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USMLE Step 1 Systems > Heme/Onc > Flashcards

Heme/Onc Flashcards

1
Q

Superficial inguinal nodes drain what?

A

All skin from the umbilicus down, including anus up to the dentate line

EXCEPT posterior calf = popliteal lymph nodes

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2
Q

What LN drain the testes?

A

abdominal aortic LN (follow blood supply)

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3
Q

Pure Red Cell Aplasia caused by what?

A
  1. Thymoma or Lymphocytic Leukemias
    - inhibition of erythroid progenitors by IgG autoAb or CD8 T cells
    - should undergo CT scan to try and remove thymoma
  2. Parvovirus B19
    - virus infects and destroys proerythroblasts
    - dx: anti-B19 IgM antibodies in serum
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4
Q

How to differentiate AML vs. ALL?

A

Presence of AUER RODS (linear, purple red inclusions) in the blasts.

Q 1570

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5
Q

Histology of Lead Poisoning

A

Microcytic Hypochromic Anemia
Basophilic Stippling

Q1865

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6
Q

How is PAH handled in the renal system?

A
  1. Freely filtered from glomerulus
  2. Secreted by proximal tubules thru carrier proteins

Estimate of renal plasma flow. RPF

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7
Q

G6PD inheritance pattern

A

X-linked recessive.

Hemolytic anemia when under oxidative stress (such as anti-malarial drugs).

Smear shows heinz bodies (dark, intracellular inclusions that stain with crystal violet)

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8
Q

t(14;18) translocation

A 
Follicular Lymphoma (Non-Hodgkin's Lymphoma) 
- Bcl2 (anti-apoptotic) translocated from chr 18 to 14 onto heavy chain Ig

Indolent - waxing, waning LAD

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9
Q

How do tumor cells get resistance against certain chemotherapeutic agents?

A

MDR1 (human multidrug resistance gene 1)
codes for P-glycoprotein (transmembrane protein(
which is an ATP dependent efflux pump.

Can decrease hydrophobic compounds getting into cytosol and increase their efflux out of cytosol.

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10
Q

What mutation in polycythemia vera?

A

JAk2 - non-receptor tyrosine kinase.

Somatic (non-hereditary)

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11
Q

How is the presentation of B-cell ALL different from T-cell ALL?

A

T-cell presents with sx related to mediastinal compression - resp sx, dysphagia, superior vena cava syndrome.

B-cell presents with fever, malaise, bleeding, bone pain, HSM.

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12
Q

What causes subacute cerebellar degeneration in a pt with hx of lung cancer?

A

Paraneoplastic Autoimmune. Immune response against tumor cells cross-reacts with Purkinje neuron antigens - Anti-Yo, Anti-P/Q, Anti-Hu,

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13
Q

What deficiency is associated with hemophilia A and B and increased what time?

A

Hemophilia A = VIII
Hemophilia B = IX

Increased PTT (extrinsic and common pathway)

Sx: hemarthrosis, easy bruising, inc. PTT
Tx: recombinant VIII

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14
Q

What antineoplastic drug is a analog of adenosine but inhibits adenosine deaminase so it can reach high intracellular concentrations?

A

Cladribine - used for hair cell leukemia.

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15
Q

What bleeding condition do we administer DDAVP for and what does it do?

A

Von willebrand’s disease.

Increases vwf - can stop bleeding in mild cases of von willebrand’s.

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16
Q

What immunological disease presents with a painless waxing and waning lymphadenopathy?

A

Follicular Lymphoma

  • indolent Non-Hodgkin B cell lymphoma
  • t(14,18) - overexpression of bcl2 oncogene
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17
Q

Lymph node enlargement - what characteristic would make it malignant?

A

Monoclonal proliferation of lymphocyte.

Ex: Monoclonal T cell-R gene rearrangement.

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18
Q

Hemoglobin A, S, C - where would they be on protein electrophoresis? What mutations cause the latter two?

A

Hemo A = negatively charged
Hemo S = Glu (+) -> Valine (-)
Hemo C = Glu (+) -> Lysine (+)

Speed of movement towards (+) electrode:
A > S > C

Q1470

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19
Q

Patients with familial retinoblastoma have an increased risk of what other malignancy?

A

Osteosarcoma

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20
Q

MOA of warfarin.

A

Inhibits vit K dependent carboxylation of glutamic residues of 1972, C, S.

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21
Q

How does the glu -> val in the beta globin subunit of HbS cause disease?

A

Fits in a complementary hydrophobic binding site on alpha-hemaglobin chain –> causes polymerization/aggregation of HbS molecules when in their deoxygenated form (under anoxic conditions, increased acidity, dehydration)

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22
Q

What organelles do RBC lack?

A

Nucleus and Mitochondria (cannot synthesize heme since part of heme synthesis occurs in the mitochondria)

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23
Q

What reactions are B12 and folate a part of ?

A

Both: Homocysteine -> Methionine
B12: Methylmalonyl CoA -> Succinyl CoA

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24
Q

Disease associated with t(15;17) translocation

A

AML - translocation of retinoic acid receptor from 17 to 15 -> forms the PML/RARalpha -> abnl retinoic acid receptor -> inhibits myeloblast differentiation -> AML

AML Responsive to all-trans retinoic acid.

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25
Q

Why would RBCS stain blue on Wright-Giemsa stain?

A

Reticulocytes with residual rRNA.

Ex: In Fe deficiency anemia, once you treat with Fe, you get enhanced erythropoiesis - accelerated release of mature and these immature reticulocytes into circulation.

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26
Q

Findings of DIC

A

Inc. PT, PTT
Thrombocytopenia, Microangiopathic Hemolytic Anemia
Low Fibrinogen
Elevated fibrin split products (D-dimers)
Low factor V and VIII levels

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27
Q 
What are the diseases and translocations associated with the following: 
t(9,22)
t(8;14) 
t(11;14) 
t(14;18) 
t(15;17) 
t(8,21)
A 
t(9,22) = CML = Philadelphia (bcr-abl) 
t(8;14) = Burkett's = c-myc 
t(11;14) = Mantle cell = cyclin-D 
t(14;18) = Follicular = bcl-2 
t(15;17) = AML = retinoic acid receptor 
t(8,21)  = AML (why Down's is more common)
28
Q

What disorder associated with persistent activation of JAK/STAT?

A

Myelofibrosis
Polycythemia Vera
Essential Thrombocytosis

29
Q

Sx and Mech: Acute Intermittent Porphyria

A

Porphobilinogen -> Hydromethylbilane

Deficient enzyme:
HMB synthase/Porphobilinogen Deaminase

Sx: 5 P’s

  • painful abd
  • psych
  • polyneuropathy
  • port wine colored urine*
  • precipitated by drugs, EtOH, starvation

Tx: Glucose, heme (inhibit ALA synthase)

30
Q

Sx and Mech: Porphyria Cutanea Tarda

A

Uroporphyrinogen III -> Coproporphyrinogen III

Deficient enzyme: Uroporphyrinogen Decarboxylase

Sx:

  • Blistering photosensitivity
  • Hypertrichosis
  • Facial hyperpigmentation
  • may be associated with Hep C, ETOH, Inc. ALT/AST
31
Q

Sx and Mech: Sideroblastic Anemia

A

Glycine + Succinyl CoA -> d-aminolevulinic acid

Deficient Enzyme: Aminolevulinic acid synthase

Sx:
Microcytic, hypochromic anemia
- ringed sideroblasts (Fe laden macrophages)
- inc. Fe, Ferritin. Normal TIBC

Tx: Pyridoxine B6 (ALA synthase cofactor)

32
Q

Sx and Mech: Lead Poisoning

A
  1. Aminolevulinic acid dehydratase:
    aminolevulinic acid -> porphobilinogen
  2. Ferrochelatase:
    Protoporphyrin + Fe -> Heme
  3. Inhibits rRNA degradation -> retain aggregates of rRNA (basophilic stippling)

Sx: LEAD

  • lead lines on gingivae and metaphyses of long bones
  • encephalopathy
  • abd colic, sideroblastic anemia
  • drops - wrist and foot drop

Smear:

  • sideroblastic anemia
  • basophilic stippling

RF: old houses with chipped paint, battery/ammunition/radiator factory

Tx:

  • EDTA, Dimercaprol
  • Succimer
33
Q

Hemophilia A and B are what type of inheritance?

A

X-linked!

34
Q

Why perform splenectomy in pt with hereditary spherocytosis?

A

Decrease hemolysis, Improve Anemia, DECREASE biliary gallstones!

35
Q

Recurrent infections + defect in tyr kinase in B cells

A

Bruton’s X-linked agammaglobulinemia.

36
Q

Presentation of Acute Leukemia

A

Anemia - pallor
Thrombocytopenia - like mucosal bleeding, etc
Leukopenia - infection (white patches on mucosa = thrush)
HSM/Lymphadenopathy

Blast Cells

37
Q

What is basophilic stippling?

A

rRNA remnants

Anemia of Chronic Disease
Thalassemia
Lead Poisoning
Alcohol abuse.

38
Q

How does desmopressin work for Hemophilia A?

A

Increase VIII and vWF release from endothelial cells.

39
Q

Area Postrema = ?

A

Dorsal surface of the Medulla.
“ChemoR trigger zone”
Responsible for the vomiting induced by chemotherapy.
This area has absent BBB - fenestrated - sample chemicals in the blood.

40
Q

How to prevent Tumor Lysis Syndrome?

A

Rasburicase (urate oxidase):
uric acid –> allantoin (which can be excreted in the urine)

Tumor Lysis = hyperK, Hyperuricemia, HyperPhos, HypoCa

41
Q

How do nitrates cause cyanosis?

A

Fe2+ (ferrous) —nitrates—> Fe3+ (ferric) = methemoglobin can’t bind O2.

PaO2 is still normal.

42
Q

What anticoagulant causes neutropenia?

A

TIclopidine

43
Q

Neurologic effects of Vit B12 deficiency?

A

Subacute combined degeneration.

  1. Posterior columns
  2. LCST
44
Q

What is the primary when mets biopsy shows large, rounded, polygonal cells with clear cytoplasm?

A

RENAL CELL CARCINOMA!

45
Q

How to prevent nephrotoxicity with cisplastin?

A

Amifostine (free radical scavenger)

IV NS - chloride diuresis.

46
Q

What histologic changes characterize the spleen in a pt with sickle cell?

A

Fibrosis and Atrophy.

Rpted splenic infarctions -> scarring, fibrosis, atrophy

47
Q

Chronic lymphedema (such as from axillary node dissection in masectomy) leads to?

A

Angiosarcoma (Lymphagiosarcoma) = Stewart Treves Syndrome

48
Q

What chemo drug causes hemorrhagic cystitis? How to prevent?

A

Cyclophosphamide - give Mesna (binds toxic metabolites in the urine)

49
Q

Hemolytic Anemia + Hypercoagulability + Pancytopenia

A

Paroxysmal Nocturnal Hemoglobinuria

Anemia: Absence of GPI anchor - decreased CD55 (DAF) and CD59 (MAC inhibition) -> increased complement mediated hemolysis.

Hypercoag: release of free hemoglobin and thrombotic factors from lysed rbcs

Pancytopenia: it’s a stem cell disorder.

50
Q

What anticoagulant most effective in inactivating thrombin?

A

Unfractionated Heparin - equal effectiveness against thrombin and Xa.

LMWH - only Xa.

51
Q

Dactylitis associated with what?

A

Dactylitis = painful swelling of hands/feet. Associated with Sickle cell - infarction of marrow, trabeculae within bones of extremities leads to this.

52
Q

How do you treat acute intermittent porphyria?

A

Heme or Glucose.

Decrease activity of ALA synthase and porphyrin synthesis.

53
Q

Follicular Lymphoma - what translocation and increases activity of what gene?

A

t(14;18) -> bcl2 oncogene

Presents as painless, waxing and waning lymphadenopathy.

54
Q

Basophilic Stippling

A

ACiD alcohol is LeThal

anemia of chronic disease
alcohol abuse
lead poisoning
thalassemias

Caused by a decrease in the enzyme that degrades rRNA.

55
Q

Pathologic RBC forms associated with G6PD

A

Heinz bodies - oxidation of hemoglobin sulfhydryl groups -> denatured hemoglobin precipitation (can be many)
- crystal violet.

Bite cells - phagocytosis of those

56
Q

Ringed sideroblast

A

Sideroblastic Anemia, Lead poisoning, Myelodysplastic

Messed up heme synthesis -> excess Fe accumulates around nucleus.

57
Q

Teardrop

A

BM infiltration - Myelofibrosis

“BM sheds a tear bc its been forced out of its home in the bone marrow”

58
Q

Acanthocyte

A

irregularly spiky.

Abetalipoproteinemia, Liver disease

59
Q

Target cells

A 
HALT
HbC disease
Asplenia
Liver disease
Thalassemia
60
Q

Plummer Vinson

A

esophageal webs
Fe deficiency anemia
atrophic glossitis

61
Q

Sideroblastic Anemia

A

Defect in heme synthesis
X-linked: d-ala synthase gene
Acquired: Myelodysplastic, Pb, Alcohol, B6 def, Cu def, INH

Smear: ringed sideroblast in BM
Labs: inc. Fe, Ferritin, nl TIBC

Tx: Pyridoxine B6 (cofactor for d-ala synthase

62
Q

X-linked anemia

A 
Sideroblastic Anemia (d ALA synthase)
G6PD deficiency
63
Q 
What are the chains associated with the following types of hemoglobin: 
HbA
HbA2 
HbH
HbC
HbS
HbBart 
HbF
A 
HbA = a2b2
HbA2 = a2d2
HbH = b4 (alpha thal 3 allele deletion)
HbC = a2 beta-c2 (beta-c: glu (-) -> lys (+))
HbS = a2 beta-s2 (beta-s: glu (-) -> val (neutral)) 
HbBart = g4 (alpha thal 4 allele deletion)
HbF = a2g2
64
Q

Sx of PNH

A
  1. Coombs (-) hemolytic anemia
  2. Pancytopenia
  3. Venous Thrombosis

Mech: Complement mediated RBC lysis (impaired synthesis of GPI anchor for DAF that protects RBC from complement)

65
Q

Direct vs. Indirect Coombs

A

Direct = test antibody.
- Anti-Ig antibodies (Coombs reagent) added - if RBCS are coated with Ig - will agglutinate)

Indirect = test antigen

  • normal RBCs added to patients serum.
  • then add coombs reagent - if serum has anti-RBC surface Ig, will agglutinate.
66
Q

What are the direct thrombin inhibitors?

What are they used for clinically?

A

Argatroban
Bivalirudin

Used for anticoagulating patients with HIT.

67
Q

What are the direct factor Xa inhibitors?

A

Apixaban

Rivaroxaban

USMLE Step 1 Systems (11 decks)

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