Differential Diagnosis Primary Care Final Exam
Review 2026/2027 – Questions and Answers |
100% Verified | Detailed Rationales – Pass
Guaranteed – A+ Graded
1. A 45-year-old male presents with a 3-day history of sharp, pleuritic chest pain
that worsens with deep inspiration. He also reports a low-grade fever and a
productive cough. What is the most likely diagnosis?
A. Myocardial infarction
B. Pneumonia
C. Pulmonary embolism
D. Pericarditis
Rationale: The combination of sharp, pleuritic chest pain (worsened by
inspiration), fever, and a productive cough is the classic triad for pneumonia.
Myocardial infarction pain is typically pressure-like and not pleuritic. Pulmonary
embolism often presents with sudden-onset dyspnea and pleuritic pain but is less
likely to have a productive cough and fever as primary features. Pericarditis pain is
often positional and relieved by leaning forward.
2. A 28-year-old female presents with a unilateral, throbbing headache, nausea,
and photophobia. She reports similar episodes since her teenage years. What is
the most likely diagnosis?
A. Tension headache
B. Cluster headache
C. Migraine headache
D. Sinusitis
Rationale: The patient's presentation of a unilateral, throbbing headache with
associated nausea and photophobia is classic for a migraine. Tension headaches
are typically bilateral and pressure-like. Cluster headaches are severe, unilateral,
,and associated with autonomic symptoms like tearing and nasal congestion.
Sinusitis headache is usually associated with facial pain and purulent nasal
discharge.
3. A 65-year-old male with a history of hypertension and diabetes presents with
sudden-onset, painless vision loss in his right eye. What is the most critical
diagnosis to rule out?
A. Cataract
B. Open-angle glaucoma
C. Central retinal artery occlusion
D. Macular degeneration
Rationale: Sudden, painless, monocular vision loss is a medical emergency
and is the hallmark of central retinal artery occlusion (CRAO). Cataracts and
macular degeneration cause gradual vision loss. Open-angle glaucoma is typically
painless but causes gradual peripheral vision loss. CRAO requires immediate
intervention to potentially save vision.
4. A 30-year-old female presents with a 2-week history of generalized fatigue,
low-grade fevers, and a new rash on her cheeks that she describes as a
"butterfly" shape. What is the most likely diagnosis?
A. Rosacea
B. Systemic Lupus Erythematosus (SLE)
C. Lyme disease
D. Contact dermatitis
Rationale: The malar ("butterfly") rash, in combination with constitutional
symptoms like fatigue and fever, is highly suggestive of Systemic Lupus
Erythematosus (SLE). Rosacea typically affects the central face but is not
associated with systemic symptoms. Lyme disease has a characteristic "bull's-eye"
rash (erythema migrans). Contact dermatitis is usually pruritic and related to a
specific exposure.
5. A 70-year-old male presents with a gradual onset of exertional chest pressure
and shortness of breath over the past 6 months. The symptoms are relieved by
,rest. What is the most likely diagnosis?
A. Stable angina
B. Unstable angina
C. Myocardial infarction
D. GERD
Rationale: The key features of stable angina are chest discomfort that is
predictably triggered by exertion and relieved by rest or nitroglycerin. Unstable
angina is a change in the pattern of stable angina (more frequent, severe, or at
rest). A myocardial infarction would cause more prolonged and severe pain not
relieved by rest. GERD is typically postprandial and burning in nature.
6. A 24-year-old female presents with dysuria, urinary frequency, and urgency.
She has no fever or flank pain. What is the most likely diagnosis?
A. Pyelonephritis
B. Uncomplicated cystitis
C. Vaginitis
D. Interstitial cystitis
Rationale: The classic symptoms of dysuria, frequency, and urgency without
systemic signs (like fever) or flank pain point to uncomplicated cystitis (a bladder
infection). Pyelonephritis would present with fever and flank pain. Vaginitis
typically presents with discharge and irritation, not primarily urinary symptoms.
Interstitial cystitis is a chronic condition with pain and frequency, but acute onset
is more typical of a UTI.
7. A 55-year-old male with a history of COPD presents with increased shortness
of breath, a change in the color of his sputum, and increased sputum volume.
What is the most likely diagnosis?
A. Acute bronchitis
B. Pneumonia
C. Acute exacerbation of COPD
D. Pulmonary embolism
, Rationale: In a patient with known COPD, the triad of increased dyspnea,
increased sputum volume, and increased sputum purulence is the definition of an
acute exacerbation of COPD. While pneumonia can cause similar symptoms, an
exacerbation is the most direct diagnosis given the history. Acute bronchitis is
typically viral and not associated with a chronic underlying lung disease.
8. A 3-year-old child is brought to the clinic with a barky, "seal-like" cough and
inspiratory stridor that started at night. What is the most likely diagnosis?
A. Epiglottitis
B. Croup (Laryngotracheobronchitis)
C. Asthma
D. Foreign body aspiration
Rationale: The classic presentation of a barky cough and inspiratory stridor in
a young child is croup. Epiglottitis presents with a rapidly progressing sore throat
and drooling, with the child in a "tripod" position. Asthma presents with
wheezing. Foreign body aspiration is usually sudden and without a preceding
illness.
9. A 40-year-old female presents with a new, painless lump in her right breast
that she found during a self-exam. What is the most important next step in her
evaluation?
A. Reassurance and follow-up in 3 months
B. Prescribe antibiotics
C. Order a diagnostic mammogram and ultrasound
D. Refer for immediate surgery
Rationale: Any new, palpable breast lump requires a thorough evaluation to
rule out malignancy. The standard next step is imaging, typically a diagnostic
mammogram and ultrasound. Reassurance is inappropriate. Antibiotics are for
mastitis, which is usually painful and associated with signs of infection. Immediate
surgery is not the first step without a diagnosis.
10. A 22-year-old male presents with a 1-day history of severe, right lower
quadrant abdominal pain that started as a dull ache around his umbilicus. He
Review 2026/2027 – Questions and Answers |
100% Verified | Detailed Rationales – Pass
Guaranteed – A+ Graded
1. A 45-year-old male presents with a 3-day history of sharp, pleuritic chest pain
that worsens with deep inspiration. He also reports a low-grade fever and a
productive cough. What is the most likely diagnosis?
A. Myocardial infarction
B. Pneumonia
C. Pulmonary embolism
D. Pericarditis
Rationale: The combination of sharp, pleuritic chest pain (worsened by
inspiration), fever, and a productive cough is the classic triad for pneumonia.
Myocardial infarction pain is typically pressure-like and not pleuritic. Pulmonary
embolism often presents with sudden-onset dyspnea and pleuritic pain but is less
likely to have a productive cough and fever as primary features. Pericarditis pain is
often positional and relieved by leaning forward.
2. A 28-year-old female presents with a unilateral, throbbing headache, nausea,
and photophobia. She reports similar episodes since her teenage years. What is
the most likely diagnosis?
A. Tension headache
B. Cluster headache
C. Migraine headache
D. Sinusitis
Rationale: The patient's presentation of a unilateral, throbbing headache with
associated nausea and photophobia is classic for a migraine. Tension headaches
are typically bilateral and pressure-like. Cluster headaches are severe, unilateral,
,and associated with autonomic symptoms like tearing and nasal congestion.
Sinusitis headache is usually associated with facial pain and purulent nasal
discharge.
3. A 65-year-old male with a history of hypertension and diabetes presents with
sudden-onset, painless vision loss in his right eye. What is the most critical
diagnosis to rule out?
A. Cataract
B. Open-angle glaucoma
C. Central retinal artery occlusion
D. Macular degeneration
Rationale: Sudden, painless, monocular vision loss is a medical emergency
and is the hallmark of central retinal artery occlusion (CRAO). Cataracts and
macular degeneration cause gradual vision loss. Open-angle glaucoma is typically
painless but causes gradual peripheral vision loss. CRAO requires immediate
intervention to potentially save vision.
4. A 30-year-old female presents with a 2-week history of generalized fatigue,
low-grade fevers, and a new rash on her cheeks that she describes as a
"butterfly" shape. What is the most likely diagnosis?
A. Rosacea
B. Systemic Lupus Erythematosus (SLE)
C. Lyme disease
D. Contact dermatitis
Rationale: The malar ("butterfly") rash, in combination with constitutional
symptoms like fatigue and fever, is highly suggestive of Systemic Lupus
Erythematosus (SLE). Rosacea typically affects the central face but is not
associated with systemic symptoms. Lyme disease has a characteristic "bull's-eye"
rash (erythema migrans). Contact dermatitis is usually pruritic and related to a
specific exposure.
5. A 70-year-old male presents with a gradual onset of exertional chest pressure
and shortness of breath over the past 6 months. The symptoms are relieved by
,rest. What is the most likely diagnosis?
A. Stable angina
B. Unstable angina
C. Myocardial infarction
D. GERD
Rationale: The key features of stable angina are chest discomfort that is
predictably triggered by exertion and relieved by rest or nitroglycerin. Unstable
angina is a change in the pattern of stable angina (more frequent, severe, or at
rest). A myocardial infarction would cause more prolonged and severe pain not
relieved by rest. GERD is typically postprandial and burning in nature.
6. A 24-year-old female presents with dysuria, urinary frequency, and urgency.
She has no fever or flank pain. What is the most likely diagnosis?
A. Pyelonephritis
B. Uncomplicated cystitis
C. Vaginitis
D. Interstitial cystitis
Rationale: The classic symptoms of dysuria, frequency, and urgency without
systemic signs (like fever) or flank pain point to uncomplicated cystitis (a bladder
infection). Pyelonephritis would present with fever and flank pain. Vaginitis
typically presents with discharge and irritation, not primarily urinary symptoms.
Interstitial cystitis is a chronic condition with pain and frequency, but acute onset
is more typical of a UTI.
7. A 55-year-old male with a history of COPD presents with increased shortness
of breath, a change in the color of his sputum, and increased sputum volume.
What is the most likely diagnosis?
A. Acute bronchitis
B. Pneumonia
C. Acute exacerbation of COPD
D. Pulmonary embolism
, Rationale: In a patient with known COPD, the triad of increased dyspnea,
increased sputum volume, and increased sputum purulence is the definition of an
acute exacerbation of COPD. While pneumonia can cause similar symptoms, an
exacerbation is the most direct diagnosis given the history. Acute bronchitis is
typically viral and not associated with a chronic underlying lung disease.
8. A 3-year-old child is brought to the clinic with a barky, "seal-like" cough and
inspiratory stridor that started at night. What is the most likely diagnosis?
A. Epiglottitis
B. Croup (Laryngotracheobronchitis)
C. Asthma
D. Foreign body aspiration
Rationale: The classic presentation of a barky cough and inspiratory stridor in
a young child is croup. Epiglottitis presents with a rapidly progressing sore throat
and drooling, with the child in a "tripod" position. Asthma presents with
wheezing. Foreign body aspiration is usually sudden and without a preceding
illness.
9. A 40-year-old female presents with a new, painless lump in her right breast
that she found during a self-exam. What is the most important next step in her
evaluation?
A. Reassurance and follow-up in 3 months
B. Prescribe antibiotics
C. Order a diagnostic mammogram and ultrasound
D. Refer for immediate surgery
Rationale: Any new, palpable breast lump requires a thorough evaluation to
rule out malignancy. The standard next step is imaging, typically a diagnostic
mammogram and ultrasound. Reassurance is inappropriate. Antibiotics are for
mastitis, which is usually painful and associated with signs of infection. Immediate
surgery is not the first step without a diagnosis.
10. A 22-year-old male presents with a 1-day history of severe, right lower
quadrant abdominal pain that started as a dull ache around his umbilicus. He
