Deck 20: Hemolytic Anemia: Nonimmune Defects

Question 1

Which of the following conditions is not characterized by the presence of schistocytes?

A)HUS
B)TTP
C)Malaria
D)HELLP syndrome

Answer 1

Malaria

Question 2

The destruction of erythrocytes in MAHA is primarily the result of what mechanism?

A)Extravascular hemolysis
B)Loss of membrane proteins
C)Complement-mediated hemolysis
D)DIC

Answer 2

Extravascular hemolysis

Question 3

A mother brings her 3-year-old daughter to the emergency department because she is having trouble urinating.The child is not feverish.She has otherwise been healthy except for a bout of diarrhea about 10 days ago.Laboratory test results are as follows:
Based on the history and the laboratory results,what is the most likely diagnosis?

A)DIC
B)Bartonella sp.infection
C)HUS
D)Previous Clostridium sp.infection

Answer 3

HUS

Question 4

Laboratory testing in DIC helps distinguish this condition from others.Which of the following results would be expected in DIC?

A)PT normal;APTT prolonged;normal D-dimer test;normal fibrinogen
B)PT,APTT,and TT prolonged;elevated D-dimer test;decrease in fibrinogen
C)Fibrinogen increased;FDP and D-dimer decreased;PT,APTT,and TT prolonged
D)PT,APTT,and TT normal;fibrinogen decreased;FDP and D-dimer increased

Question 5

Which of the following organisms causes erythrocyte damage by releasing hemolytic toxins?

A)Plasmodium sp.
B)Babesia sp.
C)Clostridium sp.
D)Bartonella sp.

Question 6

The primary difference between D+ and D- forms of HUS is related to the:

A)Extent of damage to the kidney
B)Length of the symptomatic period
C)Severity of thrombocytopenia
D)Presence of diarrhea

Question 7

Which of the following results are typically found in HUS?
PT aPTT

A)ProlongedProlonged
B)NormalProlonged
C)ProlongedNormal
D)NormalNormal

Question 8

Bone marrow response in MAHA is reflected in the peripheral blood smear by the presence of:

A)Spherocytes
B)Reticulocytes
C)Schistocytes
D)Keratocytes

Question 9

Plasmodium falciparum infection is accompanied by a severe form of anemia from what factor?

A)Toxins produced by P.falciparum
B)High levels of parasitemia
C)Lack of spleen removal of the infected cells (red blood cells)
D)Production of exotoxins that affect host cell membranes

Question 10

Which of the following analytes would be increased in MAHA?

A)BUN
B)Haptoglobin
C)Creatinine
D)Bilirubin

Question 11

What features are identified on the peripheral blood smear in TTP?

A)Increase in presence of reticulocytes,nucleated erythrocytes,abundance of schistocytes
B)Leukocytosis with left shift,and schistocytes present reticulocytopenia
C)Abundance of schistocytes,thrombocytosis,and leukopenia
D)Nucleated erythrocytes,Howell-Jolly bodies,and absence of schistocytes

Question 12

Which of following is identified as an initiator of exercise-induced hemoglobinuria associated with running?

A)Prosthetic heart valves
B)Extensive thermal burns
C)Erythrocyte membrane disorder
D)Exercise-induced oxidative stress and erythrocyte age

Question 13

Which of the following laboratory findings occur in both HUS and TTP?

A)Increased reticulocytes;thrombocytopenia;decrease in haptoglobin
B)Decreased reticulocytes;decrease in haptoglobin and thrombocytopenia
C)Increased total and unconjugated serum bilirubin;increase in haptoglobin
D)Decreased total and unconjugated serum bilirubin;decreased haptoglobin

Question 14

Which of the following is found to be a factor in TTP?

A)Escherichia coli O157:H7
B)Shigella species
C)S.pneumoniae
D)Shigella dysenteriae serotype I

Question 15

A 7-year-old girl is brought to a physician because she has a swollen hand with an ischemic lesion.The physician suspects a brown recluse spider bite.What is the suspected mechanism of erythrocyte damage caused by venom of this spider?

A)Changes in glycophorin on the erythrocyte membrane
B)DIC
C)Lysis caused by passage through the fibrin clot
D)Changes in the permeability of the cell membrane

Question 16

What are typical findings on the blood smear in DIC?

A)Spherocytes and leukopenia
B)Target cells and leukocytosis
C)Schistocytes and thrombocytopenia
D)Helmet cells and thrombocytosis

Question 17

Hemolytic uremic syndrome and thrombotic thrombocytopenic purpura can present with similar initial clinical symptoms.Which of following distinguishes TTP?

A)It occurs in children younger than 5 years old.
B)Acute renal failure is present.
C)There are severe CNS symptoms.
D)There is thrombocytopenia.

Question 18

A child presents to the hospital emergency department with clinical findings of bloody diarrhea and fever.Laboratory findings reveal an elevated neutrophil count,increased C-reactive protein,thrombocytopenia,and a decreased haptoglobin.With what diagnosis are these findings associated ?

A)TTP
B)HUS
C)DIC
D)HELLP syndrome

Question 19

In what type of hemolytic anemia does damage to the endothelial lining of the small vessels result in deposits of fibrin with the vessels?

A)Exercise-induced hemoglobinuria
B)The type associated with infectious agents
C)The type associated with animal venoms
D)Microangiopathic hemolytic anemia

Question 20

Which of the following analytes is decreased in HUS?

A)Bilirubin
B)Lactate dehydrogenase
C)Haptoglobin
D)BUN

Question 21

A woman visits her obstetrician for a routine prenatal visit at 24 weeks.Her blood pressure is 180/100 and her urinalysis shows 3+ proteins.The peripheral blood smear demonstrated the presence of schistocytes.What other elevated test results might be found?

A)Liver enzymes
B)BUN and creatinine
C)PT and APTT
D)Haptoglobin

Question 22

A 20-year-old disoriented female is brought to the hospital with a fever of 102°F.Results of the CBC demonstrate a platelet count of 68 × 10⁹/L,a hemoglobin of 9.0 gm/dl,WBC count of 22 × 10⁹/L,and the presence of polychromasia and schistocytes on the peripheral blood smear.Her husband indicated she had no recent episodes of diarrhea but had been taking penicillin for an ongoing infection.The most likely diagnosis for the patient is:

A)TTP
B)D-HUS
C)DIC
D)HELLP syndrome

Question 23

The underlying cause of TTP is:

A)An unregulated coagulation cascade
B)Deficiency in VWF multimers
C)Deficiency of ADAMTS-13 protease
D)Overproduction of cryoprecipitate

Question 24

Explain why infections with Clostridium perfringens lead to hemolysis of the RBCs.

Question 25

A runner is in training for the Chicago Marathon.After his most recent 26 mile run,he notices that his urine was reddish-brown.The next morning,his urine is clear and yellow,but he decided to see his primary care physician.All of the hematology and chemistry results are within the reference range.What is the most likely reason for this scenario?

A)Initial dark color was caused by dehydration.
B)This is exercise-induced hemoglobinuria.
C)Uric acid crystals were precipitated in the initial urine.
D)There is insufficient information to determine the reason.

Question 26

A patient who presents with DIC would most likely have which of the following sets of coagulation test results?
PT aPTT D-dimer Fibrinogen

A)ProlongedProlongedElevatedDecreased
B)NormalProlongedNormalNormal
C)ProlongedProlongedDecreasedIncreased
D)NormalProlongedDecreasedDecreased

Question 27

The type of anemia commonly associated with HUS is:

A)Microcytic,hypochromic
B)Macrocytic,normochromic
C)Normocytic,normochromic
D)Microcytic,normochromic

Question 28

A patient presented with fever,mild anemia,and thrombocytopenia.The peripheral blood smear showed the presence of intracellular organisms that were present as singles,doubles,and tetrads.What is the most likely identification of the organism?

A)Plasmodium falciparum
B)Babesia microti
C)Bartonella bacilliformis
D)Trypanosoma cruzi

Question 29

Describe the mechanism that causes the production of schistocytes in microangiopathic hemolytic anemia.

Question 30

Explain how the action of E.coli O157:H7 toxin is related to the development of HUS.