Diagnostic thoroughness (Hickam's dictum) US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Diagnostic thoroughness (Hickam's dictum). These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Diagnostic thoroughness (Hickam's dictum) US Medical PG 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?
- A. Valid and reliable
- B. Reliable (Correct Answer)
- C. Valid
- D. Biased
- E. Neither valid nor reliable
Diagnostic thoroughness (Hickam's dictum) Explanation: ***Reliable***
- The test produces **similar results repeatedly** upon repeated measures, indicating high **reliability** or **precision**.
- Reliability refers to the **consistency** of a measure, even if it is not accurate.
*Valid and reliable*
- While the test is **reliable**, it is explicitly stated that the results are **not consistent with the gold standard**, meaning it lacks **validity**.
- A test must be both **consistent** (reliable) and **accurate** (valid) to be described as valid and reliable.
*Valid*
- **Validity** refers to the **accuracy** of a test, or how well it measures what it is supposed to measure.
- The test is explicitly stated to **not be consistent with the gold standard**, indicating a lack of agreement with the true measure of Alzheimer's.
*Biased*
- **Bias** refers to a **systematic error** in measurement that can lead to consistently high or low results compared to the true value.
- While the test might be biased due to its lack of consistency with the gold standard, "biased" is not the most accurate single descriptor of its measurement properties given the information provided.
*Neither valid nor reliable*
- The test is described as producing **very similar results repeatedly**, which directly indicates it has **high reliability**.
- Therefore, stating it is neither valid nor reliable is incorrect, as it possesses reliability.
Diagnostic thoroughness (Hickam's dictum) US Medical PG Question 2: A 55-year-old caucasian man presents to his primary care physician with a complaint of double vision, which started suddenly with no precipitating trauma. Twelve years ago, he presented to his physician with painful vision loss, which has since resolved. Since that initial episode, he had numerous episodes early-on in his disease course: two additional episodes of painful vision loss, as well as three episodes of right arm weakness and three episodes of urinary retention requiring catheterization. All of his prior episodes responded to supportive therapy and steroids. Which of the following features of this patient's disease is linked to a more benign disease course?
- A. Gender
- B. Age at onset
- C. Number of episodes early in the disease
- D. Initial presenting symptoms (Correct Answer)
- E. Race
Diagnostic thoroughness (Hickam's dictum) Explanation: ***Initial presenting symptoms***
- **Optic neuritis** (painful vision loss) or **sensory symptoms** as initial presentations are associated with a **more benign disease course** in multiple sclerosis.
- This patient presented with optic neuritis 12 years ago, which is a favorable prognostic indicator.
- Motor symptoms, cerebellar symptoms, or polysymptomatic onset at presentation typically indicate a **more aggressive prognosis** with faster disability accumulation.
*Age at onset*
- This patient had onset at approximately **43 years old** (late onset).
- **Later age of onset** (after 40 years) is associated with a **more aggressive disease course** and poorer prognosis in MS.
- Earlier age of onset (20s-30s) is typically linked to a more benign relapsing-remitting course with slower progression.
*Number of episodes early in the disease*
- A **higher number of relapses** early in the disease course (this patient had 8 episodes) is associated with **worse prognosis** and faster disability accumulation.
- Frequent early attacks indicate higher disease activity and greater neurological damage.
*Gender*
- **Female gender** is associated with higher MS incidence and often a slightly more benign course compared to males.
- This patient is **male**, which is not a favorable prognostic factor.
*Race*
- **Caucasian ethnicity** has the highest MS prevalence but does not predict a more benign course.
- African Americans tend to have more aggressive disease with faster disability progression, making Caucasian race relatively neutral prognostically.
Diagnostic thoroughness (Hickam's dictum) 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
Diagnostic thoroughness (Hickam's dictum) 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.
Diagnostic thoroughness (Hickam's dictum) US Medical PG Question 4: A 66-year-old man is brought into the emergency department by his daughter for a change in behavior. Yesterday the patient seemed more confused than usual and was asking the same questions repetitively. His symptoms have not improved over the past 24 hours, thus the decision to bring him in today. Last year, the patient was almost completely independent but he then suffered a "series of falls," after which his ability to care for himself declined. After this episode he was no longer able to cook for himself or pay his bills but otherwise had been fine up until this episode. The patient has a past medical history of myocardial infarction, hypertension, depression, diabetes mellitus type II, constipation, diverticulitis, and peripheral neuropathy. His current medications include metformin, insulin, lisinopril, hydrochlorothiazide, sodium docusate, atorvastatin, metoprolol, fluoxetine, and gabapentin. On exam you note a confused man who is poorly kept. He has bruises over his legs and his gait seems unstable. He is alert to person and place, and answers some questions inappropriately. The patient's pulse is 90/minute and his blood pressure is 170/100 mmHg. Which of the following is the most likely diagnosis?
- A. Normal aging
- B. Lewy body dementia
- C. Vascular dementia (Correct Answer)
- D. Pseudodementia (depression-related cognitive impairment)
- E. Alzheimer's dementia
Diagnostic thoroughness (Hickam's dictum) Explanation: ***Vascular dementia***
- This diagnosis is strongly supported by the patient's **stepwise decline** in cognitive function following a "series of falls" (likely small strokes or transient ischemic attacks) and his extensive history of **vascular risk factors** including hypertension, diabetes, and previous myocardial infarction.
- The acute worsening of confusion over 24 hours, coupled with pre-existing impaired executive function (inability to cook or pay bills), is characteristic of **vascular dementia's fluctuating course** and presentation often linked to new cerebrovascular events.
*Incorrect: Normal aging*
- **Normal aging** involves a very gradual and mild decline in cognitive functions, primarily affecting processing speed and memory recall, without significant impairment in daily activities.
- This patient's rapid, stepwise decline and inability to perform instrumental activities of daily living (IADLs) such as cooking and managing finances go beyond what is considered normal cognitive changes with aging.
*Incorrect: Lewy body dementia*
- **Lewy body dementia** is characterized by prominent **fluctuations in attention and alertness**, recurrent visual hallucinations, and spontaneous parkinsonism, none of which are explicitly mentioned as primary features in this patient's presentation.
- While fluctuations in confusion are present, the history of a clear stepwise decline post-falls and significant vascular risk factors points away from Lewy body dementia as the most likely primary cause.
*Incorrect: Pseudodementia (depression-related cognitive impairment)*
- **Pseudodementia** refers to cognitive impairment that occurs in the context of **major depression**, where patients may exhibit poor concentration, memory difficulties, and psychomotor slowing that mimics dementia.
- While this patient is on fluoxetine for depression, the **stepwise decline** after clear vascular events (falls), multiple vascular risk factors, and impaired executive function point to a true neurodegenerative process rather than depression-induced cognitive changes, which typically improve with treatment of the underlying mood disorder.
*Incorrect: Alzheimer's dementia*
- **Alzheimer's dementia** typically presents with a **gradual and progressive decline** in memory, particularly episodic memory, followed by other cognitive domains over several years.
- The patient's history of a clear **stepwise decline** in function after acute events (falls) and the strong presence of **vascular risk factors** make vascular dementia a more fitting diagnosis than Alzheimer's, which is not typically associated with such a sudden, step-like progression.
Diagnostic thoroughness (Hickam's dictum) US Medical PG Question 5: A 62-year-old man comes to the physician in May for a routine health maintenance examination. He feels well. He underwent a right inguinal hernia repair 6 months ago. He has hypertension and type 2 diabetes mellitus. There is no family history of serious illness. Current medications include metformin, sitagliptin, enalapril, and metoprolol. He received the zoster vaccine 1 year ago. He received the PPSV23 vaccine 4 years ago. His last colonoscopy was 7 years ago and was normal. He smoked a pack of cigarettes a day for 20 years but quit 17 years ago. He drinks two to three alcoholic beverages on weekends. He is allergic to amoxicillin. He is scheduled to visit Australia and New Zealand in 2 weeks to celebrate his 25th wedding anniversary. He appears healthy. Vital signs are within normal limits. An S4 is heard at the apex. The remainder of the examination shows no abnormalities. Which of the following is the most appropriate recommendation at this time?
- A. Colonoscopy
- B. Influenza vaccine (Correct Answer)
- C. Pneumococcal conjugate vaccine 13
- D. Cardiac stress test
- E. Abdominal ultrasound
Diagnostic thoroughness (Hickam's dictum) Explanation: ***Influenza vaccine***
- Current guidelines recommend annual **influenza vaccination** for all adults, particularly those over 60 years old and those with chronic medical conditions like diabetes and hypertension.
- **Critical timing consideration**: The patient is traveling to Australia and New Zealand (Southern Hemisphere) in 2 weeks, where it will be **winter season** (May-September) with peak influenza activity.
- He is a **high-risk patient** (age >60, diabetes, hypertension, cardiovascular disease) who should receive influenza vaccine before travel to areas experiencing influenza season.
- This is the **most appropriate and time-sensitive recommendation** at this visit.
*Colonoscopy*
- The patient had a normal colonoscopy 7 years ago; current guidelines suggest a repeat colonoscopy every **10 years** for average-risk individuals.
- There are no new symptoms, family history, or risk factors that would necessitate an earlier repeat colonoscopy at this time.
*Pneumococcal conjugate vaccine 13*
- The patient received **PPSV23** four years ago at approximately age 58.
- Per **current CDC guidelines (2019+)**, PCV13 is **no longer routinely recommended** for immunocompetent adults ≥65 years old.
- PPSV23 alone is now the standard recommendation for adults ≥65, which this patient has already received.
- PCV13 may be considered through **shared decision-making** in specific circumstances, but is not a routine or urgent recommendation.
*Cardiac stress test*
- Although the patient has risk factors for cardiovascular disease (hypertension, diabetes, former smoker) and an **S4 heart sound** (indicating **left ventricular hypertrophy**), he is asymptomatic.
- Routine **screening stress tests** are not recommended for asymptomatic individuals without signs of active cardiac ischemia.
*Abdominal ultrasound*
- There are **no symptoms** or specific indications (e.g., abdominal aortic aneurysm screening criteria not met - would need age 65-75 with smoking history).
- The patient is 62 years old and quit smoking 17 years ago, so AAA screening criteria are not yet met.
- Routine screening abdominal ultrasounds are not indicated.
Diagnostic thoroughness (Hickam's dictum) US Medical PG Question 6: 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 thoroughness (Hickam's dictum) 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 thoroughness (Hickam's dictum) US Medical PG Question 7: 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 thoroughness (Hickam's dictum) 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 thoroughness (Hickam's dictum) US Medical PG Question 8: A 24-year-old woman is brought to the hospital by her mother because she has "not been herself" for the past 3 months. The patient says she hears voices in her head. The mother said that when she is talking to her daughter she can’t seem to make out what she is saying; it is as if her thoughts are disorganized. When talking with the patient, you notice a lack of energy and an apathetic affect. Which of the following is the most likely diagnosis for this patient?
- A. Major depressive disorder
- B. Schizophrenia
- C. Brief psychotic disorder
- D. Schizotypal disorder
- E. Schizophreniform disorder (Correct Answer)
Diagnostic thoroughness (Hickam's dictum) Explanation: ***Schizophreniform disorder***
- The patient exhibits core **psychotic symptoms** (hearing voices, disorganized thoughts) for a duration of **3 months**, which is characteristic of schizophreniform disorder (symptoms lasting **1 to 6 months**).
- Her **lack of energy** and **apathetic affect** align with the negative symptoms commonly seen in psychotic disorders.
*Major depressive disorder*
- While **lack of energy** and **apathetic affect** can be present, the prominent **hallucinations** (hearing voices) and **disorganized thoughts** are not primary features of major depressive disorder.
- A diagnosis of depression alone would not fully account for her psychotic symptoms.
*Schizophrenia*
- Schizophrenia requires symptoms to be present for **at least 6 months**, including at least one month of **active phase symptoms**. This patient's symptoms have only been present for 3 months.
- While the symptoms are consistent with schizophrenia, the **duration criterion** has not yet been met.
*Brief psychotic disorder*
- Brief psychotic disorder is characterized by psychotic symptoms lasting **less than 1 month**. This patient's symptoms have been ongoing for 3 months.
- The chronicity of symptoms makes this diagnosis unlikely.
*Schizotypal disorder*
- Schizotypal disorder is a **personality disorder** characterized by peculiar thoughts and behaviors, but typically **without overt psychotic episodes** or pronounced disorganized speech/hallucinations as described.
- While there may be odd beliefs or ideas of reference, the clear **auditory hallucinations** and **thought disorder** in this case point to a more severe psychotic condition.
Diagnostic thoroughness (Hickam's dictum) US Medical PG Question 9: A 67-year-old man presents to the emergency department with confusion. The patient is generally healthy, but his wife noticed him becoming progressively more confused as the day went on. The patient is not currently taking any medications and has no recent falls or trauma. His temperature is 102°F (38.9°C), blood pressure is 126/64 mmHg, pulse is 120/min, respirations are 17/min, and oxygen saturation is 98% on room air. Physical exam is notable for a confused man who cannot participate in a neurological exam secondary to his confusion. No symptoms are elicited with flexion of the neck and jolt accentuation of headache is negative. Initial laboratory values are unremarkable and the patient's chest radiograph and urinalysis are within normal limits. An initial CT scan of the head is unremarkable. Which of the following is the best next step in management?
- A. CT angiogram of the head and neck
- B. Vancomycin, ceftriaxone, ampicillin, and dexamethasone
- C. Acyclovir (Correct Answer)
- D. PCR of the cerebrospinal fluid
- E. MRI of the head
Diagnostic thoroughness (Hickam's dictum) Explanation: ***Acyclovir***
- This patient presents with **acute confusion and fever** without an obvious infectious source, negative meningeal signs, and normal initial imaging, highly suggestive of **herpes simplex encephalitis (HSE)**.
- HSE is a **medical emergency** with high mortality (70-80%) if untreated, but mortality drops to 20-30% with early acyclovir therapy.
- **Empiric acyclovir must be started immediately** upon clinical suspicion of HSE, **without waiting for diagnostic confirmation**.
- Standard management includes obtaining CSF for PCR **concurrently** with starting acyclovir, but treatment should never be delayed for diagnostic testing.
- The best next step in **management** is initiating acyclovir; CSF PCR is obtained for confirmation but does not delay treatment.
*PCR of the cerebrospinal fluid*
- **CSF PCR for HSV** is the gold standard **diagnostic test** for HSE with high sensitivity (96%) and specificity (99%).
- While lumbar puncture should be performed to obtain CSF for PCR, this is a **diagnostic step** that should be done **concurrently** with starting acyclovir, not instead of it.
- The question asks for best next step in **management**, not diagnosis—acyclovir therapy takes precedence.
- Delaying acyclovir while awaiting diagnostic confirmation significantly increases morbidity and mortality.
*Vancomycin, ceftriaxone, ampicillin, and dexamethasone*
- This broad-spectrum antibiotic regimen is empiric therapy for **bacterial meningitis** and should be considered in patients with fever and altered mental status.
- However, the **absence of meningeal signs** (negative nuchal rigidity, negative jolt accentuation) makes bacterial meningitis less likely.
- In practice, when HSE is suspected but bacterial meningitis cannot be excluded, both antimicrobial regimens may be initiated empirically, but the primary concern here is HSE given the clinical presentation.
*MRI of the head*
- **MRI with FLAIR sequences** is highly sensitive for HSE and typically shows **temporal lobe involvement** (especially medial temporal lobes).
- However, MRI findings may be **normal early in the disease course** (first 48-72 hours).
- MRI is useful for supporting the diagnosis but should **not delay empiric acyclovir therapy**.
- Obtaining MRI before treatment would be inappropriate given the time-sensitive nature of HSE.
*CT angiogram of the head and neck*
- CT angiography evaluates vascular structures and is indicated for suspected **stroke, aneurysm, or vascular dissection**.
- This patient lacks focal neurological deficits, signs of acute stroke, or vascular risk factors that would prioritize vascular imaging.
- The presentation with fever and diffuse encephalopathy points toward an infectious/inflammatory process rather than a vascular etiology.
Diagnostic thoroughness (Hickam's dictum) US Medical PG Question 10: 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 thoroughness (Hickam's dictum) 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.
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