USMLE - Heme Onc
Terms
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- source of energy for erythrocytes?
- glucose (90% anaerobically degraded to lactate; 10% by HMP shunt)
- densely basophilic granules containing heparin, histamine & other vasoactive amines, and leukotrienes (LTD-4)
- basophil
- where are mast cells found?
- tissue
- cells that mediate allergic reaction?
- mast cells and basophils
- what does cromolyn sodium prevent?
- mast cell degranulation
- cells that defend against helminthic and protozoan infections?
- eosinophils
- causes of eosinophilia?
- NAACP:
- major - homozygote - beta chain is absent
- when are hypersegmented neutrophils seen?
- vitamin B12 deficiecncy
- large, spherical, azurophilic primary granules that contain hydrolytic enzymes, lysozyme, myeloperoxidase, and lactoferrin
- neutrophils
- kidney-shaped nucleus; extensive 'frosted glass' cytoplasm; differentiates into macrophages in tissues
- monocyte
- off-center nucleus, clock-face chromatin distribution, abundant RER and well-developed Golgi
- plasma cell
- multiple myeloma is what type of neoplasm?
- plasma cell
- what are the main inducers of the primary antibody response?
- dendritic cells
- what is the role of tPA?
- generates plasmin, which cleaves fibrin
- what does PTT measure?
- intrinsic pathway
- what does PT measure?
- extrinsic pathway
- what initiates the intrinsic pathway?
- factor XII
- what initiates the extrinsic pathway?
- factor VII
- what do proteins C and S inactivate?
- Va and VIIIa; dependent on vitamin K
- waht does antithrombin III inactivate?
- thrombin, IXa, Xa, XIa; activated by heparin
- what usually has more prognostic value - stage or grade?
- stage
- degree of cellular differentiation based on histologic appearance of tumor?
- grade
- degree of localization/spread based on site and size of primary lesion, spread to regional lymph nodes, presence of metastases, etc.
- stage (S-spread)
- macro-ovalocytes are seen in what?
- megaloblastic anemia (also hypersegmented PMNs), marrow failure
- helmet cells and schistocytes are seen when?
- DIC, traumatic hemolysis
- teardrop cells are seen when?
- myeloid metaplasia with myelofibrosis
- acanthocytes are seen when
- spiny appearance in abetalipoproteinemia
- when are target cells seen?
- HALT: HbC disease, asplenia, liver disease, thalassemia
- what are poikilocytes & when are they seen?
- nonuniform shapes in TTP/HUS, microvascular damge, DIC
- when are Burr cells seen?
- TTP/HUS
- etiologies of microcytic, hypochromic anemia?
- iron deficiency, thalassemias, lead poisoning, sideroblastic anemias
- etiologies of macrocytic anemia?
- megaloblastic - vit B12/folate deficiency: drugs that block DNA synthesis (sufla,AZT), marked reticulocytosis
- causes of normocytic, normochromic anemia?
- enzyme defects (G6PD, PK), RBC membrane defects (e.g. hereditary spherocytosis), bone marrow disorders (aplastic anemia, leukemia), hemoglobinopathies (sickle cell), anemia of chronic disease, AI hemolytic anemia
- what do decreased serum haptoglobin and increased serum LDH indicate?
- RBC hemolysis
- causes of aplastic anemia?
- radiation, benzene, chloramphenicol, alkylating agents, antimetabolites, viral agents (parvovirus B19, EBV, HIV), Fanconi's anemia, idiopathic; may follow acute hepatitis
- symptoms of aplastic anemia?
- fatigue, malaise, pallor, purpura, mucosal bleeding, petechiae, infection
- pancytopenia with normal cell morphology, hypocellular bone marrow with fatty infiltration
- aplastic anemia
- what is the HbS mutation?
- single AA replacement in beta chain - substitution of normal glutamic acid with valine
- therapies for sickle cell anemia?
- hydroxyurea (increases HbF), bone marrow transplant
- what percent of blacks carry the Hb trait? what percent have the disease?
- 8%, 0.2%
- crew cut on skull x-ray?
- sickle cell anemia, thalassemias - due to marrow expansion from increased erythropoeisis
- what is the defect in beta thalassemia minor? major?
- minor - heterozygote - beta chain is underproduced
- why does cardiac failure occur in thalassemia?
- secondary hemochromatosis
- marked erythrocytosis, moderate increase in granulocytes and platelets, splenomegaly, decreased epo?
- polycythemia vera
- labs in anemia of chronic disease?
- decreased TIBC, increased ferritin, low serum iron
- findings in hemolytic anemia?
- increased serum bilirubin, increased reticulocytes (marrow compensating for anemia)
- test for AI hemolytic anemia?
- Coombs positive
- chronic anemia seen in SLE, CLL, or with certain drugs (e.g. alpha methyldopa)
- warm agglutinin (IgG)
- anti-Ig Ab added to patient's RBCs agglutinate if RBCs are coated with IgG
- direct Coombs' test
- normal RBCs added to patient's serum agglutinate if serum has anti-RBC surface IgG
- indirect Coombs' test
- microvascular hemolysis seen in DIC, TTP/HUS, SLE, or malignant hypertension
- microangiopathic anemia
- what is seen on blood smear in microangiopathic anemia?
- schistocytes (helmet cells)
- what is increased in paroxysmal nocturnal hemoglobinuria?
- urine hemosiderin
- activation of coagulation cascade leading to microthrombi and global consumption of platelets, fibrin, and coagulation factors
- DIC
- lab findings in DIC?
- increased PT, PTT, fibrin split products (D dimers); decreased platelet count
- what is seen on blood smear in DIC?
- helmet-shaped cells and schistocytes
- antiplatelet antibodies, megakaryocytes?
- ITP
- schistocytes, increased LDH, neuro sx
- TTP
- microhemorrhage - mucous membrane bleeding, epistaxis, petechiae, purpura, increased bleeding time
- platelet abnormalities - ITP, TTP, DIC, aplastic anemia, drugs (e.g. immunosuppressive agents)
- factor VIII deficiency
- hemophilia A
- factor IX deficiency
- hemophilia B
- von Willebrand's disease
- mild; most common bleeding disorder; deficiency of vWF - defect of platelet adhesion and decreased factor VIII survival
- macrohemorrhage - hemarthroses (bleeding into joints), easy bruising, increased PT, PTT
- coagulation factor deficiencies
- Bernard-Soulier disease?
- defect of platelet adhesion (decreased GP Ib) - prolonged bleeding time
- Glanzmann's thrombasthenia
- defect of platelet aGgregation - decreased GP IIb-IIIa - prolonged bleeding time
- decresed platelet count, increased bleeding time?
- thrombocytopenia
- lab findings in hemophilia A or B?
- normal platelet count, bleeding time, PT, increased PTT
- increased bleeding time and increased PTT
- von Willebrand's disease
- findings in DIC
- decreased platelet count, increased bleeding time, PT, and PTT
- PT measures what?
- extrinsic pathway - factors, II, V, VII, X
- PTT measures what?
- intrinsic pathway
- origin/markers of RS cells?
- B cell origin - CD30+, CD15+
- good prognosis in Hodgkins?
- increased lymphocytes, decreased RS cells
- 50% of cases of Hodgkin's are associated with what?
- EBV
- what is non-Hodgkin's associated with?
- HIV and immunosuppression
- peak incidence of non-Hodgkin's?
- 20-40 years old
- peak incidence of Hodgkin's?
- bimodal distribution - young and old
- most common type of Hodgkin's?
- nodular sclerosing type
- collagen banding, lacunar cells in Hodgkin's?
- nodular sclerosing type - most common in young women
- numerous RS cells are found in what type of Hodgkin's?
- mixed cellularity (25% of cases)
- Hodgkin's in older males with disseminated disease; poor prognosis?
- lymphocyte depleted
- cell type in SLL, follicular lymphoma (small cleaved cell)?
- B cells
- this is like CLL with focal mass, low grade
- small lymphocytic lymphoma
- most common in children; commonly presents with ALL and mediastinal mass; very aggressive T cell lymphoma
- lymphoblastic lymphoma
- cell type in diffuse large cell lymphoma? who does it affect
- 80% B cells; 20% T cells; usually older adults, but 20% occur in children
- starry sky appearance - sheets of lymphocytes with interspersed macrophages?
- Burkitt's lymphoma
- jaw lesion in endemic from in Africa; pelvis or abdomen in sporadic form
- Burkitt's lymphoma
- cell type in Burkitt's lymphoma?
- B cells - most often affects kids
- leukemia most responsive to therapy?
- ALL
- children, lymphoblasts; may spread to CNS and testes
- ALL
- auer rods, myeloblasts, adults
- AML
- leukemia affecting older adults; lymphadenopathy, hepatosplenomegaly, few symptoms, indolent course?
- CLL
- findings on blood smear in CLL?
- smudge cells
- leukemia that can cause warm antibody AI hemolytic anemia?
- CLL
- leukemia that presents with increased neutrophils and metamelocytes, splenomegaly
- CML
- what is low in CML
- leukocytic alkaline phosphatase
- peroxidase-positive cytoplasmic inclusions in granulocytes adn myeloblasts
- Auer rods
- in which type of AML are Auer rods primarily seen?
- acute promyelocytic leukemia (M3)
- treatment of this leukemia can release Auer rods, causing DIC
- AML M3
- monoclonal plasma cell (fried egg appearance) cancer that arises in the marrow and produces large amounts of IgG (55%) or IgA (25%)
- multiple myeloma
- most common primary tumor arising from bone in adults
- multiple myeloma
- these are laminated, concentric, calcific spherules
- psammoma bodies
- where are psammoma bodies seen?
- PSaMMoma: papillary (thyroid), serous (ovary), meningioma, mesothelioma