Respiratory Pathology Practice Questions

Q: Which of the following statements concerning alveolar macrophages is true?

They secrete elastase.. ### Explanation **Correct Option: B (They secrete elastase)** Alveolar macrophages (Dust cells) are the primary immune defense in the distal airways. When activated—particularly by irritants like cigarette smoke—they secrete various inflammatory mediators, including **elastase** (a matrix metalloproteinase). Elastase breaks down elastin, the protein responsible for the elastic recoil of the lungs. Under normal physiological conditions, this enzyme is neutralized by **$\alpha_1$-antitrypsin**. An imbalance between elastase and its inhibitor leads to the destruction of alveolar walls, resulting in **emphysema**. **Analysis of Incorrect Options:** * **Option A:** $\alpha_1$-antitrypsin is primarily synthesized and secreted by the **liver (hepatocytes)**, not macrophages. It serves as a protective protease inhibitor. * **Option C:** Alveolar macrophages originate from **blood monocytes**, which migrate into the lung tissue and differentiate. Neutrophils are different myeloid cells that are recruited to the lungs only during acute inflammation. * **Option D:** Hyaline membrane disease (Infant Respiratory Distress Syndrome) is caused by a **deficiency of surfactant** produced by **Type II pneumocytes**, not by macrophage activity. **High-Yield NEET-PG Pearls:** * **Protease-Antiprotease Hypothesis:** Emphysema is the result of excessive elastase (from macrophages and neutrophils) or deficient $\alpha_1$-antitrypsin. * **Smoking Effect:** Smoking increases the number of macrophages and inhibits the activity of $\alpha_1$-antitrypsin, accelerating lung tissue destruction. * **Heart Failure Cells:** In left-sided heart failure, alveolar macrophages that ingest extravasated RBCs and contain hemosiderin are called "Heart Failure Cells."

Q: Ciliocytophthoria is seen in which of the following conditions?

Acute respiratory infection. **Explanation:** **Ciliocytophthoria (CCP)** refers to a specific cytopathological change characterized by the **degeneration and fragmentation of ciliated columnar epithelial cells**. In this process, the apical portion of the cell (containing the cilia and a pyknotic nucleus or nuclear fragment) separates from the basal portion. 1. **Why "Acute Respiratory Infection" is correct:** CCP is most commonly associated with **viral respiratory infections**, particularly those caused by **Adenovirus**, Influenza, and Parainfluenza. The virus induces a cytopathic effect that leads to the tufting and detachment of the ciliated border. Recognizing CCP is clinically significant in sputum or bronchoalveolar lavage (BAL) cytology because it can be mistaken for protozoa (like *Balantidium coli*) or malignant cells, potentially leading to a misdiagnosis. 2. **Why other options are incorrect:** * **Kartagener Syndrome & Situs Inversus:** These are related to **Primary Ciliary Dyskinesia (PCD)**, which involves a structural/functional defect in the dynein arms of cilia. While the cilia are dysfunctional, they do not typically undergo the specific fragmentation (CCP) seen in acute viral insults. * **Cystic Fibrosis:** This is a genetic disorder affecting chloride channels (CFTR), leading to thick mucus and secondary chronic infections. While chronic inflammation occurs, CCP is not a hallmark diagnostic feature of this condition. **High-Yield Pearls for NEET-PG:** * **Key Association:** Adenovirus infection is the classic trigger for CCP. * **Morphology:** Look for "tufts" of cilia attached to a small rim of cytoplasm with a pyknotic nucleus. * **Differential Diagnosis:** Must be distinguished from *Lophomonas blattarum* (a multiflagellated protozoan) in respiratory samples. * **Clinical Context:** It is a non-specific marker of epithelial injury but strongly points toward a viral etiology in the respiratory tract.

Question 1

A 25-year-old woman presents with progressive dyspnea and fatigue over the past 2 years. Physical examination reveals pedal edema, jugular venous distention, and hepatomegaly. Lung auscultation is clear. A chest CT scan shows right heart enlargement. Cardiac catheterization demonstrates increased pulmonary arterial pressure without pulmonic valve gradients and no shunts. A transbronchial biopsy reveals plexiform lesions. A mutation in a gene encoding for which of the following is most likely responsible for her pulmonary disease?

Accepted Answer

Bone morphogenetic receptor 2 (BMPR2)

Answer

B-type natriuretic peptide (BNP)

Answer

Endothelial nitric oxide synthetase (eNOS)

Answer

Fibrillin-1

Question 2

Which of the following statements concerning alveolar macrophages is true?

Accepted Answer

They secrete elastase.

Answer

They secrete a1-antitrypsin.

Answer

They originate from blood neutrophils.

Answer

They may play a role in causing hyaline membrane disease.

Question 3

Charcot-Leyden crystals and Curshmann's spirals are seen in which of the following conditions?

Accepted Answer

Bronchial asthma

Answer

Chronic bronchitis

Answer

Bronchiectasis

Answer

Emphysema

Question 4

How is pulmonary infarction differentiated from pulmonary edema?

Accepted Answer

Heart failure cells

Answer

Necrotizing alveolar sac

Answer

Capillary congestion

Answer

Pulmonary wedge pressure

Question 5

Which tumor suppressor gene is primarily responsible for lung squamous cell carcinoma?

Accepted Answer

p53

Answer

Rb

Answer

PTEN

Answer

p63

Question 6

A 30-year-old man undergoes a lung biopsy, which shows multiple nodular lesions consisting of large epithelioid cells surrounded by lymphocytes and fibroblasts. There is an area of necrosis in the center of some nodules. Numerous acid-fast bacilli are demonstrated by Ziehl-Neelsen staining within the cytoplasm of epithelioid cells. Silver stains for fungi are negative. Which of the following is the MOST likely condition that predisposed the patient to this pulmonary disease?

Accepted Answer

Acquired immunodeficiency syndrome (AIDS)

Answer

Common variable immunodeficiency

Answer

Cystic fibrosis

Answer

Depressed level of consciousness

Question 7

A 64-year-old man with a history of occupational exposure presents with an 8-month history of chest discomfort, malaise, fever, night sweats, and weight loss. Imaging reveals a pleural effusion and a pleural mass encasing the lung. The patient died of cardiorespiratory failure. Histologic examination of the pleural mass shows a biphasic pattern of epithelial and sarcomatous elements. What is the most likely diagnosis?

Accepted Answer

Malignant mesothelioma

Answer

Carcinoid tumor

Answer

Large cell carcinoma

Answer

Malignant melanoma

Question 8

Few RBCs, raised neutrophils with some hemorrhage in alveoli is seen in which stage of pneumonia?

Accepted Answer

Red hepatization

Answer

Gray hepatization

Answer

Viral pneumonia

Answer

Resolving phase of lobar pneumonia

Question 9

Adenocarcinoma of the lung is NOT associated with which of the following features?

Accepted Answer

Often produces ectopic hormones

Answer

Is not associated with cigarette smoking

Answer

Is usually found in the periphery of the lung

Answer

Is more common in women than men

Question 10

Ciliocytophthoria is seen in which of the following conditions?

Accepted Answer

Acute respiratory infection

Answer

Kartagener syndrome

Answer

Situs inversus

Answer

Cystic fibrosis

Respiratory Pathology — MCQs

Respiratory Pathology — MCQs

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