Deck 17: Hemolytic Anemia: Nonimmune Defects

Question 1

Damage to the endothelial lining of the small vessels results in deposits of fibrin with the vessels in what type of hemolytic anemia?

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

Answer 1

Microangiopathic hemolytic anemia

Question 2

Which of the following findings on the peripheral blood smear are typically associated with DIC?

A)Target cells
B)Schistocytes and thrombocytopenia
C)Helmet cells
D)Spherocytes and polychromasia

Answer 2

Schistocytes and thrombocytopenia

Question 3

Which of the following analytes would be increased in MAHA?

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

Answer 3

Bilirubin

Question 4

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

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

Question 5

A child presents to the 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.These findings are associated with what diagnosis? ?

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

Question 6

A 7-year-old girl is brought to a physician due to 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 7

Which of the following analytes would be decreased in HUS?

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

Question 8

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, schistocytes present reticulocytopenia
C)Abundance of schistocytes, thrombocytosis and leukopenia
D)Nucleated erythrocytes, Howell-Jolly bodies and absence of schistocytes

Question 9

What 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 10

The destruction of erythrocytes in MAHA is primarily due to what mechanism?

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

Question 11

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 12

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 13

Which of the following mechanisms is thought to cause exercise-induced hemoglobinuria?

A)Erythrocyte membrane protein changes
B)Oxidative stress and erythrocyte age
C)Excessive thermal buildup and damage to membranes
D)Foot strike damage

Question 14

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

A)Spherocytes.
B)Reticulocytes.
C)Schistocytes.
D)Keratorcytes.

Question 15

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

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

Question 16

All of the following can lead to the formation of schistocytes EXCEPT:

A)DIC.
B)Malignant hypertension.
C)Insertion of prosthetic heart valves.
D)AIHA.

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

Which of the following laboratory findings are similar 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, and increase in haptoglobin
D)Decreased total and unconjugated serum bilirubin, and decreased haptoglobin

Question 19

Laboratory testing in DIC helps distinguish this condition from others.Which of the following would be expected results 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 20

Which of the following results would typically be found in HUS?

$\begin{array}{ll}{\text { PT }} & \text { PTT } \\ \hline\text { a. Prolonged } & \text { prolonged } \\\text { b. Normal } & \text { prolonged } \\\text { c. Prolonged } & \text { prolonged } \\\text { d. Normal } & \text { normal }\end{array}$

Question 21

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

Question 22

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: $\begin{array}{|l|l|}\hline\text { TEST } & \text { RESULT } \\\hline \text { RBC } & 4.30 \times 10^{12} / \mathrm{L} \text { (moderate schistocytes }\\&\text { present on peripheral blood smear) }\\\hline \text { WBC } & 5.00 \times 10^{9} / \mathrm{L} \\\hline \text { PLT } & 28 \times 10^{9} / \mathrm{L} \\\hline \text { HGB } & 13.0 \mathrm{~g} / \mathrm{dL} \\\hline \text { HCT } & 39 \% \\\hline \text { MCV } & 89 \mathrm{fl} \\\hline \text { MCH } & 28 \mathrm{pg} \\\hline \text { MCHC } & 33 \% \\\hline \text { BUN } & 85 \mathrm{mg} / \mathrm{dL}(\mathrm{RR}: 8-24 \mathrm{mg} / \mathrm{dL}) \\\hline \text { CREAT } & 3.3 \mathrm{mg} / \mathrm{dL}(\mathrm{RR}: 0.2-1.3 \mathrm{mg} / \mathrm{dL})\\\hline\end{array}$
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

Question 23

A runner is in training for the Chicago Marathon.After his most recent 26 mile run, he notices that his urine is reddish-brown.By the next morning his urine is clear and yellow but he decides 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 due to dehydration.
B)This is exercise induced hemoglobinuria.
C)There were uric acid crystals precipitated in the initial urine.
D)There is insufficient information to determine the reason.

Question 24

A woman visits her obstetrician for a routine prenatal visit at 24 weeks.Her blood pressure is 180/100 and her urinalysis shows 3+ protein.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 25

A patient who presents with DIC would most likely have which of the following sets of coagulation test results? $\begin{array}{llll}&\text { PT } & \text { PTT } & \text { D-dimer } & \text { Fibrinogen } \\\hline a.&\text { Prolonged } & \text { prolonged } & \text { elevated } & \text { decreased } \\b.&\text { Normal } & \text { prolonged } & \text { normal } & \text { normal } \\c.&\text { Prolonged } & \text { prolonged } & \text { decreased } & \text { increased } \\d.&\text { Normal } & \text { prolonged } & \text { decreased } & \text { decreased }\end{array}$

Question 26

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 x 109/L, a hemoglobin of 9.0 gm/dl, WBC count of 22x 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 27

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 sp.
B)Babesia microti
C)Bartonella bacilliformis
D)Trypanosoma cruzi

Question 28

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

Question 29

The underlying cause of TTP is:

A)An unregulated coagulation cascade.
B)Deficiency in vWF multimers.
C)Deficiency of ADAMTS13 protease.
D)Overproduction of cryoprecipitate.

Question 30

The type of anemia commonly associated with HUS is:

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

Question 31

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 32

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