Pulmonology Practice Questions

Q: A 40-year-old male presents with excessive hyperventilation. Arterial blood gas (ABG) analysis reveals a pH of 7.5, PCO2 of 24 mm Hg, and PO2 of 88 mm of Hg. Which of the following statements is true regarding this patient's acid-base status?

Respiratory alkalosis. ### Explanation The patient’s acid-base status is determined by a systematic analysis of the ABG parameters: 1. **pH Analysis:** The pH is **7.5** (Normal: 7.35–7.45). Since the pH is >7.45, the primary condition is **Alkalosis** [2]. 2. **Primary Driver:** We look at the $PCO_2$ and $HCO_3^-$. Here, the $PCO_2$ is **24 mmHg** (Normal: 35–45 mmHg). A decrease in $PCO_2$ (hypocapnia) leads to an increase in pH [1]. Since the low $PCO_2$ matches the alkalotic pH, the primary disturbance is **Respiratory** [2]. 3. **Clinical Correlation:** The patient is hyperventilating. Hyperventilation causes excessive "blowing off" of $CO_2$, leading to a rise in pH [1]. **Why the other options are incorrect:** * **Metabolic Alkalosis:** This would be characterized by a high pH (>7.45) driven by an elevated $HCO_3^-$ (>26 mEq/L), usually with a compensatory rise in $PCO_2$ [1], [3]. * **Respiratory Acidosis:** This occurs when there is alveolar hypoventilation, leading to $CO_2$ retention ($PCO_2$ >45 mmHg) and a low pH (<7.35) [2]. * **Metabolic Acidosis:** This is characterized by a low pH (<7.35) and a primary decrease in $HCO_3^-$ (<22 mEq/L) [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Acute vs. Chronic:** In acute respiratory alkalosis, for every 10 mmHg drop in $PCO_2$, the $HCO_3^-$ drops by **2 mEq/L**. In chronic cases (e.g., high altitude), it drops by **4–5 mEq/L**. * **Common Causes:** Anxiety (Hyperventilation syndrome), Pulmonary Embolism, Salicylate poisoning (early phase), and High altitude [1]. * **Ionized Calcium:** Alkalosis increases the binding of calcium to albumin, decreasing ionized calcium. This can lead to **tetany** and perioral numbness despite normal total serum calcium levels.

Q: Which of the following does NOT constitute the Berlin definition of acute respiratory distress syndrome?

Pulmonary artery end-diastolic pressure less than 18 mm Hg. ### Explanation The **Berlin Definition (2012)** replaced the older AECC definition to provide clearer criteria for diagnosing Acute Respiratory Distress Syndrome (ARDS) [1]. **Why Option D is the correct answer:** Under the old criteria, a Pulmonary Capillary Wedge Pressure (PCWP) ≤ 18 mmHg was required to rule out cardiogenic edema. However, the Berlin Definition **removed the requirement for invasive pressure monitoring** (like pulmonary artery catheterization). Instead, it states that respiratory failure must not be fully explained by cardiac failure or fluid overload, as determined by objective assessment (e.g., echocardiography) if no risk factor is present [1]. Therefore, a specific pressure value is no longer part of the definition. **Analysis of Incorrect Options:** * **Option A:** The **Timing** must be acute, occurring within **one week** of a known clinical insult or new/worsening respiratory symptoms [1]. * **Option B:** **Chest Imaging** (X-ray or CT) must show **bilateral opacities** not fully explained by effusions, lobar/lung collapse, or nodules [1]. * **Option C:** The **Origin of Edema** must be non-cardiogenic. If no clear risk factor (like sepsis or pneumonia) is identified, an objective evaluation is needed to exclude hydrostatic edema [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Severity Categorization:** ARDS is graded based on the **PaO2/FiO2 ratio** with a minimum PEEP of 5 cm H2O [1]: * **Mild:** 200–300 mmHg * **Moderate:** 100–200 mmHg * **Severe:** < 100 mmHg * **Pathology:** The hallmark of ARDS is **Diffuse Alveolar Damage (DAD)**. * **Management:** The gold standard is **Low Tidal Volume Ventilation (6 mL/kg)** to prevent volutrauma [2].

Q: What is the most common cause of chronic cor pulmonale?

COPD. **Explanation:** **Cor pulmonale** is defined as hypertrophy or dilation of the right ventricle resulting from diseases affecting the function and/or structure of the lungs, provided that the right-sided heart failure is not secondary to left-sided heart disease or congenital heart defects. **Why COPD is the Correct Answer:** Chronic Obstructive Pulmonary Disease (COPD) is the most common cause of chronic cor pulmonale worldwide, accounting for over 50% of cases [1]. The underlying mechanism involves chronic alveolar hypoxia, which triggers **hypoxic pulmonary vasoconstriction**. Over time, this leads to structural remodeling of pulmonary vessels, increased pulmonary vascular resistance, and permanent pulmonary hypertension. The right ventricle must pump against this high pressure, eventually leading to hypertrophy and failure. **Analysis of Incorrect Options:** * **Recurrent pulmonary embolization:** This is a significant cause of *Chronic Thromboembolic Pulmonary Hypertension (CTEPH)*, but it is far less frequent than COPD in the general population. * **Cystic fibrosis:** While a common cause of cor pulmonale in the pediatric and young adult population [2], it does not match the overall prevalence of COPD in adults. * **Bronchial asthma:** Although severe, poorly controlled asthma can lead to remodeling, it rarely progresses to chronic cor pulmonale compared to the irreversible airflow obstruction seen in COPD. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of Acute Cor Pulmonale:** Massive Pulmonary Embolism. * **ECG Findings:** Right axis deviation, "P pulmonale" (tall, peaked P waves in lead II), and R/S ratio >1 in V1. * **Gold Standard for Diagnosis:** Right heart catheterization (to measure pulmonary artery pressure). * **Management Tip:** Oxygen therapy is the only intervention proven to improve survival in COPD-associated cor pulmonale by reducing hypoxic vasoconstriction.

Q: A 65-year-old man with a history of 30 pack-years of smoking presents with weight loss, cough with expectoration, and hemoptysis for 40 days. His serum sodium was found to be 124 mEq/L and serum calcium was 10 mg/dL. A chest X-ray showed a hilar mass. Brush cytology and sputum were positive for tumor cells. What subtype of lung carcinoma does this patient most likely have?

Small cell carcinoma. The patient presents with a classic triad of lung malignancy: chronic smoking history, constitutional symptoms (weight loss, cough, hemoptysis), and a **hilar (central) mass** [1]. The key to identifying the subtype lies in the metabolic abnormality: **Hyponatremia (124 mEq/L)**. **1. Why Small Cell Carcinoma (SCLC) is correct:** SCLC is a neuroendocrine tumor strongly associated with smoking and a central (hilar) location. It is the most common lung cancer to cause **Paraneoplastic Syndromes**. Specifically, SCLC frequently secretes **Antidiuretic Hormone (SIADH)**, leading to water retention and dilutional hyponatremia, as seen in this patient [2]. **2. Why other options are incorrect:** * **Squamous Cell Carcinoma:** While also central and smoking-related, it is classically associated with **hypercalcemia** due to the secretion of Parathyroid Hormone-related Protein (PTHrP). This patient’s calcium (10 mg/dL) is normal [1]. * **Adenocarcinoma:** This is the most common lung cancer overall, but it typically presents as a **peripheral lesion** and is less strongly associated with smoking or SIADH [1]. * **Large Cell Carcinoma:** This is a diagnosis of exclusion that usually presents as a large peripheral mass and is associated with gynecomastia, not SIADH. ### High-Yield Clinical Pearls for NEET-PG: * **Central Tumors (The 2 S's):** **S**mall cell and **S**quamous cell carcinoma. * **Small Cell Carcinoma Associations:** SIADH (Hyponatremia), ACTH secretion (Cushing’s Syndrome), and Lambert-Eaton Myasthenic Syndrome [2]. * **Squamous Cell Carcinoma Association:** Hypercalcemia (PTHrP) [1]. * **Adenocarcinoma:** Most common subtype in non-smokers and females; associated with hypertrophic osteoarthropathy (clubbing) [1]. * **Pancoast Tumor:** Usually Squamous or Adenocarcinoma; presents with Horner’s syndrome.

Q: Which of the following are diagnostic criteria for Allergic Bronchopulmonary Aspergillosis?

Central lower lobe bronchiectasis. Allergic Bronchopulmonary Aspergillosis (ABPA) is a complex hypersensitivity reaction to *Aspergillus fumigatus* colonization, typically occurring in patients with Asthma or Cystic Fibrosis. **Why the correct answer is right:** **Central Bronchiectasis (CB)** is a hallmark radiological feature of ABPA. Unlike post-infective bronchiectasis, which is usually peripheral, ABPA characteristically affects the **inner two-thirds** of the lung fields (central). While it can involve any lobe, it classically involves the upper and middle lobes; however, in the context of the provided options, "Central Bronchiectasis" is the defining diagnostic criterion (part of the Rosenberg-Patterson criteria). **Why the incorrect options are wrong:** * **Option A:** Peripheral eosinophilia is a criterion, but the threshold is much higher: **>0.5 x 10⁹/L** (or >500 cells/μL). 0.1 x 10⁹/L is within the normal range. * **Option C:** Detection of *Aspergillus* in sputum is common but **not a diagnostic criterion**. Sputum cultures are often negative, and positive cultures can represent simple colonization without the hypersensitivity required for ABPA. * **Option D:** While Asthma is a major predisposing factor, it is **not "always" present**. ABPA can also occur in patients with Cystic Fibrosis without a formal diagnosis of asthma. **High-Yield Clinical Pearls for NEET-PG:** * **ISHAM Criteria:** The most updated criteria require: (1) Predisposing condition (Asthma/CF), (2) Positive Type I skin test or elevated IgE against *A. fumigatus*, (3) Total IgE >1000 IU/mL, and (4) Two of the following: IgG antibodies to *Aspergillus*, Central Bronchiectasis, or Eosinophils >500 cells/μL. * **Radiology:** Look for the **"Finger-in-glove" appearance** (mucoid impaction) and **"Tram-line" shadows**. * **Treatment:** Oral Corticosteroids (to suppress inflammation) + Itraconazole (to reduce fungal burden).

Q: Which of the following conditions does not typically present with hemoptysis?

Empyema. **Explanation:** Hemoptysis is the expectoration of blood originating from the lower respiratory tract. To understand why **Empyema** is the correct answer, one must distinguish between parenchymal/vascular lung diseases and pleural space diseases. **Why Empyema is the correct answer:** Empyema is defined as a collection of pus within the **pleural space**, which is outside the lung parenchyma and airways [2]. Since there is no direct communication between the pleural space and the bronchial tree, patients typically present with pleuritic chest pain, fever, and dyspnea, but **not hemoptysis**. If a patient with empyema develops hemoptysis, it usually suggests a complication like a bronchopleural fistula or an underlying necrotizing pneumonia [2]. **Analysis of Incorrect Options:** * **Mitral Stenosis:** A classic cardiovascular cause of hemoptysis. Increased left atrial pressure leads to pulmonary venous hypertension, causing rupture of small bronchial veins (often termed "cardiac asthma" or "apoplectic" hemoptysis). * **Pulmonary Embolism:** Can cause pulmonary infarction, leading to alveolar hemorrhage and subsequent hemoptysis, typically accompanied by pleuritic pain and acute dyspnea [1], [3]. * **Bronchiectasis:** One of the most common causes of massive hemoptysis. Chronic inflammation leads to the hypertrophy and proliferation of tortuous **bronchial arteries** (high-pressure systemic circulation), which are prone to rupture [1]. **NEET-PG High-Yield Pearls:** * **Most common cause of hemoptysis in India:** Tuberculosis. * **Most common cause of massive hemoptysis:** Bronchiectasis (due to bronchial artery erosion) [1]. * **Source of bleeding:** 90% of massive hemoptysis cases originate from the **Bronchial arteries** (systemic circulation), not the pulmonary arteries. * **Initial Investigation of choice:** CT Chest (MDCT) is preferred to localize the site and cause.

Q: Which of the following routes of infection is most responsible for lung abscess?

Aspiration of organisms from oropharynx. **Explanation:** A lung abscess is a localized area of necrosis within the pulmonary parenchyma, resulting in a cavity filled with debris or fluid. **Why Option D is Correct:** The most common mechanism for the development of a lung abscess is the **aspiration of oropharyngeal secretions** [1]. The oropharynx is colonized by a high concentration of anaerobic bacteria (such as *Peptostreptococcus*, *Fusobacterium*, and *Bacteroides*). Patients with predispositions like altered consciousness (alcoholism, seizures, general anesthesia) or esophageal/periodontal disease are at high risk [1]. Once aspirated, these organisms cause pneumonitis, which progresses to tissue necrosis and abscess formation within 7–14 days. **Why Other Options are Incorrect:** * **A. Direct inoculation:** This occurs via trauma (e.g., penetrating chest injury) or iatrogenic means. While possible, it is a rare cause compared to aspiration. * **B. Inhalation of infection:** This is the primary route for pathogens like *Mycobacterium tuberculosis* or certain fungi, but it is not the typical route for the pyogenic/anaerobic organisms that cause classic lung abscesses [2]. * **C. Spread from adjacent site:** This refers to extension from a subphrenic abscess or liver abscess (often amoebic). While clinically significant, it accounts for only a small fraction of cases. **High-Yield Clinical Pearls for NEET-PG:** * **Location:** Aspiration-related abscesses most commonly occur in the **posterior segment of the upper lobes** and the **superior segment of the lower lobes** (gravity-dependent areas). * **Microbiology:** Most lung abscesses are **polymicrobial**, involving a mix of aerobes and anaerobes. * **Clinical Sign:** Foul-smelling (putrid) sputum is highly suggestive of anaerobic infection. * **Radiology:** Characterized by a cavity with an **air-fluid level** on a chest X-ray [1].

Question 1

Which of the following are associated with spontaneous pneumothorax?

Accepted Answer

Short stature

Answer

Smokers

Answer

Male sex

Answer

Exercise

Question 2

A 40-year-old male presents with excessive hyperventilation. Arterial blood gas (ABG) analysis reveals a pH of 7.5, PCO2 of 24 mm Hg, and PO2 of 88 mm of Hg. Which of the following statements is true regarding this patient's acid-base status?

Accepted Answer

Respiratory alkalosis

Answer

Metabolic alkalosis

Answer

Respiratory acidosis

Answer

Metabolic acidosis

Question 3

Which of the following does NOT constitute the Berlin definition of acute respiratory distress syndrome?

Accepted Answer

Pulmonary artery end-diastolic pressure less than 18 mm Hg

Answer

A known clinical insult within 1 week

Answer

Bilateral opacities on chest x-ray

Answer

Respiratory failure not fully explained by cardiac failure or fluid overload

Question 4

What is the most common cause of chronic cor pulmonale?

Accepted Answer

COPD

Answer

Recurrent pulmonary embolization

Answer

Cystic fibrosis

Answer

Bronchial asthma

Question 5

A 65-year-old man with a history of 30 pack-years of smoking presents with weight loss, cough with expectoration, and hemoptysis for 40 days. His serum sodium was found to be 124 mEq/L and serum calcium was 10 mg/dL. A chest X-ray showed a hilar mass. Brush cytology and sputum were positive for tumor cells. What subtype of lung carcinoma does this patient most likely have?

Accepted Answer

Small cell carcinoma

Answer

Squamous cell carcinoma

Answer

Adenocarcinoma

Answer

Large cell carcinoma

Question 6

Which of the following are diagnostic criteria for Allergic Bronchopulmonary Aspergillosis?

Accepted Answer

Central lower lobe bronchiectasis

Answer

Peripheral eosinophilia > 0.1 x 10^9/L

Answer

Detection of Aspergillus in sputum

Answer

Asthma is always present

Question 7

Which of the following conditions does not typically present with hemoptysis?

Accepted Answer

Empyema

Answer

Mitral stenosis

Answer

Pulmonary embolism

Answer

Bronchiectasis

Question 8

Which of the following routes of infection is most responsible for lung abscess?

Accepted Answer

Aspiration of organisms from oropharynx

Answer

Direct inoculation

Answer

Inhalation of infection

Answer

Spread from adjacent site of infection

Question 9

Which of the following statements is true regarding pulmonary arterial hypertension (PAH)?

Accepted Answer

Progressive breathlessness is the most common presentation.

Answer

Edema is an early feature of PAH.

Answer

PAH is associated with bradyarrhythmias.

Answer

A systolic murmur of mitral regurgitation is present in PAH.

Question 10

A patient presents with massive thromboembolism and hypotension, with a blood pressure of 88/50 mmHg, even after a 1 L fluid bolus. An echocardiogram shows right ventricular hypokinesis. What is the next best step in management?

Accepted Answer

Administer dopamine and recombinant tissue plasminogen activator, 100 mg IV.

Answer

Continue IV fluids at 500 mL/hr for a total of 4 L of fluid resuscitation.

Answer

Refer for inferior vena cava filter placement and continue current management.

Answer

Refer for surgical embolectomy.

Pulmonology — MCQs

Pulmonology — MCQs

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