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93 Cards in this Set
- Front
- Back
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What disease is associated with hypersegmented neutrophil?
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Megaloblastic Anemia due to vitamin B12 and folate deficiency.
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What is the most accurate test for megaloblastic anemia?
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B12 and folate levels. B12 deficeincy is also confirmed with an elevated methylmalonic acid level. The etiology of B12 deficiency is confirmed with anti-intrinsic factor and antiparietal cell antibodies, which are the diagnostic test for pernicious anemia.
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What does a blood smear from a person with hairy cell leukemia show?
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Cells with cytoplasmic projections.
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When do you answer hairy cell leukemia?
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Look for a middle-aged man presenting with the gradual onset of fatigue. Splenomegaly is present and may be massive. The liver is enlarged in 50% of cases. Pancytopenia is the hallmark of hairy cell leukemia.
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What is the most accurate diagnostic test for hairy cell leukemia?
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Tartrate-resistant acid phosphatase (TRAP). This is done on a bone marrow biopsy.
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What does Heinz bodies in a peripheral smear of red blood cells show?
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Heinz bodies are precipitated, oxidized hemoglobin. They are found in glucose-6-phosphate dehydrogenase (G6PD) deficiency. G6PD is an X-linked recessive disorder affecting 10-15% of Africal-American males.
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When is Peripheral blood smear the answer?
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Look for a man who was healthy until exposed to oxidant stress and suddenly develops intravascular hemolysis resulting in weakness, tachycardia, jaundice, and dark urine. The most common type of oxidant stress is from infection, not drugs. Drugs associated with this stress include sulfa drugs, primiquine, dapsone, quinidine, and nitro-furantoin. Fava beans also cause hemolysis.
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What are other cells characteristic of G6PD deficiency?
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Bite cells.
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What is the definitive test for G6PD deficiency?
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The definitive test for this disorder is a G6PD level. You must wait 2 months to do the level, because the G6PD level will be artificially elevated immediately following a hemolytic event. All the most deficient cells are destroyed.
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What is an Auer Rod?
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An eosinophilic needle-shaped inclusion in the cytoplasm.
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What disease are Auer Rods associated with?
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Auer rods are pathognomic for acute myelogenous leukemia (AML).
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When do you answer Auer Rods?
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Answer auer rods wehn you are shown a patient with pancytopenia and blasts on teh peripheral smear or greater than 20% blasts on bone marrow exam. Histochemical stains demonstrating myeloid enzymes such as peroxidase may further aid in choosing AML as the answer.
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What are bite cells?
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These are bite cells. They are formed when Heinz bodies (denatured hemoglobin) are removed from teh cells by the spleen. Macrophages in teh spleen remove the denatured hemoglobin.
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What enzyme deficiency is responsible for bite cells?
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Bite cells are seen with G6PD deficiency, which is an X-linked disorder. It is the most common enzymatic disorder of the red blood cells in humans.
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What are the precipitating factors for G6PD induced anemia?
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Patients with G6PD deficiency are prone to developing hemolytic anemia in response to sulfonamide drugs such as dapsone and sulfasalazine. Other precipitating factors are infections, diabetic ketoacidosis, and Favism. Favism is the ingestion of fava beans resulting in hemolysis. This happens in the Mediterranean variant of G6PD deficiency.
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What are schistocytes and helmet cells?
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These are fragmented red blood cells. Collectively, this is also known as intravascular hemolysis or microangiopathic hemolytic anemia.
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What diseases are schistocytes and helmet cells associated with?
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Fragmented cells are seen in thromotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), major blood group incompatabiity, disseminated intravascular coagulation (DIC), paroxysmal nocturnal hemoglobinuria, artificial heart valves, and snake bites.
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What other abnormal lab tests are associated with hemolysis other than schistocytes or helmet cells?
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All forms of hemolysis are associated with an elevated LDH, indirect bilirubin, elevated reticulocyte count, and decreased levels of haptoglobin.
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What is a ringed sideroblast?
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Prussian blue stain is necessary in order to visualize it. The ringed sideroblast is caused by iron accumulation within mitochondria in the red cell. This is the main finding in sideroblastic anemia.
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What causes sideroblastic anemia?
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Look for a case of microcytic anemia with n elevated serum iron level in an alcoholic. Acquired sideroblastic anemias can occur as a result of the ingestion of drugs such as alcohol, isoniazid, and chloramphenicol, or toxins such as lead or zinc.
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Which hematologic disorder is associated with ringed sideroblasts?
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Ringed sideroblasts are also a feature of myelodysplastic syndrome.
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What are Rouleaux formations?
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They occur when red blood cells form stacks.
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What diseases are associated with rouleaux formations?
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Rouleaux may form due to the presence of abnormal globulins or fibrinogen. This formation of hte red blood cells is found in multiple myeloma and macroglobulinemia. Other clues that suggest multiple myeloma might be anemia, hypercalcemia, renal failure, and abnormal SPEP or UPEP.
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What are spherocytes?
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Red Blood cells with too little membrane.
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What is the most accurate test for hereditary spherocytosis?
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The fragility test.
NOT MCHC. |
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What is the genetic defect in hereditary spherocytosis?
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The defect is on the ankyrin gene, which leads to spectrin deficiency, which results in membrane instability.
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When do you answer the fragility test?
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Look for a patient with recurrent hemolysis, a big spleen, and a family history of anemia. The CBC reveals anemia and an elevated mean cell hemoglobin concentration (MCHC).
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What disease are sickled cells associated with?
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Only sickle cell disease that is homozygous (SS) will produce sickled cells. Heterozygous disease (AS) will be hematologically normal.
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What is the most accurate test to diagnose sickle cell disease?
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Hemoglobin electrophoresis.
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What are target cells?
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Associated iwth liver disease and certain hemoglobinopathies such as sickle cell disease, thalassemia, and, most notably, hemoglobin C disease. Iron deficiency can also have target cells.
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Do target cells have a shorter survival?
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Despite their abnormal appearance on peripheral smear, target cells do not have a shorter survival compared to normal cells.
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What is the diagnosis when tear drop cells are seen?
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Either show or described in teh question, you should answer infiltrative bone marrow disease such as myelofibrosis. Look for a case of pancytopenia and massive splenomegaly in which hairy cell leukemia has been excluded. The bone marrow biopsy will show reticulin fibers.
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What are anti-intrinsic factor antibodies and antiparietal cell antibodies?
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Anti-intrinsic factor (anti-IF) antibodies and antiparietal cell antibodies are highly confirmatory for the diagnosis of pernicious anemia. They are nearly 100% specific for the disease. Pernicious anemia is an autoimmune disease in which you become "allergic" to your own IF and gastric parietal cells. You can't absorb B12 without IF. You can't make IF without parietal cells.
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When do you answer anti-intrinsic factor antibodies and antiparietal cell antibodies?
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Answer anti-IF and antiparietal cells antibodies when you see a case of B12 deficiency and you want to determine the etiology. The case will describe a patient in whom the B12 level will be low or the methylmalonic acid level high. These antibodies are NOT to diagnose B12 deficiency, they are to determine the etiology.
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What is Bleeding Time?
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A test of the ability of the platelet to adhere to the endothelial lining of the capillary. Do not use it when the platelet count is abnormally low. Everyone with a low platelet count will have an abnormal bleeding time.
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How is Bleeding time done?
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A blood pressure cuff is inflated to 40mm Hg to engorge the blood vessels, then small cuts are made. This test is the amount of time it takes for the bleeding to stop.
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Whe is bleeding time the answer?
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Answer bleeding time when the patient has abnormal bleeding that seems to be from a platelet disorder but the platelet count is normal. Examples are Von Willebrand's disease or uremia induced platelet dysfunction.
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What is the most accurate test for Von Willebrand's disease?
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The most accurate tests are a Von Willebrand's factor level, ristocetin cofactor assay, or in vitro platelet aggregation studies.
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what are Burr cells?
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Burr cells are red cells with many blunt, regular spicules. Burr cells are also called echinocytes.
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What condtions are burr cells associated with?
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burr cells are present in end-stage renal disease and liver disease.
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How do you differentiate Burr cells from Spur cells?
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Spur cells, or acanthocytes, have only a few, irregular spicules. They are seen in severe liver disease and in some forms of hereditary sperocytosis adn myelodysplasia.
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What is Decay-Accelerating Factor (DAF) or CD55/CD59 Assay?
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CD55/59 is a test for paroxysmal nocturnal hemoglobinuria (PNH), also known as decay-accelerating factor. DAF is a membrane component of hte complement system.
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When are Decay-Accelerating Factor (DAF) or CD55/CD59 Assay the most accurate diagnostic test?
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Assay for DAF is the most accurate test for diagnosing PNH.
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When do you answer DAF?
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Answer DAF when you see a patient with intermittent dark urine, particularly in the morning, pancytopenia, and large vessel thrombosis.
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What are cold agglutinins?
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Cold agglutinins are IgM autoantibodies directed against RBC antigens. Titers are measured when cold agglutinin disease, which is a type of autoimmune hemolytic anemia, is suspected.
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What diseases is it associated with cold agglutinins?
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High titers have been found to be associated with malignancies such as lymphoma, CLL, and Waldenstrom's macroglobulinemia, as well as mycoplasma infections and infectious mononucleosis.
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When do you answer cold agglutinins?
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Answer cold agglutinins when you see a patient with hemolytic anemia as well as skin discoloration when exposed to cold temperatures. Do not confuse this with cryoglobulins, which give purpuric skin lesions and glomerulonephritis.
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What is a coombs' agglutinin test?
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Coombs' test measures the presence of antibodies against red cells.
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What clinical significance does coombs agglutinin test have?
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Coombs' test is used for the diagnosis of autoimmune hemolysis. A positive Coombs' test shows the agglutination of the patient's red cells.
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What is the most common cause of hemolytic anemia?
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A total of 30-50% of Coombs' positive hemolytic anemia is adiopathic. The most common identified etiologies are penicillin, quanidine, alphamethyldopa, sulfa drugs, and aspirin.
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What are D-Dimer/Fibrin Split Products?
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D-dimer is the by-product of the degradation of fibrin by plasmin. Fibrin split products (FSPs) are produced by the activation of fibrinogen by thrombin. They are abnormal only if they are present in increased amounts.
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How are D-dimer/Fibrin Split products measured?
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D-dimer can be measured by either latex agglutination (more rapid) or ELISA (more accurate). The ELISA is far more sensitive.
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What do D-dimer/Fibrin Split products detect?
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Elevated levels indicate pathology involving clot formation and lysis from activation of hte coagulation cascade. The provide no information about platelet function.
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What do the results of D-dimer/Fibrin Split products tell you?
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Elevated D-dimer/FSP levels are evidence of DIC. A negative result of the ELISA rules out DVT and PE but a positive result does not confirm the diagnosis.
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When should you order D-dimer/Fibrin Split products?
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Order these tests to confirm suspected DIC and to rule out PE in patients with a low pre-test probability.
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What is Factor V Leiden Mutation?
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Factor V Leiden mutation predisposes to thrombosis by resistance to the antithrombotic effects of activated protein C. Protein C normally slows th clotting cascade by inhibiting Factor V. The mutation allows Factor V to ignore the natural anticoagulant action of protein C. Factor V Leiden is the most common cause of inherited thrombophilia.
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When do you answer Factor V Leiden mutation?
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Anser Factor V Leiden mutation as the most accurate test for a young person with an unprovoked DVT or PE. Thrombotic events after plane flights should evoke an investigation for thrombophilia.
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What other tests should be sent along with Factor V Leiden?
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1) Protein S
2) Protein C 3) Lupus anticoagulant (when you see an elevated PTT or spontaneous abortions in the case) 4) Antithrombin III mutation (when you see resistance to heparin in the case) |
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What is Haptoglobin levels?
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Haptoglobin is used to determine hemolysis. It is a protein that binds to free ehmoglobin. So when we have hemolysis, RBCs will release free hemoglobin that will bind to haptoglobin. This will result in decreased haptoglobin levels. In hemolysis we also find an elevated levels of LDH, reticulocytes, and indirect bilirubin.
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When do you answer haptoglobin level?
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The typical scenario will be the sudden onset of anemia without gastrointestinal bleeding. The presence of jaundice is also highly suggestive. Acute anemia minus GI bleeding equals hemolysis.
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For which clinical condition(s) is hemoglobin electrophoresis used?
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Hemoglobin electrophoresis is themost sensitive test to diagnose hemoglobinopathies such as sickle cell disease (SCD) or thalasemia. It is themost accurate way to diagnose the presence of the heterozygous forms of these diseases or the "trait".
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What signs/symptoms would prompt you to order hemoblobin electrophoresis?
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With respect to SCD, clinical presentations include ulcerations o fthe skin of hte legs, recurrent infections with Pneumococcus or Haemophilus, retinopathy, aseptic necrosis of the femoral head, osteomyelitis, growth retardation, and splenomegaly. Typically, the patient will be African-American with a possible family history of the disease. Sickle cell trait will be in a patient who is asymptomatic with a family member with sickle cell disease or who has unexplained hematuria.
With respect to the thalassemia, clinical presentations range from normal to severely symptomatic with growth failure, hepatosplenomegaly, jaundice, and bony deformities. |
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What is Leukocyte Alkaline Phosphatase (LAP) Score?
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Leukocyte alkaline phosphatase (LAP) is an enzyme in white blood cells. If the cells are elevated in number and the function is normal, the LAP score will go up in proportion to the elevated cell count.
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When is LAP the answer?
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LAP is a test for chronic myelogenous leukemia (CML). Anser LAP when the white cell count is extremely high and the differential shows mostly neutrophils. The case is likely also to have a big spleen, giving left upper quadrant pain and early satiety. LAP scores should be low in CML, and are used to differentiate CML from leukemoid reaction.
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When is a lymph node needle biopsy the answer?
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Needle biopsy of a lymph node is used to detect infections such as tuberculosis, fungi, and staphylococcus. Infections are suggested by nodes that are warm, tender, and sometimes red.
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When is a lymph node excisional biopsy the answer?
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Excisional lymph node biopsy is the single most accurate test to diagnose lymphoma. A needle biopsy of a lymph node is the most common wrong answer in the diagnosis of lymphoma. There is insufficient tissue in a needle biopsy of a node to diagnosis lymphoma. In addition, the individual lymphocytes will appear normal on a needle biopsy. The diagnosis of lymphoma requires the visualization of the architecture of the entire node. Nodes with lymphoma are nontender, not red, and not warm as they would be with an infection.
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what is Methylmalonic Acid Level?
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Methylmalonic acid (MMA) builds up when itamin B12 is deficient. MMA has greater sensitivity than vitamin B12 levels. Homocysteine is elevated in both B12 and folic acid deficiency.
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When do you answer methylmalonic acid level?
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Anser MMA when the patient has macrocytic anemia and hypersegmented neutrophils but a normal B12 level. When there is a story like B12 deficiency and the B12 level is normal, answer: MMA level.
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What is a mixing study?
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Mixing studies are done to distinguish between a clotting factor deficiency and an inhibitor of the clotting factor as the cause of an abnormal partial thromboplastin time (aPTT). You mix normal pooled plasma with the patient's plasma.
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When is mixing study the best test?
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This is the best initial test when you have an abnormal aPTT.
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If the mixing study normalizes after the mixing, what doe sthis mean?
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If the test normalizes after the noxing, then teh elevated aPTT is caused by a clotting factor deficiency.
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What is the next best test if the study normalizes?
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The next best test if the mixing study normalizes is individual clotting factor assays of th patient's plasma to determine which factor is deficient.
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If the test does NOT normalize after the mixing, what does this mean?
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If the test does not normalize it means that an inhibitor is present, i.e., Factor VIII inhibitor or the lupus anticoagulant.
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What is osmotic fragility test?
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Osmotic fragility is the classic test for hereditary spherocytosis.
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How does an osmotic fragility test work?
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It measures the amount of hemoglobin released from red blood cells (RBCs) placed in hypotonic solution. RBCs with a reduced surface area-to-volume ratio will lyse at concentrations that do not affect normal cells. This is because they do not have enough cell membrane. They "stretch" and then "pop" when put in a hypotonic solution.
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When is the answer osmotic fragility?
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Answer osmotic fragility when you are presented with a case of hemolytic anemia and splenomegaly with spherocytes on teh peripheral smear. The other features that push the diagnosis and this test are: family history of recurrent episodes of anemia, and bilirubin gallstones.
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What is the philadelphia chromosome?
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A Philadelphia chromosome represents a genetic translocation between chromosomes 9 and 22. It is associated with chronic myelogenous leukemia. It is also known as BCR/Abl and can be detected by PCR.
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When is the philidelphia chromosome the most accurate diagnostic test?
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The answer is Philadelhia chromosome when you are presented a case of probable CML. The white cell count will be very high, mostly neutrophils, and the LAP (or leukocyte alkaline phosphatase) score will be low. The Philadelphia chromosome also has prognostic value. If you give imatinib and the Philadelphia chromosome goes away, the prognosis is good.
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What is ristocetin cofactor assay?
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The Ristocetin cofactor assay is a test of the function of von Willebrand's factor (VWF). Along with a VWF level, it is the most accurate test for von Willebrand's disease. Ristocetin acts as an artificial endothelial lining. If VWF is present and is functioning normally then platelets should adhere to the Ristocetin.
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Whe is ristocetin cofacor assay the answer?
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Answer Ristocetin assay when you see a patient with platelet type of bleeding and a normal platelet count and normal VWF level. Platelet tye of bleeding is superficial Examples are epistaxis, petechiae, purpura, and gum or gingival bleeding.
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What is Russell's Viper Venom Clotting Time (RVVT)?
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RVVT is a phospholipid-dependent coagulation test?
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When is RVVT indicated?
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It is used in detection of antiphospholipid antibodies or lupus anticoagulant. think of this in a patient who has a prolonged PTT that does not correct mixing a mixing study. The dilute Russel viper venom test may be indicated to confirm that the inhibitor is a lupus anticoagulant.
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What si a common clinical scenario that need RVVT?
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Clinical scenario may be of a woman, with or without features of SLE, with repeated abortions or giving birth to an infant with heart block or presenting with venous or arterial thrombosis.
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For which clinical condition(S) is the shilling test used?
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Schilling's test is used to find the etiology of a B12 deficiency. The most common cause of B12 deficiency is pernicious anemia where there is decreased intrinsic factor (IF) due to autoantibodies against IF.
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How is the shilling test performed?
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In the first stage, radiolabled cyanocobalamine is given orally, followerd by an intramuscular injection of cyanocobalamine one hour later. Urine is collected for determination of the percent excretion of the oral dose. In pernicious anemia, or malabsorption, excretion in the urine is low. The test is repeated with added oral intrinsic factor (IF). Adding IF should normalize cyanocobalamine absorption and urinary excretion in patients with pernicious anemia, but not in those with intestinal malabsorption.
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When do you answer schilling test?
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Schilling's test is rarely the right answer. Look for a case of vitamin B12 deficiency when the intrinsic factor and parietal cell antibodies are negative and the etiology of the diagnosis is not clear or the antibodies are not in the choices. Schilling's test is to doagnose B12 deficiency when the diagnosis is not pernicious anemia.
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what is Serum Protein Electrophoresis?
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The SPEP is the separation and fractionation of the patient's serum proteins in order to assess teh individual components, i.e., how much of the patient's protein is albumin, how much is immunoglobulin.
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When is SPEP the answer?
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Answer SPEP to evaluate a high total serum protein. SPEP is the best initial test to diagnose myeloma, particularly if X-ray of the bone looking for lytic lesions has already been done, or if X-ray is not one of hte answer choices.
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What is the most common reason for an abnormality?
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The most common reason to have an abnormality on teh SPEP is a monoclonal gammopathy of unknown or undetermined significance.
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What is the most accurate test?
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The most accurate test for an IgG abnormality detected as an SPEP spike is a one marrow. A total of >10% plasma cells is indicative of myeloma. Waldenstrom's macrogloulinemia will also give an abnormal SPEP with an IgM spike.
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What is a sucrose lysys test?
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The sucrose lysis test is a screening test for paroxysmal nocturnal hemoglobinuria (PNH). A sample of the patient's blood is treated with sucrose and observed for evidence of hemolysis from complement activation. The hemolysis of PNH is caused by increased sensitivity of hte patient's red cells to lysis by complement. Sucrose activates complement and evokes hemolysis.
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When do you answer sucrose lysis test?
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Answer sucrose lysis test if a patient presents with dark urine in the moning, wiht or without evidence of venous thrombosis and pancytopenia. The coombs' test will be negative.
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What is the most accurate test?
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Teh most accurate test for PNH is flow cytometry for the absence of CD55 and CD59, also known as decay-accelerating factor (DAF).
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