11 USMLE Step 1 Mixed Review Questions with Answers (Set 12)

These 11 quick USMLE review questions test high-yield facts that show up again and again on the exam: Crohn disease fistulas, acne, swallowed coins, spina bifida, burns, diabetes insipidus testing, diabetic foot ulcers, compartment syndrome, placenta previa, primary sclerosing cholangitis and aversive conditioning. 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 patient presents with recurrent urinary tract infections with episodes of compulsive diarrhea over the past year. Urine sample shows gas bubbles. Which of the following is the most likely initial diagnosis?

A- Crohn’s disease
B- Irritable bowel syndrome
C- Polycystic kidney disease
D- Ulcerative colitis

A- Crohn’s disease- It is characterized by the formation of fistula between different abdominal organs. In this patient there is a fistula between GIT and urinary system.
The correct answer is A

 

Question 2. Which of the following is the appropriate treatment of a moderate case of acne vulgaris?

A- Benzyl peroxide
B- Oral antibiotic and topical therapy
C- Oral isotretinoin
D- Topical antibiotic

B- Oral antibiotic and topical therapy- This treatment is appropriate for a moderate case of acne. Benzyl peroxide and topical antibiotic are used in mild cases. Oral isotretinoin is used for advanced cases of acne.
The correct answer is B

 

Question 3. A toddler swallowed a coin. Which of the following is the most common site of impaction of this coin?

A- Esophagus
B- Ileocecal junction
C- Stomach
D- Transverse colon

A- Esophagus- Esophagus is the most common site of impaction in all ages including adults and infants as well.
The correct answer is A

 

Question 4. A baby is born with a protruding saclike lesion on the lower back. Examination reveals decreased sensations and reduction of tone and strength of both lower extremities. Which of the following is the most appropriate next step in management?

A- Broad-spectrum antibiotics to avoid meningitis
B- Manual compression of the lesion
C- Immediate lumber puncture
D- Urgent surgical interference

D-Urgent surgical interference- This is a severe form of spina bifida called myelomeningocele. It is an emergency as it may affect respiration and vital organs.
The correct answer is D

 

Question 5. A college student presents to the emergency room with burns involving about 10% of his body surface and localized to his upper chest and right arm. His vital signs are within normal limits. The lesions are painful, erythematous and swollen. Application of pressure produces blanching and is painful. Which of the following is the best next step in management?

A- Admission to hospital
B- Broad spectrum antibiotics
C- Cleaning, dressing and analgesics
D- Surgical debridement and grafting

C-Cleaning, dressing and analgesics- This is a second-degree burn that needs cleaning, debridement if needed, dressing and analgesics as needed.
The correct answer is C

 

Question 6. Which one of the following substances is used to differentiate between central and nephrogenic diabetes insipidus?

A- Cortisol
B- Cosyntropin
C- Desmopressin
D- Dexamethasone

C-Desmopressin- If administration of desmopressin improves the condition, it is central. If does not improve it, it is nephrogenic which affects the kidney response to ADH.
The correct answer is C

 

Question 7. A 39-year-old woman presents with an inflamed ulcer on the sole of her foot not healed for 2 months. Peripheral sensations are reduced bilaterally. Elevation of which of the following laboratory tests most likely explains this condition?

A- Alanine aminotransferase (ALT)
B- Blood glucose
C- Serum creatinine
D- Urinary sodium

B- Blood glucose- This is a common presentation of type 11 diabetes. Ulcers are common peripherally because of loss of sensations.
The correct answer is B

 

Question 8. A patient with a history of lower leg fracture presents with severe pain, paresthesia, pallor, poikilothermia, pulselessness and paralysis of the affected leg. Which of the following is the immediate treatment of this case?

A- Fasciotomy and tissue perfusion
B- Intravenous broad-spectrum antibiotics
C- Referral to orthopedics
D- Send home and observation

A-Fasciotomy and tissue perfusion- This is a typical case of compartment syndrome with the 6 Ps. Immediate fasciotomy to decrease pressure and increase tissue prefusion is life saving emergency.
The correct answer is A

 

Question 9. A pregnant female presents on her third trimester with painless, bright bleeding without uterine contractions. It stopped after about one hour. Examination of the fetus reveals no distress. Which of the following is the most appropriate next step?

A- Immediate delivery
B- Hospitalization and observation until labor
C- Transabdominal ultrasonography
D- Vaginal examination

C-Transabdominal ultrasonography- This is most likely a case of placenta previa. It is characterized by painless bleeding that often stops in 1-2 hours. Vaginal exam is contraindicated before determination of placental location by ultrasonography. Other choices may be needed after further investigations but not the next steps.
The correct answer is C

 

Question 10. Which one of the following conditions is most likely associated with ulcerative colitis?

A- Acute cholecystitis
B- Chronic cholelithiasis
C- Gallstone ileus
D- Primary sclerosing cholangitis

D-Primary sclerosing cholangitis- It is common with ulcerative colitis and leads to fibrosis of bile ducts.
The correct answer is D

 

Question 11. A patient is treated for alcoholism by disulfiram. It makes him sick whenever he drinks alcohol. Which of the following types of classical conditioning explains this treatment?

A- Aversive conditioning
B- Exposure
C- Flooding
D- Systemic desensitization

A-Aversive conditioning- It occurs when a stimulus produces undesired behavior is conjugated with an aversive stimulus.
The correct answer is A

 

High-yield points from this set

  • Swallowed coins most often lodge in the esophagus.
  • Compartment syndrome: emergency fasciotomy.
  • Painless third-trimester bleeding = placenta previa; ultrasound before any vaginal exam.
  • Primary sclerosing cholangitis is linked to ulcerative colitis.

Keep practicing

Leave a Comment