The type of emphysema commonly caused by cigarette smoking is (2004 old paper)

Correct Answer: B

Rationale: Centriacinar emphysema (B) is commonly caused by smoking, affecting proximal acini while sparing distal parts, often with bronchitis'. Pan acinar (A) involves entire acini, linked to α₁-antitrypsin deficiency, not smoking alone. Distal acinar (C) occurs near fibrosis, causing pneumothorax in young adults. Irregular (D) is scarring-related, the most common overall but not smoking-specific. Choice E is false. Page 718 notes centriacinar's association with smokers neutrophil/macrophage elastase damages central lobules, creating normal-emphysematous mosaics, making B the smoking-related type.

Correct Answer: D

Rationale: Silica-induced fibrosis is less pronounced when mixed with other minerals (D), diluting its effect. Choice A is false; silicosis is the most prevalent pneumoconiosis. Choice B is incorrect; crystalline quartz is more fibrogenic than amorphous silica. Choice C is wrong; silica activates macrophages to release mediators (e.g., IL-1), not destroys them. Choice E (late detection) is true. Page 735 notes D's modification mixed dust (e.g., with coal) reduces nodule formation, contrasting with A's prevalence or B's form error.

Correct Answer: B

Rationale: Pulmonary infarcts from emboli are classically hemorrhagic (B), due to dual blood supply. Choice A is false; only 10% cause infarction (most resolve). Choice C is incorrect; death is from acute right heart failure (cor pulmonale). Choice D is wrong; recurrence risk is 30%, not 3%. Choice E (fever) is true. Page 742 details B's morphology red infarcts from bronchial artery bleeding distinguish it over A's frequency or C's heart error.

Correct Answer: D

Rationale: Suppurative arthritis (D) is not a typical pneumonia complication; dissemination targets heart, brain, or kidneys, not joints. Choice A (abscess) occurs with Klebsiella/type 3 pneumococci. Choice B (empyema) is pus in pleura. Choice C (organization) solidifies lung tissue. Choice E (metaplasia) is a response, not complication. Page 750 lists A-C as direct sequelae abscess from necrosis, empyema from spread, organization from fibrosis but arthritis, while possible in septicemia, isn't standard, distinguishing D as the outlier.

Correct Answer: C

Rationale: Small cell carcinoma (SCLC) is always high grade (C), aggressive and undifferentiated. Choice A is false; it's third (20-25%), behind adenocarcinoma/SCC. Choice B is incorrect; it's central or peripheral. Choice D is wrong; it's strongly smoking-related. Choice E (hormone production) is true. Page 762 confirms C's malignancy rapid growth and early metastasis define SCLC, unlike A's prevalence or D's smoking denial.