Pattern recognition in clinical reasoning US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Pattern recognition in clinical reasoning. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Pattern recognition in clinical reasoning US Medical PG Question 1: A 21-year-old woman is diagnosed with a rare subtype of anti-NMDA encephalitis. During the diagnostic workup, she was found to have an ovarian teratoma. Her physician is curious about the association between anti-NMDA encephalitis and ovarian teratomas. A causal relationship between this subtype of anti-NMDA encephalitis and ovarian teratomas is suspected. The physician aims to identify patients with anti-NMDA encephalitis and subsequently evaluate them for the presence of ovarian teratomas. Which type of study design would be the most appropriate?
- A. Case-control study
- B. Retrospective cohort study (Correct Answer)
- C. Cross-sectional study
- D. Case series
- E. Randomized controlled trial
Pattern recognition in clinical reasoning Explanation: ***Retrospective cohort study***
- This is the **most appropriate design** because the physician starts with a defined group of patients **with anti-NMDA encephalitis** (the exposure/condition) and then evaluates them for the **presence of ovarian teratomas** (the outcome).
- A **cohort study** follows this directional approach: identify individuals with a specific exposure or condition, then assess the frequency or presence of an outcome within that group.
- **Retrospective** cohort studies use **existing medical records** to identify the exposed cohort and determine outcome status, making this practical for studying a rare condition like anti-NMDA encephalitis.
- This design allows calculation of the **prevalence** of ovarian teratomas among anti-NMDA encephalitis patients and can suggest an association between the two conditions.
*Cross-sectional study*
- Cross-sectional studies assess **both exposure and outcome simultaneously** at a single point in time in a population, rather than starting with one condition and looking for another.
- This design would be appropriate if the physician surveyed a population and assessed both anti-NMDA encephalitis and ovarian teratomas at the same time, but the question describes a **directional evaluation** (first identify encephalitis patients, then evaluate for teratomas).
- While cross-sectional studies can identify associations, they do not follow the sequential approach described in the clinical scenario.
*Case series*
- A **case series** is a descriptive study that reports characteristics or outcomes in a group of patients with a particular condition but lacks a comparison group and does not systematically evaluate associations.
- While it could describe ovarian teratoma findings in anti-NMDA encephalitis patients, it does not provide the structured framework for assessing prevalence or association that a cohort study offers.
*Case-control study*
- **Case-control studies** work in the **opposite direction**: they start with the outcome (e.g., ovarian teratoma cases) and look backward for the exposure (e.g., anti-NMDA encephalitis).
- The physician's approach starts with the **exposure first** (anti-NMDA encephalitis), making a case-control design inappropriate.
- Case-control studies are efficient for studying rare outcomes but are not aligned with the described study plan.
*Randomized controlled trial*
- **RCTs** are experimental studies that randomly assign participants to different interventions to evaluate treatment efficacy or causation.
- This is an **observational research question** about naturally occurring associations, not an intervention study, making RCTs inappropriate and unethical for this scenario.
Pattern recognition in clinical reasoning US Medical PG Question 2: A 19-year-old woman comes to the physician because of a 2-day history of difficulty sleeping. She worries that the lack of sleep will ruin her career prospects as a model. She has been coming to the physician multiple times over the past year for minor problems. She is dressed very extravagantly and flirts with the receptionist. When she is asked to sit down in the waiting room, she begins to cry and says that no one listens to her. When she is called to the examination room, she moves close to the physician, repeatedly intends to touch his cheek, and makes inappropriate comments. She does not have a history of self-harm or suicidal ideation. Which of the following is the most likely diagnosis?
- A. Schizotypal personality disorder
- B. Borderline personality disorder
- C. Dependent personality disorder
- D. Narcissistic personality disorder
- E. Histrionic personality disorder (Correct Answer)
Pattern recognition in clinical reasoning Explanation: ***Histrionic personality disorder***
- This patient displays classic features of **histrionic personality disorder**, including **attention-seeking behaviors** (flirting, extravagant dress, dramatic crying), **inappropriate sexually seductive behavior** toward the physician, and **rapidly shifting and shallow emotions** (cries that no one listens to her, then attempts to touch the physician).
- Her excessive emotionality and constant need to be the center of attention, coupled with a tendency to use physical appearance to draw attention to herself, align well with the diagnostic criteria.
*Schizotypal personality disorder*
- Characterized by a pervasive pattern of **social and interpersonal deficits** marked by acute discomfort with, and reduced capacity for, close relationships, as well as by **cognitive or perceptual distortions** and eccentricities of behavior.
- This patient does not exhibit evidence of odd beliefs, magical thinking, unusual perceptual experiences, or paranoid ideation typical of schizotypal personality disorder.
*Borderline personality disorder*
- Marked by a pervasive pattern of **instability of interpersonal relationships, self-image, and affects**, and marked impulsivity. Patients often exhibit intense fears of abandonment, chronic feelings of emptiness, and self-harming behaviors.
- While there is some emotional dysregulation and intense relationships, the patient does not report **self-harm, suicidal ideation**, or the severe identity disturbance common in borderline personality disorder.
*Dependent personality disorder*
- Individuals with dependent personality disorder exhibit an excessive need to be cared for, leading to **submissive and clinging behavior** and fears of separation. They often have difficulty making everyday decisions without excessive reassurance.
- This patient's behaviors are geared towards attracting attention and being the center of it, rather than seeking reassurance or exhibiting submissive behavior.
*Narcissistic personality disorder*
- Characterized by a pervasive pattern of **grandiosity, a need for admiration**, and a lack of empathy. Patients often believe they are special and unique and expect to be recognized as superior.
- While this patient seeks attention, her behavior is more about being dramatic and emotionally expressive rather than a sense of inflated self-importance or a deep need for admiration stemming from grandiosity.
Pattern recognition in clinical reasoning US Medical PG Question 3: A mother presents to the family physician with her 16-year-old son. She explains, "There's something wrong with him doc. His grades are getting worse, he's cutting class, he's gaining weight, and his eyes are often bloodshot." Upon interviewing the patient apart from his mother, he seems withdrawn and angry at times when probed about his social history. The patient denies abuse and sexual history. What initial test should be sent to rule out the most likely culprit of this patient's behavior?
- A. Complete blood count
- B. Sexually transmitted infection (STI) testing
- C. Blood culture
- D. Urine toxicology screen (Correct Answer)
- E. Slit lamp examination
Pattern recognition in clinical reasoning Explanation: ***Urine toxicology screen***
- The patient's presentation with **declining grades**, **cutting class**, **weight gain**, **bloodshot eyes**, and **irritability** are classic signs of **substance abuse** in an adolescent.
- A **urine toxicology screen** is the most appropriate initial test to detect common illicit substances, especially given the clear signs pointing towards drug use.
*Slit lamp examination*
- This test is used to examine the **anterior segment of the eye**, including the conjunctiva, cornea, iris, and lens.
- While the patient has **bloodshot eyes**, this specific test would be more relevant for ruling out ocular infections or injuries, not for diagnosing the underlying cause of systemic behavioral changes.
*Complete blood count*
- A **complete blood count (CBC)** measures different components of the blood, such as red blood cells, white blood cells, and platelets.
- A CBC is a general health indicator and while it can detect infections or anemia, it is not specific or sensitive enough to identify the cause of the behavioral changes described.
*Sexually transmitted infection (STI) testing*
- Although the patient denies sexual history, all adolescents presenting with certain risk factors or symptoms may warrant STI testing in a broader health assessment.
- However, in this scenario, the primary cluster of symptoms (poor grades, cutting class, bloodshot eyes, irritability) points more directly to substance abuse than to an STI.
*Blood culture*
- A **blood culture** is used to detect the presence of bacteria or other microorganisms in the bloodstream, indicating a systemic infection (sepsis).
- The patient's symptoms are not indicative of an acute bacterial bloodstream infection, and a blood culture would not be the initial test for the presented behavioral changes.
Pattern recognition in clinical reasoning US Medical PG Question 4: A pharmaceutical company conducts a randomized clinical trial to demonstrate that their new anticoagulant drug, Aclotsaban, prevents more thrombotic events following total knee arthroplasty than the current standard of care. A significant number of patients are lost to follow-up, and many fail to complete treatment according to the study arm to which they were assigned. Despite these protocol deviations, the results for the patients who completed the course of Aclotsaban are encouraging. Which of the following analytical approaches is most appropriate for the primary analysis to establish the efficacy of Aclotsaban?
- A. Intention-to-treat analysis (Correct Answer)
- B. Sub-group analysis
- C. Per-protocol analysis
- D. As-treated analysis
- E. Non-inferiority analysis
Pattern recognition in clinical reasoning Explanation: ***Intention-to-treat analysis***
- **Intention-to-treat (ITT) analysis** is the gold standard for the **primary analysis in superiority trials** and includes all patients in the groups to which they were originally randomized, regardless of protocol deviations, loss to follow-up, or treatment discontinuation.
- ITT preserves **randomization balance**, prevents bias from selective dropout (patients may drop out due to adverse effects or lack of efficacy), and provides a **conservative, realistic estimate** of treatment effect in actual clinical practice.
- For **regulatory approval and establishing efficacy**, ITT is the most appropriate primary analysis method even when dropout rates are high, as it maintains the integrity of the randomized comparison.
*Per-protocol analysis*
- **Per-protocol analysis** includes only patients who completed the study exactly as planned without protocol deviations.
- While the encouraging results in completers are noted, per-protocol analysis can **introduce significant bias** by excluding patients who dropped out due to adverse events or lack of efficacy, potentially **overestimating treatment benefit**.
- Per-protocol is typically used as a **secondary/supportive analysis**, not the primary method for establishing superiority.
*As-treated analysis*
- **As-treated analysis** categorizes patients according to the treatment they actually received rather than their randomized assignment.
- This violates the principle of randomization and can introduce **confounding bias**, as actual treatment received may be influenced by prognostic factors.
*Sub-group analysis*
- **Sub-group analysis** evaluates treatment effects within specific patient subsets.
- This is **hypothesis-generating** rather than confirmatory and increases the risk of false-positive findings (multiple comparisons problem) unless pre-specified in the protocol.
*Non-inferiority analysis*
- **Non-inferiority analysis** tests whether a new treatment is not worse than control by more than a pre-specified margin.
- The goal here is to demonstrate **superiority** (better than standard care), not non-inferiority, making this approach inappropriate.
Pattern recognition in clinical reasoning 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
Pattern recognition in clinical reasoning 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.
Pattern recognition in clinical reasoning US Medical PG Question 6: Two studies are reviewed for submission to an oncology journal. In Study A, a novel MRI technology is evaluated as a screening tool for ovarian cancer. The authors find that the mean survival time is 4 years in the control group and 10 years in the MRI-screened group. In Study B, cognitive behavioral therapy (CBT) and a novel antidepressant are used to treat patients with comorbid pancreatic cancer and major depression. Patients receiving the new drug are told that they are expected to have quick resolution of their depression, while those who do not receive the drug are not told anything about their prognosis. Which of the following describes the likely type of bias in Study A and Study B?
- A. Latency Bias; Golem effect
- B. Confounding; Golem effect
- C. Lead time bias; Golem effect
- D. Lead time bias; Pygmalion effect (Correct Answer)
- E. Latency bias; Pygmalion effect
Pattern recognition in clinical reasoning Explanation: ***Lead time bias; Pygmalion effect***
- In Study A, the MRI technology detects ovarian cancer earlier, artificially making the survival time appear longer simply due to earlier diagnosis, not necessarily improved outcomes, which is characteristic of **lead time bias**.
- In Study B, the patients receiving the new drug are told to expect quick resolution of their depression, leading to increased expectation of improvement, which describes the **Pygmalion effect** (a form of observer-expectancy effect where higher expectations lead to increased performance).
*Latency Bias; Golem effect*
- **Latency bias** refers to a delay in the manifestation of an outcome, which is not the primary issue in Study A's screening context.
- The **Golem effect** is a form of negative self-fulfilling prophecy where lower expectations placed upon individuals by superiors/researchers lead to poorer performance, which is opposite to what is described in Study B.
*Confounding; Golem effect*
- **Confounding** occurs when an unmeasured third variable is associated with both the exposure and the outcome, distorting the observed relationship; while confounding is common, the scenario in Study A specifically points to a screening effect on survival time.
- As mentioned, the **Golem effect** refers to negative expectations leading to poorer outcomes, which is not present in Study B.
*Lead time bias; Golem effect*
- **Lead time bias** correctly identifies the issue in Study A, as explaining the apparently longer survival as a result of earlier detection.
- However, the **Golem effect** incorrectly describes the scenario in Study B, where positive expectations are given, not negative ones.
*Latency bias; Pygmalion effect*
- **Latency bias** is not the primary bias described in Study A; the immediate impact of early detection on survival statistics points to lead time bias.
- The **Pygmalion effect** correctly describes the bias in Study B, where positive expectations from the researchers influence patient outcomes.
Pattern recognition in clinical reasoning US Medical PG Question 7: An academic medical center in the United States is approached by a pharmaceutical company to run a small clinical trial to test the effectiveness of its new drug, compound X. The company wants to know if the measured hemoglobin a1c (Hba1c) of patients with type 2 diabetes receiving metformin and compound X would be lower than that of control subjects receiving only metformin. After a year of study and data analysis, researchers conclude that the control and treatment groups did not differ significantly in their Hba1c levels.
However, parallel clinical trials in several other countries found that compound X led to a significant decrease in Hba1c. Interested in the discrepancy between these findings, the company funded a larger study in the United States, which confirmed that compound X decreased Hba1c levels. After compound X was approved by the FDA, and after several years of use in the general population, outcomes data confirmed that it effectively lowered Hba1c levels and increased overall survival. What term best describes the discrepant findings in the initial clinical trial run by institution A?
- A. Type I error
- B. Hawthorne effect
- C. Type II error (Correct Answer)
- D. Publication bias
- E. Confirmation bias
Pattern recognition in clinical reasoning Explanation: ***Type II error***
- A **Type II error** occurs when a study fails to **reject a false null hypothesis**, meaning it concludes there is no significant difference or effect when one actually exists.
- In this case, the initial US trial incorrectly concluded that Compound X had no significant effect on HbA1c, while subsequent larger studies and real-world data proved it did.
*Type I error*
- A **Type I error** (alpha error) occurs when a study incorrectly **rejects a true null hypothesis**, concluding there is a significant difference or effect when there isn't.
- This scenario describes the opposite: the initial study failed to find an effect that genuinely existed, indicating a Type II error, not a Type I error.
*Hawthorne effect*
- The **Hawthorne effect** is a type of reactivity in which individuals modify an aspect of their behavior in response to their awareness of being observed.
- This effect does not explain the initial trial's failure to detect a real drug effect; rather, it relates to participants changing behavior due to study participation itself.
*Publication bias*
- **Publication bias** occurs when studies with positive or statistically significant results are more likely to be published than those with negative or non-significant results.
- While relevant to the literature as a whole, it doesn't explain the discrepancy in findings within a single drug's development where a real effect was initially missed.
*Confirmation bias*
- **Confirmation bias** is the tendency to search for, interpret, favor, and recall information in a way that confirms one's preexisting beliefs or hypotheses.
- This bias would likely lead researchers to *find* an effect if they expected one, or to disregard data that contradicts their beliefs, which is not what happened in the initial trial.
Pattern recognition in clinical reasoning US Medical PG Question 8: A regional academic medical center has 10 cases of adenovirus in the span of a week among its ICU patients. A committee is formed to investigate this outbreak. They are tasked with identifying the patients and interviewing the care providers to understand how adenovirus could have been spread from patient to patient. This committee will review charts, talk to the care provider teams, and investigate current patient safety and sanitation measures in the ICU. The goal of the committee is to identify weaknesses in the current system and to put in place a plan to help prevent this sort of outbreak from reoccurring in the future. The committee is most likely using what type of analysis?
- A. Simulation
- B. Root cause analysis (Correct Answer)
- C. Algorithmic analysis
- D. Heuristic analysis
- E. Failure mode and effects analysis
Pattern recognition in clinical reasoning Explanation: ***Root cause analysis***
- The committee's goal is to **identify weaknesses** in the current system and **prevent recurrence**, which aligns perfectly with the principles of **root cause analysis (RCA)**.
- RCA is a structured method for **identifying the underlying causes** of problems or incidents, rather than just addressing symptoms.
*Simulation*
- **Simulation** involves creating a model of a process or system to test different scenarios and predict outcomes.
- While useful for planning, it's not the primary method for investigating an actual past event or identifying causative factors after an outbreak has occurred.
*Algorithmic analysis*
- **Algorithmic analysis** is primarily used in computer science to evaluate the efficiency and complexity of algorithms.
- It does not apply to investigating the spread of infectious diseases or healthcare system failures.
*Heuristic analysis*
- **Heuristic analysis** involves using a rule of thumb or an educated guess to solve a problem quickly and efficiently, especially when perfect solutions are not feasible.
- This approach is less systematic and comprehensive than what is required to thoroughly investigate an outbreak and identify root causes.
*Failure mode and effects analysis*
- **Failure mode and effects analysis (FMEA)** is a proactive method used to identify **potential failure modes** in a system and their effects *before* an event occurs.
- The committee is investigating an **already existing problem**, making RCA more appropriate than FMEA, which is used for risk assessment of future processes.
Pattern recognition in clinical reasoning US Medical PG Question 9: A 27-year-old woman presents to her primary care physician for minor aches and pains in her bones and muscles. She states that these symptoms have persisted throughout her entire life but have worsened recently when she moved to attend college. The patient is physically active, and states that she eats a balanced diet. She is currently a full-time student and is sexually active with 1 partner. She states that she has been particularly stressed lately studying for final exams and occasionally experiences diarrhea. She has been taking acyclovir for a dermatologic herpes simplex virus infection with minimal improvement. On physical exam, the patient exhibits 4/5 strength in her upper and lower extremities, and diffuse tenderness over her limbs that is non-specific. Laboratory values are ordered as seen below:
Serum:
Na+: 144 mEq/L
Cl-: 102 mEq/L
K+: 4.7 mEq/L
HCO3-: 24 mEq/L
Ca2+: 5.0
Urea nitrogen: 15 mg/dL
Glucose: 81 mg/dL
Creatinine: 1.0 mg/dL
Alkaline phosphatase: 225 U/L
Aspartate aminotransferase (AST, GOT): 11 U/L
Alanine aminotransferase (ALT, GPT): 15 U/L
Which of the following is most likely associated with this patient’s presentation?
- A. Vitamin D deficiency (Correct Answer)
- B. Fibromyalgia
- C. Primary hyperparathyroidism
- D. Chronic fatigue syndrome
- E. Systemic lupus erythematosus
Pattern recognition in clinical reasoning Explanation: ***Correct: Vitamin D deficiency***
- The patient presents with the **classic biochemical findings of vitamin D deficiency**: **severe hypocalcemia (Ca2+ 5.0 mg/dL, normal 8.5-10.5)** and **elevated alkaline phosphatase (225 U/L)**.
- **Clinical features of osteomalacia** are present: diffuse bone and muscle pain, proximal muscle weakness (4/5 strength in extremities), and bone tenderness—all consistent with bone demineralization and secondary myopathy.
- **Risk factor identified**: Recent move to college may represent lifestyle changes including reduced sun exposure, dietary changes, or increased indoor time studying.
- The elevated alkaline phosphatase reflects increased osteoblastic activity attempting to compensate for undermineralized bone matrix.
- Severe vitamin D deficiency also impairs immune function, which may explain the herpes simplex infection with poor response to acyclovir.
*Incorrect: Chronic fatigue syndrome*
- Chronic fatigue syndrome (CFS) is a **diagnosis of exclusion** characterized by persistent unexplained fatigue for at least 6 months with **normal laboratory findings**.
- This patient has **significant biochemical abnormalities** (severe hypocalcemia, elevated alkaline phosphatase) that exclude CFS and point to a specific metabolic disorder.
- CFS does not cause hypocalcemia, elevated alkaline phosphatase, or objective muscle weakness on examination.
*Incorrect: Fibromyalgia*
- While fibromyalgia presents with widespread musculoskeletal pain, it is characterized by **normal laboratory studies** including normal calcium and alkaline phosphatase.
- The patient's severe hypocalcemia and elevated alkaline phosphatase exclude fibromyalgia as the primary diagnosis.
- Fibromyalgia typically requires identification of specific tender points on examination, which are not described here.
*Incorrect: Systemic lupus erythematosus*
- SLE typically presents with **multisystem involvement** including malar rash, photosensitivity, serositis, nephritis, and hematologic abnormalities.
- Laboratory findings would show **positive autoantibodies** (ANA, anti-dsDNA, anti-Smith), not isolated hypocalcemia with elevated alkaline phosphatase.
- The patient's normal liver and kidney function, absence of systemic features, and specific biochemical pattern do not support SLE.
*Incorrect: Primary hyperparathyroidism*
- Primary hyperparathyroidism is defined by **hypercalcemia** with elevated or inappropriately normal PTH levels.
- This patient has **severe hypocalcemia (Ca2+ 5.0)**, which is the **opposite** of what occurs in hyperparathyroidism.
- The biochemical pattern (low calcium, high alkaline phosphatase) is consistent with hypoparathyroidism or vitamin D deficiency, not hyperparathyroidism.
Pattern recognition in clinical reasoning US Medical PG Question 10: A 38-year-old woman is voted off the board of her garden club for tardiness and incomplete work on the spring fair. When she arrives home, her husband attempts to console her and she yells at him for constantly criticizing her. Which defense mechanism is the woman using?
- A. Displacement (Correct Answer)
- B. Intellectualization
- C. Reaction formation
- D. Projection
- E. Isolation of affect
Pattern recognition in clinical reasoning Explanation: ***Displacement***
- **Displacement** is a defense mechanism where an individual redirects their emotions, often anger or frustration, from their initial target to a less threatening substitute.
- In this scenario, the woman's anger at being voted off the board is **displaced** onto her husband, who is a safer target for her pent-up emotions.
*Intellectualization*
- **Intellectualization** involves focusing on the intellectual aspects of a situation to avoid emotional distress, using logic and reason to analyze a problem without experiencing its associated feelings.
- The woman is clearly expressing raw emotion (anger), not engaging in an objective, logical analysis of her board removal.
*Reaction formation*
- **Reaction formation** is a defense mechanism in which an individual outwardly expresses the opposite of their true feelings or impulses.
- There is no indication here that the woman is acting in a way contrary to her internal feelings; she is directly expressing her anger.
*Projection*
- **Projection** involves attributing one's own unacceptable thoughts, feelings, or impulses to another person.
- The woman is not accusing her husband of being angry or criticizing; she is directing her own anger at him.
*Isolation of affect*
- **Isolation of affect** occurs when an individual acknowledges a factual event but detaches from the emotional component of it.
- The woman is clearly experiencing and expressing strong emotions (anger), indicating that affect has not been isolated from the event.
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