NR 569 MIDTERM EXAM 2026/2027 | Differential
Diagnosis in Acute Care Practicum Review |
Chamberlain
SECTION I: FOUNDATIONS OF DIAGNOSTIC REASONING & CLINICAL DECISION-
MAKING (Q1–Q20)
Q1. A 68-year-old male presents to the emergency department with acute onset
chest pain. The ACNP begins generating diagnostic hypotheses. Which approach
best reflects the hypothesis-driven method of diagnostic reasoning per 2026
guidelines?
A. Order a comprehensive metabolic panel and wait for results before forming
any clinical impression
B. Generate multiple competing diagnoses simultaneously based on the initial
presentation, then systematically rule them in or out
C. Rely solely on pattern recognition from previous similar patients to arrive at a
single diagnosis immediately
D. Refer the patient to a specialist before initiating any diagnostic workup given
the complexity
Correct Answer: B
Rationale: The hypothesis-driven method involves generating multiple
diagnostic hypotheses early based on initial data, then systematically testing each
through focused assessment. This reduces cognitive bias and anchoring, which are
leading causes of diagnostic error in acute care per the 2026 National Academies
of Medicine report. Option A delays clinical reasoning inappropriately. Option C
describes pattern recognition alone, which is prone to bias with atypical
presentations. Option D defers reasoning without initial assessment by the ACNP,
which contradicts the scope of practice.
,Q2. An ACNP evaluates a 55-year-old female with dyspnea. The Wells score
estimates PE pre-test probability at 15%. A D-dimer returns at 450 ng/mL
(negative below 500). Using Bayesian analysis, what is the most appropriate next
step?
A. Discharge the patient since the negative D-dimer conclusively rules out PE
B. Proceed directly to CTPA because the pre-test probability is too high for D-
dimer
C. Calculate post-test probability using the negative likelihood ratio to determine
if PE is excluded
D. Repeat the D-dimer in 24 hours to confirm the negative result before
disposition
Correct Answer: C
Rationale: Bayesian analysis requires combining pre-test probability with test
characteristics (likelihood ratios) to determine post-test probability. The 2026
ACCP/ESC guidelines emphasize D-dimer interpretation must integrate clinical
probability via validated scoring. A D-dimer near the cutoff with moderate pre-
test probability does not automatically exclude PE; the negative likelihood ratio
must be applied. If post-test probability remains above the test-treatment
threshold, further imaging is warranted. Simply discharging or reflexively imaging
both represent suboptimal diagnostic reasoning.
Q3. A 42-year-old female has 2 weeks of progressive fatigue, myalgias, and low-
grade fevers. She was diagnosed with viral syndrome 5 days ago but now presents
with new petechiae on her lower extremities and gum bleeding. Which red flag
most significantly changes diagnostic urgency?
A. Duration of symptoms extending beyond 10 days without improvement
B. New onset bleeding manifestations suggesting a potential hematologic
emergency
C. Presence of myalgias which could indicate an autoimmune process
,D. Low-grade fevers suggesting an undiagnosed infectious etiology
Correct Answer: B
Rationale: New bleeding manifestations (petechiae, gum bleeding) in the
setting of a recent viral illness raise immediate concern for immune
thrombocytopenia (ITP), thrombotic thrombocytopenic purpura (TTP), or
disseminated intravascular coagulation (DIC). These are hematologic emergencies
requiring urgent CBC with platelet count, peripheral smear, and coagulation
studies. Duration of symptoms and myalgias are nonspecific. Low-grade fever
alone does not change urgency as dramatically as active bleeding.
Q4. A 45-year-old female presents with acute chest pain. The NP uses the "most
dangerous first" approach to differential diagnosis. Which condition must be ruled
out immediately before considering less life-threatening causes?
A. Costochondritis
B. Gastroesophageal reflux disease
C. Acute coronary syndrome
D. Panic disorder
Correct Answer: C
Rationale: In acute chest pain, acute coronary syndrome (ACS) represents the
most dangerous differential and must be excluded first through ECG and
troponins before attributing symptoms to benign causes like GERD or
costochondritis. The "most dangerous first" principle ensures life-threatening
conditions are prioritized in the diagnostic workup.
Q5. A 62-year-old male with HTN and hyperlipidemia presents with acute-onset
severe headache. The NP applies Bayesian reasoning with a pretest probability of
15% for subarachnoid hemorrhage. Which clinical feature most significantly
increases the post-test probability?
A. Gradual onset over 2 hours
, B. Pain relieved by acetaminophen
C. "Thunderclap" onset with meningismus
D. Bilateral frontal location
Correct Answer: C
Rationale: Thunderclap headache with meningismus is the classic
presentation of subarachnoid hemorrhage; this finding dramatically increases
post-test probability and mandates immediate non-contrast head CT. Gradual
onset, response to acetaminophen, and bilateral frontal location are not
characteristic of SAH.
Q6. A 38-year-old female presents with dyspnea and pleuritic chest pain. The NP
constructs a differential using the VINDICATE mnemonic. Which condition
represents the "I" (inflammatory/infectious) category that is both common and
potentially life-threatening?
A. Pulmonary embolism
B. Pneumonia
C. Pneumothorax
D. Pericarditis
Correct Answer: B
Rationale: Pneumonia is an infectious/inflammatory cause of dyspnea and
pleuritic chest pain that is both common in acute care and potentially life-
threatening if severe or complicated by sepsis. PE is vascular, pneumothorax is
structural, and pericarditis is inflammatory but less common as a primary life-
threatening cause.
Q7. A 55-year-old male with DM presents with fever, hypotension, and altered
mental status. The NP prioritizes differentials using the "sepsis bundle"
framework. What is the first diagnostic step?
Diagnosis in Acute Care Practicum Review |
Chamberlain
SECTION I: FOUNDATIONS OF DIAGNOSTIC REASONING & CLINICAL DECISION-
MAKING (Q1–Q20)
Q1. A 68-year-old male presents to the emergency department with acute onset
chest pain. The ACNP begins generating diagnostic hypotheses. Which approach
best reflects the hypothesis-driven method of diagnostic reasoning per 2026
guidelines?
A. Order a comprehensive metabolic panel and wait for results before forming
any clinical impression
B. Generate multiple competing diagnoses simultaneously based on the initial
presentation, then systematically rule them in or out
C. Rely solely on pattern recognition from previous similar patients to arrive at a
single diagnosis immediately
D. Refer the patient to a specialist before initiating any diagnostic workup given
the complexity
Correct Answer: B
Rationale: The hypothesis-driven method involves generating multiple
diagnostic hypotheses early based on initial data, then systematically testing each
through focused assessment. This reduces cognitive bias and anchoring, which are
leading causes of diagnostic error in acute care per the 2026 National Academies
of Medicine report. Option A delays clinical reasoning inappropriately. Option C
describes pattern recognition alone, which is prone to bias with atypical
presentations. Option D defers reasoning without initial assessment by the ACNP,
which contradicts the scope of practice.
,Q2. An ACNP evaluates a 55-year-old female with dyspnea. The Wells score
estimates PE pre-test probability at 15%. A D-dimer returns at 450 ng/mL
(negative below 500). Using Bayesian analysis, what is the most appropriate next
step?
A. Discharge the patient since the negative D-dimer conclusively rules out PE
B. Proceed directly to CTPA because the pre-test probability is too high for D-
dimer
C. Calculate post-test probability using the negative likelihood ratio to determine
if PE is excluded
D. Repeat the D-dimer in 24 hours to confirm the negative result before
disposition
Correct Answer: C
Rationale: Bayesian analysis requires combining pre-test probability with test
characteristics (likelihood ratios) to determine post-test probability. The 2026
ACCP/ESC guidelines emphasize D-dimer interpretation must integrate clinical
probability via validated scoring. A D-dimer near the cutoff with moderate pre-
test probability does not automatically exclude PE; the negative likelihood ratio
must be applied. If post-test probability remains above the test-treatment
threshold, further imaging is warranted. Simply discharging or reflexively imaging
both represent suboptimal diagnostic reasoning.
Q3. A 42-year-old female has 2 weeks of progressive fatigue, myalgias, and low-
grade fevers. She was diagnosed with viral syndrome 5 days ago but now presents
with new petechiae on her lower extremities and gum bleeding. Which red flag
most significantly changes diagnostic urgency?
A. Duration of symptoms extending beyond 10 days without improvement
B. New onset bleeding manifestations suggesting a potential hematologic
emergency
C. Presence of myalgias which could indicate an autoimmune process
,D. Low-grade fevers suggesting an undiagnosed infectious etiology
Correct Answer: B
Rationale: New bleeding manifestations (petechiae, gum bleeding) in the
setting of a recent viral illness raise immediate concern for immune
thrombocytopenia (ITP), thrombotic thrombocytopenic purpura (TTP), or
disseminated intravascular coagulation (DIC). These are hematologic emergencies
requiring urgent CBC with platelet count, peripheral smear, and coagulation
studies. Duration of symptoms and myalgias are nonspecific. Low-grade fever
alone does not change urgency as dramatically as active bleeding.
Q4. A 45-year-old female presents with acute chest pain. The NP uses the "most
dangerous first" approach to differential diagnosis. Which condition must be ruled
out immediately before considering less life-threatening causes?
A. Costochondritis
B. Gastroesophageal reflux disease
C. Acute coronary syndrome
D. Panic disorder
Correct Answer: C
Rationale: In acute chest pain, acute coronary syndrome (ACS) represents the
most dangerous differential and must be excluded first through ECG and
troponins before attributing symptoms to benign causes like GERD or
costochondritis. The "most dangerous first" principle ensures life-threatening
conditions are prioritized in the diagnostic workup.
Q5. A 62-year-old male with HTN and hyperlipidemia presents with acute-onset
severe headache. The NP applies Bayesian reasoning with a pretest probability of
15% for subarachnoid hemorrhage. Which clinical feature most significantly
increases the post-test probability?
A. Gradual onset over 2 hours
, B. Pain relieved by acetaminophen
C. "Thunderclap" onset with meningismus
D. Bilateral frontal location
Correct Answer: C
Rationale: Thunderclap headache with meningismus is the classic
presentation of subarachnoid hemorrhage; this finding dramatically increases
post-test probability and mandates immediate non-contrast head CT. Gradual
onset, response to acetaminophen, and bilateral frontal location are not
characteristic of SAH.
Q6. A 38-year-old female presents with dyspnea and pleuritic chest pain. The NP
constructs a differential using the VINDICATE mnemonic. Which condition
represents the "I" (inflammatory/infectious) category that is both common and
potentially life-threatening?
A. Pulmonary embolism
B. Pneumonia
C. Pneumothorax
D. Pericarditis
Correct Answer: B
Rationale: Pneumonia is an infectious/inflammatory cause of dyspnea and
pleuritic chest pain that is both common in acute care and potentially life-
threatening if severe or complicated by sepsis. PE is vascular, pneumothorax is
structural, and pericarditis is inflammatory but less common as a primary life-
threatening cause.
Q7. A 55-year-old male with DM presents with fever, hypotension, and altered
mental status. The NP prioritizes differentials using the "sepsis bundle"
framework. What is the first diagnostic step?
