Diagnostic error analysis US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Diagnostic error analysis. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Diagnostic error analysis US Medical PG Question 1: Two dizygotic twins present to the university clinic because they believe they are being poisoned through the school's cafeteria food. They have brought these concerns up in the past, but no other students or cafeteria staff support this belief. Both of them are average students with strong and weak subject areas as demonstrated by their course grade-books. They have no known medical conditions and are not known to abuse illicit substances. Which statement best describes the condition these patients have?
- A. A trial separation is likely to worsen symptoms.
- B. The disorder is its own disease entity in DSM-5.
- C. Antipsychotic medications are rarely beneficial.
- D. Can affect two or more closely related individuals. (Correct Answer)
- E. Cognitive behavioral therapy is a good first-line.
Diagnostic error analysis Explanation: ***Can affect two or more closely related individuals.***
- The shared delusional belief in **folie à deux**, also known as **shared psychotic disorder**, typically occurs in two or more people who are closely associated.
- In this case, the **dizygotic twins** sharing the same delusional belief about being poisoned from cafeteria food fits this pattern.
*A trial separation is likely to worsen symptoms.*
- **Separating the individuals** involved in **folie à deux** is often a crucial step in treatment, as it can help break the cycle of shared delusion and allow for individual therapy.
- Separation typically IMPROVES rather than worsens symptoms by removing the reinforcement of the shared delusion.
*The disorder is its own disease entity in DSM-5.*
- In the **DSM-5**, **folie à deux** is no longer considered a separate diagnostic category.
- Instead, it is classified under **Other Specified Schizophrenia Spectrum and Other Psychotic Disorder** or **Unspecified Schizophrenia Spectrum and Other Psychotic Disorder**, with the specific context of shared delusion noted.
*Antipsychotic medications are rarely beneficial.*
- **Antipsychotics** are actually commonly used in treating folie à deux, particularly for the **primary individual** who initially developed the delusion.
- They can be an important component of treatment, often combined with separation and psychotherapy.
*Cognitive behavioral therapy is a good first-line.*
- **Cognitive Behavioral Therapy (CBT)** can be beneficial, particularly after separation, to help individuals challenge and reframe their delusional beliefs.
- However, the **first-line intervention** for shared psychotic disorder is **separation of the involved individuals**, followed by individual therapy (which may include CBT) and medication as needed.
Diagnostic error analysis US Medical PG Question 2: 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?
- A. Validity
- B. Specificity
- C. Predictive value
- D. Sensitivity
- E. Precision (Correct Answer)
Diagnostic error analysis Explanation: ***Precision***
- **Precision** refers to the consistency or reproducibility of a measurement or diagnosis. When multiple physicians reach the same diagnosis for the same patient, it indicates high precision.
- In this context, it specifically assesses **inter-rater reliability**, which is the extent to which different observers agree on the same assessment.
*Validity*
- **Validity** refers to the extent to which a test or measure accurately assesses what it is intended to measure. It is about the "truthfulness" of the diagnosis.
- While important for diagnosis, validity is about accuracy against a gold standard, not consistency among different observers.
*Specificity*
- **Specificity** is the ability of a test to correctly identify individuals who do *not* have the disease (true negatives).
- It measures the proportion of healthy individuals who are correctly identified as healthy by the test, which is not what is being evaluated here.
*Predictive value*
- **Predictive value** assesses the probability that a person *actually has* (positive predictive value) or *does not have* (negative predictive value) a disease given their test result.
- This concept relates to the diagnostic utility of a test in a population, not the consistency of different clinician diagnoses.
*Sensitivity*
- **Sensitivity** is the ability of a test to correctly identify individuals who *do* have the disease (true positives).
- It measures the proportion of diseased individuals who are correctly identified as diseased by the test, which is distinct from inter-rater agreement.
Diagnostic error analysis US Medical PG Question 3: A 25-year-old man comes to the physician for severe back pain. He describes the pain as shooting and stabbing. On a 10-point scale, he rates the pain as a 9 to 10. The pain started after he lifted a heavy box at work; he works at a supermarket and recently switched from being a cashier to a storekeeper. The patient appears to be in severe distress. Vital signs are within normal limits. On physical examination, the spine is nontender without paravertebral muscle spasms. Range of motion is normal. A straight-leg raise test is negative. After the physical examination has been completed, the patient asks for a letter to his employer attesting to his inability to work as a storekeeper. Which of the following is the most appropriate response?
- A. “Yes. Since work may worsen your condition, I would prefer that you stay home a few days. I will write a letter to your employer to explain the situation.”
- B. You say you are in severe pain. However, the physical examination findings do not suggest a physical problem that can be addressed with medications or surgery. I'd like to meet on a regular basis to see how you're doing.
- C. I understand that you are uncomfortable, but the findings do not match the severity of your symptoms. Let's talk about the recent changes at your job. (Correct Answer)
- D. The physical exam findings do not match your symptoms, which suggests a psychological problem. I would be happy to refer you to a mental health professional.
- E. The physical exam findings suggest a psychological rather than a physical problem. But there is a good chance that we can address it with cognitive-behavioral therapy.
Diagnostic error analysis Explanation: ***"I understand that you are uncomfortable, but the findings do not match the severity of your symptoms. Let's talk about the recent changes at your job."***
- This response acknowledges the patient's reported discomfort while gently highlighting the **discrepancy between symptoms and objective findings**, which is crucial in cases of suspected **somatoform or functional pain**.
- It also opens communication about potential **psychosocial stressors** related to his job change, which could be contributing to his symptoms, without dismissing his pain or making a premature diagnosis.
*"You say you are in severe pain. However, the physical examination findings do not suggest a physical problem that can be addressed with medications or surgery. I'd like to meet on a regular basis to see how you're doing."*
- While this option correctly identifies the lack of physical findings, it can be perceived as dismissive of the patient's pain, potentially damaging the **physician-patient relationship**.
- Suggesting regular meetings without a clear plan for addressing his immediate concerns or exploring underlying issues might not be the most effective initial approach.
*“Yes. Since work may worsen your condition, I would prefer that you stay home a few days. I will write a letter to your employer to explain the situation.”*
- This response would **validate the patient's claim of severe pain** without objective evidence, potentially reinforcing illness behavior and avoiding addressing the underlying issue.
- Providing a doctor's note for inability to work without a clear diagnostic basis or understanding of the pain's origin is **medically inappropriate** and could set a precedent for future such requests.
*"The physical exam findings do not match your symptoms, which suggests a psychological problem. I would be happy to refer you to a mental health professional."*
- Directly labeling the problem as "psychological" can be **stigmatizing and alienating** to the patient, leading to distrust and resistance to care.
- While a psychological component might be present, immediately referring to mental health without further exploration of the patient's situation or current stressors is premature and lacks empathy.
*"The physical exam findings suggest a psychological rather than a physical problem. But there is a good chance that we can address it with cognitive-behavioral therapy."*
- Similar to the previous option, explicitly stating a "psychological problem" can be **stigmatizing**.
- Jumping directly to recommending **cognitive-behavioral therapy (CBT)** without a comprehensive discussion and patient buy-in is premature and may lead to non-compliance.
Diagnostic error analysis US Medical PG Question 4: A 52-year-old man comes to the physician because of a 3-week history of a cough and hoarseness. He reports that the cough is worse when he lies down after lunch. His temperature is 37.5°C (99.5°F); the remainder of his vital signs are within normal limits. Because the physician has recently been seeing several patients with the common cold, the diagnosis of a viral upper respiratory tract infection readily comes to mind. The physician fails to consider the diagnosis of gastroesophageal reflux disease, which the patient is later found to have. Which of the following most accurately describes the cognitive bias that the physician had?
- A. Framing
- B. Anchoring
- C. Visceral
- D. Confirmation
- E. Availability (Correct Answer)
Diagnostic error analysis Explanation: ***Availability***
- The physician recently seeing several patients with the common cold led to this diagnosis readily coming to mind, demonstrating how easily recalled examples can disproportionately influence diagnosis.
- This bias occurs when easily recalled instances or information (like recent cases of common cold) are used to estimate the likelihood or frequency of an event, even if other more relevant data exist.
*Framing*
- This bias occurs when the way information is presented (e.g., as a gain or a loss) influences a decision, rather than the intrinsic characteristics of the options themselves.
- The scenario does not involve the presentation of information in different ways to sway the physician's judgment.
*Anchoring*
- This bias involves relying too heavily on an initial piece of information (the "anchor") when making subsequent judgments, often leading to insufficient adjustment away from that anchor.
- While the physician initially considered a viral URI, the setup is more about the ease of recall influencing the decision rather than being stuck on an initial data point.
*Visceral*
- This is not a commonly recognized cognitive bias in the context of medical decision-making; "visceral" largely refers to emotional or intuitive feelings rather than a structured cognitive bias.
- Cognitive biases describe systematic patterns of deviation from norm or rationality in judgment, not merely emotional responses.
*Confirmation*
- This bias involves seeking, interpreting, favoring, and recalling information in a way that confirms one's pre-existing beliefs or hypotheses.
- The physician did not actively seek information to confirm the common cold diagnosis; rather, the diagnosis came to mind due to recent encounters, which aligns with availability bias.
Diagnostic error analysis US Medical PG Question 5: A 28-year-old woman dies shortly after receiving a blood transfusion. Autopsy reveals widespread intravascular hemolysis and acute renal failure. Investigation reveals that she received type A blood, but her medical record indicates she was type O. In a malpractice lawsuit, which of the following elements must be proven?
- A. Duty, breach, causation, and damages (Correct Answer)
- B. Only duty and breach
- C. Only breach and causation
- D. Duty, breach, and damages
Diagnostic error analysis Explanation: ***Duty, breach, causation, and damages***
- In a medical malpractice lawsuit, all four elements—**duty, breach, causation, and damages**—must be proven for a successful claim.
- The healthcare provider had a **duty** to provide competent care, they **breached** that duty by administering the wrong blood type, this breach **caused** the patient's death and renal failure, and these injuries constitute **damages**.
*Only duty and breach*
- While **duty** and **breach** are necessary components, proving only these two is insufficient for a malpractice claim.
- It must also be demonstrated that the breach directly led to the patient's harm and resulted in legally recognized damages.
*Only breach and causation*
- This option omits the crucial elements of professional **duty** owed to the patient and the resulting **damages**.
- A claim cannot succeed without establishing that a duty existed and that quantifiable harm occurred.
*Duty, breach, and damages*
- This option misses the critical element of **causation**, which links the provider's breach of duty to the patient's injuries.
- Without proving that the breach *caused* the damages, even if a duty was owed and breached, and damages occurred, the claim would fail.
Diagnostic error analysis US Medical PG Question 6: A research study is comparing 2 novel tests for the diagnosis of Alzheimer’s disease (AD). The first is a serum blood test, and the second is a novel PET radiotracer that binds to beta-amyloid plaques. The researchers intend to have one group of patients with AD assessed via the novel blood test, and the other group assessed via the novel PET examination. In comparing these 2 trial subsets, the authors of the study may encounter which type of bias?
- A. Selection bias (Correct Answer)
- B. Confounding bias
- C. Recall bias
- D. Measurement bias
- E. Lead-time bias
Diagnostic error analysis Explanation: ***Selection bias***
- This occurs when different patient groups are assigned to different interventions or measurements in a way that creates **systematic differences** between comparison groups.
- In this study, having **separate patient groups** assessed with different diagnostic methods (blood test vs. PET scan) means any differences observed could be due to **differences in the patient populations** rather than differences in test performance.
- To validly compare two diagnostic tests, both tests should ideally be performed on the **same patients** (paired design) or patients should be **randomly assigned** to receive one test or the other, ensuring comparable groups.
- This is a fundamental **study design flaw** that prevents valid comparison of the two diagnostic methods.
*Measurement bias*
- Also called information bias, this occurs when there are systematic errors in how outcomes or exposures are measured.
- While using different measurement tools could introduce measurement variability, the primary issue here is that **different patient populations** are being compared, not just different measurement methods on the same population.
- Measurement bias would be more relevant if the same patients were assessed with both methods but one method was systematically misapplied or measured incorrectly.
*Confounding bias*
- This occurs when an extraneous variable is associated with both the exposure and outcome, distorting the observed relationship.
- While patient characteristics could confound results, the fundamental problem is the **study design itself** (separate groups for separate tests), which is selection bias.
*Recall bias*
- This involves systematic differences in how participants remember or report past events, common in **retrospective case-control studies**.
- Not relevant here, as this involves prospective diagnostic testing, not recollection of past exposures.
*Lead-time bias*
- Occurs in screening studies when earlier detection makes survival appear longer without changing disease outcomes.
- Not applicable to this scenario, which focuses on comparing two diagnostic methods in separate patient groups, not on survival or disease progression timing.
Diagnostic error analysis US Medical PG Question 7: A pharmaceutical corporation is developing a research study to evaluate a novel blood test to screen for breast cancer. They enrolled 800 patients in the study, half of which have breast cancer. The remaining enrolled patients are age-matched controls who do not have the disease. Of those in the diseased arm, 330 are found positive for the test. Of the patients in the control arm, only 30 are found positive. What is this test’s sensitivity?
- A. 330 / (330 + 30)
- B. 330 / (330 + 70) (Correct Answer)
- C. 370 / (30 + 370)
- D. 370 / (70 + 370)
- E. 330 / (400 + 400)
Diagnostic error analysis Explanation: ***330 / (330 + 70)***
- **Sensitivity** measures the proportion of actual **positives** that are correctly identified as such.
- In this study, there are **400 diseased patients** (half of 800). Of these, 330 tested positive (true positives), meaning 70 tested negative (false negatives). So sensitivity is **330 / (330 + 70)**.
*330 / (330 + 30)*
- This calculation represents the **positive predictive value**, which is the probability that subjects with a positive screening test truly have the disease. It uses **true positives / (true positives + false positives)**.
- It does not correctly calculate **sensitivity**, which requires knowing the total number of diseased individuals.
*370 / (30 + 370)*
- This expression is attempting to calculate **specificity**, which is the proportion of actual negatives that are correctly identified. It would be **true negatives / (true negatives + false positives)**.
- However, the numbers used are incorrect for specificity in this context given the data provided.
*370 / (70 + 370)*
- This formula is an incorrect combination of values and does not represent any standard epidemiological measure like **sensitivity** or **specificity**.
- It is attempting to combine false negatives (70) and true negatives (370 from control arm) in a non-standard way.
*330 / (400 + 400)*
- This calculation attempts to divide true positives by the total study population (800 patients).
- This metric represents the **prevalence of true positives within the entire study cohort**, not the test's **sensitivity**.
Diagnostic error analysis US Medical PG Question 8: A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?
- A. "Does the diarrhea typically precede the constipation, or vice-versa?"
- B. "Is the diarrhea foul-smelling?"
- C. "Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life"
- D. "Are the symptoms worse in the morning or at night?"
- E. "Can you tell me more about the symptoms you have been experiencing?" (Correct Answer)
Diagnostic error analysis Explanation: ***Can you tell me more about the symptoms you have been experiencing?***
- This **open-ended question** encourages the patient to provide a **comprehensive narrative** of their symptoms, including details about onset, frequency, duration, alleviating/aggravating factors, and associated symptoms, which is crucial for diagnosis.
- In a patient presenting with vague, intermittent symptoms like alternating constipation and diarrhea, allowing them to elaborate freely can reveal important clues that might not be captured by more targeted questions.
*Does the diarrhea typically precede the constipation, or vice-versa?*
- While knowing the sequence of symptoms can be helpful in understanding the **pattern of bowel dysfunction**, it is a very specific question that might overlook other important aspects of the patient's experience.
- It prematurely narrows the focus without first obtaining a broad understanding of the patient's overall symptomatic picture.
*Is the diarrhea foul-smelling?*
- Foul-smelling diarrhea can indicate **malabsorption** or **bacterial overgrowth**, which are important to consider in some gastrointestinal conditions.
- However, this is a **specific symptom inquiry** that should follow a more general exploration of the patient's symptoms, as it may not be relevant if other crucial details are missed.
*Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life*
- Quantifying pain intensity is useful for assessing the **severity of discomfort** and monitoring changes over time.
- However, for a patient with intermittent rather than acute, severe pain, understanding the **character, location, and triggers** of the pain is often more diagnostically valuable than just a numerical rating initially.
*Are the symptoms worse in the morning or at night?*
- Diurnal variation can be relevant in certain conditions, such as inflammatory bowel diseases where nocturnal symptoms might be more concerning, or functional disorders whose symptoms might be stress-related.
- This is another **specific question** that should come after gathering a more complete initial picture of the patient's symptoms to ensure no key information is overlooked.
Diagnostic error analysis US Medical PG Question 9: A 57-year-old man presents to the emergency department for weight loss and abdominal pain. The patient states that he has felt steadily more fatigued over the past month and has lost 22 pounds without effort. Today, he fainted prompting his presentation. The patient has no significant past medical history. He does have a 33 pack-year smoking history and drinks 4 to 5 alcoholic drinks per day. His temperature is 99.5°F (37.5°C), blood pressure is 100/58 mmHg, pulse is 100/min, respirations are 17/min, and oxygen saturation is 98% on room air. On physical exam, you see a patient who is very thin and appears to be pale. Stool fecal occult blood testing is positive. A CT scan of the abdomen is performed demonstrating a mass in the colon with multiple metastatic lesions scattered throughout the abdomen. The patient is informed of his diagnosis of metastatic colon cancer. When the patient conveys the information to his family he focuses his efforts on discussing the current literature in the field and the novel therapies that have been invented. He demonstrates his likely mortality outcome which he calculated using the results of a large multi-center study. Which of the following is this patient most likely demonstrating?
- A. Intellectualization (Correct Answer)
- B. Dissociation
- C. Rationalization
- D. Optimism
- E. Pessimism
Diagnostic error analysis Explanation: ***Intellectualization***
- This defense mechanism involves **focusing on the intellectual aspects** of a stressful situation, using logical reasoning and factual analysis to avoid experiencing distressing emotions.
- The patient demonstrates this by discussing **literature, novel therapies, and mortality statistics** regarding his metastatic colon cancer.
*Dissociation*
- **Dissociation** involves a mental process that causes a lack of connection in a person's thoughts, memory, and sense of identity.
- This patient is actively engaging with the information, not disconnecting from it.
*Rationalization*
- **Rationalization** is creating logical but false explanations for unacceptable thoughts, feelings, or behaviors to justify them.
- The patient is not trying to justify his actions or feelings, but rather to understand his disease intellectually.
*Optimism*
- **Optimism** is a disposition to look on the favorable side of events or conditions and to expect the most favorable outcome.
- While hope for novel therapies could be seen as optimistic, his detailed calculation of mortality outcomes is a realistic, rather than purely optimistic, approach.
*Pessimism*
- **Pessimism** is a tendency to see the worst aspect of things or believe that the worst will happen.
- The patient is engaging with the facts of his diagnosis, even calculating his mortality outcome, which is not necessarily a pessimistic but rather a realistic and intellectual approach.
Diagnostic error analysis US Medical PG Question 10: A 53-year-old man presents with a 2-year-history of dull, nonspecific flank pain that subsides with rest. His past medical history is significant for hypertension, hypercholesterolemia, and type 2 diabetes mellitus. He has no allergies and takes no medications. His father died of kidney disease at the age of 51, and his mother has been treated for ovarian cancer. On presentation, his blood pressure is 168/98 mm Hg, and his heart rate is 102/min. Abdominal examination is significant for palpable bilateral renal masses. His laboratory tests are significant for creatinine of 2.0 mg/dL and a BUN of 22 mg/dL. Which of the following tests is most recommended in this patient?
- A. Chest X-ray
- B. Genetic testing for polycystic kidney disease
- C. CT scan of abdomen and pelvis
- D. 24-hour urine protein collection
- E. Renal ultrasound (Correct Answer)
Diagnostic error analysis Explanation: ***Renal ultrasound***
- This patient presents with classic features of **autosomal dominant polycystic kidney disease (ADPKD)**: bilateral palpable renal masses, hypertension, elevated creatinine, and a strong family history (father died of kidney disease at 51).
- **Renal ultrasound is the first-line imaging test** for diagnosing ADPKD due to its **non-invasiveness, no radiation exposure, high sensitivity for detecting cysts, and cost-effectiveness**.
- Ultrasound can establish the diagnosis using **established diagnostic criteria** (Pei-Ravine criteria based on age and number of cysts) and is recommended by **KDIGO guidelines** as the initial imaging modality.
- In this patient with clear clinical features and palpable masses, ultrasound will readily confirm the diagnosis by demonstrating multiple bilateral renal cysts.
*24-hour urine protein collection*
- This test quantifies **proteinuria** to assess for glomerular damage.
- While proteinuria can occur in ADPKD, it is not a diagnostic test and would not help identify or characterize the bilateral renal masses in this presentation.
*Chest X-ray*
- A chest X-ray evaluates the **lungs and heart**.
- It provides no diagnostic information regarding renal masses or kidney pathology and is not indicated in this case.
*Genetic testing for polycystic kidney disease*
- **Genetic testing** (for PKD1 or PKD2 mutations) can confirm ADPKD definitively and is useful for family counseling and cases with uncertain imaging findings.
- However, it is **not the first-line test** and is typically performed *after* imaging has established the diagnosis, or in specific situations (e.g., young patients, potential living kidney donors, atypical presentations).
- In this patient with clear clinical and anticipated imaging findings, genetic testing is unnecessary for initial diagnosis.
*CT scan of abdomen and pelvis*
- CT scan provides excellent anatomic detail and is useful in ADPKD for **evaluating complications** such as cyst hemorrhage, infection, suspected malignancy, or for **preoperative planning**.
- However, it is **not the first-line diagnostic test** due to higher cost, radiation exposure, and the fact that ultrasound is equally effective for initial diagnosis.
- CT would be reserved for situations where ultrasound is inconclusive or when complications are suspected.
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