KMU Past Paper Practice

Question:

A 60-year-old man has gradually progressive exertional breathlessness. Pulmonary function tests show reduced lung volumes, and histology demonstrates widespread thickening of alveolar septa by fibrous tissue. Which change best explains the reduced lung volumes?

Options:

Correct Answer:
Reduced parenchymal compliance from interstitial scarring

Explanation: Fibrous tissue makes the lung stiff and difficult to expand, reducing compliance and lung volumes and thereby producing restrictive physiology.

Question:

A patient with a chronic infiltrative lung disorder develops progressive fibrosis after repeated microscopic injury to alveolar epithelial cells. Which response most directly converts the epithelial injury into permanent structural remodeling?

Options:

Correct Answer:
Activation of fibroblasts with extracellular matrix synthesis

Explanation: Persistent epithelial injury generates profibrotic signals that activate fibroblasts and myofibroblasts, causing excessive matrix deposition and permanent interstitial remodeling.

Question:

A lung biopsy from a 64-year-old patient shows dense peripheral fibrosis alternating with relatively preserved parenchyma. Several small collections of proliferating fibroblasts and myofibroblasts are present at the advancing edges of fibrosis. What do these small lesions represent?

Options:

Correct Answer:
Sites of active fibrotic repair

Explanation: Fibroblastic foci are active areas of fibroblast and myofibroblast proliferation and indicate ongoing fibrogenesis within the UIP pattern.

Question:

Two patients undergo biopsy for chronic fibrosing lung disease. The first biopsy contains alternating normal lung, active fibrotic areas and old scars. The second shows fibrosis of similar intensity throughout the sampled tissue. Which interpretation is most appropriate?

Options:

Correct Answer:
The first favors UIP and the second NSIP

Explanation: UIP is spatially and temporally heterogeneous, whereas NSIP is characterized by more uniform involvement with lesions at a similar stage.

Question:

A 67-year-old patient has end-stage chronic interstitial fibrosis. Examination of the lung shows marked distortion with irregular cystic spaces lined by bronchiolar-type epithelium and separated by dense fibrous tissue. Which stage of disease does this finding indicate?

Options:

Correct Answer:
Advanced irreversible architectural remodeling

Explanation: Cystic spaces separated by dense scars represent end-stage honeycomb remodeling caused by severe destruction and fibrosis of normal lung architecture.

Question:

Three workers have prolonged exposure to different airborne mineral particles. Their occupational physician explains that only particles reaching the distal airspaces are likely to produce significant pneumoconiosis. Which property of the inhaled material most directly influences its ability to reach this region?

Options:

Correct Answer:
Particle size

Explanation: Particle size strongly influences deposition; appropriately small respirable particles can bypass proximal clearance and reach terminal respiratory units.

Question:

A miner’s lung specimen contains numerous dust-laden macrophages but little fibrosis, whereas a stone cutter with a comparable exposure duration has marked nodular fibrosis. Which property best explains the stronger tissue reaction in the stone cutter?

Options:

Correct Answer:
Greater fibrogenic activity of crystalline silica

Explanation: Crystalline silica is strongly fibrogenic because it injures and activates macrophages, promoting repeated mediator release and collagen-producing fibroblast responses.

Question:

At autopsy, the lungs of a long-term coal miner contain scattered black macules around respiratory bronchioles but no large confluent scars. Which pathological process best accounts for these lesions?

Options:

Correct Answer:
Accumulation of carbon-bearing macrophages

Explanation: Coal macules arise when macrophages containing inhaled carbonaceous material accumulate around respiratory bronchioles, representing simple coal workers’ pneumoconiosis.

Question:

A pathology practical includes three lung specimens from occupationally exposed workers. One contains black peribronchiolar lesions, another contains pale firm nodules with whorled collagen, and the third has diffuse interstitial scarring with pleural plaques. Which sequence correctly identifies the exposures?

Options:

Correct Answer:
Coal dust, silica, asbestos

Explanation: Coal produces pigmented peribronchiolar macules, silica produces whorled collagenous nodules, and asbestos produces diffuse interstitial fibrosis with characteristic pleural involvement.

Question:

A 56-year-old quarry worker has long-standing mineral dust exposure. A biopsy shows sharply defined nodules composed of dense collagen arranged in a concentric pattern. Which additional distribution would be most consistent with the same occupational disease?

Options:

Correct Answer:
Predominant involvement of upper lung regions

Explanation: Mature silicotic nodules contain concentrically arranged hyalinized collagen and characteristically show greater involvement of the upper portions of the lungs.

Question:

A 68-year-old retired insulation worker has diffuse interstitial fibrosis. Histological examination reveals golden-brown beaded structures containing a translucent central core. Which process produced this microscopic appearance?

Options:

Correct Answer:
Iron-containing protein coating persistent fibres

Explanation: Persistent asbestos fibres may become coated by iron-containing protein material, forming the characteristic golden-brown asbestos bodies seen microscopically.

Question:

A pathologist receives a lung specimen showing diffuse fibrosis that is most marked near the pleural surface and in the lower portions of the lungs. The pleura contains discrete fibrous plaques. Which occupational history would be most relevant?

Options:

Correct Answer:
Work involving asbestos-containing insulation

Explanation: Lower-zone subpleural interstitial fibrosis together with pleural plaques strongly supports asbestos exposure rather than coal or silica pneumoconiosis.

Question:

A stone-processing plant records several cases of pneumoconiosis despite issuing respirators. Inspection shows large amounts of dust escaping directly from cutting equipment into the work area. Which control strategy should receive priority?

Options:

Correct Answer:
Control dust generation and extraction at machinery

Explanation: Engineering control at the source reduces airborne dust before workers inhale it and therefore provides broader protection than relying mainly on personal equipment.

Question:

An occupational health programme combines enclosure of dust-producing equipment with periodic assessment of exposed workers. What is the main additional purpose of the worker assessments after environmental controls have been introduced?

Options:

Correct Answer:
To identify disease early and assess control effectiveness

Explanation: Medical surveillance complements environmental prevention by detecting early occupational disease and indicating whether existing workplace controls are adequately protecting workers.

Question:

A workplace has reduced airborne mineral dust substantially by enclosing machinery, using wet methods and improving local ventilation. Some residual exposure remains during maintenance procedures. Which additional measure is most appropriate for these workers?

Options:

Correct Answer:
Use appropriate respiratory protection with worker training

Explanation: When engineering controls cannot completely eliminate exposure, suitable respiratory protection and correct-use training provide an additional layer of prevention.

Question:

A 61-year-old patient develops progressive respiratory symptoms after prolonged treatment with a medication capable of pulmonary toxicity. Histology demonstrates alveolar epithelial injury followed by interstitial scarring. Which pathological principle best explains the chronic lesion?

Options:

Correct Answer:
Drug toxicity may trigger injury followed by excessive fibrotic repair

Explanation: Drug-related alveolar or interstitial toxicity may initiate inflammation and tissue damage, followed by fibroblast activation and persistent collagen deposition.

Question:

A patient develops cough and breathlessness following therapeutic irradiation of the thorax. The initial inflammatory lung injury later evolves into dense fibrosis. Which sequence most accurately describes this progression?

Options:

Correct Answer:
Radiation pneumonitis followed by reparative fibrosis

Explanation: Thoracic radiation may first produce inflammatory pneumonitis; persistent cellular injury and abnormal repair can subsequently lead to interstitial collagen deposition and fibrosis.

Question:

Two patients present with interstitial lung disease. One recently completed thoracic radiotherapy, while the other has no known exposure. Imaging in the first patient shows abnormalities that closely follow the region treated by radiation. What is the strongest interpretation of this distribution?

Options:

Correct Answer:
It supports a treatment-related pulmonary injury

Explanation: Lung abnormalities conforming to the irradiated region provide an important causal clue linking the interstitial injury to previous thoracic radiation.

Question:

A patient with advanced chronic interstitial fibrosis becomes increasingly breathless during exertion. The alveolar walls are markedly thickened by collagen, while the conducting airways remain patent. Which functional problem is most directly produced by this morphological change?

Options:

Correct Answer:
Increased diffusion distance for respiratory gases

Explanation: Interstitial collagen thickens the alveolar-capillary interface, increasing diffusion distance and impairing oxygen transfer despite patent conducting airways.

Question:

An occupational health team reviews three workers: one has coal macules, one has silicotic nodules, and one has asbestos-related interstitial fibrosis. Although their morphological lesions differ, which pathological process can contribute to progression in all three disorders?

Options:

Correct Answer:
Persistent particle-driven fibrogenic tissue response

Explanation: Retained occupational particles can sustain macrophage and fibrogenic signalling, promoting fibroblast activation and progressive collagen deposition despite differing characteristic lesions.