PANCE Pulmonary System 4 — Questions and Answers
Question 1: A 50-year-old male smoker presents with weight loss, hemoptysis, and hyponatremia (Na 122 mEq/L). Chest CT shows a central hilar mass. Which cell type is most likely responsible for his electrolyte abnormality?
- Squamous cell carcinoma
- Adenocarcinoma
- Small cell carcinoma (Correct answer)
- Large cell carcinoma
Correct answer: Small cell carcinoma
Small cell lung carcinoma is the most common cause of SIADH-mediated hyponatremia due to ectopic ADH secretion.
Question 2: Which finding is MOST specific for exudative pleural effusion using Light's criteria?
- Pleural fluid protein >3 g/dL
- Pleural fluid LDH >200 U/L
- Pleural fluid LDH to serum LDH ratio >0.6 (Correct answer)
- Pleural fluid to serum protein ratio >0.5
Correct answer: Pleural fluid LDH to serum LDH ratio >0.6
A pleural fluid/serum LDH ratio >0.6 is one of Light's three criteria; meeting any one criterion classifies the effusion as an exudate.
Question 3: A patient develops worsening hypoxemia 48 hours after an aspiration event. CXR shows bilateral infiltrates with no evidence of cardiogenic edema. PaO2/FiO2 ratio is 150. How is this classified?
- Mild ARDS
- Moderate ARDS
- Severe ARDS (Correct answer)
- Acute lung injury (ALI)
Correct answer: Severe ARDS
Per Berlin definition, severe ARDS is defined by a PaO2/FiO2 ratio ≤100 mmHg with PEEP ≥5 cmH2O; PaO2/FiO2 of 150 classifies as moderate (100-200).
Question 4: A 68-year-old presents with productive cough, fever, and consolidation in the right lower lobe. Blood cultures are negative. She was hospitalized 3 weeks ago. Which organism is the most likely causative agent?
- Streptococcus pneumoniae
- Methicillin-resistant Staphylococcus aureus (MRSA) (Correct answer)
- Haemophilus influenzae
- Klebsiella pneumoniae
Correct answer: Methicillin-resistant Staphylococcus aureus (MRSA)
Healthcare-associated pneumonia occurring within 90 days of hospitalization has higher prevalence of MRSA and gram-negative rods, with MRSA being a key concern.
Question 5: A 40-year-old African American woman presents with bilateral hilar lymphadenopathy, uveitis, and erythema nodosum. Serum ACE level is elevated. What is the most likely diagnosis?
- Lymphoma
- Sarcoidosis (Correct answer)
- Tuberculosis
- Histoplasmosis
Correct answer: Sarcoidosis
The triad of bilateral hilar lymphadenopathy, uveitis, and erythema nodosum with elevated ACE is classic for sarcoidosis, which has higher prevalence in African Americans.
Question 6: A patient on mechanical ventilation has high peak airway pressures but normal plateau pressures. Which condition best explains this finding?
- ARDS
- Pulmonary fibrosis
- Kinked endotracheal tube (Correct answer)
- Auto-PEEP
Correct answer: Kinked endotracheal tube
High peak with normal plateau pressure indicates increased airway resistance (not decreased compliance), classically caused by a kinked or partially obstructed ETT.
Question 7: A 55-year-old presents with slowly progressive dyspnea, pleural plaques on CT, and a restrictive pattern on PFTs. He worked in shipbuilding for 30 years. Which lung cancer type carries the highest risk in this patient?
- Squamous cell carcinoma
- Small cell carcinoma
- Adenocarcinoma
- Mesothelioma (Correct answer)
Correct answer: Mesothelioma
Asbestos exposure is the primary risk factor for malignant pleural mesothelioma, with pleural plaques being a marker of significant prior exposure.
PANCE Pulmonary System 4
A 50-year-old male smoker presents with weight loss, hemoptysis, and hyponatremia (Na 122 mEq/L).
Chest CT shows a central hilar mass.
Which cell type is most likely responsible for his electrolyte abnormality?