Pulmonology Practice Questions

Q: Which of the following is NOT a cause of decreased DLCO?

Goodpasture syndrome. Explanation: DLCO (Diffusing Capacity of the Lungs for Carbon Monoxide) measures the ability of the lungs to transfer gas from inhaled air to the red blood cells in pulmonary capillaries. It depends on the surface area available for gas exchange, the thickness of the alveolar-capillary membrane, and the hemoglobin concentration [1]. **Why Goodpasture Syndrome is the correct answer:** In **Goodpasture syndrome**, there is diffuse alveolar hemorrhage. The presence of "free" hemoglobin within the alveoli (extravasated RBCs) binds to the carbon monoxide used during the test. This results in an **increased DLCO**, rather than a decrease. This is a classic "exception" frequently tested in exams. **Analysis of incorrect options (Causes of decreased DLCO):** * **Anemia:** Since DLCO relies on hemoglobin to bind the CO, a reduction in total hemoglobin leads to a lower carrying capacity and thus a **decreased DLCO**. * **Interstitial Lung Diseases (ILD):** These conditions cause fibrosis and thickening of the alveolar-capillary membrane, increasing the distance the gas must travel, which **decreases DLCO**. * **Emphysema:** This involves the destruction of alveolar walls, which significantly reduces the total surface area available for gas exchange, leading to a **decreased DLCO** [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Increased DLCO is seen in:** Alveolar hemorrhage (Goodpasture’s), Polycythemia, Left-to-right shunts, Obesity, and sometimes early-stage Asthma. * **DLCO in Asthma vs. COPD:** DLCO is typically **normal or increased in Asthma**, but **decreased in Emphysema** [2]. This is a key physiological differentiator. * **Isolated low DLCO** with normal lung volumes often suggests Pulmonary Hypertension or Pulmonary Embolism.

Q: Carbon monoxide diffusion capacity decreases in all, except?

Alveolar hemorrhage. ### Explanation The **Carbon Monoxide Diffusing Capacity (DLCO)** measures the ability of the lungs to transfer gas from inhaled air to the red blood cells in pulmonary capillaries. It depends on the surface area of the alveolar-capillary membrane, the capillary blood volume, and the hemoglobin concentration [1]. **Why Alveolar Hemorrhage is the Correct Answer:** In **Alveolar Hemorrhage** (e.g., Goodpasture syndrome, Wegener’s), there is "extravasated" blood sitting within the alveoli. Carbon monoxide (CO) has an extremely high affinity for hemoglobin [1]. When the patient inhales the test gas, this intra-alveolar hemoglobin binds the CO before it even reaches the capillaries. This results in an **increased DLCO** (or a pseudo-elevation), making it the only condition among the choices where DLCO does not decrease. **Analysis of Incorrect Options:** * **Emphysema (A):** DLCO **decreases** due to the destruction of alveolar walls, which significantly reduces the total surface area available for gas exchange [1]. * **Primary Pulmonary Hypertension (B):** DLCO **decreases** because of the destruction or narrowing of the pulmonary vascular bed, reducing the effective capillary blood volume. * **Infiltrative Lung Disease (D):** Conditions like Interstitial Lung Disease (ILD) **decrease** DLCO because the alveolar-capillary membrane becomes thickened and scarred (fibrosis), increasing the barrier for diffusion [1]. **High-Yield Clinical Pearls for NEET-PG:** * **DLCO Increases in:** Alveolar hemorrhage, Polycythemia, Left-to-right shunts, and sometimes Obesity or Asthma (due to increased apical blood flow). * **DLCO Decreases in:** Anemia, Emphysema, ILD, Pulmonary Embolism, and Pulmonary Hypertension. * **Key Distinction:** DLCO is **normal** in Chronic Bronchitis but **decreased** in Emphysema [1]. This is a classic board-style differentiator for COPD phenotypes.

Q: Fleeting pulmonary infiltrates on sequential chest skiagrams in an individual who suffers from asthma are characteristic of?

Allergic bronchopulmonary aspergillosis. ### Explanation **Correct Option: A. Allergic bronchopulmonary aspergillosis (ABPA)** ABPA is a hypersensitivity reaction to *Aspergillus fumigatus* colonization in the airways, typically occurring in patients with **long-standing asthma** or cystic fibrosis. The "fleeting" or "evanescent" pulmonary infiltrates (also known as **Rosenberg-Patterson criteria**) represent areas of mucoid impaction and eosinophilic pneumonia that resolve in one area and reappear in another. This is a classic radiological hallmark of ABPA. **Why the other options are incorrect:** * **B. Mycobacterium tuberculosis:** Typically presents with persistent, progressive cavitary lesions (upper lobes) or miliary patterns. Infiltrates are chronic and do not "flee" or shift rapidly. * **C. Pneumocystis jirovecii (PJP):** Characterized by bilateral, symmetrical ground-glass opacities radiating from the hilum (perihilar distribution), usually in immunocompromised patients (HIV/AIDS). * **D. Nocardia infection:** Usually presents as subacute pneumonia with nodules or abscesses [2], often with cavitation, primarily in immunocompromised hosts. It does not show a migratory pattern. **High-Yield Clinical Pearls for NEET-PG:** * **Radiological Signs of ABPA:** * **Finger-in-glove appearance:** Due to mucoid impaction in dilated bronchi [1]. * **Central Bronchiectasis:** A highly specific diagnostic feature. * **Fleeting Opacities:** Migratory shadows on sequential X-rays. * **Diagnostic Markers:** Elevated serum **IgE levels** (>1000 IU/mL) [3], peripheral blood **eosinophilia**, and positive skin test for *Aspergillus* antigen. * **Treatment:** The mainstay of treatment is **Oral Corticosteroids** (to reduce inflammation) and **Itraconazole** (to reduce fungal burden).

Q: Which of the following is NOT true about Interstitial Fibrosis?

FEV1/FVC ratio is normal or increased. Interstitial Fibrosis is the hallmark of **Restrictive Lung Diseases (RLD)**. The fundamental pathology involves stiffening of the lung parenchyma, which reduces lung compliance [2] and impairs gas exchange. Pulmonary function tests typically show a restrictive ventilatory defect in the presence of small lung volumes and reduced gas transfer [1]. ### **Analysis of Options** * **Option B (Correct Answer):** The question asks which statement is **NOT** true. However, in Restrictive Lung Disease, the FEV1/FVC ratio is typically **normal or even increased** (often >0.8). This occurs because both FEV1 and FVC decrease proportionately, or FVC decreases more significantly due to loss of lung volume. Since the statement "FEV1/FVC ratio is normal or increased" is actually **TRUE**, it serves as the correct answer choice for this "Except" type question format. * **Option A:** **FVC < 80%** is a diagnostic criterion for restriction. As the lungs become fibrotic and "small," the total volume of air that can be forcibly exhaled is significantly reduced [1]. * **Option C:** **DLCO is decreased** because fibrosis increases the thickness of the alveolar-capillary membrane, creating a physical barrier that hinders the diffusion of carbon monoxide (and oxygen) [1]. * **Option D:** **TLC is decreased** is the gold standard for diagnosing restriction. Fibrosis prevents the lungs from expanding fully, leading to reduced total lung capacity [1]. ### **NEET-PG High-Yield Pearls** * **PFT Pattern in RLD:** ↓ TLC, ↓ FVC, ↓ FRC, and **Normal/↑ FEV1/FVC ratio**. * **Compliance:** Lung compliance is **decreased** (stiff lungs), while elastic recoil is **increased** [2]. * **Radiology:** Look for "Honeycombing" and "Traction Bronchiectasis" on HRCT, which are classic signs of advanced interstitial fibrosis [1]. * **Clinical Sign:** Fine "Velcro" inspiratory crackles on auscultation and digital clubbing [1].

Q: Which of the following are non-metastatic manifestations of carcinoma of the lung?

Cushing syndrome. **Explanation:** The question refers to **Paraneoplastic Syndromes (PNS)**, which are signs and symptoms occurring at sites distant from a tumor or its metastasis [1]. These are "non-metastatic" manifestations caused by the ectopic production of hormones, peptides, or cytokines by tumor cells [4]. **Why Cushing Syndrome is Correct:** Cushing syndrome is a classic paraneoplastic manifestation of **Small Cell Lung Carcinoma (SCLC)** [1]. It occurs due to the ectopic production of **ACTH (Adrenocorticotropic Hormone)** [3]. This leads to bilateral adrenal hyperplasia and excess cortisol production, presenting clinically with hypertension, hypokalemia, and metabolic alkalosis (often more rapidly progressive than pituitary-based Cushing’s). **Analysis of Incorrect Options:** * **Diabetes Mellitus:** While chronic steroid excess (from Cushing’s) can cause secondary hyperglycemia, DM itself is not considered a specific paraneoplastic syndrome of lung cancer. * **Carcinoid Syndrome:** Although bronchial carcinoids exist, classic carcinoid syndrome (flushing, diarrhea) is rare unless there are massive liver metastases. It is not a standard paraneoplastic feature of primary lung adenocarcinoma or squamous cell carcinoma. * **Jaundice:** This is typically a **metastatic** manifestation, occurring due to liver involvement (hepatic metastases) or biliary obstruction, rather than a paraneoplastic process [2]. **NEET-PG High-Yield Pearls:** 1. **Small Cell Carcinoma (SCLC):** Associated with ACTH (Cushing’s), SIADH (hyponatremia), and Lambert-Eaton Myasthenic Syndrome [4]. 2. **Squamous Cell Carcinoma:** Associated with **PTHrP** (Parathyroid Hormone-related Protein) leading to **Hypercalcemia**. (Mnemonic: **S**quamous = **S**tones/Calcium) [1]. 3. **Adenocarcinoma:** Associated with Hypertrophic Osteoarthropathy (HOA) and Digital Clubbing [2]. 4. **Large Cell Carcinoma:** Associated with Gynecomastia.

Q: Presence of cholesterol crystals in pleural effusion is a feature of which condition?

Myxedema. **Explanation:** The presence of cholesterol crystals in pleural fluid is the hallmark of a **Pseudochylothorax** (also known as Cholesterol Pleurisy). This condition occurs when cholesterol accumulates in a long-standing, chronic pleural effusion, typically due to the breakdown of red blood cells and neutrophils. **1. Why Myxedema is Correct:** Myxedema (severe hypothyroidism) is a classic cause of pseudochylothorax. In hypothyroidism, there is decreased clearance of lipids and increased capillary permeability, leading to chronic effusions. Over time, the trapped lipids crystallize into cholesterol crystals, giving the fluid a characteristic "satin-like" or "shimmering" appearance. **2. Why other options are incorrect:** * **Hypertriglyceridemia:** This is associated with **Chylothorax** (leakage of thoracic duct lymph), which is characterized by high triglycerides (>110 mg/dL) and chylomicrons, but *not* cholesterol crystals [1]. * **Hyperthyroidism:** This typically does not cause chronic pleural effusions. If an effusion occurs, it is usually related to associated heart failure (transudate). * **Sarcoidosis:** While sarcoidosis can cause pleural effusions, they are typically lymphocytic exudates. It is not a classic cause of cholesterol crystal formation. **NEET-PG High-Yield Pearls:** * **Pseudochylothorax:** Cholesterol >200 mg/dL, Triglycerides 110 mg/dL, presence of **chylomicrons**, low cholesterol. Most common cause: **Trauma/Surgery** or **Lymphoma** [1]. * **Visual Clue:** Pseudochylothorax fluid looks milky or metallic/shimmering.

Question 1

Which of the following is NOT a cause of decreased DLCO?

Accepted Answer

Goodpasture syndrome

Answer

Anemia

Answer

Interstitial lung diseases

Answer

Emphysema

Question 2

Carbon monoxide diffusion capacity decreases in all, except?

Accepted Answer

Alveolar hemorrhage

Answer

Emphysema

Answer

Primary pulmonary hypertension

Answer

Infiltrative lung disease

Question 3

A 40-year-old man presents with recurrent hemoptysis and purulent cough. Chest X-ray was found to be normal. What is the next investigation to aid in diagnosis?

Accepted Answer

Bronchoscopy

Answer

MRI

Answer

HRCT

Answer

CT guided biopsy

Question 4

Fleeting pulmonary infiltrates on sequential chest skiagrams in an individual who suffers from asthma are characteristic of?

Accepted Answer

Allergic bronchopulmonary aspergillosis

Answer

Mycobacterium tuberculosis infection

Answer

Pneumocystis jirovecii pneumonia

Answer

Nocardia infection

Question 5

Which of the following is NOT true about Interstitial Fibrosis?

Accepted Answer

FEV1/FVC ratio is normal or increased

Answer

FVC < 80% Predicted

Answer

DLCO is decreased

Answer

TLC is decreased

Question 6

Exercise-induced asthma is not precipitated by which of the following?

Accepted Answer

Swimming in hot water

Answer

High altitude climb and exercise

Answer

Cycling in cold weather

Answer

Swimming in cold water

Question 7

Which of the following is NOT seen in precapillary pulmonary hypertension?

Accepted Answer

Increased pulmonary wedge pressure

Answer

Increased pressure in pulmonary circulation

Answer

Increased capillary pressure

Answer

Right ventricular hypertrophy

Question 8

A 60-year old male with a long-standing history of breathlessness and a heavy smoking history since age 20 presents with an anxious, emaciated appearance, puffing for breath without cyanosis, and a barrel-shaped chest. What is the investigation of choice for this patient?

Accepted Answer

High-resolution CT

Answer

Contrast-enhanced CT

Answer

Plain skiagram of the chest

Answer

Ultrasound test

Question 9

Which of the following are non-metastatic manifestations of carcinoma of the lung?

Accepted Answer

Cushing syndrome

Answer

Diabetes mellitus

Answer

Carcinoid syndrome

Answer

Jaundice

Question 10

Presence of cholesterol crystals in pleural effusion is a feature of which condition?

Accepted Answer

Myxedema

Answer

Hypertriglyceridemia

Answer

Hyperthyroidism

Answer

Sarcoidosis

Pulmonology — MCQs

Pulmonology — MCQs

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