Pulmonology — MCQs

Pulmonology Indian Medical PG Practice Questions and MCQs

Question 241: Tuberculosis is associated with which of the following conditions?

A. Asbestosis
B. Coal worker's pneumoconiosis
C. Silicosis (Correct Answer)
D. Farmer's lung

Explanation: The correct answer is **Silicosis**. **Why Silicosis is the correct answer:** Silicosis is uniquely and strongly associated with an increased risk of developing Tuberculosis (TB), a condition termed **Silicotuberculosis**. The underlying pathophysiology involves the inhalation of crystalline silica particles, which are toxic to **alveolar macrophages**. Silica causes macrophage lysis and impairs their phagocytic capacity and phagolysosome formation. Since macrophages are the primary defense against *Mycobacterium tuberculosis*, their dysfunction allows the bacteria to proliferate unchecked [1]. Patients with silicosis have a 3-fold to 30-fold increased risk of TB compared to the general population. **Analysis of Incorrect Options:** * **Asbestosis:** While asbestos exposure significantly increases the risk of bronchogenic carcinoma and mesothelioma (especially when combined with smoking), it does not specifically predispose to TB [1]. * **Coal Worker’s Pneumoconiosis (CWP):** Simple CWP is generally not associated with an increased risk of TB unless there is concurrent silica exposure (anthracosilicosis) [1]. It is more commonly associated with Caplan Syndrome (RA nodules in the lung). * **Farmer’s Lung:** This is a type of Hypersensitivity Pneumonitis (Type III/IV hypersensitivity) caused by inhaling thermophilic actinomycetes from moldy hay. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** Silicosis typically presents with "Eggshell calcification" of hilar lymph nodes [1]. * **Pathology:** The characteristic lesion is the "Silicotic nodule" (concentric whorls of collagen). * **Screening:** All patients diagnosed with silicosis should receive a tuberculin skin test (TST) or IGRA, as they are considered a high-risk group. * **Upper Lobe Predominance:** Like TB, silicosis primarily affects the upper lobes of the lungs [1].

Question 242: A 30-year-old male presents with bilateral lymphadenitis characterized by non-caseating granulomas on biopsy. What is the most likely diagnosis?

A. Tuberculosis
B. Lymphoma
C. Sarcoidosis (Correct Answer)
D. Any of the above

Explanation: **Explanation:** The hallmark of **Sarcoidosis** is the presence of **non-caseating granulomas**. In a young adult presenting with bilateral lymphadenopathy (typically hilar or cervical), the finding of granulomas without central necrosis (caseation) is highly suggestive of Sarcoidosis [1]. This is a multi-system inflammatory disease characterized by an exaggerated T-cell mediated immune response to unknown antigens. **Analysis of Options:** * **A. Tuberculosis (TB):** This is the most important differential. However, TB typically presents with **caseating** (cheesy, necrotic) granulomas. While non-caseating granulomas can occasionally be seen in early TB, "non-caseating" in a medical exam context is a classic buzzword for Sarcoidosis. * **B. Lymphoma:** While lymphoma causes significant lymphadenopathy, the biopsy would show **malignant lymphoid cells** (e.g., Reed-Sternberg cells in Hodgkin’s) rather than organized granulomatous structures. * **D. Any of the above:** Incorrect because the specific pathological description of "non-caseating granulomas" specifically points toward a granulomatous disease like Sarcoidosis rather than malignancy or typical TB. **NEET-PG High-Yield Pearls:** * **Pathology:** Look for **Asteroid bodies** and **Schaumann bodies** within the giant cells of the granuloma. * **Biomarkers:** Elevated **Serum ACE (Angiotensin-Converting Enzyme)** levels and **Hypercalcemia** (due to 1-alpha hydroxylase activity in macrophages) are common [1]. * **Imaging:** Stage I Sarcoidosis presents as **Bilateral Hilar Lymphadenopathy (BHL)** on Chest X-ray [1]. * **Kveim Test:** Historically used for diagnosis (though rarely used now).

Question 243: Which of the following is a false statement about Type I respiratory failure?

A. Decreased PaO2
B. Decreased PaCO2
C. Normal PaCO2
D. Normal A-a gradient (Correct Answer)

Explanation: ### Explanation Respiratory failure is classified into two main types based on arterial blood gas (ABG) patterns [1]. **Type I (Hypoxemic)** respiratory failure is defined by a failure of oxygenation, while **Type II (Hypercapnic)** is a failure of ventilation [2]. #### Why Option D is the Correct Answer (The False Statement) In Type I respiratory failure, the underlying pathology usually involves **V/Q mismatch, shunting, or diffusion defects** (e.g., pneumonia, pulmonary edema, PE) [1, 3]. These conditions impair the transfer of oxygen from the alveoli to the blood, leading to an **increased A-a gradient** (Alveolar-arterial oxygen gradient). A **normal A-a gradient** is typically seen in hypoxemia caused by extrinsic factors like high altitude or hypoventilation (Type II failure), not Type I. #### Analysis of Incorrect Options * **A. Decreased PaO2:** This is the hallmark of Type I failure. It is defined as a $PaO_2 < 60$ mmHg [1]. * **B & C. Decreased or Normal PaCO2:** In Type I failure, the $PaCO_2$ is typically **low or normal** [2]. Hypoxemia triggers the peripheral chemoreceptors, leading to hyperventilation (tachypnea). This causes "washing out" of $CO_2$, resulting in hypocapnia. If the patient tires, $PaCO_2$ may normalize before eventually rising (signaling a shift to Type II). #### NEET-PG High-Yield Pearls * **Type I (Hypoxemic):** $PaO_2 \downarrow$, $PaCO_2 \downarrow$ or Normal, **A-a gradient \uparrow**. Common causes: ARDS, Pulmonary Edema, Pneumonia [1]. * **Type II (Hypercapnic):** $PaO_2 \downarrow$, $PaCO_2 \uparrow$ ($>50$ mmHg), **A-a gradient Normal**. Common causes: COPD, Myasthenia Gravis, Obesity Hypoventilation Syndrome. * **Formula for A-a gradient:** $P_AO_2 - P_aO_2$. A quick estimate for normal age-adjusted gradient is $(Age/4) + 4$.

Question 244: Pre-capillary Pulmonary Hypertension is defined as:

A. Pulmonary Artery Pressure (PAP) > 25 mm Hg; Pulmonary Capillary Wedge Pressure (PCWP) > 15 mmHg
B. Pulmonary Artery Pressure (PAP) > 25 mmHg; Pulmonary Capillary Wedge Pressure (PCWP) < 15 mmHg (Correct Answer)
C. Pulmonary Capillary Wedge Pressure (PCWP) > 25 mmHg; Pulmonary Artery Pressure (PAP) > 15 mmHg
D. Pulmonary Capillary Wedge Pressure (PCWP) > 25 mmHg; Pulmonary Artery Pressure (PAP) < 15 mmHg

Explanation: **Explanation:** Pulmonary Hypertension (PH) is hemodynamically defined by an elevation in the **Mean Pulmonary Artery Pressure (mPAP)**. To differentiate between the causes, we look at the **Pulmonary Capillary Wedge Pressure (PCWP)**, which reflects the pressure in the left atrium [1]. 1. **Why Option B is Correct:** Pre-capillary PH occurs when the pathology is located *before* the pulmonary capillaries (i.e., in the pulmonary arteries themselves). This results in a high mPAP (>25 mmHg) but a **normal PCWP (≤15 mmHg)**, because the left heart is functioning normally and there is no back-pressure from the left atrium. This is characteristic of WHO Group 1 (PAH), Group 3 (Lung disease), and Group 4 (CTEPH). 2. **Why Other Options are Incorrect:** * **Option A:** Describes **Post-capillary PH** (mPAP >25, PCWP >15). This occurs when left-sided heart disease (e.g., Mitral Stenosis or LV failure) causes back-pressure into the lungs [1]. * **Options C & D:** These are hemodynamically illogical. The PCWP cannot typically be higher than the mPAP, as blood flows from the pulmonary artery toward the left atrium [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Updated Definition:** While the traditional threshold was >25 mmHg, the **2022 ESC/ERS guidelines** have lowered the definition of PH to **mPAP >20 mmHg**. However, many exams still use the classic >25 mmHg cutoff. * **PVR:** For a diagnosis of Pre-capillary PH, the Pulmonary Vascular Resistance (PVR) must be **>2 Wood Units** (formerly >3). * **Gold Standard:** Right Heart Catheterization (RHC) is the gold standard for diagnosis; Echocardiography is only a screening tool.

Question 245: Which of the following is the cause of sudden and unexpected onset of dyspnea at rest?

A. Severe anemia
B. Spontaneous pneumothorax (Correct Answer)
C. COPD
D. Large pleural effusion

Explanation: **Explanation:** The key to this question lies in the temporal profile of the symptoms: **sudden and unexpected onset at rest.** **Spontaneous Pneumothorax (Correct Answer):** A spontaneous pneumothorax occurs when air enters the pleural space without an external trigger (often due to the rupture of a subpleural bleb) [1]. This leads to an immediate loss of negative intrapleural pressure and lung collapse. Because this event is mechanical and instantaneous, the patient experiences a "thunderclap" onset of pleuritic chest pain and dyspnea, even while sedentary [1]. **Analysis of Incorrect Options:** * **Severe Anemia:** Dyspnea in anemia is typically **exertional** (dyspnea on exertion) because the reduced oxygen-carrying capacity of the blood is most apparent when metabolic demands increase. It is a chronic, progressive condition rather than a sudden event at rest. * **COPD:** While COPD causes significant dyspnea, it is generally **chronic and progressive** [3]. Even during an acute exacerbation, the onset is usually subacute (over hours or days) and associated with increased cough and sputum production, rather than a "split-second" onset. * **Large Pleural Effusion:** Fluid accumulation in the pleural space is typically a **gradual process** (e.g., in CHF, malignancy, or TB). Dyspnea develops slowly as the fluid volume increases and compresses the lung parenchyma. **NEET-PG High-Yield Pearls:** * **Differential for Sudden Dyspnea:** Always consider the "Big 3": Pulmonary Embolism, Spontaneous Pneumothorax, and Acute Myocardial Infarction/Acute Left Ventricular Failure [2]. * **Primary Spontaneous Pneumothorax (PSP):** Classically seen in tall, thin young males (ectomorphic build) who are smokers [1]. * **Physical Exam Findings:** Look for hyper-resonant percussion notes, decreased breath sounds, and decreased vocal fremitus on the affected side. * **Diagnosis:** Confirmed by an upright Chest X-ray showing a visible visceral pleural line without peripheral lung markings [4].

Question 246: Pneumothorax is seen in all of the following conditions, except?

A. Marfan syndrome
B. Assisted ventilation
C. Eosinophilic granuloma
D. Bronchopulmonary Aspergillosis (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Bronchopulmonary Aspergillosis (ABPA).** **1. Why ABPA is the correct answer:** Allergic Bronchopulmonary Aspergillosis (ABPA) is a hypersensitivity reaction to *Aspergillus fumigatus* colonization in the bronchi. It typically presents with asthma, fleeting pulmonary opacities, and **central bronchiectasis**. While it causes airway destruction and mucus plugging, it does not typically lead to the formation of subpleural blebs or cystic lung destruction that results in a pneumothorax. **2. Analysis of Incorrect Options:** * **Marfan Syndrome:** This connective tissue disorder involves mutations in the Fibrillin-1 gene. Patients often have apical subpleural blebs due to structural weakness in the lung parenchyma, making them highly prone to spontaneous pneumothorax [1]. * **Assisted Ventilation:** Mechanical ventilation, especially with high Positive End-Expiratory Pressure (PEEP), can lead to **barotrauma**. This causes alveolar rupture, leading to air tracking into the pleura (pneumothorax) or mediastinum [1]. * **Eosinophilic Granuloma (Langerhans Cell Histiocytosis):** This is a classic cause of cystic lung disease. The formation of thin-walled cysts and their subsequent rupture is a hallmark feature, with pneumothorax occurring in approximately 25% of patients. **Clinical Pearls for NEET-PG:** * **Most common cause of Spontaneous Pneumothorax:** Rupture of subpleural blebs (usually in tall, thin young males) [1]. * **Most common cause of Secondary Spontaneous Pneumothorax:** COPD (due to ruptured bullae) [1]. * **High-yield associations with Pneumothorax:** Birt-Hogg-Dubé syndrome, Lymphangioleiomyomatosis (LAM), and Pneumocystis jirovecii pneumonia (PCP). * **ABPA Diagnostic Triad:** Asthma + Central Bronchiectasis + High IgE levels (>1000 IU/mL).

Question 247: Differential diagnosis of a solitary pulmonary nodule includes all of the following except?

A. Neurofibroma (Correct Answer)
B. Hamartoma
C. Tuberculoma
D. Bronchial adenoma

Explanation: ### Explanation A **Solitary Pulmonary Nodule (SPN)** is defined as a single, well-circumscribed, discrete opacity $\leq$ 3 cm in diameter that is completely surrounded by lung parenchyma (no associated atelectasis, hilar enlargement, or pleural effusion) [1]. **Why Neurofibroma is the Correct Answer:** Neurofibromas are neurogenic tumors. While they can occur in the thorax, they are typically found in the **posterior mediastinum** or along the chest wall (intercostal nerves) [2]. Because they are not entirely surrounded by lung parenchyma and originate from extrapulmonary structures, they do not meet the strict radiological definition of an SPN [2]. **Analysis of Incorrect Options:** * **Hamartoma:** The most common benign tumor of the lung. It typically presents as a peripheral SPN with characteristic "popcorn calcification" on CT. * **Tuberculoma:** A common infectious cause of SPN in endemic regions like India. It represents a healed or persistent focus of tuberculosis, often showing "satellite lesions" or solid/laminar calcification. * **Bronchial Adenoma:** This is an older term for low-grade malignancies like **Carcinoid tumors**. These can present as peripheral solitary nodules, though they are often central and endobronchial. **NEET-PG High-Yield Pearls:** 1. **Size Matters:** If the lesion is $>3$ cm, it is termed a **Lung Mass**, which has a much higher risk of malignancy. 2. **Calcification Patterns:** Benign nodules often show popcorn (Hamartoma), concentric, or diffuse calcification. Eccentric or stippled calcification suggests malignancy. 3. **Doubling Time:** Malignant nodules typically double in volume between 20 to 400 days. Stability for $>2$ years is a strong indicator of benignity [1]. 4. **Management:** The first step in evaluating an SPN is always to **compare with previous chest X-rays/CT scans** [1].

Question 248: Pulmonary embolism causes all of the following except?

A. Bradycardia (Correct Answer)
B. Decreased cardiac output
C. Alveolar hypoxemia
D. Acute right ventricular strain

Explanation: **Explanation:** Pulmonary Embolism (PE) typically presents with **Tachycardia**, not bradycardia. The sudden obstruction of the pulmonary artery leads to a series of hemodynamic and gas exchange abnormalities. **1. Why Bradycardia is the correct answer (The Exception):** In PE, the body initiates a sympathetic response to compensate for decreased oxygenation and falling blood pressure. This results in **sinus tachycardia**, which is the most common ECG finding in PE [1]. Bradycardia is not a feature of PE; if present, it may indicate a pre-terminal event or an alternative diagnosis. **2. Analysis of other options:** * **Decreased Cardiac Output:** Large emboli increase pulmonary vascular resistance, leading to right ventricular (RV) failure [1]. As the RV fails, left ventricular filling decreases (due to interventricular septal shift and reduced venous return), resulting in a drop in systemic cardiac output and potential shock [2]. * **Alveolar Hypoxemia:** PE causes a **Ventilation-Perfusion (V/Q) mismatch** [3]. Areas of the lung are ventilated but not perfused (increased dead space). Additionally, shunting and low mixed venous oxygen saturation contribute to systemic hypoxemia [1]. * **Acute Right Ventricular Strain:** The sudden increase in pulmonary artery pressure forces the RV to work against high resistance. This leads to RV dilation, wall stress, and potential ischemia, often visible on ECG as the **S1Q3T3 pattern** or T-wave inversions in V1-V4 [1]. **Clinical Pearls for NEET-PG:** * **Most common ECG finding:** Sinus Tachycardia [1]. * **Most specific ECG finding:** S1Q3T3 pattern (indicates acute cor pulmonale) [1]. * **Gold Standard Investigation:** CT Pulmonary Angiography (CTPA) [4]. * **ABG finding:** Typically shows Hypoxemia with **Respiratory Alkalosis** (due to hyperventilation) [1].

Question 249: Shifting dullness is the characteristic sign of which condition?

A. Hydropneumothorax (Correct Answer)
B. Pneumothorax
C. Consolidation
D. Collapse

Explanation: ### Explanation **Correct Answer: A. Hydropneumothorax** **Underlying Medical Concept:** Shifting dullness occurs when there is a combination of **free fluid and air** within the pleural space. In a normal pleural effusion, the fluid is under negative pressure and is held against the chest wall by surface tension (forming a meniscus/Ellis S-shaped curve), which does not shift easily with position. However, in **hydropneumothorax**, the presence of air eliminates this surface tension. This allows the fluid to form a perfectly horizontal level that shifts rapidly and significantly with gravity when the patient changes position. **Analysis of Incorrect Options:** * **B. Pneumothorax:** This involves only air in the pleural space [1]. The percussion note is **hyper-resonant** or tympanitic, not dull. * **C. Consolidation:** This occurs when alveoli are filled with fluid or exudate (e.g., pneumonia). Since the fluid is intra-alveolar and fixed within the lung parenchyma, it does not shift with change in posture. The percussion note is **stony dull**. * **D. Collapse:** This involves the loss of lung volume. Percussion yields a **dull note**, but because the pathology is structural and internal to the lung, there is no mobile fluid to produce shifting dullness. **Clinical Pearls for NEET-PG:** * **Succussion Splash:** A splashing sound heard with the stethoscope while shaking the patient's patient's torso; it is pathognomonic for **hydropneumothorax** (or a large hiatus hernia). * **Chest X-ray:** Hydropneumothorax is characterized by a **horizontal fluid level** rather than the typical curved meniscus seen in simple pleural effusion. * **Traube’s Space:** Shifting dullness is also a classic sign of **ascites** (abdominal fluid), but in the thorax, it specifically points to the air-fluid interface of hydropneumothorax.

Question 250: All of the following statements about silicosis are true, EXCEPT:

A. Pleural plaques (Correct Answer)
B. Predilection for upper lobes
C. Calcific hilar lymphadenopathy
D. Associated with tuberculosis

Explanation: The correct answer is **A (Pleural plaques)** because pleural plaques are the hallmark radiologic feature of **Asbestosis**, not Silicosis [1]. While silicosis primarily affects the lung parenchyma and hilar nodes, it does not typically involve the pleura. **Analysis of Options:** * **Option B (Predilection for upper lobes):** This is a true statement. Silicosis, like most inorganic dust pneumoconioses (except asbestosis), primarily involves the upper lobes of the lungs [1]. Small, rounded opacities (nodules) first appear in the upper zones [1]. * **Option C (Calcific hilar lymphadenopathy):** This is a classic feature of silicosis. The hilar lymph nodes may enlarge and develop a characteristic peripheral calcification pattern known as **"Eggshell calcification."** * **Option D (Associated with tuberculosis):** This is true. Silica is toxic to alveolar macrophages, impairing their ability to kill mycobacteria. This leads to a significantly increased risk (up to 30-fold) of developing tuberculosis, a condition termed **Silicotuberculosis**. **High-Yield Clinical Pearls for NEET-PG:** * **Occupational History:** Look for keywords like sandblasting, mining, stone cutting, or glass manufacturing. * **Pathology:** The characteristic lesion is the **Silicotic nodule**, which shows a central area of whorled collagen fibers and peripheral "dust-laden" macrophages. * **Birefringence:** Under polarized light, silica particles appear as weakly birefringent crystals. * **PMF:** Progressive Massive Fibrosis (PMF) occurs when nodules coalesce into large masses (>1 cm), leading to restrictive lung disease [1]. * **Caplan Syndrome:** The association of silicosis (or coal worker's pneumoconiosis) with Rheumatoid Arthritis.

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Obstructive Airway Diseases (Asthma, COPD)

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Interstitial Lung Diseases

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Pulmonary Infections

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Pulmonary Vascular Diseases

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Pleural Diseases

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Sleep-Disordered Breathing

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Respiratory Failure

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Mediastinal Disorders

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Occupational Lung Diseases

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Pulmonary Function Testing

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Bronchiectasis and Cystic Fibrosis

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Lung Cancer Approach

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