Respiratory Pathology 2 – 30 MCQs | Kenya MBChB

30 Year 3: Respiratory System Pathology exam questions on Respiratory Pathology 2 for medical students. Includes MCQs, answers, explanations and written questio

This MCQ set contains 30 questions on Respiratory Pathology 2 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 patient presents with transient pulmonary infiltrates, blood eosinophilia, and a completely benign self-limiting clinical course. No cause is identified. This is best described as:

  1. A. Idiopathic chronic eosinophilic pneumonia
  2. B. Tropical eosinophilia from helminthic infection
  3. C. Löffler syndrome (simple pulmonary eosinophilia)
  4. D. Acute eosinophilic pneumonia with respiratory failure

Correct answer: C – Löffler syndrome (simple pulmonary eosinophilia)

Löffler syndrome = simple pulmonary eosinophilia + transient lesions + benign clinical course. It is self-limiting. Acute eosinophilic pneumonia is more severe with rapid onset hypoxia and BAL 25% eosinophils.

Q2: BAL fluid in acute eosinophilic pneumonia shows what threshold of eosinophils to support the diagnosis?

  1. A. Greater than 5% eosinophils
  2. B. Greater than 10% eosinophils
  3. C. Greater than 15% eosinophils
  4. D. Greater than 25% eosinophils

Correct answer: D – Greater than 25% eosinophils

Acute eosinophilic pneumonia requires BAL eosinophils 25%. It presents with rapid onset fever, dyspnea, and hypoxia, and responds promptly and dramatically to corticosteroids.

Q3: A patient with idiopathic chronic eosinophilic pneumonia presents with high fever, night sweats, and dyspnea. CXR shows peripheral infiltrates. This diagnosis requires:

  1. A. Positive precipitating antibodies in serum
  2. B. BAL eosinophils greater than 5%
  3. C. Exclusion of all other causes of pulmonary eosinophilia
  4. D. Presence of noncaseating granulomas on biopsy

Correct answer: C – Exclusion of all other causes of pulmonary eosinophilia

Idiopathic chronic eosinophilic pneumonia is a diagnosis of exclusion. All other causes (asthma, drug allergies, parasites, vasculitis) must be ruled out first. It characteristically affects the peripheral lung fields.

Q4: Which of the following correctly describes the eosinophil-activating cytokine central to pulmonary eosinophilia?

  1. A. IL-8 drives eosinophil chemotaxis into alveoli
  2. B. IL-5 drives eosinophil infiltration and activation
  3. C. IL-4 activates eosinophils in alveolar spaces
  4. D. TNF drives eosinophilic alveolar inflammation

Correct answer: B – IL-5 drives eosinophil infiltration and activation

Elevated alveolar IL-5 is the key driver of eosinophil activation in pulmonary eosinophilia. IL-5 is produced by TH2 cells and is also the cytokine responsible for eosinophil activation in asthma.

Q5: Desquamative interstitial pneumonia (DIP) is best characterized by:

  1. A. Bronchiolocentric pigmented macrophages with peribronchiolar fibrosis
  2. B. Diffuse air space accumulation of smoker's macrophages with mild septal thickening
  3. C. Noncaseating granulomas in a peribronchiolar distribution
  4. D. Polypoid organizing connective tissue plugs in alveolar ducts

Correct answer: B – Diffuse air space accumulation of smoker's macrophages with mild septal thickening

DIP shows diffuse accumulation of smoker's macrophages (dusty-brown pigment) in air spaces throughout the lung, with mild alveolar septal thickening. The macrophage distribution is diffuse, unlike RB-ILD which is bronchiolocentric.

Q6: Respiratory bronchiolitis-ILD differs from DIP in that the macrophage distribution is:

  1. A. Diffuse throughout all alveolar air spaces
  2. B. Concentrated around first and second order respiratory bronchioles
  3. C. Predominantly subpleural and along interlobular septa
  4. D. Confined to alveolar ducts and terminal bronchioles only

Correct answer: B – Concentrated around first and second order respiratory bronchioles

RB-ILD shares the same smoker's macrophages as DIP but in a bronchiolocentric distribution — first and second order respiratory bronchioles. DIP has diffuse air space distribution. Both improve with smoking cessation.

Q7: A patient with rheumatoid arthritis develops progressive bilateral interstitial lung disease. Biopsy shows diffuse uniform interstitial fibrosis without temporal heterogeneity and no honeycombing. The pattern is:

  1. A. UIP pattern identical to IPF
  2. B. NSIP (nonspecific interstitial pneumonia) pattern
  3. C. Cryptogenic organizing pneumonia pattern
  4. D. Desquamative interstitial pneumonia pattern

Correct answer: B – NSIP (nonspecific interstitial pneumonia) pattern

NSIP is the most common pattern in collagen vascular disease lung involvement. It lacks the temporal heterogeneity of UIP and typically has no honeycombing or fibroblastic foci. Prognosis is better than IPF.

Q8: When a UIP pattern is found on lung biopsy, which of the following must be excluded before diagnosing IPF?

  1. A. Sarcoidosis and hypersensitivity pneumonitis only
  2. B. Collagen vascular diseases and asbestosis among others
  3. C. Silicosis and coal worker's pneumoconiosis
  4. D. Cryptogenic organizing pneumonia and NSIP

Correct answer: B – Collagen vascular diseases and asbestosis among others

UIP pattern can be seen in asbestosis, collagen vascular diseases, drug reactions, and other conditions. These known causes must be excluded before the diagnosis of IPF (idiopathic) can be made.

Q9: Bleomycin causes pulmonary toxicity through which mechanism?

  1. A. Hypersensitivity reaction causing eosinophilic pneumonia
  2. B. Direct drug toxicity and inflammatory cell influx into alveoli
  3. C. Immune complex deposition in alveolar capillary walls
  4. D. Inhibition of surfactant production by type II pneumocytes

Correct answer: B – Direct drug toxicity and inflammatory cell influx into alveoli

Bleomycin causes pneumonitis and interstitial fibrosis through direct drug toxicity combined with stimulation of inflammatory cell influx into the alveoli. Amiodarone similarly causes pneumonitis and fibrosis.

Q10: Acute radiation pneumonitis characteristically occurs at what time interval after therapy?

  1. A. Within the first 2 weeks of radiation
  2. B. Immediately during radiation treatment
  3. C. Between 1 and 6 months after therapy
  4. D. More than 1 year after completion of treatment

Correct answer: C – Between 1 and 6 months after therapy

Acute radiation pneumonitis occurs 1–6 months after therapy in up to 20% of patients. The infiltrates precisely correspond to the radiation field. It may progress to chronic radiation pneumonitis with fibrosis.

Q11: Idiopathic pulmonary hemosiderosis most commonly affects which age group?

  1. A. Elderly males over 60 years
  2. B. Young adults aged 20–40 years
  3. C. Children predominantly
  4. D. Middle-aged females with autoimmune history

Correct answer: C – Children predominantly

Idiopathic pulmonary hemosiderosis predominantly affects children, though it also occurs in adults who have a better prognosis. Historical mean survival was only 2.5 years, now improved with steroids and immunosuppression.

Q12: The key feature distinguishing idiopathic pulmonary hemosiderosis from Goodpasture syndrome is:

  1. A. Presence of hemoptysis and anemia in Goodpasture only
  2. B. Absence of renal disease and anti-GBM antibody in IPH
  3. C. Linear IgG deposition found only in IPH on biopsy
  4. D. Diffuse pulmonary infiltrates seen only in Goodpasture

Correct answer: B – Absence of renal disease and anti-GBM antibody in IPH

Both conditions share hemoptysis, anemia, and diffuse pulmonary infiltrates. IPH lacks renal disease and anti-GBM antibody — the two defining features of Goodpasture syndrome.

Q13: Wegener granulomatosis causes nasal perforation because of:

  1. A. Granulomatous inflammation eroding the nasal septum
  2. B. Vasculitis causing ischemic necrosis of nasal cartilage
  3. C. Recurrent nosebleeds leading to pressure necrosis
  4. D. Direct bacterial invasion from chronic sinusitis

Correct answer: A – Granulomatous inflammation eroding the nasal septum

The necrotizing granulomatous inflammation of Wegener granulomatosis in the upper respiratory tract can erode and perforate the nasal septum. Nasal perforation is a classic pathognomonic clinical feature.

Q14: Lung lesions in Wegener granulomatosis are characterized by which combination?

  1. A. Noncaseating granulomas with lymphocytic infiltrate only
  2. B. Eosinophilic infiltration with bronchospasm and mucus plugs
  3. C. Necrotizing vasculitis combined with necrotizing granulomatous inflammation
  4. D. Organizing pneumonia with polypoid connective tissue plugs

Correct answer: C – Necrotizing vasculitis combined with necrotizing granulomatous inflammation

Wegener granulomatosis lung lesions have two components: necrotizing vasculitis (angiitis) AND parenchymal necrotizing granulomatous inflammation. Both features together are characteristic of WG.

Q15: Fat embolism syndrome typically develops within what time frame after long bone fracture?

  1. A. Immediately within 1–2 hours of injury
  2. B. Within 24–72 hours after injury
  3. C. Between 1 and 2 weeks after injury
  4. D. More than 4 weeks after the initial trauma

Correct answer: B – Within 24–72 hours after injury

Fat embolism syndrome (petechiae, neurologic symptoms, respiratory failure) typically develops 24–72 hours after massive trauma or long bone fracture. The mechanism involves mechanical obstruction plus toxic fatty acid release causing endothelial damage.

Q16: Amniotic fluid embolism is a catastrophic obstetric emergency primarily because it causes:

  1. A. Massive pulmonary infarction from large vessel occlusion
  2. B. Sudden dyspnea, hypotension, hypoxia, and DIC
  3. C. Right heart failure from chronic pulmonary hypertension
  4. D. Granulomatous pneumonitis from fetal squamous cells

Correct answer: B – Sudden dyspnea, hypotension, hypoxia, and DIC

Amniotic fluid embolism presents with sudden dyspnea, hypoxia, hypotension, and DIC. It carries high maternal mortality. The mechanism involves fetal squamous cells and debris triggering inflammatory response and coagulopathy in pulmonary microvasculature.

Q17: Air embolism causes cardiovascular collapse primarily by:

  1. A. Obstructing multiple small pulmonary arterioles diffusely
  2. B. Blocking right heart outflow with a large air bolus
  3. C. Triggering massive release of pulmonary vasoconstrictors
  4. D. Causing acute left ventricular failure from hypoxia

Correct answer: B – Blocking right heart outflow with a large air bolus

A large air bolus causes right heart outflow obstruction leading to cardiovascular collapse. The characteristic auscultatory finding is a "mill wheel" murmur. Common causes are iatrogenic (IV lines, surgery, barotrauma).

Q18: Blastomyces dermatitidis is pathognomonic for which morphologic finding in tissue?

  1. A. Spherules containing endospores in granulomas
  2. B. Small yeast forms within alveolar macrophages
  3. C. Thick-walled yeast with broad-based budding
  4. D. Non-septate hyphae branching at right angles

Correct answer: C – Thick-walled yeast with broad-based budding

Blastomyces dermatitidis forms thick-walled yeast with broad-based budding — this is pathognomonic. Blastomycosis causes mixed suppurative and granulomatous inflammation and is most likely to cause symptomatic disease.

Q19: The most common extrapulmonary site of dissemination in blastomycosis is:

  1. A. Central nervous system and meninges
  2. B. Liver and spleen
  3. C. Skin
  4. D. Adrenal glands

Correct answer: C – Skin

Skin is the most common extrapulmonary site of blastomycosis dissemination. Contrast with coccidioidomycosis where meningeal involvement is the most serious complication, and histoplasmosis where liver, spleen, and adrenals are affected.

Q20: In coccidioidomycosis, the most serious complication of dissemination involves:

  1. A. Cutaneous ulceration and scarring
  2. B. Meningeal involvement
  3. C. Adrenal gland destruction
  4. D. Osteomyelitis of long bones

Correct answer: B – Meningeal involvement

Meningeal involvement is the most serious and life-threatening complication of disseminated coccidioidomycosis. It causes chronic meningitis that is difficult to treat. Dissemination is rare but more likely in immunocompromised patients.

Q21: Invasive aspergillosis in a neutropenic patient is angioinvasive. The characteristic CT finding in early disease is:

  1. A. Bilateral ground-glass perihilar infiltrates
  2. B. Halo sign — ground-glass opacity surrounding a nodule
  3. C. Eggshell calcification of hilar lymph nodes
  4. D. Wedge-shaped pleural-based consolidation

Correct answer: B – Halo sign — ground-glass opacity surrounding a nodule

The "halo sign" on CT (ground-glass opacity surrounding a pulmonary nodule) is characteristic of early invasive aspergillosis. The "air-crescent sign" appears later. Aspergillus shows septate hyphae branching at 45 degrees.

Q22: Which antifungal is first-line treatment for invasive aspergillosis?

  1. A. Fluconazole
  2. B. Amphotericin B deoxycholate
  3. C. Voriconazole
  4. D. Caspofungin

Correct answer: C – Voriconazole

Voriconazole is the first-line treatment for invasive aspergillosis. Diagnosis is supported by galactomannan antigen and beta-D-glucan in serum or BAL. Aspergillus shows septate hyphae branching at 45-degree angles.

Q23: Which immune defect primarily predisposes to infections with encapsulated bacteria like S. pneumoniae and H. influenzae in the lung?

  1. A. Neutrophil deficiency
  2. B. T cell deficiency
  3. C. Humoral (antibody) deficiency
  4. D. Complement pathway deficiency

Correct answer: C – Humoral (antibody) deficiency

Humoral immunodeficiency (antibody/B cell deficiency) primarily predisposes to infections with encapsulated organisms (S. pneumoniae, H. influenzae) that require opsonization by antibody for effective clearance.

Q24: A transplant recipient develops interstitial pneumonitis. Biopsy shows enlarged cells with large basophilic intranuclear inclusions surrounded by a clear halo. Treatment is:

  1. A. Voriconazole
  2. B. TMP-SMX
  3. C. Ganciclovir
  4. D. Amphotericin B

Correct answer: C – Ganciclovir

CMV pneumonia shows "owl-eye" intranuclear inclusions (large, basophilic, with clear halo) plus cytoplasmic inclusions in enlarged cells. It is the most common viral pneumonia in immunocompromised/transplant patients. Treatment is ganciclovir.

Q25: A typical carcinoid tumor of the lung differs from atypical carcinoid by:

  1. A. Typical carcinoid has 2–10 mitoses per 10 HPF
  2. B. Typical carcinoid shows necrosis and vascular invasion
  3. C. Typical carcinoid has fewer than 2 mitoses per 10 HPF and no necrosis
  4. D. Typical carcinoid arises peripherally rather than centrally

Correct answer: C – Typical carcinoid has fewer than 2 mitoses per 10 HPF and no necrosis

Typical carcinoid: 90% 5-year survival). Atypical carcinoid: 2–10 mitoses/10 HPF, may have necrosis, worse prognosis (50–70% 5-year survival).

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