Respiratory Pathology Practice Questions

Q: What is the most common pattern of pneumonia seen in Klebsiella infection?

Lobar Pneumonia. **Explanation:** **1. Why Lobar Pneumonia is Correct:** *Klebsiella pneumoniae* is a classic cause of **Lobar Pneumonia**, a pattern characterized by diffuse inflammation and consolidation involving an entire lobe of the lung [1]. The organism possesses a thick, prominent polysaccharide capsule that protects it from phagocytosis, leading to an intense inflammatory response. This results in the production of thick, mucoid, and blood-stained sputum (classically described as **"Currant Jelly Sputum"**). The heavy inflammatory exudate often causes the affected lobe to swell, leading to the characteristic **"Bulging Fissure Sign"** on chest X-ray. **2. Why Other Options are Incorrect:** * **Bronchopneumonia:** This pattern involves patchy consolidation centered around bronchioles. While many Gram-negative bacteria cause bronchopneumonia, *Klebsiella* is specifically notorious for its rapid progression into a confluent lobar pattern. * **Interstitial Pneumonia:** This is typically caused by viruses (e.g., Influenza, RSV) or atypical bacteria (e.g., *Mycoplasma pneumoniae*). It involves the alveolar walls rather than the alveolar spaces [1]. * **Miliary Pneumonia:** This refers to multiple, tiny, millet-seed-sized lesions spread hematogenously, most commonly seen in Miliary Tuberculosis. **3. Clinical Pearls for NEET-PG:** * **Risk Groups:** Most common in chronic alcoholics, diabetics, and elderly patients (due to aspiration of oropharyngeal flora) [1]. * **Complications:** *Klebsiella* is highly destructive and frequently leads to **abscess formation** and cavitation (unlike *Streptococcus pneumoniae*, which rarely causes necrosis). * **Radiology:** Look for the "Bulging Fissure Sign" (usually the minor fissure). * **Gram Stain:** Shows Gram-negative, encapsulated, "plump" bacilli. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, p. 715.

Q: Potato nodes are a feature of which condition?

Sarcoidosis. **Explanation:** **Sarcoidosis (Correct Answer):** "Potato nodes" is a classic radiological and pathological description for the massive, symmetrical, and non-adherent **bilateral hilar lymphadenopathy** seen in Sarcoidosis. These nodes are typically firm, discrete, and rubbery, resembling potatoes on a chest X-ray or CT scan [1]. Pathologically, they are characterized by **non-caseating granulomas**. The lack of periadenitis (inflammation of surrounding tissue) ensures the nodes remain distinct and do not matted together, unlike in infectious processes [1]. **Incorrect Options:** * **Tuberculosis:** Characterized by **caseating granulomas**. Lymph nodes in TB tend to be "matted" due to periadenitis and necrosis, rather than discrete "potato-like" structures. It usually presents with unilateral or asymmetrical lymphadenopathy. * **Carcinoid:** This is a neuroendocrine tumor typically presenting as a polypoid endobronchial mass. While it may cause obstructive features, it is not associated with the specific "potato node" morphology. * **Lymphoma:** While lymphoma causes significant lymphadenopathy, the nodes are often described as "bulky" or "conglomerate." In Hodgkin Lymphoma, nodes may be rubbery, but the term "potato nodes" is specifically reserved for the classic presentation of Sarcoidosis in medical literature. **NEET-PG High-Yield Pearls for Sarcoidosis:** * **Schaumann bodies:** Laminated concretions of calcium and proteins. * **Asteroid bodies:** Stellate inclusions within giant cells. * **Kveim-Siltzbach Test:** Historically used skin test (now largely replaced by biopsy). * **Biochemical marker:** Elevated **Serum ACE** (Angiotensin-Converting Enzyme) levels. * **Staging:** Stage I specifically refers to Bilateral Hilar Lymphadenopathy (BHL) alone. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 700-701.

Q: Which of the following is NOT a feature of primary tuberculosis?

Apical lung cavity. **Explanation:** The distinction between primary and secondary tuberculosis (TB) is a high-yield topic for NEET-PG. **Why Option A is the correct answer:** **Apical lung cavities** are the hallmark of **Secondary (Reactivation) Tuberculosis**, not primary TB. Secondary TB occurs in a previously sensitized host, typically localized to the apices of the upper lobes where high oxygen tension favors the growth of *Mycobacterium tuberculosis*. The intense hypersensitivity reaction leads to tissue necrosis and cavitation [1]. **Analysis of incorrect options:** * **B. Ghon’s focus:** This is a 1–1.5 cm area of gray-white inflammation/consolidation found in the subpleural region of the mid or lower lung zones. It is the classic initial lesion of **Primary TB** [1]. * **C. Paratracheal lymphadenopathy:** In primary TB, the bacilli drain via lymphatics to the regional (hilar and paratracheal) nodes. The combination of the Ghon focus and involved nodes is called the **Ghon Complex** [1]. * **D. Heals spontaneously by fibrosis:** In 90-95% of immunocompetent individuals, the cell-mediated immune response successfully arrests the infection, leading to fibrosis and often calcification (Ranke Complex) [2]. **NEET-PG Clinical Pearls:** 1. **Ranke Complex:** Ghon Complex + Radiologic Calcification. 2. **Simon’s Focus:** Initial secondary TB lesion at the lung apex. 3. **Epithelioid Granuloma:** The characteristic histological feature, driven by **IFN-gamma** (secreted by TH1 cells) activating macrophages [2]. 4. **Primary TB** is usually asymptomatic or presents as a mild flu-like illness, whereas **Secondary TB** presents with "B-symptoms" (night sweats, weight loss, and hemoptysis) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 379-380. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 380-381.

Question 1

The alveoli are filled with exudate and the air is displaced, converting the lung into a solid organ. This description suggests:

Accepted Answer

Lobar pneumonia

Answer

Chronic bronchitis

Answer

Bronchial asthma

Answer

Bronchiectasis

Question 2

Which of the following conditions is a cause of granulomatous lung disease?

Accepted Answer

Hypersensitivity pneumonitis

Answer

Sarcoma

Answer

Bronchogenic carcinoma

Answer

Bronchogenic cyst

Question 3

In Kartagener syndrome, all are seen except?

Accepted Answer

Bronchial asthma

Answer

Bronchiectasis

Answer

Situs inversus

Answer

Sinusitis

Question 4

What is the most common pattern of pneumonia seen in Klebsiella infection?

Accepted Answer

Lobar Pneumonia

Answer

Bronchopneumonia

Answer

Interstitial Pneumonia

Answer

Miliary Pneumonia

Question 5

Potato nodes are a feature of which condition?

Accepted Answer

Sarcoidosis

Answer

Tuberculosis

Answer

Carcinoid

Answer

Lymphoma

Question 6

Which of the following is NOT a feature of primary tuberculosis?

Accepted Answer

Apical lung cavity

Answer

Ghon's focus

Answer

Paratracheal lymphadenopathy

Answer

Heals spontaneously by fibrosis

Question 7

Liver cirrhosis is associated with which type of emphysema in PIZZ phenotype mutation?

Accepted Answer

Panacinar

Answer

Centriacinar

Answer

Paraseptal

Answer

Multifocal

Question 8

What is true about adenocarcinoma of the lung?

Accepted Answer

More common in females

Answer

Not associated with smoking

Answer

Associated with central cavitations

Answer

Most common in the upper lobes

Question 9

Which of the following would most likely be observed in the lung during an autopsy of a 2-week-old infant who died of neonatal respiratory distress syndrome?

Accepted Answer

Hyaline membranes and collapsed alveoli

Answer

Alveoli filled with neutrophils

Answer

Dense fibrosis of the alveolar walls

Answer

Enlarged air spaces

Question 10

What is the dominant cell type in the grey hepatization stage of community-acquired pneumonia?

Accepted Answer

Neutrophils

Answer

Eosinophils

Answer

Macrophages

Answer

Monocytes

Respiratory Pathology — MCQs

Respiratory Pathology — MCQs

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