Question 1

Which of the following infections is responsible for the most deaths worldwide?&#10;A) Malaria&#10;B) Babesia infection&#10;C) Bartonella infection&#10;D) Clostridial septicemia

Accepted Answer

Malaria is responsible for the most deaths worldwide, accounting for approximately 400,000 deaths annually. Babesia infection, Bartonella infection, and Clostridial septicemia are all serious infections, but they do not result in as many deaths as malaria.

Question 2

Why does Plasmodium falciparum infection result in the most serious hemolysis of the various forms of malaria?&#10;A) Only reticulocytes are invaded.&#10;B) Reticulocytes and RBCs less than 10 days old are invaded.&#10;C) Only mature RBCs are invaded.&#10;D) RBCs of all ages are invaded.

Accepted Answer

Plasmodium falciparum is capable of invading red blood cells (RBCs) of all ages, which leads to a higher rate of hemolysis and more severe symptoms compared to other malaria-causing Plasmodium species that have more restricted RBC age preferences for invasion.

Question 3

Renal failure is a prominent feature of:&#10;A) Hemolytic uremic syndrome&#10;B) Thrombotic thrombocytopenic purpura&#10;C) Plasmodium malariae infection&#10;D) March hemoglobinuria

Accepted Answer

Hemolytic uremic syndrome (HUS) is characterized by the triad of hemolytic anemia, acute renal failure, and thrombocytopenia.

Question 4

Which of the following techniques most often diagnoses malaria and Babesia infections?&#10;A) Polymerase chain reaction (PCR)&#10;B) Observing the organisms in blood films&#10;C) Serologic tests&#10;D) Culture

Accepted Answer

The most common method of diagnosing malaria and Babesia infections is by observing the organisms in blood films. PCR can also be used in some cases, but is less commonly used. Serologic tests and culture are not typically used for diagnosing these infections.

Question 5

Which of the following conditions is associated with a deficiency of von Willebrand factor (VWF)-cleaving protease?&#10;A) Hemolytic uremic syndrome&#10;B) Thrombotic thrombocytopenic purpura&#10;C) March hemoglobinuria&#10;D) DIC

Accepted Answer

Thrombotic thrombocytopenic purpura (TTP) is associated with a deficiency of Von Willebrand factor (VWF)-cleaving protease, also known as ADAMTS13. Deficiency of this enzyme leads to the accumulation of ultra-large VWF multimers, causing microthrombi formation in small vessels and platelet consumption, resulting in thrombocytopenia and microangiopathic hemolytic anemia. Hemolytic uremic syndrome is also associated with microangiopathic hemolytic anemia and thrombocytopenia but is caused by different mechanisms. March hemoglobinuria is a condition associated with the destruction of red blood cells during marching, and DIC is a condition associated with increased clotting and bleeding tendencies.

Question 6

A patient's red cells show globular fragmentation, budding, and microspherocytes. To what have the red cells probably been exposed?&#10;A) Heat&#10;B) Chemicals&#10;C) Oxidant drugs&#10;D) Bartonellosis

Accepted Answer

The presence of globular fragmentation, budding, and microspherocytes in red cells is indicative of thermal injury, which is typically caused by exposure to heat.

Question 7

A patient has crescent- or banana-shaped malarial gametocytes. Which of the following is probably true regarding the species of malaria and its clinical course?&#10;A) Plasmodium malariae, which is benign and needs no treatment&#10;B) Plasmodium ovale, which is found mostly in Southern United States and is usually fatal&#10;C) Plasmodium falciparum, which is the most clinically serious&#10;D) Plasmodium vivax, which is the most clinically serious

Accepted Answer

Crescent- or banana-shaped gametocytes are characteristic of Plasmodium falciparum, the most clinically serious species of malaria. The other options are incorrect as Plasmodium malariae can cause symptoms, Plasmodium ovale is not usually fatal and is found in West Africa, and Plasmodium vivax is less clinically serious than falciparum.

Question 8

All of the following are examples of microangiopathic hemolytic anemias (MAHAs) except:&#10;A) Thrombotic thrombocytopenia purpura&#10;B) Hemolytic uremic syndrome&#10;C) Disseminated intravascular coagulation (DIC)&#10;D) Immune thrombocytopenia purpura

Accepted Answer

Immune thrombocytopenia purpura (ITP) is not a form of MAHA. It is an autoimmune disorder characterized by the destruction of platelets by the immune system, resulting in a decreased platelet count and an increased risk of bleeding. Thrombotic thrombocytopenia purpura (TTP), hemolytic uremic syndrome (HUS), and disseminated intravascular coagulation (DIC) are all examples of MAHAs characterized by the formation of microthrombi in small blood vessels, leading to hemolysis, thrombocytopenia, and organ damage.

Question 9

Which of the following decreases the ability of malaria species to infect RBCs?&#10;A) Duffy-positive phenotype&#10;B) Heterozygosity for hemoglobin S (Hb S)&#10;C) Hereditary spherocytosis&#10;D) Rh-negative genotype

Accepted Answer

Heterozygosity for hemoglobin S (Hb S) decreases the ability of malaria species to infect RBCs because it leads to the production of abnormal hemoglobin which makes it difficult for the parasite to survive within the RBC. The other options listed do not have a significant impact on the ability of malaria species to infect RBCs.

Question 10

Which of the following is an expected finding in MAHA?&#10;A) Elevated platelets&#10;B) Schistocytes or red cell fragments&#10;C) Low white count&#10;D) Extravascular hemolysis

Accepted Answer

MAHA (microangiopathic hemolytic anemia) is characterized by the presence of schistocytes or red cell fragments in the blood smear. Elevated platelets and low white count can be seen in other conditions, and extravascular hemolysis is not typically associated with MAHA.

Question 11

Thick blood films for malaria diagnosis are best used for which purpose?&#10;A) Initial screening&#10;B) Determination of the percent of parasitemia&#10;C) Speciation&#10;D) Identification of stages

Accepted Answer

The answer of Thick blood films for malaria diagnosis are...

Question 12

What is the pathogenesis of MAHA?&#10;A) Microthrombi and fibrin formed on damaged endothelial cells trap and break red cells.&#10;B) Chemicals or heat destroy red blood cells (RBCs).&#10;C) The spleen sequesters red cells in an attempt to remove abnormal inclusions.&#10;D) Antibodies that activate complement are formed and destroy the red cell membrane.

Accepted Answer

The answer of What is the pathogenesis of MAHA?&#10;A) Microthrombi...

Question 13

A mild intravascular hemolytic anemia resulting from forceful repeated effect of the feet on hard surfaces is called:&#10;A) Traumatic cardiac hemolytic anemia&#10;B) Exercise-induced hemoglobinuria&#10;C) Bartonellosis&#10;D) Thrombotic thrombocytopenic purpura

Accepted Answer

The answer of A mild intravascular hemolytic anemia resulting from...

Question 14

MAHA is often secondary to all of the following conditions except:&#10;A) Infections, especially sepsis&#10;B) Obstetric complications&#10;C) Renal disease&#10;D) Cancer

Accepted Answer

The answer of MAHA is often secondary to all of...

Deck 24: Extrinsic Defects Leading to Increased Erythrocytedestructionnonimmune Causes