Respiratory Pathology – 60 MCQs | Kenya MBChB

60 Year 3: Respiratory System Pathology exam questions on Respiratory Pathology for medical students. Includes MCQs, answers, explanations and written questions

This MCQ set contains 60 questions on Respiratory Pathology in the Year 3: Respiratory System Pathology unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.

Q1: A 45-year-old male smoker presents with chronic productive cough for 4 months every year for the past 3 years. What is the histologic hallmark in the large airways?

  1. A. Goblet cell metaplasia in alveoli
  2. B. Hyaline membrane formation
  3. C. Enlarged mucus-secreting submucosal glands
  4. D. Noncaseating granuloma formation

Correct answer: C – Enlarged mucus-secreting submucosal glands

Chronic bronchitis is defined clinically (3 months/year × 2 years). The histologic hallmark is enlarged submucosal mucous glands, quantified by the Reid index ( 0.4 = abnormal).

Q2: A child presents with inspiratory stridor and harsh barking cough. The most common causative agent is:

  1. A. Respiratory syncytial virus
  2. B. Parainfluenza virus
  3. C. Adenovirus
  4. D. Rhinovirus

Correct answer: B – Parainfluenza virus

Croup (laryngotracheobronchitis) is most commonly caused by parainfluenza virus in children. RSV can also cause it but is less common.

Q3: A 30-year-old presents with spontaneous pneumothorax. The most likely underlying emphysema type is:

  1. A. Centriacinar emphysema
  2. B. Panacinar emphysema
  3. C. Irregular emphysema
  4. D. Distal acinar (paraseptal) emphysema

Correct answer: D – Distal acinar (paraseptal) emphysema

Paraseptal emphysema affects the distal acinus adjacent to the pleura, forming bullae. Rupture of subpleural bullae causes spontaneous pneumothorax in young adults.

Q4: Which cytokine is released within 30 minutes of acute lung injury and drives neutrophil chemotaxis?

  1. A. Interleukin-5
  2. B. Interleukin-13
  3. C. Interleukin-8
  4. D. Tumor necrosis factor

Correct answer: C – Interleukin-8

IL-8 is released by pulmonary macrophages within 30 minutes of an acute insult. It is a potent neutrophil chemotactic and activating agent central to ARDS pathogenesis.

Q5: The FEV1/FVC ratio is characteristically decreased in which condition?

  1. A. Idiopathic pulmonary fibrosis
  2. B. Sarcoidosis
  3. C. Severe obesity with normal lungs
  4. D. Chronic obstructive pulmonary disease

Correct answer: D – Chronic obstructive pulmonary disease

COPD (obstructive disease) reduces FEV1 significantly while FVC is near normal, giving a decreased FEV1/FVC ratio. Restrictive diseases maintain a near-normal ratio.

Q6: A patient with α1-antitrypsin deficiency develops emphysema. Which type and distribution is expected?

  1. A. Centriacinar, upper lobe predominance
  2. B. Irregular, associated with scarring
  3. C. Panacinar, lower lobe predominance
  4. D. Distal acinar, adjacent to pleura

Correct answer: C – Panacinar, lower lobe predominance

α1-antitrypsin deficiency leads to panacinar emphysema affecting the entire acinus, with lower lobe predominance. Over 80% of patients with this deficiency develop symptomatic emphysema.

Q7: Which morphologic finding is the HALLMARK of ARDS on microscopy?

  1. A. Noncaseating granulomas in alveolar walls
  2. B. Hyaline membranes lining alveolar ducts
  3. C. Foamy intra-alveolar macrophage exudate
  4. D. Eosinophilic infiltration of alveolar septa

Correct answer: B – Hyaline membranes lining alveolar ducts

Hyaline membranes (fibrin-rich edema fluid mixed with necrotic epithelial cells) lining distended alveolar ducts are the pathologic hallmark of ARDS/diffuse alveolar damage.

Q8: Streptococcal tonsillitis is important to recognize early because it can lead to all EXCEPT:

  1. A. Peritonsillar abscess (quinsy)
  2. B. Poststreptococcal glomerulonephritis
  3. C. Acute rheumatic fever
  4. D. Infectious mononucleosis

Correct answer: D – Infectious mononucleosis

Infectious mononucleosis is caused by EBV, not streptococcal infection. The three important complications of streptococcal tonsillitis are quinsy, glomerulonephritis, and rheumatic fever.

Q9: A biopsy shows polypoid plugs of organizing connective tissue within alveolar ducts, all of the same age, with normal underlying lung architecture. The diagnosis is:

  1. A. Usual interstitial pneumonia
  2. B. Nonspecific interstitial pneumonia
  3. C. Cryptogenic organizing pneumonia
  4. D. Hypersensitivity pneumonitis

Correct answer: C – Cryptogenic organizing pneumonia

COP (formerly BOOP) is characterized by polypoid plugs of loose organizing connective tissue within alveolar ducts and bronchioles. All connective tissue is the same age (no temporal heterogeneity) and underlying architecture is preserved.

Q10: Which of the following is TRUE about nasopharyngeal carcinoma?

  1. A. EBV genome is found only in Asian patients
  2. B. Keratinizing type is the most common variant
  3. C. It is poorly radiosensitive with less than 10% survival
  4. D. Undifferentiated type is most common and most linked to EBV

Correct answer: D – Undifferentiated type is most common and most linked to EBV

Undifferentiated carcinoma is the most common variant and most closely associated with EBV. EBV genome is found in virtually ALL nasopharyngeal carcinomas regardless of geography.

Q11: A farmer presents with fever, cough, and dyspnea 6 hours after entering a barn with moldy hay. Serum shows precipitating antibodies. BAL shows increased CD4+ and CD8+ T cells. What is the diagnosis?

  1. A. Atopic asthma
  2. B. Hypersensitivity pneumonitis
  3. C. Sarcoidosis
  4. D. Cryptogenic organizing pneumonia

Correct answer: B – Hypersensitivity pneumonitis

Hypersensitivity pneumonitis (Farmer's Lung) presents 4–8 hours after antigen exposure. Both Type III and Type IV hypersensitivity are involved. BAL shows increased CD4+ AND CD8+ T cells, distinguishing it from sarcoidosis (CD4+ only).

Q12: A patient with asthma dies during status asthmaticus. Whorls of shed epithelium found within mucous plugs are called:

  1. A. Asteroid bodies
  2. B. Charcot-Leyden crystals
  3. C. Curschmann spirals
  4. D. Schaumann bodies

Correct answer: C – Curschmann spirals

Curschmann spirals are whorls of shed epithelium found in the mucous plugs of asthma. Charcot-Leyden crystals are eosinophil protein crystalloids — both are found in asthma plugs.

Q13: The Reid index in chronic bronchitis is:

  1. A. Ratio of alveolar wall thickness to capillary diameter
  2. B. Ratio of submucosal gland thickness to bronchial wall thickness
  3. C. Ratio of FEV1 to FVC on spirometry
  4. D. Ratio of goblet cells to ciliated cells in epithelium

Correct answer: B – Ratio of submucosal gland thickness to bronchial wall thickness

The Reid index measures submucosal gland layer thickness divided by bronchial wall thickness. Normal is ≤0.4; chronic bronchitis exceeds 0.4 due to gland hypertrophy.

Q14: Which lung cancer subtype is almost always metastatic at presentation and should NOT be treated surgically?

  1. A. Squamous cell carcinoma
  2. B. Large cell carcinoma
  3. C. Adenocarcinoma
  4. D. Small cell carcinoma

Correct answer: D – Small cell carcinoma

SCLC is almost always metastatic at presentation. It is treated with chemotherapy, not surgery. Despite initial sensitivity to chemotherapy, it invariably recurs with a median survival of 1 year.

Q15: Silicosis is associated with increased susceptibility to which infection?

  1. A. Aspergillus fumigatus
  2. B. Mycobacterium tuberculosis
  3. C. Pneumocystis jiroveci
  4. D. Cytomegalovirus

Correct answer: B – Mycobacterium tuberculosis

Silicosis depresses cell-mediated immunity and impairs macrophage killing of mycobacteria. The combination of silicosis and TB is called silicotuberculosis, with nodules showing central caseation.

Q16: A 35-year-old presents with hemoptysis, anemia, diffuse pulmonary infiltrates, and rapidly progressive glomerulonephritis. Lung biopsy shows linear IgG deposition. The target antigen is:

  1. A. α3 chain of collagen IV
  2. B. Double-stranded DNA
  3. C. Neutrophil proteinase-3
  4. D. Myeloperoxidase antigen

Correct answer: A – α3 chain of collagen IV

Goodpasture syndrome is caused by antibodies targeting the noncollagenous domain of the α3 chain of collagen IV, affecting both pulmonary and glomerular basement membranes.

Q17: A child develops multiple laryngeal papillomas that recur after excision. The causative HPV types are:

  1. A. HPV types 16 and 18
  2. B. HPV types 6 and 11
  3. C. HPV types 31 and 33
  4. D. HPV types 45 and 56

Correct answer: B – HPV types 6 and 11

Recurrent respiratory papillomatosis in children is caused by HPV types 6 and 11, transmitted vertically during delivery. These do not become malignant and often regress at puberty.

Q18: Which emphysema type is 20 times more common than panacinar emphysema and is most associated with cigarette smoking?

  1. A. Irregular emphysema
  2. B. Distal acinar emphysema
  3. C. Centriacinar emphysema
  4. D. Panacinar emphysema

Correct answer: C – Centriacinar emphysema

Centriacinar (centrilobular) emphysema affects the central/proximal acinus (respiratory bronchioles), sparing distal alveoli. It is strongly associated with cigarette smoking and affects the upper lobes predominantly.

Q19: In sarcoidosis, hypercalcemia occurs due to:

  1. A. Osteolytic bone destruction by granulomas
  2. B. PTHrP secretion from activated lymphocytes
  3. C. Active vitamin D production by granuloma macrophages
  4. D. Increased renal tubular calcium reabsorption

Correct answer: C – Active vitamin D production by granuloma macrophages

In sarcoidosis, mononuclear phagocytes within granulomas produce active vitamin D (1,25-dihydroxyvitamin D), increasing intestinal calcium absorption and causing hypercalcemia.

Q20: A 60-year-old asbestos worker develops progressive lower lobe fibrosis. Microscopy reveals interstitial fibrosis with golden-brown beaded rods. These structures consist of:

  1. A. Silica particles coated with calcium salts
  2. B. Asbestos fibers coated with iron-containing protein
  3. C. Carbon pigment within alveolar macrophages
  4. D. Fibrin deposits from recurrent hemorrhage

Correct answer: B – Asbestos fibers coated with iron-containing protein

Asbestos bodies are asbestos fibers coated with iron-containing proteinaceous material derived from phagocyte ferritin. They appear as golden-brown, fusiform or beaded rods with a translucent center.

Q21: The "hygiene hypothesis" in asthma suggests that:

  1. A. Poor hygiene increases bacterial colonization reducing asthma
  2. B. Eradication of infections alters immune homeostasis promoting allergic responses
  3. C. Viral infections in childhood always prevent asthma development
  4. D. Helminth infections directly trigger bronchial hyperreactivity

Correct answer: B – Eradication of infections alters immune homeostasis promoting allergic responses

The hygiene hypothesis proposes that eradication of infections alters immune homeostasis and promotes allergic and other harmful immune responses, explaining the increased asthma incidence in Western countries.

Q22: Which of the following is the most common manifestation of asbestos exposure?

  1. A. Malignant mesothelioma
  2. B. Diffuse pleural fibrosis
  3. C. Asbestosis (pulmonary fibrosis)
  4. D. Pleural plaques

Correct answer: D – Pleural plaques

Pleural plaques are the most common manifestation of asbestos exposure. They are well-circumscribed plaques of dense collagen, often calcified, on the parietal pleura. They are usually asymptomatic.

Q23: In Wegener granulomatosis, which ANCA subtype is positive in approximately 95% of cases?

  1. A. p-ANCA (MPO-ANCA)
  2. B. c-ANCA (PR3-ANCA)
  3. C. Anti-GBM antibody
  4. D. Anti-dsDNA antibody

Correct answer: B – c-ANCA (PR3-ANCA)

Wegener granulomatosis is associated with c-ANCA (PR3-ANCA — proteinase 3 antineutrophil cytoplasmic antibody) in approximately 95% of cases. The classic triad includes upper respiratory, lower respiratory, and renal involvement.

Q24: Lobar pneumonia evolves through four stages. What characterizes the "red hepatization" stage?

  1. A. Vascular congestion with protein-rich fluid and neutrophils
  2. B. Lysis of red cells with persistent fibrinosuppurative exudate
  3. C. Enzymatic digestion of exudate with macrophage clearance
  4. D. Alveoli packed with neutrophils, red cells, and fibrin

Correct answer: D – Alveoli packed with neutrophils, red cells, and fibrin

Red hepatization follows congestion and is characterized by liver-like consistency of the lung. Alveolar spaces are packed with neutrophils, red blood cells, and fibrin — giving the red, firm appearance.

Q25: A patient with HIV and CD4 count of 150 cells/µL develops bilateral ground-glass perihilar infiltrates. BAL shows foamy alveolar exudate on H&E. GMS stain confirms the diagnosis. The organism is:

  1. A. Cytomegalovirus
  2. B. Aspergillus fumigatus
  3. C. Pneumocystis jiroveci
  4. D. Mycobacterium avium complex

Correct answer: C – Pneumocystis jiroveci

PCP (Pneumocystis jiroveci pneumonia) is the most common opportunistic infection in AIDS when CD4 <200. CXR shows bilateral ground-glass perihilar infiltrates. GMS stain shows cysts; H&E shows foamy exudate.

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