Review | Wilkes University | Pass Guaranteed - A+ Graded
SECTION 1: COMPLEX DIFFERENTIAL DIAGNOSIS DEVELOPMENT
(25 Questions)
Q1: A 58-year-old male presents with progressive dyspnea, nonproductive cough, and
bilateral lower extremity edema over 6 weeks. He has a 40 pack-year smoking history.
Chest X-ray shows bilateral hilar lymphadenopathy and interstitial infiltrates. Serum ACE
is elevated. Which diagnostic approach most effectively differentiates sarcoidosis from
lymphoma, tuberculosis, and occupational lung disease in this presentation?
A. Perform transbronchial biopsy alone to confirm noncaseating granulomas
B. Order PET-CT to assess metabolic activity and guide biopsy site selection [CORRECT]
C. Initiate empiric anti-tubercular therapy while awaiting cultures
D. Obtain serum calcium and 24-hour urine calcium to confirm sarcoidosis
Correct Answer: B
Rationale: PET-CT identifies hypermetabolic lymph nodes or pulmonary lesions,
enabling targeted biopsy that distinguishes sarcoidosis (noncaseating granulomas)
from lymphoma (monoclonal lymphoid proliferation) and TB (caseating granulomas
with acid-fast bacilli). Transbronchial biopsy alone has high sampling error. Empiric TB
therapy risks toxicity without confirmation. Hypercalcemia supports sarcoidosis but
lacks specificity for differentiation.
Q2: A 45-year-old female presents with episodic severe headaches, palpitations,
diaphoresis, and anxiety attacks. Blood pressure is 180/110 mmHg during episodes but
normal between episodes. Plasma metanephrines are mildly elevated. Which
,differential diagnosis strategy best distinguishes pheochromocytoma from panic
disorder, essential hypertension, and carcinoid syndrome?
A. Begin clonidine suppression testing to rule out essential hypertension
B. Order 24-hour urinary catecholamines and fractionated metanephrines with
creatinine correction [CORRECT]
C. Initiate SSRI therapy for presumed panic disorder and monitor response
D. Perform CT abdomen with contrast as the first diagnostic step
Correct Answer: B
Rationale: Twenty-four-hour urinary fractionated metanephrines with creatinine
correction provides superior sensitivity and specificity for pheochromocytoma
compared to plasma testing alone, effectively distinguishing catecholamine-secreting
tumors from panic disorder (normal catecholamines), essential hypertension
(suppressed with clonidine), and carcinoid (elevated 5-HIAA). CT localization follows
biochemical confirmation. SSRI initiation without ruling out pheochromocytoma risks
hypertensive crisis.
Q3: A 67-year-old male with diabetes and hypertension presents with acute-onset
left-sided weakness, dysarthria, and visual field defect. CT head is negative for
hemorrhage. Which differential prioritization best guides immediate management when
distinguishing ischemic stroke, hemorrhagic conversion, seizure with Todd's paralysis,
and complicated migraine?
A. Obtain MRI with diffusion-weighted imaging immediately to confirm ischemia before
treatment
B. Administer IV thrombolysis based on clinical presentation and CT exclusion of
hemorrhage [CORRECT]
C. Order EEG first to exclude seizure with postictal paralysis
D. Perform lumbar puncture to exclude subarachnoid hemorrhage
Correct Answer: B
,Rationale: In acute stroke presentation with CT-negative hemorrhage, IV thrombolysis
within the therapeutic window is indicated based on clinical criteria without awaiting
MRI, as delayed treatment increases disability and mortality. MRI confirms ischemia but
should not delay thrombolysis. EEG for seizure and LP for SAH are appropriate
differentials but do not take precedence over time-critical reperfusion therapy when
hemorrhage is excluded.
Q4: A 52-year-old female presents with fatigue, arthralgias, Raynaud phenomenon, and
new-onset hypertension. Laboratory studies reveal positive ANA (1:640, speckled),
anti-dsDNA negative, normal complements, and creatinine 1.8 mg/dL. Which diagnostic
reasoning approach best differentiates systemic lupus erythematosus from mixed
connective tissue disease, scleroderma renal crisis, and drug-induced lupus?
A. Order anti-Smith and anti-RNP antibodies to distinguish SLE from MCTD and
scleroderma [CORRECT]
B. Perform renal biopsy immediately to confirm lupus nephritis
C. Discontinue all medications and observe for resolution of symptoms
D. Initiate high-dose corticosteroids empirically for presumed scleroderma renal crisis
Correct Answer: A
Rationale: Anti-Smith antibodies are highly specific for SLE, while anti-RNP antibodies
characterize MCTD; anti-Scl-70 or anti-centromere antibodies indicate scleroderma. This
serological differentiation guides targeted management before invasive biopsy. Renal
biopsy is indicated for confirmed lupus nephritis classification but not before
establishing the underlying autoimmune diagnosis. Drug-induced lupus typically shows
anti-histone antibodies and lacks renal involvement.
Q5: A 38-year-old male presents with progressive dysphagia to solids and liquids,
regurgitation of undigested food, and nocturnal cough. Barium swallow reveals a dilated
esophagus with bird-beak tapering at the LES. Which differential strategy best
, distinguishes achalasia from pseudoachalasia, Chagas disease, and esophageal
stricture?
A. Perform esophageal manometry to assess LES pressure and relaxation with
peristaltic function [CORRECT]
B. Order Trypanosoma cruzi serology immediately to exclude Chagas disease
C. Proceed directly to laparoscopic Heller myotomy for definitive treatment
D. Perform EGD with biopsy to rule out malignancy before any functional testing
Correct Answer: A
Rationale: Esophageal manometry is the gold standard for achalasia diagnosis,
demonstrating impaired LES relaxation and absent peristalsis; it distinguishes primary
achalasia from pseudoachalasia (often normal or incomplete relaxation with underlying
malignancy). EGD with biopsy follows manometry to exclude malignancy. Chagas
serology is relevant only in endemic areas. Surgical intervention requires confirmed
diagnosis.
Q6: A 29-year-old female presents with recurrent abdominal pain, diarrhea, and
15-pound weight loss. Colonoscopy reveals skip lesions, cobblestoning, and
noncaseating granulomas on biopsy. Which approach best differentiates Crohn disease
from ulcerative colitis, intestinal tuberculosis, and Behçet disease?
A. Order ASCA and p-ANCA serologies to differentiate Crohn disease from ulcerative
colitis [CORRECT]
B. Initiate empiric anti-tubercular therapy for presumed intestinal TB
C. Perform upper endoscopy and small bowel capsule study to confirm pan-enteric
involvement
D. Start mesalamine therapy immediately as it treats both Crohn disease and ulcerative
colitis
Correct Answer: A
Rationale: ASCA (anti-Saccharomyces cerevisiae antibodies) positivity with p-ANCA
negativity strongly supports Crohn disease, while p-ANCA positivity with ASCA