Respiratory Pathology | MCQ Quiz | OmpathStudy Kenya

Question 1

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?

Accepted Answer

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).

Question 2

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

Accepted Answer

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

Question 3

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

Accepted Answer

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.

Question 4

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

Accepted Answer

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.

Question 5

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

Accepted Answer

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.

Question 6

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

Accepted Answer

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.

Question 7

Which morphologic finding is the HALLMARK of ARDS on microscopy?

Accepted Answer

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.

Question 8

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

Accepted Answer

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

Question 9

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:

Accepted Answer

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.

Question 10

Which of the following is TRUE about nasopharyngeal carcinoma?

Accepted Answer

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.

Question 11

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?

Accepted Answer

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).

Question 12

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

Accepted Answer

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.

Question 13

The Reid index in chronic bronchitis is:

Accepted Answer

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.

Question 14

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

Accepted Answer

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.

Question 15

Silicosis is associated with increased susceptibility to which infection?

Accepted Answer

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.

Question 16

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:

Accepted Answer

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.

Question 17

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

Accepted Answer

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.

Question 18

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

Accepted Answer

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.

Question 19

In sarcoidosis, hypercalcemia occurs due to:

Accepted Answer

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.

Question 20

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

Accepted Answer

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.

Question 21

The "hygiene hypothesis" in asthma suggests that:

Accepted Answer

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.

Question 22

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

Accepted Answer

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.

Question 23

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

Accepted Answer

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.

Question 24

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

Accepted Answer

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.

Question 25

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:

Accepted Answer

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.

Question 26

Which of the following is TRUE about kartagener syndrome?

Accepted Answer

It involves structural ciliary abnormalities causing bronchiectasis and male sterility — Kartagener syndrome is a rare autosomal recessive disorder. Structural ciliary abnormalities impair mucociliary clearance leading to bronchiectasis and recurrent infections, and reduce spermatozoa motility causing male sterility.

Question 27

A 25-year-old non-smoker develops sudden chest pain and dyspnea. CXR shows a collapsed right lung. He is found to have multiple contiguous enlarged air spaces near the right pleural surface. This is:

Accepted Answer

Distal acinar emphysema with bulla formation — Distal acinar (paraseptal) emphysema is most often seen in young adults with spontaneous pneumothorax. It affects the distal acinus adjacent to the pleura, forming characteristic bullae that can rupture.

Question 28

Eggshell calcification of hilar lymph nodes on CXR is characteristic of:

Accepted Answer

Silicosis — Eggshell calcification (calcium surrounding a zone lacking calcification in lymph nodes) is characteristic of silicosis. This represents calcium deposition around the periphery of the fibrotic lymph node.

Question 29

In IPF, the histologic pattern is called UIP. The hallmark of UIP is:

Accepted Answer

Patchy interstitial fibrosis with temporal heterogeneity — The hallmark of UIP (and thus IPF) is patchy interstitial fibrosis with temporal heterogeneity — early fibroblastic foci and late collagenous scars coexist in the same biopsy specimen.

Question 30

Which of the following best describes the "Pink Puffer" in emphysema?

Accepted Answer

Patient with barrel chest, dyspnea, prolonged expiration, adequate oxygenation — "Pink Puffer" describes pure emphysema: barrel chest, dyspnea, prolonged expiration (sitting hunched forward), but adequate oxygenation until late in disease. They hyperventilate to maintain oxygen levels.

Question 31

More than 95% of pulmonary emboli arise from thrombi in:

Accepted Answer

Deep veins of the lower legs — Over 95% of pulmonary emboli originate from thrombi in the deep veins of the lower legs, typically in the popliteal vein and larger veins above it.

Question 32

A 50-year-old male develops progressive dyspnea over 2 years. Lung biopsy shows honeycomb fibrosis, fibroblastic foci, and temporal heterogeneity. Mean survival from diagnosis is approximately:

Accepted Answer

3 years or less — IPF has a mean survival of 3 years or less from diagnosis, with relentless progression despite medical therapy. Lung transplantation is the only definitive treatment.

Question 33

Which cell type is central to the pathogenesis of atopic asthma?

Accepted Answer

TH2 helper T cells — TH2 cells are central to atopic asthma. They produce IL-4 (IgE production), IL-5 (eosinophil activation), and IL-13 (mucus production), orchestrating the allergic inflammatory response.

Question 34

A lung carcinoma secretes PTHrP causing hypercalcemia. Which histologic type is most commonly responsible?

Accepted Answer

Squamous cell carcinoma — Hypercalcemia from PTHrP secretion (paraneoplastic) is most commonly associated with squamous cell carcinoma of the lung. This is distinct from hypercalcemia caused by osteolytic metastases.

Question 35

The Ghon complex in primary tuberculosis consists of:

Accepted Answer

Subpleural nodule plus hilar/lymph node involvement — The Ghon complex = Ghon focus (subpleural nodule, often upper part of lower lobe) + lymphatic drainage + hilar lymph node involvement. When calcified, it becomes the Ranke complex.

Question 36

Which of the following is a feature of atypical pneumonia that distinguishes it from typical bacterial pneumonia?

Accepted Answer

Respiratory distress out of proportion to radiologic signs — Atypical pneumonia is characterized by respiratory distress disproportionate to clinical/radiologic findings. Inflammation is predominantly interstitial (alveolar septa), with alveolar spaces generally clear.

Question 37

In pulmonary hypertension, plexiform lesions are characteristic of which type?

Accepted Answer

Idiopathic (primary) pulmonary arterial hypertension — Plexiform lesions — endothelial proliferation forming multiple lumina within small arteries — are characteristic of idiopathic (primary) pulmonary arterial hypertension, not secondary forms.

Question 38

A patient with systemic sclerosis develops bilateral interstitial lung disease. The most common histologic pattern in systemic sclerosis lung involvement is:

Accepted Answer

NSIP (nonspecific interstitial pneumonia) pattern — NSIP is the most common histologic pattern of lung involvement in collagen vascular diseases, particularly systemic sclerosis. UIP pattern can also occur but NSIP predominates.

Question 39

A 70-year-old male with a 50-pack-year smoking history develops progressive dyspnea. Spirometry shows FEV1 40% predicted, FVC 75% predicted. What is the FEV1/FVC pattern?

Accepted Answer

Decreased ratio indicating obstructive disease — FEV1/FVC = 40/75 = 0.53, which is significantly decreased (normal 0.70). This decreased ratio is the characteristic finding in obstructive lung disease such as COPD.

Question 40

Aspirin-induced asthma occurs because aspirin:

Accepted Answer

Inhibits COX → shifts arachidonic acid toward leukotriene production — Aspirin inhibits the cyclooxygenase (COX) pathway without affecting lipoxygenase, shifting arachidonic acid metabolism toward leukotriene production. Leukotrienes are potent bronchoconstrictors.

Question 41

A coal miner develops multiple intensely black scars 2 cm in diameter in the lungs. This represents:

Accepted Answer

Silicotic nodule coalescence — Progressive massive fibrosis (PMF/complicated CWP) is characterized by multiple intensely black scars 2 cm (up to 10 cm). It develops from coalescence of coal nodules and causes significant pulmonary dysfunction.

Question 42

Coccidioidomycosis is pathognomonic for which histologic finding?

Accepted Answer

Large spherules containing endospores — Coccidioides immitis forms characteristic spherules — large round structures containing endospores — in tissue. This is pathognomonic for coccidioidomycosis and distinguishes it from other fungal infections.

Question 43

Which of the following regarding sarcoidosis lymph node involvement is CORRECT?

Accepted Answer

Peripheral lymphadenopathy occurs but nodes are nonadherent — Sarcoidosis lymph nodes are characteristically "nonmatted" (nonadherent) and do not ulcerate — unlike tuberculosis where nodes are matted. Hilar/paratracheal nodes are enlarged in 75–90% of patients.

Question 44

Contraction (cicatrization) atelectasis differs from the other types because:

Accepted Answer

It is irreversible due to fibrotic changes — Contraction atelectasis occurs when local or generalized fibrosis hampers lung expansion and increases elastic recoil. Unlike resorption and compression atelectasis, it is irreversible.

Question 45

In malignant mesothelioma, which immunohistochemical marker is positive (distinguishing it from adenocarcinoma)?

Accepted Answer

Calretinin — Calretinin is positive in mesothelioma and negative in adenocarcinoma. Conversely, CEA, TTF-1, and MOC-31 are positive in adenocarcinoma and negative in mesothelioma.

Question 46

A patient develops fever, dyspnea, and pulmonary infiltrates exactly matching the radiation field 4 months after thoracic radiotherapy. This is:

Accepted Answer

Radiation-induced acute pneumonitis — Acute radiation pneumonitis occurs 1–6 months after therapy in up to 20% of patients. Infiltrates precisely corresponding to the radiation field is the diagnostic clue. It may resolve with corticosteroids.

Question 47

A 10-year-old child presents with hemoptysis and anemia. Investigation shows no renal disease and no anti-GBM antibody. The most likely diagnosis is:

Accepted Answer

Pulmonary vasculitis — Idiopathic pulmonary hemosiderosis has the same pulmonary features as Goodpasture (hemoptysis, anemia, diffuse infiltrates) but with NO renal disease and NO anti-GBM antibody. It predominantly affects children.

Question 48

Bronchiectasis in Kartagener syndrome results from:

Accepted Answer

Structural ciliary abnormalities impairing mucociliary clearance — Kartagener syndrome involves structural ciliary abnormalities (autosomal recessive). Impaired mucociliary clearance leads to persistent infections, bronchial wall destruction, and bronchiectasis.

Question 49

The BMPR-2 gene mutation in primary pulmonary hypertension leads to:

Accepted Answer

Abnormal endothelial and smooth muscle cell proliferation — BMPR-2 normally inhibits cell proliferation. Loss-of-function mutations found in 50% of familial primary pulmonary hypertension cases result in abnormal vascular endothelial and smooth muscle proliferation.

Question 50

Which organism most commonly causes community-acquired lobar pneumonia?

Accepted Answer

Streptococcus pneumoniae — Streptococcus pneumoniae (pneumococcus) causes more than 90% of lobar pneumonias and is the most common cause of community-acquired acute pneumonia overall.

Respiratory Pathology | MCQ Quiz | OmpathStudy Kenya

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