,NSG550/NSG 550 Exam 2 Diagnostic Reasoning for
1. Which imaging modality provides the most detailed visualization of brain anatomy, including
tumors and edema, but does not demonstrate blood flow?
A) Computed tomography (CT)
B) Magnetic resonance imaging (MRI)
C) Positron emission tomography (PET)
D) Functional MRI (fMRI)
Correct Answer: Magnetic resonance imaging (MRI)
Rationale: MRI provides superior soft-tissue contrast and detailed anatomical images of the brain,
making it ideal for detecting tumors and edema. CT is faster but has lower soft-tissue resolution. PET
and fMRI assess metabolic activity and blood flow, respectively, rather than static anatomy.
2. A 55-year-old male with a 40-pack-year smoking history presents with chronic cough, wheezing, and
progressive dyspnea. Spirometry reveals an FEV1/FVC ratio of 65%. Which diagnosis is most consistent
with these findings?
A) Asthma
B) Chronic bronchitis
C) Emphysema
D) Bronchiectasis
Correct Answer: Emphysema
Rationale: Emphysema, a subtype of COPD, is characterized by irreversible airflow obstruction
(FEV1/FVC < 70%) with destruction of alveolar walls and loss of elastic recoil, often in smokers.
Asthma is reversible. Chronic bronchitis involves productive cough but shares the obstructive pattern.
Bronchiectasis involves permanent airway dilation.
3. A 68-year-old female presents with acute confusion, urinary incontinence, and unsteady gait. Her
family reports a recent urinary tract infection. Which diagnosis is most likely?
A) Alzheimer's disease
B) Vascular dementia
C) Delirium
D) Parkinson's disease
,Correct Answer: Delirium
Rationale: Delirium is an acute, fluctuating disturbance in attention and awareness often triggered by
an underlying medical condition such as a UTI in older adults. Alzheimer's and vascular dementia have
gradual onsets. Parkinson's disease presents with motor symptoms, not acute confusion.
4. In the context of diagnostic reasoning, which of the following best defines the positive predictive
value (PPV) of a test?
A) The probability of disease given a positive test result
B) The probability of a positive test result given disease
C) The probability of no disease given a negative test result
D) The proportion of people without disease who test negative
Correct Answer: The probability of disease given a positive test result
Rationale: Positive predictive value is the proportion of individuals with a positive test result who
actually have the disease, reflecting the test's ability to confirm a diagnosis. Sensitivity is the
probability of a positive test given disease. Negative predictive value is the probability of no disease
given a negative test. Specificity is the proportion without disease who test negative.
5. A 45-year-old male presents with acute substernal chest pain radiating to the left arm,
accompanied by diaphoresis and nausea. ECG reveals ST-segment elevation in leads II, III, and aVF.
Which coronary artery is most likely occluded?
A) Left anterior descending artery
B) Left circumflex artery
C) Right coronary artery
D) Left main coronary artery
Correct Answer: Right coronary artery
Rationale: ST-segment elevation in the inferior leads (II, III, aVF) indicates an inferior wall myocardial
infarction, typically caused by occlusion of the right coronary artery. The left anterior descending
artery causes anterior wall infarction (V1-V4). The left circumflex artery causes lateral wall infarction
(I, aVL, V5-V6). Left main occlusion is usually catastrophic.
6. A 62-year-old female with a history of hypertension presents with progressive dyspnea on exertion,
orthopnea, and bilateral lower extremity edema. Physical examination reveals an S3 gallop and
elevated jugular venous pressure. Which diagnosis is most consistent with these findings?
, A) Chronic obstructive pulmonary disease
B) Congestive heart failure
C) Pulmonary embolism
D) Pericardial effusion
Correct Answer: Congestive heart failure
Rationale: Congestive heart failure presents with dyspnea, orthopnea, edema, and signs of volume
overload including an S3 gallop and elevated JVP. COPD presents with chronic cough and wheezing.
Pulmonary embolism presents with acute dyspnea and pleuritic chest pain. Pericardial effusion
presents with muffled heart sounds.
7. A 38-year-old female presents with a 3-month history of progressive fatigue, unintentional weight
gain, cold intolerance, and constipation. Laboratory studies reveal a TSH of 8.5 mIU/L and a low free
T4. Which diagnosis is most likely?
A) Graves' disease
B) Hashimoto's thyroiditis
C) Subacute thyroiditis
D) Pituitary adenoma
Correct Answer: Hashimoto's thyroiditis
Rationale: Hashimoto's thyroiditis is the most common cause of primary hypothyroidism, presenting
with elevated TSH and low free T4, along with symptoms of hypothyroidism. Graves' disease causes
hyperthyroidism with low TSH. Subacute thyroiditis may present with transient hyperthyroidism.
Pituitary adenoma causing secondary hypothyroidism would show low TSH and low free T4.
8. A 28-year-old female with irregular menses, hirsutism, and acne is found to have a BMI of 32.
Which diagnostic criteria are most consistent with polycystic ovary syndrome?
A) Oligo-ovulation, hyperandrogenism, and polycystic ovaries
B) Elevated FSH and low estradiol
C) Elevated prolactin and galactorrhea
D) Low TSH and elevated free T4
Correct Answer: Oligo-ovulation, hyperandrogenism, and polycystic ovaries
Rationale: The Rotterdam criteria for PCOS require two of three features: oligo-ovulation or
anovulation, clinical or biochemical hyperandrogenism, and polycystic ovaries on ultrasound. Elevated
1. Which imaging modality provides the most detailed visualization of brain anatomy, including
tumors and edema, but does not demonstrate blood flow?
A) Computed tomography (CT)
B) Magnetic resonance imaging (MRI)
C) Positron emission tomography (PET)
D) Functional MRI (fMRI)
Correct Answer: Magnetic resonance imaging (MRI)
Rationale: MRI provides superior soft-tissue contrast and detailed anatomical images of the brain,
making it ideal for detecting tumors and edema. CT is faster but has lower soft-tissue resolution. PET
and fMRI assess metabolic activity and blood flow, respectively, rather than static anatomy.
2. A 55-year-old male with a 40-pack-year smoking history presents with chronic cough, wheezing, and
progressive dyspnea. Spirometry reveals an FEV1/FVC ratio of 65%. Which diagnosis is most consistent
with these findings?
A) Asthma
B) Chronic bronchitis
C) Emphysema
D) Bronchiectasis
Correct Answer: Emphysema
Rationale: Emphysema, a subtype of COPD, is characterized by irreversible airflow obstruction
(FEV1/FVC < 70%) with destruction of alveolar walls and loss of elastic recoil, often in smokers.
Asthma is reversible. Chronic bronchitis involves productive cough but shares the obstructive pattern.
Bronchiectasis involves permanent airway dilation.
3. A 68-year-old female presents with acute confusion, urinary incontinence, and unsteady gait. Her
family reports a recent urinary tract infection. Which diagnosis is most likely?
A) Alzheimer's disease
B) Vascular dementia
C) Delirium
D) Parkinson's disease
,Correct Answer: Delirium
Rationale: Delirium is an acute, fluctuating disturbance in attention and awareness often triggered by
an underlying medical condition such as a UTI in older adults. Alzheimer's and vascular dementia have
gradual onsets. Parkinson's disease presents with motor symptoms, not acute confusion.
4. In the context of diagnostic reasoning, which of the following best defines the positive predictive
value (PPV) of a test?
A) The probability of disease given a positive test result
B) The probability of a positive test result given disease
C) The probability of no disease given a negative test result
D) The proportion of people without disease who test negative
Correct Answer: The probability of disease given a positive test result
Rationale: Positive predictive value is the proportion of individuals with a positive test result who
actually have the disease, reflecting the test's ability to confirm a diagnosis. Sensitivity is the
probability of a positive test given disease. Negative predictive value is the probability of no disease
given a negative test. Specificity is the proportion without disease who test negative.
5. A 45-year-old male presents with acute substernal chest pain radiating to the left arm,
accompanied by diaphoresis and nausea. ECG reveals ST-segment elevation in leads II, III, and aVF.
Which coronary artery is most likely occluded?
A) Left anterior descending artery
B) Left circumflex artery
C) Right coronary artery
D) Left main coronary artery
Correct Answer: Right coronary artery
Rationale: ST-segment elevation in the inferior leads (II, III, aVF) indicates an inferior wall myocardial
infarction, typically caused by occlusion of the right coronary artery. The left anterior descending
artery causes anterior wall infarction (V1-V4). The left circumflex artery causes lateral wall infarction
(I, aVL, V5-V6). Left main occlusion is usually catastrophic.
6. A 62-year-old female with a history of hypertension presents with progressive dyspnea on exertion,
orthopnea, and bilateral lower extremity edema. Physical examination reveals an S3 gallop and
elevated jugular venous pressure. Which diagnosis is most consistent with these findings?
, A) Chronic obstructive pulmonary disease
B) Congestive heart failure
C) Pulmonary embolism
D) Pericardial effusion
Correct Answer: Congestive heart failure
Rationale: Congestive heart failure presents with dyspnea, orthopnea, edema, and signs of volume
overload including an S3 gallop and elevated JVP. COPD presents with chronic cough and wheezing.
Pulmonary embolism presents with acute dyspnea and pleuritic chest pain. Pericardial effusion
presents with muffled heart sounds.
7. A 38-year-old female presents with a 3-month history of progressive fatigue, unintentional weight
gain, cold intolerance, and constipation. Laboratory studies reveal a TSH of 8.5 mIU/L and a low free
T4. Which diagnosis is most likely?
A) Graves' disease
B) Hashimoto's thyroiditis
C) Subacute thyroiditis
D) Pituitary adenoma
Correct Answer: Hashimoto's thyroiditis
Rationale: Hashimoto's thyroiditis is the most common cause of primary hypothyroidism, presenting
with elevated TSH and low free T4, along with symptoms of hypothyroidism. Graves' disease causes
hyperthyroidism with low TSH. Subacute thyroiditis may present with transient hyperthyroidism.
Pituitary adenoma causing secondary hypothyroidism would show low TSH and low free T4.
8. A 28-year-old female with irregular menses, hirsutism, and acne is found to have a BMI of 32.
Which diagnostic criteria are most consistent with polycystic ovary syndrome?
A) Oligo-ovulation, hyperandrogenism, and polycystic ovaries
B) Elevated FSH and low estradiol
C) Elevated prolactin and galactorrhea
D) Low TSH and elevated free T4
Correct Answer: Oligo-ovulation, hyperandrogenism, and polycystic ovaries
Rationale: The Rotterdam criteria for PCOS require two of three features: oligo-ovulation or
anovulation, clinical or biochemical hyperandrogenism, and polycystic ovaries on ultrasound. Elevated
