USMLE Step 3 Exam Questions and Answers (2025
Edition) – Full-Length Clinical Case-Based Q&A with
CCS Scenarios, Verified Answers
1. A 75-year-old man is brought to the emergency department by his son 2 hours after the sudden onset of fever, chills, pleuritic
chest pain, and cough productive of rust-colored sputum. He rates his chest pain as an 8 on a 10-point scale. Temperature is
38.9°C (102°F), pulse is 106/min, respirations are 22/min, and blood pressure is 130/80 mm Hg. Oxygen saturation is 94%
on room air. The patient appears to be in moderate respiratory distress. Physical examination shows splinting on the left side.
There is dullness to percussion and egophony over the left lower lobe. Abdominal examination shows no abnormalities.
Results of laboratory studies are shown:
Serum
Calcium 8.4 mg/dL
Urea nitrogen 18 mg/dL
Creatinine 1.4 mg/dL
Na+ 131 mEq/L
K+ 4.1 mEq/L
Cl− 108 mEq/L
HCO3− 25 mEq/L
Blood
Hematocrit 37%
Hemoglobin 12.4 g/dL
WBC 21,000/mm3
Neutrophils, segmented 79%
Neutrophils, bands 10%
Lymphocytes 11%
Platelet count 250,000/mm3
Arterial blood gas analysis on room air:
pH 7.45
PCO2 45 mm Hg
PO2 62 mm Hg
HCO3− 24 mEq/L
O2 saturation 95%
Urinalysis shows no abnormalities. An ECG shows sinus tachycardia. A chest x-ray shows consolidation in the left lower
lobe and no cardiomegaly. Intravenous antibiotics are administered, and the patient receives oxygen via nasal cannula. Three
hours later, he is lying on his left side and has increased dyspnea; he is rolled to his right side and his symptoms improve
within minutes. Which of the following best explains this improvement?
(A) Positionally apparent pulmonary emboli
(B) Positionally decreased alveolar-arterial gradient
(C) Positionally impeded filling of the left ventricle
(D) Positionally impeded movement of the diaphragm
(E) Positionally increased left pleural effusion
2. A 55-year-old woman, gravida 4, para 4, comes to the office because of vaginal spotting that has occurred once monthly for
the past 2 months. Menopause occurred 1 year ago, and this is the patient's first postmenopausal examination. Medical
history is significant for elevated blood pressure readings during the past 2 years and diabetes mellitus for which she follows
an 1800-calorie diet. She takes no medications. Her most recent cervical cytology and mammography obtained 1 year ago
disclosed no abnormalities. Family history is significant for hypertension in her mother who died at age 58 years from an
unknown cancer. The patient has smoked one pack of cigarettes daily for the past 30 years and drinks beer occasionally. BMI
1
, is 42 kg/m2. Temperature is 36.7°C (98.0°F), pulse is 90/min, respirations are 16/min, and blood pressure is 136/84 mm Hg.
Bimanual examination discloses a firm, smooth, mobile, nontender uterus that is consistent in size with a 6-week gestation.
The remainder of the physical examination discloses no abnormalities. Results of dipstick urinalysis are within the reference
ranges; fingerstick hematocrit is 35% and 2-hour postprandial serum glucose concentration is 188 mg/dL. Which of the
following is the most appropriate diagnostic study at this time?
(A) Complete blood count
(B) CT scan of the pelvis
(C) Endometrial biopsy
(D) Hysterosalpingography
(E) Serum CA 125 concentration
3. A 28-year-old woman comes to the health center for an initial visit. The patient appears somewhat anxious. After
introductions she says, "Doctor, something has been happening to me for the past 6 weeks or so that has me a bit scared.
About once or twice a week, and out of nowhere and for no reason, I have this sudden feeling of anxiety. It really gets severe
and I get short of breath. I just don't know what's going on." She has recently divorced her husband of 7 years. Given the
evidence at this time, which of the following is the most likely diagnosis?
(A) Adjustment disorder with anxiety
(B) Agoraphobia
(C) Dysthymic disorder
(D) Generalized anxiety disorder
(E) Posttraumatic stress disorder
4. A 71-year-old woman with a 15-year history of severe chronic obstructive pulmonary disease (COPD) is admitted to the
intensive care unit for treatment of an acute COPD exacerbation. The patient has been receiving home oxygen therapy for the
past 3 years; FEV11 year ago was 27%. She has a do-not-resuscitate order stating that she does not want cardiopulmonary
resuscitation, with no specific comment on intubation. Her daughter, who is not present, has power of attorney for the
patient's health care decisions, although the patient has made all decisions in the past. Medical history also is significant for
hypertension. Medications are lisinopril and hydrochlorothiazide, as well as inhaled tiotropium, albuterol, and fluticasone.
The patient is intubated and mechanical ventilation is begun. She is treated with antibiotics, corticosteroids, and nebulized
bronchodilators. Her condition gradually improves and she is extubated 4 days later. Within 2 hours of extubation, the patient
becomes short of breath and has difficulty clearing her secretions. She is not using accessory muscles of respiration.
Temperature is 37.0°C (98.6°F), pulse is 98/min, respirations are 25/min, and blood pressure is 168/98 mm Hg. Oxygen
saturation is 89% on oxygen at 6 L/min. The patient is alert, fully oriented, and conversant. Results of arterial blood gas
analysis are shown:
PO2 61 mm Hg
PCO2 55 mm Hg
pH 7.32
An attempt is made to manage the patient with noninvasive positive pressure ventilation, but the patient reports discomfort
caused by the mask and requests that it be removed. When initially asked, she declines to be reintubated. Which of the
following is the most appropriate next step in management?
(A) Clearly state to the patient that if she again declines intubation when offered to her one more time, she will receive
comfort care only
(B) Contact the patient's daughter to request additional information regarding the patient's previous feelings regarding
intubation
(C) Explain to the patient that because her advance directive is confusing, discussing her options would be helpful
(D) Proceed with reintubating the patient
(E) Request psychiatric evaluation of the patient's capacity to make health care decisions
2
,5. A phase 3 trial is planned to investigate the use of a new medication for the prevention of type 2 diabetes mellitus. Which of
the following inclusion criteria should be selected to design the most efficient study?
(A) Patients aged 18 years and older who have a BMI of less than 23 kg/m2 and are smokers
(B) Patients aged 18 years and older with no significant medical history
(C) Patients aged 45 years and older with hyperlipidemia and central obesity
(D) Patients aged 65 years and older with a hemoglobin A1c of 6.5% or greater
6. A 60-year-old man is admitted to the hospital 4 hours after he awoke early this morning with shortness of breath, dizziness,
and pleuritic chest pain. Medical history is significant for coronary artery disease, hyperlipidemia, and chronic obstructive
pulmonary disease. Medications are atorvastatin, enteric-coated 81-mg aspirin, atenolol, albuterol, ipratropium, and home
oxygen at 1 L/min via nasal cannula. He has not had any recent illness or exposure to anyone known to be ill. He has smoked
one pack of cigarettes daily for the past 40 years and he drinks three to four alcoholic beverages monthly. BMI is 21 kg/m2.
Temperature is 36.9°C (98.4°F), pulse is 150/min, respirations are 36/min, and blood pressure is 105/72 mm Hg. Oxygen
saturation is 84% on oxygen at 1 L/min via nasal cannula. The patient appears uncomfortable and is speaking in three- to
four-word sentences. Jugular venous pressure is 10 cm H2O at 45 degrees. Auscultation of the lungs discloses poor air
movement and diffuse scattered inspiratory wheezes bilaterally. Cardiac examination discloses a palpable parasternal lift.
The abdomen is protuberant with a visible fluid wave and a palpable epigastric pulsation. The liver edge is palpated 3 cm
below the right costal margin and the area is tender. Examination of the lower extremities shows 2+ bilateral pitting edema.
Chest x-ray and ECG are shown. Which of the following is the most likely underlying explanation for this patient's
condition?
3
, (A) External compression of the superior vena cava
(B) Helicobacter pylori infection with transmural ulceration and peritoneal leaking
(C) Lactic acidosis caused by systemic hypoperfusion
(D) Pulmonary vasculature compromise and cor pulmonale
(E) Widespread hepatocellular necrosis and parenchymal edema
4
Edition) – Full-Length Clinical Case-Based Q&A with
CCS Scenarios, Verified Answers
1. A 75-year-old man is brought to the emergency department by his son 2 hours after the sudden onset of fever, chills, pleuritic
chest pain, and cough productive of rust-colored sputum. He rates his chest pain as an 8 on a 10-point scale. Temperature is
38.9°C (102°F), pulse is 106/min, respirations are 22/min, and blood pressure is 130/80 mm Hg. Oxygen saturation is 94%
on room air. The patient appears to be in moderate respiratory distress. Physical examination shows splinting on the left side.
There is dullness to percussion and egophony over the left lower lobe. Abdominal examination shows no abnormalities.
Results of laboratory studies are shown:
Serum
Calcium 8.4 mg/dL
Urea nitrogen 18 mg/dL
Creatinine 1.4 mg/dL
Na+ 131 mEq/L
K+ 4.1 mEq/L
Cl− 108 mEq/L
HCO3− 25 mEq/L
Blood
Hematocrit 37%
Hemoglobin 12.4 g/dL
WBC 21,000/mm3
Neutrophils, segmented 79%
Neutrophils, bands 10%
Lymphocytes 11%
Platelet count 250,000/mm3
Arterial blood gas analysis on room air:
pH 7.45
PCO2 45 mm Hg
PO2 62 mm Hg
HCO3− 24 mEq/L
O2 saturation 95%
Urinalysis shows no abnormalities. An ECG shows sinus tachycardia. A chest x-ray shows consolidation in the left lower
lobe and no cardiomegaly. Intravenous antibiotics are administered, and the patient receives oxygen via nasal cannula. Three
hours later, he is lying on his left side and has increased dyspnea; he is rolled to his right side and his symptoms improve
within minutes. Which of the following best explains this improvement?
(A) Positionally apparent pulmonary emboli
(B) Positionally decreased alveolar-arterial gradient
(C) Positionally impeded filling of the left ventricle
(D) Positionally impeded movement of the diaphragm
(E) Positionally increased left pleural effusion
2. A 55-year-old woman, gravida 4, para 4, comes to the office because of vaginal spotting that has occurred once monthly for
the past 2 months. Menopause occurred 1 year ago, and this is the patient's first postmenopausal examination. Medical
history is significant for elevated blood pressure readings during the past 2 years and diabetes mellitus for which she follows
an 1800-calorie diet. She takes no medications. Her most recent cervical cytology and mammography obtained 1 year ago
disclosed no abnormalities. Family history is significant for hypertension in her mother who died at age 58 years from an
unknown cancer. The patient has smoked one pack of cigarettes daily for the past 30 years and drinks beer occasionally. BMI
1
, is 42 kg/m2. Temperature is 36.7°C (98.0°F), pulse is 90/min, respirations are 16/min, and blood pressure is 136/84 mm Hg.
Bimanual examination discloses a firm, smooth, mobile, nontender uterus that is consistent in size with a 6-week gestation.
The remainder of the physical examination discloses no abnormalities. Results of dipstick urinalysis are within the reference
ranges; fingerstick hematocrit is 35% and 2-hour postprandial serum glucose concentration is 188 mg/dL. Which of the
following is the most appropriate diagnostic study at this time?
(A) Complete blood count
(B) CT scan of the pelvis
(C) Endometrial biopsy
(D) Hysterosalpingography
(E) Serum CA 125 concentration
3. A 28-year-old woman comes to the health center for an initial visit. The patient appears somewhat anxious. After
introductions she says, "Doctor, something has been happening to me for the past 6 weeks or so that has me a bit scared.
About once or twice a week, and out of nowhere and for no reason, I have this sudden feeling of anxiety. It really gets severe
and I get short of breath. I just don't know what's going on." She has recently divorced her husband of 7 years. Given the
evidence at this time, which of the following is the most likely diagnosis?
(A) Adjustment disorder with anxiety
(B) Agoraphobia
(C) Dysthymic disorder
(D) Generalized anxiety disorder
(E) Posttraumatic stress disorder
4. A 71-year-old woman with a 15-year history of severe chronic obstructive pulmonary disease (COPD) is admitted to the
intensive care unit for treatment of an acute COPD exacerbation. The patient has been receiving home oxygen therapy for the
past 3 years; FEV11 year ago was 27%. She has a do-not-resuscitate order stating that she does not want cardiopulmonary
resuscitation, with no specific comment on intubation. Her daughter, who is not present, has power of attorney for the
patient's health care decisions, although the patient has made all decisions in the past. Medical history also is significant for
hypertension. Medications are lisinopril and hydrochlorothiazide, as well as inhaled tiotropium, albuterol, and fluticasone.
The patient is intubated and mechanical ventilation is begun. She is treated with antibiotics, corticosteroids, and nebulized
bronchodilators. Her condition gradually improves and she is extubated 4 days later. Within 2 hours of extubation, the patient
becomes short of breath and has difficulty clearing her secretions. She is not using accessory muscles of respiration.
Temperature is 37.0°C (98.6°F), pulse is 98/min, respirations are 25/min, and blood pressure is 168/98 mm Hg. Oxygen
saturation is 89% on oxygen at 6 L/min. The patient is alert, fully oriented, and conversant. Results of arterial blood gas
analysis are shown:
PO2 61 mm Hg
PCO2 55 mm Hg
pH 7.32
An attempt is made to manage the patient with noninvasive positive pressure ventilation, but the patient reports discomfort
caused by the mask and requests that it be removed. When initially asked, she declines to be reintubated. Which of the
following is the most appropriate next step in management?
(A) Clearly state to the patient that if she again declines intubation when offered to her one more time, she will receive
comfort care only
(B) Contact the patient's daughter to request additional information regarding the patient's previous feelings regarding
intubation
(C) Explain to the patient that because her advance directive is confusing, discussing her options would be helpful
(D) Proceed with reintubating the patient
(E) Request psychiatric evaluation of the patient's capacity to make health care decisions
2
,5. A phase 3 trial is planned to investigate the use of a new medication for the prevention of type 2 diabetes mellitus. Which of
the following inclusion criteria should be selected to design the most efficient study?
(A) Patients aged 18 years and older who have a BMI of less than 23 kg/m2 and are smokers
(B) Patients aged 18 years and older with no significant medical history
(C) Patients aged 45 years and older with hyperlipidemia and central obesity
(D) Patients aged 65 years and older with a hemoglobin A1c of 6.5% or greater
6. A 60-year-old man is admitted to the hospital 4 hours after he awoke early this morning with shortness of breath, dizziness,
and pleuritic chest pain. Medical history is significant for coronary artery disease, hyperlipidemia, and chronic obstructive
pulmonary disease. Medications are atorvastatin, enteric-coated 81-mg aspirin, atenolol, albuterol, ipratropium, and home
oxygen at 1 L/min via nasal cannula. He has not had any recent illness or exposure to anyone known to be ill. He has smoked
one pack of cigarettes daily for the past 40 years and he drinks three to four alcoholic beverages monthly. BMI is 21 kg/m2.
Temperature is 36.9°C (98.4°F), pulse is 150/min, respirations are 36/min, and blood pressure is 105/72 mm Hg. Oxygen
saturation is 84% on oxygen at 1 L/min via nasal cannula. The patient appears uncomfortable and is speaking in three- to
four-word sentences. Jugular venous pressure is 10 cm H2O at 45 degrees. Auscultation of the lungs discloses poor air
movement and diffuse scattered inspiratory wheezes bilaterally. Cardiac examination discloses a palpable parasternal lift.
The abdomen is protuberant with a visible fluid wave and a palpable epigastric pulsation. The liver edge is palpated 3 cm
below the right costal margin and the area is tender. Examination of the lower extremities shows 2+ bilateral pitting edema.
Chest x-ray and ECG are shown. Which of the following is the most likely underlying explanation for this patient's
condition?
3
, (A) External compression of the superior vena cava
(B) Helicobacter pylori infection with transmural ulceration and peritoneal leaking
(C) Lactic acidosis caused by systemic hypoperfusion
(D) Pulmonary vasculature compromise and cor pulmonale
(E) Widespread hepatocellular necrosis and parenchymal edema
4
