11 USMLE Step 1 Mixed Review Questions with Answers (Set 9)

These 11 quick USMLE review questions test high-yield facts that show up again and again on the exam: pyloric stenosis, parietal cells, Budd-Chiari syndrome, dysphagia, alcoholic liver disease, enterovesical fistula, CMV colitis, irritable bowel syndrome, neonatal jaundice and undescended testis. 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. A 2-week-old boy is brought for persistent vomiting of non-bilious material after feeding. The boy is lysergic and dehydrated. Examination reveals presence of an olive-sized mass in the epigastric area moving with peristalsis. What is the most likely diagnosis?

A- Duodenal atresia
B- Esophageal atresia
C- Meckel’s diverticulum
D- Pyloric stenosis

D- Pyloric stenosis- A and C cause similar symptoms but the vomiting would be bilious. B doesn’t show olive-sized mass which is characteristic of pyloric stenosis.
The correct answer is D

 

Question 2. Which of the following is the substance released from the parietal cells of the stomach?

A- Gastrin
B- Hydrochloric acid
C- Mucus
D- Pepsinogen

B- Hydrochloric acid- A is secreted by G cells, C is secreted by goblet cells while D is secreted by chief cells of the stomach.
The correct answer is B

 

Question 3. Which of the following tests is diagnostic in case of a 2-week old boy with persistent vomiting of non-bilious material after feeding?

A- Abdominal ultrasound
B- Barium studies
C- Chest x-ray
D- Esophagostomy

A- Abdominal ultrasound- Hypertrophic pylorus is diagnostic of pyloric stenosis. Other tests are not recommended at this age or not diagnostic of this case.
The correct answer is A

 

Question 4. Which one of the following liver disorders occurs due to hepatic vein thrombosis?

A- Alcoholic hepatitis
B- Budd-Chiari syndrome
C- Fatty liver
D- Pyogenic liver abscess

B- Budd-Chiari syndrome- This leads to severe venous congestion due to hepatic vein thrombosis, predisposed by neoplasms, pregnancy, or polycythemia vera.
The correct answer is B

 

Question 5. A 40-year-old male presents with dysphagia of fluids and solids for 2 months. Which of the following is the most appropriate next step of action?

A- Acid perfusion test
B- Barium swallow
C- Endoscopy
D- Motility studies

B- Barium swallow- It is the first step to detect diverticula to avoid perforation by endoscopy. If dysphagia is for solids only then, endoscopy should be the first step.
The correct answer is B

 

Question 6. Which of the following is the main step in treating alcoholic liver disease?

A- Abstinence
B- Baclofen
C- Disulfiram
D- Naltrexone

A- Abstinence- It is the mainstay of the treatment of alcoholic liver diseases. Drugs are used as supportive.
The correct answer is A

 

Question 7. A patient complains of worsening diarrhea over the past three months. He has a history of recurrent urinary tract infection and joint pain affecting numerous joints. A urine sample shows pneumaturia. Which of the following is the most likely cause of this patient’s symptoms?

A- Enterovesical fistula
B- Pseudomembranous colitis
C- Renal stones
D- Ulcerative colitis

A- Enterovesical fistula- This is most likely a case of Crohn’s disease leading to formation of this fistula. Fistulas don’t occur in ulcerative colitis.
The correct answer is A

 

Question 8. A patient with HIV history develops fecal urgency and bloody diarrhea. Which of the following is the most likely causative organism?

A- Entamoeba histolytica
B- Clostridium difficile
C- Cytomegalovirus
D- Giardia lamblia

C- Cytomegalovirus
The correct answer is C

 

Question 9. Which one of the following gastrointestinal conditions is NOT associated with blood in stools?

A- Cancer colon
B- Diverticulosis
C- Irritable bowel syndrome
D- Ulcerative colitis

C- Irritable bowel syndrome
The correct answer is C

 

Question 10. Which of the following differentiates physiologic jaundice from pathologic jaundice?

A- Bilirubin in physiologic jaundice rises higher than 5 mg/dL/day
B- Bilirubin peaks at higher levels (> 15 mg/dL) in physiologic jaundice
C- Direct bilirubin is lower than 10% of total bilirubin in physiologic jaundice
D- Physiologic jaundice is present in the first 24 hours of life

C- Direct bilirubin is lower than 10% of total bilirubin in physiologic jaundice- Physiologic jaundice is not present until 72 hours after birth. It resolves one week after onset in term infants and 2 weeks in premature infants.
The correct answer is C

 

Question 11. A newborn presents with the absence of the contents of the left scrotal sac. There is no other abnormality. Which of the following is the most likely diagnosis?

A- Agenesis
B- Hypopituitarism
C- Hypospadias
D- Undescended testis

D- Undescended testis- Descent of one or both testes may be delayed and this is the most common cause of otherwise normal newborn.
The correct answer is D

 

High-yield points from this set

  • Projectile non-bilious vomiting at 2–6 weeks = pyloric stenosis; confirm with ultrasound.
  • Budd-Chiari syndrome = hepatic vein thrombosis.
  • Irritable bowel syndrome does not cause rectal bleeding.
  • Pathologic neonatal jaundice: direct bilirubin above 10–20% of total.

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