13 USMLE Pathology, Infectious Disease and Oncology Quick Review Questions with Answers (Set 3)

These 13 quick USMLE review questions test high-yield facts that show up again and again on the exam: muscular dystrophy, carcinoid tumors, gonorrhea, mesothelioma, multiple myeloma, cystic fibrosis, alpha-thalassemia, hemolysis, Waterhouse-Friderichsen syndrome, lupus antibodies, cultures and sickle cell genetics. Each question includes the correct answer.

Written by Dr. Ray Makar, MD, author of the Repeated USMLE Questions eBook series.

Prefer video? Watch daily USMLE case questions on MedFocus by Dr. Ray on YouTube.

How to use this page: read the question, pick your answer, then tap Show Answer and Explanation.

Questions

Question 1. Which one of the following types of protein is the most likely deficient in a case of Duchene muscular dystrophy?

A- Actin
B- Dystrophin
C- Troponin
D- Titin

B- Dystrophin- It anchors actin reinforcing and stabilizing the sarcolemma. Troponin inhibits myosin and actin binding.
The correct answer is B

 

Question 2. Which one of the following locations is the most common site for carcinoid tumors?

A- Appendix
B- Esophagus
C- Colon
D- Small intestine
E- Stomach

A- Appendix-The tip of the appendix is the most common site of carcinoid tumors. They have less risk of malignancy than those originated from the ileum.
The correct answer is A

 

Question 3. A 27-year-old man complains of burning pain during micturition for 3 days. Milking the urethra produces a profuse yellowish discharge. He it treated with ceftriaxone. Which of the following is the most likely causative organism?

A- Hemophilus ducreyi
B- Herpes simplex virus
C- Neisseria gonorrhea
D- Treponema pallidum

C- Neisseria gonorrhea- Acute urethritis due to gonorrhea is a common complication of sexually active males.
The correct answer is C

 

Question 4. A 65-year-old man is diagnosed with mesothelioma. He has a long history of smoking. He works in the shipbuilding industry for 20 years. Which of the following statements is correct about the association of smoking, asbestos exposure and mesothelioma?

A- Asbestos exposure increases the risk of mesothelioma regardless of smoking
B- Both smoking and asbestos exposure are synergistically increase the risk of mesothelioma
C- No relation between smoking or asbestos exposure to mesothelioma
D- Smoking increases the risk of mesothelioma regardless of asbestos exposure

A- Asbestos exposure increases the risk of mesothelioma regardless of smoking- It is not approved that smoking with or without asbestos exposure has any relation to mesothelioma. Prolonged exposure has the same risk as brief exposure. There is also no relationship between the dose of exposure and the risk of mesothelioma.
The correct answer is A

 

Question 5. Which one of the following pathologic findings is most likely seen in the bone marrow biopsy in a patient diagnosed with multiple myeloma?

A- Hypercellularity with many blasts
B- Numerous plasma cells
C- Numerous small mature lymphocytes
D- Reed-Sternberg cells

B- Numerous plasma cells- These appear as lytic bone lesions due to accumulation of plasma cells. Multiple myeloma usually leads to renal failure due to deposition of light chains in the kidneys.
The correct answer is B

 

Question 6. Which one of the following pulmonary abnormalities is a complication of cystic fibrosis?

A- Adenocarcinoma
B- Bronchiectasis
C- Pleural fibrosis
D- Pneumothorax

B- Bronchiectasis- Cystic fibrosis may lead to inflammation and obstruction of bronchi with results in dilation and destruction of these bronchi.
The correct answer is B

 

Question 7. A Southeast Asian woman gives birth to a male infant. Peripheral blood studies show a hematocrit ratio 18% with numerous nucleated red cells, anisocytosis and poikilocytosis. Hemoglobin lacks some chains. Which of the following is the most likely diagnosis?

A- Alpha-thalassemia
B- Glucose-6-phosphate dehydrogenase deficiency
C- Hereditary spherocytosis
D- Sickle cell anemia

A- Alpha-thalassemia- It is common in Southeast Asia. Lack of alpha globulin chain formation is diagnostic.
The correct answer is A

 

Question 8. A college student complains of a recent yellow discoloration of her eyes. She has no change in her stool and she does not drink any alcohols. Her liver enzymes and direct bilirubin are normal while total bilirubin is high. Which of the following is the most likely cause of her jaundice?

A- Alcoholic liver
B- Hemolysis
C- Hepatoma
D- Liver congestion

B- Hemolysis- Destruction of RBCs can lead to high level of indirect bilirubin and jaundice. Liver will not be able to conjugate this large amount of bilirubin leading to accumulation of indirect (unconjugated) bilirubin in the blood. Liver pathology will result in high level of direct (conjugated) bilirubin.
The correct answer is B

 

Question 9. Waterhouse-Friderichsen syndrome is characterized by which of the following conditions?

A- Abdominal pain, diarrhea and leukocytosis
B- Adrenal insufficiency, hypotension and disseminated intravascular coagulation
C- Back pain, fever and night sweats
D- Chest pain, pericardial effusion and persistent fever

B- Adrenal insufficiency, hypotension and disseminated intravascular coagulation- Bacterial infection with some organisms such as Neisseria meningitides can lead to sepsis and massive bleeding into one or both adrenal glands. Hypotension and multiple organ failures may follow.
The correct answer is B

 

Question 10. Which one of the following tests is highly diagnostic of systemic lupus erythematosus (SLE)?

A- Anti-citrullinated protein antibodies
B- Anti-double stranded DNA (Anti-dsDNA)
C- Anti-RNP antibodies
D- Anti-SSA/Ro autoantibodies

B- Anti-double stranded DNA (Anti-dsDNA)- This is the only test on the list that is highly specific to systemic lupus erythematosus.
The correct answer is B

 

Question 11. Which one of the following tests is the most accurate for an infectious disease?

A- Antibiotic sensitivity test
B- Culture
C- Serum IgM level
D- Serum IgG level

B- Culture- It is the most confirmatory test for the organisms that grow in culture including staphylococci and streptococci.
The correct answer is B

 

Question 12. 1 in 13 African American babies is born with sickle cell trait. Which of the following is the chance that a newly married African American couple to have a child affected by sickle cell disease?

A- 1/13
B- 1/26
C- 1/169
D- 1/676

D- 1/676- Each parent has 1/13 chance to be a carrier. Sickle cell disease is an autosomal recessive so; the chance of offspring to have the disease is 1/4. The chance that the child is affected by the disease is 1/13X1/13X1/4= 1/676
The correct answer is D

 

Question 13. Which of the following is the enzymatic defect in cases of xeroderma pigmentosa?

A- DNA polymerase
B- DNA ligase
C- Excision repair enzymes
D- RNA polymerase III

C- Excision repair enzymes- Xeroderma pigmentosa is a genetic disease characterized by inability to remove pyrimidine dimers caused by exposure to ultraviolet light. Excision repair enzymes are responsible for fixing this and are defective in this condition.
The correct answer is C

 

High-yield points from this set

  • Duchenne muscular dystrophy = absent dystrophin.
  • The appendix is a common site of carcinoid tumors.
  • Waterhouse-Friderichsen = meningococcal adrenal hemorrhage and shock.
  • Anti-dsDNA is highly specific for lupus.

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