Clinical Reasoning Practice Questions

Question 1

A group of neurologists develop a new blood test for Alzheimer's. They are optimistic about the test, as they have found that for any given patient, the test repeatedly produces very similar results. However, they find that the new test results are not necessarily consistent with the gold standard of diagnosis. How would this new test most accurately be described?

Accepted Answer

Reliable

Answer

Valid and reliable

Answer

Valid

Answer

Biased

Answer

Neither valid nor reliable

Question 2

A 25-year-old man with a genetic disorder presents for genetic counseling because he is concerned about the risk that any children he has will have the same disease as himself. Specifically, since childhood he has had difficulty breathing requiring bronchodilators, inhaled corticosteroids, and chest physiotherapy. He has also had diarrhea and malabsorption requiring enzyme replacement therapy. If his wife comes from a population where 1 in 10,000 people are affected by this same disorder, which of the following best represents the likelihood a child would be affected as well?

Accepted Answer

1%

Answer

0.01%

Answer

2%

Answer

0.5%

Answer

50%

Question 3

A 26-year-old medical student comes to the physician with a 3-week history of night sweats and myalgias. During this time, he has also had a 3.6-kg (8-lb) weight loss. He returned from a 6-month tropical medicine rotation in Cambodia 1 month ago. A chest x-ray (CXR) shows reticulonodular opacities suggestive of active tuberculosis (TB). The student is curious about his likelihood of having active TB. He reads a study that compares sputum testing results between 2,800 patients with likely active TB on a basis of history, clinical symptoms, and CXR pattern and 2,400 controls. The results are shown:
Sputum testing positive for TB Sputum testing negative for TB Total
Active TB likely on basis of history, clinical symptoms, and CXR pattern 700 2100 2,800
Active TB not likely on basis of history, clinical symptoms, and CXR pattern 300 2100 2,400
Total 1000 4200 5,200
Which of the following values reflects the probability that a patient with a diagnosis of active TB on the basis of history, clinical symptoms, and CXR pattern actually has active TB?

Accepted Answer

0.25

Answer

1.4

Answer

0.50

Answer

0.70

Answer

0.88

Question 4

A scientist in Boston is studying a new blood test to detect Ab to the parainfluenza virus with increased sensitivity and specificity. So far, her best attempt at creating such an exam reached 82% sensitivity and 88% specificity. She is hoping to increase these numbers by at least 2 percent for each value. After several years of work, she believes that she has actually managed to reach a sensitivity and specificity even greater than what she had originally hoped for. She travels to South America to begin testing her newest blood test. She finds 2,000 patients who are willing to participate in her study. Of the 2,000 patients, 1,200 of them are known to be infected with the parainfluenza virus. The scientist tests these 1,200 patients’ blood and finds that only 120 of them tested negative with her new test. Of the following options, which describes the sensitivity of the test?

Accepted Answer

90%

Answer

82%

Answer

86%

Answer

98%

Answer

84%

Question 5

A geriatric investigator is evaluating the consistency of Alzheimer dementia diagnoses based on clinical symptoms. Patients with known chart diagnoses of Alzheimer dementia were evaluated by multiple physicians during a fixed time interval. Each evaluator was blinded to the others' assessments. The extent to which the diagnosis by one physician was replicated by another clinician examining the same patient is best described by which of the following terms?

Accepted Answer

Precision

Answer

Validity

Answer

Specificity

Answer

Predictive value

Answer

Sensitivity

Question 6

You are reading through a recent article that reports significant decreases in all-cause mortality for patients with malignant melanoma following treatment with a novel biological infusion. Which of the following choices refers to the probability that a study will find a statistically significant difference when one truly does exist?

Accepted Answer

Power

Answer

Type II error

Answer

Type I error

Answer

Confidence interval

Answer

p-value

Question 7

A 55-year-old woman presents with fatigue and flu-like symptoms. She says her symptoms started 5 days ago with a low-grade fever and myalgia, which have not improved. For the past 4 days, she has also had chills, sore throat, and rhinorrhea. She works as a kindergarten teacher and says several children in her class have had similar symptoms. Her past medical history is significant for depression managed with escitalopram, and dysmenorrhea. A review of systems is significant for general fatigue for the past 5 months. Her vital signs include: temperature 38.5°C (101.3°F), pulse 99/min, blood pressure 115/75 mm Hg, and respiratory rate 22/min. Physical examination reveals pallor of the mucous membranes. Initial laboratory findings are significant for the following:
Hematocrit 24.5%
Hemoglobin 11.0 g/dL
Platelet Count 215,000/mm3
Mean corpuscular volume (MCV) 82 fL
Red cell distribution width (RDW) 10.5%
Which of the following is the best next diagnostic test in this patient?

Accepted Answer

Reticulocyte count

Answer

Serum iron level

Answer

Serum ferritin level

Answer

Hemoglobin electrophoresis

Answer

Serum folate level

Question 8

A research group wants to assess the safety and toxicity profile of a new drug. A clinical trial is conducted with 20 volunteers to estimate the maximum tolerated dose and monitor the apparent toxicity of the drug. The study design is best described as which of the following phases of a clinical trial?

Accepted Answer

Phase I

Answer

Phase 0

Answer

Phase III

Answer

Phase V

Answer

Phase II

Question 9

An epidemiologist is evaluating the efficacy of Noxbinle in preventing HCC deaths at the population level. A clinical trial shows that over 5 years, the mortality rate from HCC was 25% in the control group and 15% in patients treated with Noxbinle 100 mg daily. Based on this data, how many patients need to be treated with Noxbinle 100 mg to prevent, on average, one death from HCC?

Accepted Answer

10

Answer

20

Answer

73

Answer

50

Answer

100

Question 10

A 15-year-old boy is referred to a child psychologist because of worsening behavior and constant disruption in class. He has received multiple reprimands in the past 6 months for not doing the homework his teacher assigned, and he refuses to listen to the classroom instructions. Additionally, his teachers say he is very argumentative and blames other children for not letting him do his work. He was previously well behaved and one of the top students in his class. He denies any recent major life events or changes at home. His past medical history is noncontributory. His vital signs are all within normal limits. Which of the following is the most likely diagnosis?

Accepted Answer

Oppositional defiant disorder

Answer

Attention deficit hyperactivity disorder

Answer

Antisocial personality disorder

Answer

Conduct disorder

Answer

Major depressive disorder

Clinical Reasoning

Study Resources

Lessons

Questions

Flashcards

Lessons

Analytical vs non-analytical reasoning

Hypothetico-deductive reasoning

Pattern recognition in clinical reasoning

Probabilistic reasoning

Bayesian approach to diagnosis

Decision making under uncertainty

Cognitive biases in clinical reasoning

Metacognition and diagnostic calibration

Clinical decision rules

Diagnostic parsimony (Occam's razor)

Diagnostic thoroughness (Hickam's dictum)

Diagnostic error analysis

Integrating evidence-based medicine into reasoning

Practice Questions

Flashcards

About Clinical Reasoning for USMLE

Lessons in Clinical Reasoning

Master Clinical Reasoning