USMLE Step 2: HEME/ONC Flashcards by Matt DeWolf

Effects of Heparain

Increases PTT, activates antithrombin III and affects the INTRINSIC pathway, and decreases fibrinogen.

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Antidote for heparin

Protamine Sulfate

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Effects of Warfarin

Increases PT, extrinsic pathway

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How is the intrinsic pathway measured?

PTT

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How is intrinsic pathway initiated?

By exposure of collagen following vascular trauma

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how is extrinsic pathway measured?

by PT

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How is extrinsic pathway initiated?

By endothelium-produced tissue factor

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intrinsic pathway

12, 11, 9, 8

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Intrinsic pathway

7 (3 is cofactor)

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Common pathway

10 (activated by 8 and 7), 5, prothrombin, thrombin

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What does thrombin activate?

Fibrinogen & 13 (13 does cross linking of fibrin)

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Labs in hemophilia

PT, thrombin time, fibrinogen, and bleeding time are NORMAL.

aPTT is PROLONGED!!

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What is the inheritance of hemophilia?

X-linked

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What is the inheritance of von Willebrand’s Disease?

Autosomal dominant

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Labs in vWD

Platlet count and PT are NORMAL

aPTT and Bleeding time are PROLONGED

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What is DIC?

Deposition of fibrin in small blood vessels leading to thrombosis and end-organ damage. Depletion of clotting factors and platlets leads to a bleeding diathesis

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What is thrombotic thrombocytopenic purpura?

A bleeding disorder due to platelet microthrombi that block off small blood vessels, leading to end-organ ischemia and dysfunction
**similar to DIC

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What happens to RBCs in TTP?

They become fragmented by contact with the microthrombi leading to hemolysis (microangiopathic hemolytic anemia)

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What are the 5 s/sx of TTP?

Low platlet count
Microangiopathic hemolytic anemia
Neurologic Changes
Impaired Renal Function
Fever

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How is TTP diagnosed?

3/5 of the s/sx + schistocytes, low platlets, and rising creatinine

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What else is on the same spectrum of disease as TTP?

HUS (which has more severe elevations of creatinine) & HELLP

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What are the 3 causes of microangiopathic hemolytic anemia?

HUS, TTP, DIC

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What is idiopathic thrombocytopenic Purpura?

IgG antibodies formed against the patient’s platelets

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What do lymphoblasts differentiate into?

B & T Cells

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What do myeloblasts differenciate into?

Neutrophils, Eosinophils, and Basophils

What is the value of looking at the retic?

2.5 hemolysis/hemorrhage

Causes of microcytic anemia?

TICS: thalassemia, iron deficiency, chronic disease, sideroblastic anemia

What is the Schilling test?

The patient is first given unlabeled B12 IM to saturate B12 receptors in the liver, followed by an oral challenge of radiolabeled B12. The radiolabeled B12 will pass into the urine if it is properly absorbed, as the liver's B12 receptors will be saturated from the IM dose

What does it mean is radiolabeled B12 is in the urine for the schilling test?

It means there is a dietary B12 deficiency

What doe sit mean if there is no radiolabeled B12 in the urine for the schilling test?

Consider pernicious anemia, bacterial overgrowth, or pancreatic enzyme deficienc

What happens to MMA and homocysteine in B12 deficiency?

Both are elevated

What happens to MMA and homocysteine in folate deficiency

MMA is normal & homocysteine is elevated

What is PNH?

A disorder in which blood cell sensitivity to complement activation is increased; patients are prone to thrombotic events

LDH, indirect bilirubin, and haptoglobin in hemolytic anemia

LDH: elevated Indirect bilirubin: elevated Haptoglobin: decreased

how do patients with aplastic anemia present?

Pancytopenic- lack of RBCs, WBCs, and platelets

What does the indirect Coombs' Test detect?

Antibodies to RBCs in the patients serum

What does the direct Coombs test detect?

Sensitized erythrocytes

What is the #1 and #2 cause of osteomyelitis in patients with sickle cel disease?

``` #1: S. aureus #2: Salmonella ```

Health maintenance in patients with sickle cell disease?

Treating cholelithiasis with lap chole, chronic folate supplementation, pneumococcal vaccination

Thalassemia: 0/4 alpha-chain

hydrops fetalis- patients die in utero

Thalassemia: 1/4 alpha-chain

Hemoglobin H disease (severe hypochromic, microcyticc anemia with chronic hemolysis, splenomegaly, jaundice, and cholelithiasis; skeletal changes

Thalassemia: 2/4 alpha

Alpha-thal trait; patients have low MCV but are usually asymptomatic

Thalassemia: 3/4 alpha

Silent carrier patients have no s/sx of disease

What is polycythemia vera from?

Clonal proliferation of a pluripotent marrow stem cell due to a JAK2 mutation

What cell line is affected in polycythemia vera?

ALL cell lines are affected- RBCs are most affected

What are the types of porphyrias?

1. Acute Intermittent 2. Porphyria cutanea tarda 3 Erythropoietic porphyria

Leukocyte Alkaline Phosphatase (LAP)

Elevated from a leukemoid reaction and decreased in hematologic malignancy

Effective of glucose on porphyria

Glucose provides negative feedback to the heme synthetic pathway, so high doses may be administered to decrease heme synthesis during an attack

AML and ALL

Marrow that is infiltrated wtih blast cells (>20-30%); in AML the leukemic cells are myeloblasts; in ALL they are lymphoblasts

What is the treatment for M3 AML?

all-trans-retinoic acid

Genetic mutation in M3 AML?

Translocation involving chromosomes 15 & 17

What do myeloblasts look like?

Large (2-4x RBC), lots of cytoplasm, conspicuous nucleoli, fine granules, +myeloperoxidase

What do lymphoblasts look like?

Smaller (1.5-3x RBC), less cytoplasm, inconspicuous nucleoli, =myeloperoxidase

Age groups for leukemia's

ALL: 60

Triad for multiple myeloma

Anemia, renal failure, and bone pain

What is neutropenia?

Absolute neutrophil count <1500

How is ANC calculated?

(WBC) X (%bands + % segmented neutrophils)

What bacterial infections are associated with acute neutropenia?

S. aureus, Pseudomonas, E coli, Proteus, Klebsiella

How is fever in a patient with neuropenia treated?

Broad-spectrum antibiotic (cefepime)

Pathomechanism of hyperacute rejection

Preformed antibodies

Pathomechanism of acute rejection

T-cell mediated

Pathomechanism of chronic rejection

Chronic immune reaction causing fibrosis

Neoplasm associated with down syndrome

ALL (we ALL go down)

Neoplasm associated with xeroderma pigmentosum

SCC and BCC carcinomas of the skin

Neoplasm associated with pernicious anemia

gastric adenocarcinoma

Neoplasm associated with tuberous sclerosis

astrocytoma and cardiac rhabdomyoma

Neoplasm associated with actinic keratosis

SCC of skin

Neoplasm associated with Plummer-vinson syndrome

SCC of esophagus

Neoplasm associated with Paget's disease of bone

secondary osteosarcoma and fibrosarcoma

Neoplasm associated with AIDS

Aggressive malignant NHLs and Kaposi's sarcoma

Neoplasm associated with acanthosis nigricans

Visceral malignancy (stomach, lung, breast, uterus)