USMLE STEP3 Exam
Step3 (Page 27 )

Updated On: 12-Feb-2026

A21-year-old Asian female, with past medical history of exertional asthma, comes to your office complaining of mild low back pain. It started after her working out in the gym 3 days ago. The pain is 24 out of 10 in intensity, has no radiation, increases with bending or lying down for a long time, and improves with warm showers. You examine the patient, diagnose her with paravertebral muscle spasm, and give her prescriptions for cyclobenzaprine and naproxen to use as needed for pain and stiffness. You receive a call from your patient 2 hours later. She is having generalized itching, dizziness, and swelling of the tongue and lips. She is having difficulty breathing. She tells you that she took the first dose of the medication you prescribed about 30 minutes ago.

What should you do at this time?

  1. Advise patient to use her albuterol inhaler as she is having an asthma attack.
  2. Advise her to take another dose of naproxen and stop cyclobenzaprine for now.
  3. Assure her that this is a common side effect to cyclobenzaprine; she will get used to it as she takes the next dose.
  4. Ask her to return to your clinic for evaluation.
  5. Ask her to call 911 immediately.

Answer(s): E

Explanation:

This patient is exhibiting signs and symptoms of an anaphylactic reaction, likely to one of the medications that she recently took. Angioedema is occurring (swelling of the lips and tongue). Her dyspnea may be a manifestation of laryngeal edema or of bronchospasm. She is at high risk for respiratory compromise and, therefore, of the options listed, having her activate the emergency medical system is the most appropriate. Calling 911 from your office would be another option. Of the interventions listed, epinephrine would provide the most benefit in correcting the underlying problem. The alpha- and betaadrenergic effects result in vasoconstriction, bronchial smooth-muscle relaxation, and reduction on vascular permeability. Oxygen may be required if the patient is hypoxic, IV fluids may be necessary for persistent hypotension and albuterol may benefit the treatment of bronchospasm, but epinephrine would most immediately address the multiple systemic effects of anaphylaxis.



A21-year-old Asian female, with past medical history of exertional asthma, comes to your office complaining of mild low back pain. It started after her working out in the gym 3 days ago. The pain is 24 out of 10 in intensity, has no radiation, increases with bending or lying down for a long time, and improves with warm showers. You examine the patient, diagnose her with paravertebral muscle spasm, and give her prescriptions for cyclobenzaprine and naproxen to use as needed for pain and stiffness. You receive a call from your patient 2 hours later. She is having generalized itching, dizziness, and swelling of the tongue and lips. She is having difficulty breathing. She tells you that she took the first dose of the medication you prescribed about 30 minutes ago. The most beneficial immediate intervention for this patient would be which of the following?

  1. oxygen
  2. albuterol nebulizer treatment
  3. IV fluids
  4. epinephrine
  5. diphenhydramine

Answer(s): D

Explanation:

This patient is exhibiting signs and symptoms of an anaphylactic reaction, likely to one of the medications that she recently took. Angioedema is occurring (swelling of the lips and tongue). Her dyspnea may be a manifestation of laryngeal edema or of bronchospasm. She is at high risk for respiratory compromise and, therefore, of the options listed, having her activate the emergency medical system is the most appropriate. Calling 911 from your office would be another option. Of the interventions listed, epinephrine would provide the most benefit in correcting the underlying problem. The alpha- and betaadrenergic effects result in vasoconstriction, bronchial smooth-muscle relaxation, and reduction on vascular permeability. Oxygen may be required if the patient is hypoxic, IV fluids may be necessary for persistent hypotension and albuterol may benefit the treatment of bronchospasm, but epinephrine would most immediately address the multiple systemic effects of anaphylaxis



A 34-year-old male presents with a penile lesion. Your history, physical examination, and serology confirm a diagnosis of syphilis. The patient reports that his mother told him he was "allergic" to penicillin. He does not recall any personal history of anaphylaxis or rash to antibiotics however he has never been "sick." How would you manage this patient?

  1. Admit to the ICU for penicillin desensitization as you don't want to risk anaphylaxis especially with the uncertain history.
  2. Do skin testing for penicillin allergy.
  3. Avoid penicillin or cephalosporins in future.
  4. Treat with erythromycin.
  5. Treat with penicillin as he is not likely to have a true allergy.

Answer(s): B

Explanation:

A questionable history of penicillin allergy by a patient often incorrectly labels patients as penicillin allergic. Physicians are often afraid of a true anaphylactic reaction and turn to a second-line medication. Most patients who state they were penicillin allergic or were told by a parent they were allergic were confusing a complication of the illness, such as a rash from viral prodrome. In fact, 80 90% of patients who self-report a nonanaphylactic reaction or were informed by a parent of a penicillin allergy are not penicillin allergic when assessed with skin allergy testing. The frequency of all adverse reactions to penicillin in the general population ranges from 0.7 to 10%. Approximately 98% of patients with a reported history of penicillin allergy (except anaphylaxis) and a negative skin test can safely receive penicillin. In patients who have an unclear history of penicillin allergy (pretest likelihood greater than that of general population) and who would benefit from penicillin, skin testing should be performed and penicillin used for patients with negative results. If however, the pretest likelihood of allergy is similar to the prevalence in the general population, skin testing can be foregone, and treatment with penicillin offered. In patients with definite penicillin allergy or anaphylaxis in whom penicillin therapy is the only option, inpatient admission for penicillin desensitization is warranted.



A57-year-old male presents for annual examination. On history, you note a history of colon cancer that was successfully surgically resected 2 years ago. He had a negative postoperative colonoscopy 6 months later and another negative colonoscopy last year. Which of the following would be the most appropriate colon cancer screening regimen for this patient?

  1. colonoscopy or virtual colonoscopy in 1 year
  2. colonoscopy in 3 years
  3. colonoscopy or double contrast barium enema in 5 years
  4. colonoscopy annually
  5. digital examination and fecal occult blood test (FOBT) annually with colonoscopy in 10 years

Answer(s): B

Explanation:

As per the American Cancer Society, American College of Colorectal Surgery, and the American College of Gastroenterology, the colon cancer screening guidelines for persons with prior history of colon cancer are as follows:
· Initially, a "clearing" colonoscopy should be performed to evaluate for synchronous disease located elsewhere in the colon. If the cancer is not obstructing, this can be done with a preoperative colonoscopy. If it is obstructing, CT colonography (virtual colonoscopy) or barium enema can be used preoperatively and colonoscopy can be performed either intraoperatively or 36 months postoperatively. · If curative resection is performed for colon or rectal cancer, a follow-up colonoscopy should be performed 1 year postoperatively. If this is normal, the next scope should be 3 years later. If all endoscopy is normal then a subsequent interval of 5 years is recommened.



A19-year-old male who moved to your city 3 months ago comes to your office complaining of dry cough for the past 23 months. Along with the cough, he has had some shortness of breath with exertion. He denies fever, chills, nausea, vomiting, wheezing, and sneezing. The cough occurs mostly in the morning and improves as the day goes on. He denies similar complaints in the past and has no history of allergies. He says that his father had eczema and an allergy to eggs. You order a CXR. Which of the following are you most likely to find?

  1. normal
  2. diffuse pulmonary congestion
  3. increased bronchial wall markings
  4. cardiomegaly
  5. flattening of the diaphragms

Answer(s): A

Explanation:

This patient is manifesting symptoms consistent with asthma. With the history of recently moving to a new area, along with a family history of allergies and eczema, his asthma may be further classified as allergic asthma. Episodic symptoms of cough, dyspnea, and wheezing are likely to occur. The diagnosis of asthma is made by demonstrating reversible airway obstruction. Airway obstruction is likely to be manifested by a reduction in the FEV1. An increase in the FEV1 of 15% after the use of a bronchodilator is the definition of reversibility. A CXR is most likely to be normal. Numerous cardiac conditions, such as CHF, cardiomyopathies, or pericardial effusions, may result in cardiomegaly on a CXR. Diffuse infiltrates may be seen with infections, interstitial lung disease, or other conditions. Flattened diaphragms would be consistent with prolonged obstructive lung disease, such as emphysema. The treatment of choice for the prevention of symptoms in all stages of asthma other than mild intermittent is inhaled steroid. All patients with asthma should also have a short-acting bronchodilator for acute symptomatic relief. A leukotriene modifier would be an alternative recommendation and might be a good addition to an inhaled steroid, as they also have FDA indications for patients with allergic rhinitis.






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