Medicine — USMLE Step style

Las preguntas del cuestionario

1. 1. A 67-year-old woman comes to the physician for a follow-up examination. She had a pulmonary embolism and required treatment in the hospital for 3 weeks. She had a retroperitoneal hemorrhage; anticoagulant therapy was temporarily discontinued, and she underwent placement of an inferior vena cava (IVC) filter. She had a hematoma that was resolving on discharge from the hospital 2 weeks ago. Today, she says she has had a persistent sensation of tingling and numbness of her left thigh that she did not report in the hospital because she thought it would go away; the sensation has improved somewhat during the past week. Her only medication is warfarin. Vital signs are within normal limits. Examination of the skin shows no abnormalities. Muscle strength is normal. Sensation to light touch is decreased over a 5 x 5-cm area on the lateral aspect of the left anterior thigh. Which of the following is the most likely cause of this patient's decreased sensation?
   1. Cerebral infarction during the hospitalization
   2. Complication of the IVC filter placement
   3. Compression of the lateral femoral cutaneous nerve
   4. Hematoma of the left thigh
2. 2. A 25-year-old gravida 3 para 2 female is admitted to the hospital at 39 weeks' gestation in active labor. She had been having regular contractions every 4 minutes, but is now having only a few intermittent, weak contractions. She has received medication for pain twice in the past 6 hours. Examination shows no reason for obstructed labor. The fetal head is engaged, the membranes are intact, the fetal heart tones are normal, and the cervix is 100% effaced and 7 cm dilated. The most likely diagnosis is
   1. Braxton Hicks contractions
   2. lower uterine retraction ring
   3. hypotonic uterine dysfunction
   4. primary dysfunctional labor
3. 3. A 5-year-old boy is brought to the physician by his mother because of a 2-day history of a low-grade fever, cough, and runny nose. His temperature is 38°C (100.4°F). Examination findings are consistent with a diagnosis of a common cold. The physician refers to a randomized, double-blind, placebo-controlled clinical trial that evaluated the effectiveness of a new drug for the treatment of the common cold. The mean time for resolution of symptoms for patients receiving the new drug was 6.4 days, compared with a mean time of 6.7 days for patients receiving the placebo (p=0.04). Which of the following is the most appropriate interpretation of these study results?
   1. The findings are clinically and statistically significant
   2. The findings are clinically insignificant but statistically significant
   3. The findings are clinically significant but statistically insignificant
   4. The findings are neither clinically nor statistically significant
4. 4. A 9-year-old boy is brought to the office by his parents for a well-child examination. The patient and his family immigrated to the United States 2 months ago and he has not been evaluated by a physician in 4 years. He has been generally healthy. Medical history is significant for pneumonia at age 3 years. He takes no medications. He is at the 25th percentile for height, weight, and BMI. Vital signs are temperature 37.0°C (98.6°F), pulse 82/min, respirations 20/min, and blood pressure 112/74 mm Hg. Cardiac examination discloses a grade 3/6 systolic murmur audible along the left sternal border at the third and fourth intercostal spaces. Femoral pulses are weak and brachial pulses are strong; there is a radiofemoral delay. Chest xray discloses mild cardiomegaly with left ventricular prominence. ECG shows left ventricular hypertrophy. This patient is at greatest risk for which of the following complications?
   1. Atrial fibrillation
   2. Cor pulmonale
   3. Systemic hypertension
   4. Tricuspid valve regurgitation
5. 5. A 25-year-old woman comes to the physician because of a 2-month history of numbness in her right hand. During this period, she has had tingling in the right ring and small fingers most of the time. She has no history of serious illness and takes no medications. She is employed as a cashier and uses a computer at home. She played as a pitcher in a softball league for 5 years until she stopped 2 years ago. Vital signs are within normal limits. Examination shows full muscle strength. Palpation of the right elbow produces a jolt of severe pain in the right ring and small fingers. Sensation to pinprick and light touch is decreased over the medial half of the right ring finger and the entire small finger. The most likely cause of these findings is entrapment of which of the following on the right?
   1. Median nerve at the wrist
   2. Musculocutaneous nerve at the forearm
   3. Radial nerve at the forearm
   4. Ulnar nerve at the elbow
6. 6. Six healthy subjects participate in a study of muscle metabolism during which hyperglycemia and hyperinsulinemia is induced. Muscle biopsy specimens obtained from the subjects during the resting state show significantly increased concentrations of malonyl-CoA. The increased malonyl-CoA concentration most likely directly inhibits which of the following processes in these subjects?
   1. Fatty acid oxidation
   2. Fatty acid synthesis
   3. Gluconeogenesis
   4. Glycogenolysis
7. 7. A 72-year-old woman with advanced ovarian cancer metastatic to the liver is brought to the physician by her son because she cries all the time and will not get out of bed. On a 10-point scale, she rates the pain as a 1 to 2. She also has hypertension and major depressive disorder. She has received chemotherapy for 2 years. Current medications also include oxycodone (10 mg twice daily), hydrochlorothiazide (25 mg/d), and fluoxetine (20 mg/d). She is 165 cm (5 ft 5 in) tall and weighs 66 kg (145 lb); BMI is 24 kg/m2 . Her temperature is 37°C (98.6°F), pulse is 110/min, respirations are 12/min, and blood pressure is 120/80 mm Hg. Examination shows a firm, distended abdomen with moderate tenderness over the liver. On mental status examination, she is oriented to person, place, and time. She has good eye contact but appears sad and cries easily. Which of the following is the most appropriate next step in management?
   1. Reassurance
   2. Assess for suicidal ideation
   3. Begin dextroamphetamine therapy
   4. Increase oxycodone dosage
8. 8. A 65-year-old woman has a 6-month history of progressive irritability, palpitations, heat intolerance, frequent bowel movements, and a 6.8-kg (15-lb) weight loss. She has had a neck mass for more than 10 years. 131I scan shows an enlarged thyroid gland with multiple areas of increased and decreased uptake. Which of the following is the most likely diagnosis?
   1. Defect in thyroxine (T4) biosynthesis
   2. Graves' disease
   3. Multinodular goiter
   4. Riedel's thyroiditis
9. 9. A 51-year-old man comes to the office because of a 6-month history of a lump on his tongue that is interfering with his speech and eating; he also has had a 6.8-kg (15-lb) weight loss during this period. He has smoked 1 pack of cigarettes daily and has consumed six 12-oz bottles of beer on weekend nights during the past 30 years. His vital signs are within normal limits. Physical examination shows a 1.5-cm mass on the apex of the tongue. Further evaluation of the mass confirms squamous cell carcinoma. It is most appropriate to evaluate which of the following lymph nodes first for evidence of metastasis in this patient?
   1. Inferior deep cervical
   2. Parotid
   3. Retropharyngeal
   4. Submental
10. 10. A 42-year-old man comes to the physician for a follow-up examination 1 week after he passed a renal calculus. X-ray crystallographic analysis of the calculus showed calcium as the primary cation. Physical examination today shows no abnormalities. A 24-hour collection of urine shows increased calcium excretion. Which of the following is the most appropriate pharmacotherapy?
    1. Carbonic anhydrase inhibitor
    2. Na+ –Cl− symport inhibitor
    3. Na+ –K + –2Cl− symport inhibitor
    4. Osmotic diuretic
11. 11. While you are on rounds at a local nursing facility, the nurse mentions that your patient, a 79-year-old woman, appears to be a "poor eater." She was admitted to the nursing facility 3 months ago from the hospital where she was treated for congestive heart failure. Her daughter had moved away from the area, and nursing home placement was necessary because the patient could no longer function independently. Her present medications include furosemide and digoxin. Physical examination is normal except for a weight loss of 3.5 kg (7 lb) during the past 3 months. In your conversation with the patient, she says, "No, I'm not depressed, I just don't have an appetite anymore. Nothing tastes good to me. I have a little bit of nausea most of the time." Which of the following is the most appropriate initial diagnostic study?
    1. Chest x-ray
    2. Complete blood count
    3. Determination of serum albumin concentration
    4. Determination of serum digoxin level
12. 12. A previously healthy 24-year-old woman comes to the physician because of a low-grade fever and a nonproductive cough for 7 days. She has been able to continue her daily activities. Her temperature is 37.7°C (99.9°F). A few scattered inspiratory crackles are heard in the thorax. An x-ray of the chest shows patchy infiltrates in both lungs. Which of the following is the most appropriate initial pharmacotherapy?
    1. Amoxicillin
    2. Cefaclor
    3. Ciprofloxacin
    4. Erythromycin
13. 13. A 15-year-old boy is brought to the emergency department by his parents because of a 2-hour history of confusion and agitation. He also has had fever, headache, stiff neck, and vomiting since he returned from summer camp 2 days ago. His parents say he does not use illicit drugs. On arrival, he is combative and there is evidence of hallucinations. His temperature is 40°C (104°F), pulse is 80/min, respirations are 17/min, and blood pressure is 100/70 mm Hg. A lumbar puncture is performed. Results of cerebrospinal fluid analysis show cysts and trophozoites. The most likely portal of pathogen entry into this patient's central nervous system is which of the following?
    1. Facial nerve
    2. Frontal sinus
    3. Mastoid sinus
    4. Olfactory nerve
14. 14. A 32-year-old male presents to the office with the complaint of pain in his right shoulder for the past two weeks. Physical examination reveals tenderness at the greater tubercle of the humerus and painful abduction of the right upper extremity. The cause of this patient's condition is most likely a somatic dysfunction of which of the following muscles?
    1. anterior scalene
    2. latissimus dorsi
    3. pectoralis minor
    4. supraspinatus
15. 15. A 19-year-old male presents to the office for evaluation after he was hit from behind below the right knee while playing football. Gait analysis reveals a lack of fluid motion. Standing flexion test results are negative. Cruciate and collateral knee ligaments appear intact. Foot drop on the right is noted. The most likely diagnosis is
    1. anteriorly deviated distal femur
    2. plantar flexed cuboid
    3. posteriorly deviated fibular head
    4. unilateral sacral shear
16. 16. A 45-year-old limousine driver comes to the office for an initial appointment because he would like you to fill out and sign a legal document at the request of his attorney. The patient states that he is filing a lawsuit against the limousine company that employs him because he developed post-traumatic stress disorder following a motor vehicle collision. He appears irritable and tense as he provides his history. He relays his symptoms by reading them aloud from a written list. At this time, which of the following is the most appropriate approach toward confirming the underlying diagnosis of this patient?
    1. Administer amobarbital and then interview the patient
    2. Ask the patient to provide a narrative with detailed description of the incident and of his symptoms
    3. Interview the patient under hypnosis
    4. Interview the patient while paying close attention to his willingness to make eye contact
17. 17. A 5-year-old boy is admitted to the hospital because of a 1-week history of fever and increasingly severe abdominal discomfort. At the age of 7 months, he was treated for osteomyelitis caused by Aspergillus fumigatus. He has been admitted to the hospital three times during the past 4 years for severe pneumonia. He appears moderately ill. His temperature is 39°C (102.2°F). Abdominal examination shows an enlarged, tender liver. Ultrasonography of the abdomen shows an intrahepatic abscess. Culture of the abscess fluid grows Staphylococcus aureus. Further analysis shows failure of the neutrophils to undergo an oxidative burst when exposed to S. aureus. This patient has an increased susceptibility to infection as a result of which of the following abnormalities?
    1. Failure of leukocytes to migrate between endothelial cells
    2. Failure of leukocytes to roll along the endothelial surface
    3. Inability of leukocytes to ingest microorganisms
    4. Inability of leukocytes to kill intracellular microorganisms
18. 18. A technician wants to determine whether cytomegalovirus (CMV) DNA is present in the blood of a bone marrow transplant recipient. DNA purified from the leukocytes of the patient is reacted in a mixture containing oligonucleotides specific for CMV DNA, thermostable DNA polymerase, and nucleotides. Repetitive cycles of heating and cooling are performed, and the reaction product is detected by gel electrophoresis. The technician most likely used which of the following laboratory procedures on this patient's blood?
    1. Northern blotting
    2. Polymerase chain reaction
    3. Reverse transcription
    4. Southern blotting
19. 19. What size of cannula would you use in a patient who needed a rapid blood transfusion (as of 2020 medical knowledge)?
    1. 18 gauge.
    2. 20 gauge.
    3. 22 gauge.
    4. 24 gauge.
20. 20. The key attribute in successful marathon running is:
    1. strength.
    2. power.
    3. stride length.
    4. stamina.
21. 21. Which of the following is the commonest cause of dementia in the UK?
    1. Alzheimer's disease.
    2. Cerebrovascular (stroke) disease.
    3. Lewy body dementia.
    4. HIV infection.
22. 22. Which of the following is NOT a symptom of anaphylaxis?
    1. Stridor.
    2. Bradycardia.
    3. Severe wheeze.
    4. Rash.
23. 23. In what situation are closed pouches applied?
    1. The patient has a semi-formed or liquid output.
    2. The patient has a colostomy.
    3. In the immediate post-operative period.
    4. The patient has a urostomy.
24. 24. With an increasing number of sprints the:
    1. anaerobic contribution progressively increases.
    2. pH of the muscle falls below 6.0.
    3. blood glucose concentration falls below 3 mmol/L.
    4. relative contribution of aerobic metabolism increases.
25. 25. Which of the following is true in diplopia?
    1. Diplopia can never occur if one eye is covered
    2. The outer image is always the false image
    3. A fourth nerve palsy occurs when the patient looks upwards
    4. A sixth nerve palsy causes a divergent squint
26. 26. Sodium bicarbonate ingestion improves middle distance running performance by:
    1. elevating the pH and buffering capacity of the extracellular fluid allowing a faster efflux of hydrogen ions from muscle.
    2. reducing the pH and buffering capacity of the extracellular fluid allowing a faster efflux of hydrogen ions from muscle.
    3. elevating the pH and buffering capacity of the extracellular fluid allowing a faster influx of hydrogen ions into muscle.
    4. elevating the pre-exercise muscle pH.
27. 27. Codons are composed of:
    1. triplet sequences of nucleotide bases in mRNA or DNA .
    2. quadruplet sequences of nucleotide bases in mRNA or DNA.
    3. triplet sequences of amino acids in polypeptide chains.
    4. triplet sequences of deoxyribose sugars in DNA.
28. 28. Fatty acids are transported into the mitochondria bound to:
    1. thiokinase.
    2. coenzyme A (CoA).
    3. acetyl-CoA.
    4. carnitine.
29. 29. Which of the answers below best indicates the compatible blood types that can be given to a person with a blood group B (rhesus negative)?
    1. Blood type AB (rhesus negative), blood type B, and blood type O (rhesus negative).
    2. Blood type B (rhesus positive) and blood type O (rhesus positive).
    3. Blood type B (rhesus negative) and blood type O (rhesus negative).
    4. Blood type B (rhesus negative) only.
30. 30. Which of the following is true of a lower motor neurone lesion in the arm?
    1. It leads to increased tone in the arm (hypertonia)
    2. Fasciculations are never seen
    3. The reflexes are brisk
    4. An ulna nerve palsy is an example of a lower motor neurone lesion

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