myeloid cells, particularly granulocytes, due to a t(9;22) mutation creating a BCR-ABL fusion protein with excess tyrosine kinase activity
  • classically presents with basophilia and pruritus, splenomegaly, and a high WBC
  • treat with imatinib (aka Gleevec), which binds and blocks the ATP-binding domain of the fusion protein