Respiratory Pathology — MCQs

Respiratory Pathology Indian Medical PG Practice Questions and MCQs

Question 421: Which among the following has two general phases - first, simple pneumoconiosis and a second phase characterized by progressive massive fibrosis (PMF)?

A. Bagassosis
B. Anthracosis (Correct Answer)
C. Byssinosis
D. Siderosis

Explanation: ***Anthracosis (Coal Worker's Pneumoconiosis)*** - **Coal Worker's Pneumoconiosis (CWP)**, also known as **anthracosis** or **black lung disease**, is caused by prolonged inhalation of **coal dust** [1]. - It characteristically progresses through **two distinct phases** [2]: - **Simple CWP (Simple Pneumoconiosis)**: Characterized by coal macules and nodules (<1 cm) visible on chest X-ray, usually asymptomatic [2]. - **Complicated CWP (Progressive Massive Fibrosis - PMF)**: Large confluent fibrotic masses (>1 cm), often in upper lobes, leading to significant respiratory impairment [1][2]. - **PMF develops in 10-15%** of cases with simple CWP and represents irreversible progressive fibrosis. *Bagassosis* - **Bagassosis** is a **hypersensitivity pneumonitis** (extrinsic allergic alveolitis) caused by exposure to **bagasse**, the fibrous residue of sugarcane containing thermophilic actinomycetes [1]. - It presents as an **acute or chronic inflammatory response**, not a two-phase pneumoconiosis with PMF. *Byssinosis* - **Byssinosis** is an occupational lung disease caused by exposure to **cotton, flax, or hemp dust** in textile workers. - It manifests as **reversible airway obstruction** with characteristic **"Monday morning" chest tightness** and does not progress to PMF. - It is a reactive airway disease, not a fibrotic pneumoconiosis. *Siderosis* - **Siderosis** is a **benign pneumoconiosis** caused by inhalation of **iron oxide particles** (welders, iron miners) [1]. - It causes **radiographic opacities** but is **non-fibrogenic** and does not cause functional impairment or progress to PMF [1]. - Iron particles are inert and do not trigger significant inflammatory or fibrotic response. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, p. 695. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 331-332.

Question 422: The following table shows some of the pneumoconioses diseases along with the most implicated causative chemical agents. Which among the following represent the correct combinations of diseases and causative chemical agents? Select the correct answer using the code given below.

A. 2 and 4
B. 2 and 3
C. 1 and 3
D. 1 and 2 (Correct Answer)

Explanation: ***Correct: 1 and 2*** - **Statement 1 (Anthracosis - Coal dust)** is correct. Anthracosis, also known as **coal worker's pneumoconiosis**, is caused by chronic inhalation of coal dust particles [1]. - **Statement 2 (Byssinosis - Cotton dust)** is correct. Byssinosis is an occupational lung disease affecting **textile workers** exposed to cotton, flax, or hemp dust, causing airway obstruction. *Incorrect: 2 and 4* - Statement 4 is incorrect. **Siderosis** is caused by inhalation of **iron dust** (common in welders and miners), not asbestos [1]. Asbestos exposure causes **asbestosis** [1]. *Incorrect: 2 and 3* - Statement 3 is incorrect. **Bagassosis** is caused by inhalation of **sugarcane bagasse dust** (a hypersensitivity pneumonitis), not silica dust [1]. Silica causes **silicosis** [1]. *Incorrect: 1 and 3* - While statement 1 is correct (Anthracosis - Coal dust), statement 3 is incorrect as explained above (Bagassosis is caused by sugarcane bagasse dust, not silica dust) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, p. 695.

Question 423: A male patient with hemoptysis. On examination, hilar mass was present. The histopathological image is shown below. Immunohistochemistry revealed that the cells were positive for p40. What is the diagnosis?

A. Squamous cell carcinoma (Correct Answer)
B. Adenocarcinoma lung
C. Small cell carcinoma
D. Large cell carcinoma

Explanation: ***Squamous cell carcinoma*** - The image displays features characteristic of **squamous cell carcinoma**, including nests of polygonal cells, prominent nucleoli, and areas of **keratinization** (forming keratin pearls) which are indicative of squamous differentiation [1]. - The positive immunohistochemistry staining for **p40** is a highly specific marker for squamous cell differentiation, further confirming the diagnosis in the context of a hilar mass and hemoptysis, which are common presentations for this type of lung cancer [2]. *Adenocarcinoma lung* - **Adenocarcinoma lung** typically presents with glandular differentiation, featuring structures like acini, tubules, or papillae, and often produces mucin, none of which are evident in the provided image [1]. - Immunohistochemically, adenocarcinoma would typically stain positive for **TTF-1** or **Napsin A**, and would be negative for p40. *Small cell carcinoma* - **Small cell carcinoma** shows small, round to oval cells with scant cytoplasm, finely granular chromatin (salt and pepper pattern), and frequent mitoses with extensive necrosis [3]. - These cells are much smaller than squamous cells and lack keratinization. IHC would show positivity for **synaptophysin, chromogranin, and CD56** (neuroendocrine markers), not p40 [3]. *Large cell carcinoma* - **Large cell carcinoma** is a diagnosis of exclusion showing undifferentiated large cells without glandular or squamous differentiation features. - It lacks the keratinization and intercellular bridges seen here, and would be **p40 negative** as it shows no squamous differentiation. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 723-724. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 336-337. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 337-338.

Question 424: Match the following columns A. Caplan syndrome B. Mesothelioma C. Silicosis D. Asbestosis 1. Pleural effusion without shift 2. Crazy Paving 3. Lower lobe involved 4. Described in coal workers

A. A4-B1-C3-D2 (Correct Answer)
B. A4-B1-C3-D3
C. A2-B1-C4-D3
D. A4-B3-C1-D2

Explanation: ***A4-B1-C2-D3*** - **Caplan syndrome** is a rare lung condition characterized by the development of discrete **rheumatoid nodules** (0.5 to 5.0 cm in diameter) in the lungs of individuals with **rheumatoid arthritis** who also have a history of exposure to coal dust, thus it is described in **coal workers (A4)** [3], [4]. - **Mesothelioma** is an aggressive cancer arising from the lining of the lungs and abdomen, with hallmark features of **pleural effusion** without a mediastinal shift due to pleural encasement. It is strongly associated with **asbestos exposure (B1)** [2]. - **Silicosis** is a form of pneumoconiosis caused by the inhalation of crystalline silica. It characteristically causes fibrosis in the **upper and mid lung zones** [1]. The **"crazy paving" pattern** can be seen when silicosis is complicated by secondary **pulmonary alveolar proteinosis (PAP)**, making C2 the correct association. - **Asbestosis** is a chronic lung disease caused by inhaling asbestos fibers. It typically causes fibrosis in the **lower lobes** of the lungs, as asbestos fibers tend to accumulate in these areas due to gravity and ventilation patterns **(D3)** [1]. *A2-B1-C4-D3* - This option incorrectly associates "crazy paving" with asbestosis (D2 interpretation error) and incorrectly describes silicosis as primarily described in coal workers (C4), while silicosis is specifically due to silica exposure, not coal dust (though coal workers can develop silicosis from silica in coal mines). *A4-B3-C1-D2* - This option incorrectly states that mesothelioma primarily causes lower lobe involvement (B3), whereas its defining feature is pleural effusion without shift. - It also misidentifies pleural effusion without shift as a feature of silicosis (C1) and crazy paving as characteristic of asbestosis (D2). *A4-B1-C3-D3* - This option has a fundamental error: both silicosis (C) and asbestosis (D) are matched to feature 3 (lower lobe), which is impossible in a matching question. - Medically, silicosis affects **upper lobes**, not lower lobes, making this matching incorrect [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 698-699. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 339-340. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 331-332. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 333-334.

Question 425: A CT scan shows the 'crazy paving' pattern in both lungs. Which bronchoalveolar lavage finding would confirm pulmonary alveolar proteinosis?

A. Milky fluid with PAS-positive material (Correct Answer)
B. Hemosiderin-laden macrophages
C. Eosinophilia >25%
D. CD4/CD8 ratio >3.5

Explanation: ***Milky fluid with PAS-positive material*** - A **milky, turbid bronchoalveolar lavage (BAL) fluid** is characteristic of **pulmonary alveolar proteinosis (PAP)** due to the accumulation of lipoproteinaceous material [1]. - **Periodic Acid-Schiff (PAS) staining** confirms the presence of this **glycoprotein-rich surfactant material**, which reacts positively [1]. *Hemosiderin-laden macrophages* - These are indicative of **pulmonary hemorrhage**, not PAP. - They are commonly seen in conditions like **Goodpasture syndrome** or **idiopathic pulmonary hemosiderosis**. *Eosinophilia >25%* - Significant **eosinophilia in BAL fluid** is a hallmark of **eosinophilic pneumonia**, a different interstitial lung disease. - It suggests an **allergic or hypersensitivity reaction** in the lungs. *CD4/CD8 ratio >3.5* - An **elevated CD4/CD8 ratio** in BAL fluid is highly suggestive of **sarcoidosis**, a granulomatous inflammatory disease. - This ratio reflects the **lymphocyte population** in the alveoli, not lipoproteinaceous accumulation. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 703-705.

Question 426: Heart failure cells are:-

A. Pigmented alveolar macrophages (Correct Answer)
B. Lipofuscin granules in cardiac cells
C. Pigmented cells in pancreas
D. Pigmented hepatocytes

Explanation: ***Pigmented alveolar macrophages*** - **Heart failure cells** are **alveolar macrophages** that have phagocytosed **hemosiderin** [1], which is derived from extravasated red blood cells. - This occurs in conditions causing **pulmonary congestion** and **hemorrhage**, most notably in chronic left-sided heart failure [2]. *Lipofuscin granules in cardiac cells* - **Lipofuscin** is a "wear-and-tear" pigment that accumulates in various aging cells, including **cardiac myocytes** [3]. - While present in heart cells, **lipofuscin granules** do not represent the classic "heart failure cells" which are found in the lung [3]. *Pigmented cells in pancreas* - **Pigmented cells in the pancreas** are not a recognized pathological entity described as "heart failure cells." - This option is medically irrelevant in the context of heart failure pathophysiology. *Pigmented hepatocytes* - **Pigmented hepatocytes** can be seen in various conditions, such as **hemochromatosis** (iron overload) or certain drug-induced liver injuries. - However, they are not referred to as "heart failure cells," which specifically refers to hemosiderin-laden macrophages in the lungs. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 75-76. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 536-537. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, p. 75.

Question 427: Which of the following conditions is characterized by the presence of hyaline deposits in alveolar walls?

A. Asthma
B. Hyaline membrane disease (Correct Answer)
C. Chronic bronchitis
D. Interstitial lung disease

Explanation: ***Hyaline membrane disease*** - This condition is pathologically characterized by the presence of **eosinophilic (hyaline) membranes** lining the distal airspaces, which are composed of fibrin, cellular debris, and necrotic cells [1]. - These **hyaline deposits obstruct gas exchange** and are a hallmark of **acute lung injury** in neonates due to surfactant deficiency [2]. *Asthma* - Characterized by **bronchoconstriction**, **mucus plugging**, and **airway inflammation**, but not hyaline deposits in alveolar walls. - Pathologically, there is hyperplasia of goblet cells, hypertrophy of bronchial smooth muscle, and eosinophilic infiltration. *Chronic bronchitis* - Defined by **chronic productive cough** due to hypertrophy of mucous glands and increased mucus production in the bronchi, not alveolar hyaline deposits. - It primarily affects the **large airways** and is associated with chronic inflammation and airway obstruction. *Interstitial lung disease* - Involves inflammation and fibrosis of the **interstitium of the lung**, leading to impaired gas exchange. - While it causes architectural distortion, **hyaline deposits** in the alveolar walls are not a defining pathological feature. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 679-681. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, p. 466.

Question 428: Maximum predisposition to tuberculosis is seen in which pneumoconiosis?

A. Anthracosis
B. Byssinosis
C. Silicosis (Correct Answer)
D. Bagassosis

Explanation: ***Silicosis*** - **Silicosis** is particularly associated with an increased risk of developing **tuberculosis** due to the impairment of alveolar macrophage function [1]. - Silica particles interfere with the ability of macrophages to destroy *Mycobacterium tuberculosis*, leading to a higher susceptibility to infection and reactivation of latent tuberculosis [1]. - This classic association is known as **silicotuberculosis**. *Anthracosis* - **Anthracosis** (coal worker's pneumoconiosis) is caused by inhaling coal dust and, while it can impair lung function, it has a weaker association with tuberculosis compared to silicosis [2]. - The carbon particles in anthracosis are relatively inert and typically do not induce the same level of macrophage dysfunction as silica. *Byssinosis* - **Byssinosis** is an occupational lung disease caused by exposure to cotton, flax, or hemp dust, often presenting with chest tightness towards the beginning of the work week. - It is not specifically predisposed to tuberculosis, as it involves an inflammatory response to organic dusts rather than crystalline silica. *Bagassosis* - **Bagassosis** is a hypersensitivity pneumonitis resulting from exposure to *Thermophilic actinomycetes* found in moldy sugarcane (bagasse) [2]. - This condition is an allergic reaction in the lungs and does not have a significant association with an increased risk of tuberculosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 697-698. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, p. 695.

Question 429: Interstitial Emphysema may be found in the following conditions -

A. All of the options (Correct Answer)
B. Surgical wound
C. Tracheostomy
D. Chest injury

Explanation: ***All of the options*** - **Interstitial emphysema** refers to the presence of air in the interstitial tissues, often due to a leak from the respiratory or gastrointestinal tract, and can occur in various traumatic or iatrogenic contexts. [1] - **Surgical wounds**, **tracheostomies**, and **chest injuries** all present pathways for air to enter the interstitial spaces. *Surgical wound* - A **surgical wound**, especially around the chest or neck, can become a site of air leakage from the respiratory system, leading to **subcutaneous emphysema** or interstitial emphysema in the surrounding tissues. - This can be due to damaged lung or airway tissue during surgery or a persistent air leak from a poorly closed incision. *Tracheostomy* - A **tracheostomy** creates an opening into the trachea, and air can leak around the stoma or through a compromised airway wall into the neck tissues, causing **subcutaneous emphysema** locally. - Incorrect placement, cuff overinflation, or infection around the tracheostomy site can exacerbate air leakage. *Chest injury* - **Chest injuries**, such as **pneumothorax** or direct trauma to the lung and airways, can cause air to escape into the pleural space and then dissect into the interstitial tissues of the chest wall or mediastinum. [1] - This is a common finding in **blunt or penetrating chest trauma**, where alveolar or bronchial rupture allows air to track into surrounding tissues. [1] **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 327-328.

Question 430: A 45-year-old patient working in a factory for past 20 years presents with breathlessness. HRCT chest shows pleural thickening and fibrosis. What is the most likely diagnosis?

A. Asbestosis (Correct Answer)
B. Coal worker pneumoconiosis
C. Silicosis
D. Cotton fiber

Explanation: ***Asbestosis*** - **Asbestosis** is a chronic lung disease caused by inhaling **asbestos fibers**, common in industrial settings like factories, leading to **pleural thickening** and **fibrosis** in the lungs [1]. - The long latency period (20 years) and presentation with breathlessness are consistent with **asbestos exposure**, which also increases the risk of **mesothelioma** [1]. *Coal worker pneumoconiosis* - This condition is caused by inhaling **coal dust**, leading to lung fibrosis and inflammation, but typically does not present with prominent **pleural thickening** [1]. - While it can cause breathlessness, the characteristic HRCT finding of **pleural thickening** points away from coal worker pneumoconiosis as the primary diagnosis [1]. *Silicosis* - **Silicosis** results from inhaling **silica dust**, causing nodular fibrosis in the upper lobes of the lungs and is common in mining, quarrying, and sandblasting [2]. - While it causes lung fibrosis and breathlessness, **pleural thickening** is not a hallmark feature of silicosis, unlike asbestosis [1]. *Cotton fiber* - Inhaling **cotton dust** can cause **byssinosis**, characterized by chest tightness and breathlessness, particularly on the first day back to work after a break. - Unlike asbestosis, byssinosis does not typically lead to significant **pleural thickening** or **fibrosis** on HRCT. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 698-699. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, p. 697.

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