Pulmonary Infections — MCQs

10 questions

Which of the following features is NOT typically seen in viral pneumonia?

Devi, a 28 year female, has diarrhea, confusion, high grade fever with bilateral pneumonitis. The diagnosis is -

Patient of pneumonia on ventilator with wt. 50 kg. RR 14/min, bicarbonate - 18, pH 7.3, pCO2 48 mmHg, pO2 110 mmHg, PEEP 12 cm H2O, tidal volume 420 mL, SpO2 - 100% with FiO2 90%. What is next step in management?

A 50-year-old farmer presents with cough, fever, and weight loss. CXR shows upper lobe cavitary lesions. Sputum culture reveals acid-fast bacilli resistant to isoniazid and rifampin. What is the next best drug?

Most common organism causing ventilator associated pneumonia -

In Revised National TB Control Program mainstay of diagnosis of pulmonary tuberculosis is:

Which of the following conditions is least likely to cause pneumothorax?

Which of the following statements about tuberculosis (TB) of the uterus is NOT true?

Gram stain shows branching filaments. Culture shows sulfur granules and grows in CO2. Which organism?

Q10

What is a likely diagnosis for a patient with persistent fever after treatment for pneumonia?

Pulmonary Infections Indian Medical PG Practice Questions and MCQs

Question 1: Which of the following features is NOT typically seen in viral pneumonia?

A. Bronchiolitis
B. Multinucleate giant cells in the bronchiolar wall
C. Predominance of alveolar exudate (Correct Answer)
D. Presence of interstitial inflammation

Explanation: ### Predominance of alveolar exudate - Viral pneumonia typically involves the **interstitium**, leading to interstitial inflammation, rather than a significant accumulation of **exudate** within the alveoli [3]. - **Alveolar exudate** is more characteristic of **bacterial pneumonia**, where neutrophils and fibrin fill the alveolar spaces [1], [2], [3]. ### Presence of interstitial inflammation - This is a **hallmark pathological feature** of viral pneumonia, where inflammatory cells infiltrate the alveolar septa and peribronchial tissues [3]. - The inflammation primarily involves the **walls of the alveoli** and the **surrounding connective tissue**, not the alveolar lumen. ### Bronchiolitis - Viral infections, especially in children, often affect the **small airways (bronchioles)**, causing inflammation and obstruction. - This can lead to symptoms such as **wheezing** and **dyspnea** in viral pneumonia. ### Multinucleate giant cells in the bronchiolar wall - The presence of **multinucleate giant cells** is a specific histological finding associated with certain viral pneumonias, particularly those caused by **measles** and **respiratory syncytial virus (RSV)**. - These cells arise from the fusion of infected cells and are found within the bronchiolar epithelium and lumen. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 317-318. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 711-712. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, p. 715.

Question 2: Devi, a 28 year female, has diarrhea, confusion, high grade fever with bilateral pneumonitis. The diagnosis is -

A. H. influenzae
B. Legionella (Correct Answer)
C. Streptococcus pneumoniae
D. Neisseria meningitidis

Explanation: ***Legionella*** - The constellation of **diarrhea, confusion (neurological symptoms), high-grade fever, and bilateral pneumonitis** is highly characteristic of **Legionnaires' disease**, caused by *Legionella pneumophila* [1]. - This organism commonly causes **extrapulmonary symptoms** such as gastrointestinal and neurological manifestations, in addition to severe pneumonia. *H. influenzae* - While *H. influenzae* can cause pneumonia, it typically presents with **lobar pneumonia** [1] and rarely involves gastrointestinal or significant neurological symptoms beyond general debility. - It is more commonly associated with **epiglottitis** and **meningitis** in unimmunized children. *Streptococcus pneumoniae* - *Streptococcus pneumoniae* is the most common cause of **community-acquired pneumonia**, often presenting with acute onset of fever, chills, and productive cough [1]. - While it can cause bacteremia and sepsis, **gastrointestinal symptoms like prominent diarrhea and significant neurological confusion** are not typical primary features of pneumococcal pneumonia. *Neisseria meningitidis* - *Neisseria meningitidis* is primarily known for causing **meningitis** and **meningococcemia**, involving symptoms like stiff neck, headache, rash, and fever [1]. - While it can sometimes cause pneumonia, the combination with **prominent diarrhea and severe, bilateral pneumonitis** as the primary presentation is not characteristic; the neurological symptoms point more towards Legionella given the other features.

Question 3: Patient of pneumonia on ventilator with wt. 50 kg. RR 14/min, bicarbonate - 18, pH 7.3, pCO2 48 mmHg, pO2 110 mmHg, PEEP 12 cm H2O, tidal volume 420 mL, SpO2 - 100% with FiO2 90%. What is next step in management?

A. Increase PEEP
B. Increase tidal volume
C. Decrease fio2 (Correct Answer)
D. Decrease RR

Explanation: **Decrease FiO2** - The patient has an **SpO2 of 100% with a FiO2 of 90%**, indicating **hyperoxia** induced by excessive oxygen delivery. - Decreasing FiO2 is the appropriate next step to prevent **oxygen toxicity** (e.g., absorption atelectasis, free radical damage) while maintaining adequate oxygenation. *Increase PEEP* - The patient's **PaO2 of 110 mmHg** is already well within the normal to high range, suggesting that oxygenation is adequate. - Increasing PEEP would be considered if the patient had **refractory hypoxemia**, not hyperoxia. *Increase tidal volume* - The current tidal volume of **420 mL for a 50 kg patient (8.4 mL/kg)** is already at the higher end of lung-protective ventilation (typically 6-8 mL/kg). - Increasing tidal volume further could lead to **ventilator-induced lung injury** (VILI) due to volutrauma, especially in a patient with pneumonia. *Decrease RR* - The patient has a **pCO2 of 48 mmHg** and a **pH of 7.3**, indicating **respiratory acidosis** (hypoventilation). - Decreasing the respiratory rate would further exacerbate the acidosis by reducing minute ventilation and increasing pCO2, which is inappropriate.

Question 4: A 50-year-old farmer presents with cough, fever, and weight loss. CXR shows upper lobe cavitary lesions. Sputum culture reveals acid-fast bacilli resistant to isoniazid and rifampin. What is the next best drug?

A. Linezolid
B. Fluoroquinolone (Correct Answer)
C. Ethambutol
D. Pyrazinamide

Explanation: **Fluoroquinolone** - In cases of **multidrug-resistant tuberculosis (MDR-TB)**, which is defined by specific resistance to both **isoniazid** and **rifampin**, fluoroquinolones are a crucial second-line agent [1]. - They demonstrate excellent **mycobactericidal activity** and are a cornerstone of MDR-TB treatment regimens [1]. *Linezolid* - While **Linezolid** is used in highly resistant TB cases (XDR-TB), it is generally reserved for situations where other core second-line drugs (like fluoroquinolones) cannot be used or are resistant. - Its use often carries a higher risk of **myelosuppression** and **neuropathy**, making it less preferred as an initial choice for MDR-TB. *Ethambutol* - **Ethambutol** is a first-line antitubercular drug, but it is typically used in conjunction with isoniazid and rifampin to prevent resistance development [1]. - It would not be the "next best" drug when **TB is already resistant to isoniazid and rifampin**, as single-drug therapy is ineffective for MDR-TB and could lead to further resistance. *Pyrazinamide* - **Pyrazinamide** is another first-line drug primarily effective against semi-dormant bacilli in acidic environments [1]. - Similar to ethambutol, it is not appropriate as the "next best" drug to manage **MDR-TB** when resistance to standard first-line agents has already been identified.

Question 5: Most common organism causing ventilator associated pneumonia -

A. Legionella
B. Pneumococcus
C. Pseudomonas (Correct Answer)
D. Coagulase negative staphylococcus

Explanation: ***Pseudomonas*** - **Pseudomonas aeruginosa** is one of the most common causes of **ventilator-associated pneumonia (VAP)**, particularly in **late-onset VAP** (≥5 days) and in patients with prolonged mechanical ventilation, prior antibiotic exposure, or underlying lung disease. - Its ability to form **biofilms** and its intrinsic antibiotic resistance contribute to its prevalence in hospital-acquired infections. - Along with **Staphylococcus aureus** (especially MRSA), Pseudomonas is consistently among the leading causes of VAP in ICU settings. *Legionella* - **Legionella** is a less common cause of VAP and is typically associated with contaminated water sources, manifesting as **Legionnaires' disease**. - It usually causes severe, rapidly progressive pneumonia and is often harder to culture than other bacteria. *Pneumococcus* - **Streptococcus pneumoniae (Pneumococcus)** is the most common cause of **community-acquired pneumonia (CAP)**, but it is less frequently implicated in VAP. - While it can cause severe pneumonia and may be seen in **early-onset VAP**, its incidence in late-onset VAP is lower compared to Gram-negative rods like Pseudomonas. *Coagulase negative staphylococcus* - **Coagulase-negative Staphylococci** (e.g., *Staphylococcus epidermidis*) are common **contaminants** in cultures and primarily cause device-related infections, such as those associated with central venous catheters. - They are rarely a primary cause of VAP, as they typically have low virulence in the respiratory tract.

Question 6: In Revised National TB Control Program mainstay of diagnosis of pulmonary tuberculosis is:

A. Clinical examination
B. PCR
C. Microscopy for Acid-Fast Bacilli (AFB) (Correct Answer)
D. Chest X-Ray

Explanation: ***Microscopy for Acid-Fast Bacilli (AFB)*** - Under the Revised National TB Control Program (RNTCP), **sputum smear microscopy** for **Acid-Fast Bacilli (AFB)** was the primary diagnostic method due to its **affordability**, accessibility, and ability to identify infectious cases. - It involves examining sputum samples under a microscope to detect the presence of **Mycobacterium tuberculosis**. - **Note**: RNTCP was renamed to **National Tuberculosis Elimination Programme (NTEP)** in 2017-2018, and **CBNAAT (GeneXpert MTB/RIF)** is now the upfront diagnostic modality. However, this question specifically refers to the RNTCP era when microscopy was the mainstay. *Clinical examination* - While important for suspecting TB, **clinical examination alone** cannot confirm the diagnosis of pulmonary tuberculosis. - It helps in identifying symptoms and signs but requires **laboratory confirmation** for definitive diagnosis. *PCR* - **PCR (Polymerase Chain Reaction)** is a highly sensitive and specific molecular test, but under RNTCP it was generally used for drug resistance testing or in cases where smear microscopy was negative and suspicion remained high. - It was **more expensive** and less widely available than microscopy, thus not the mainstay for initial diagnosis in RNTCP settings. *Chest X-Ray* - A **Chest X-Ray (CXR)** can show abnormalities suggestive of TB, but it is **not specific** and cannot differentiate between active and inactive disease without further tests. - It is often used as a **screening tool** or to assess the extent of lung involvement, but not the definitive diagnostic method in RNTCP.

Question 7: Which of the following conditions is least likely to cause pneumothorax?

A. Marfan syndrome
B. Assisted ventilation
C. Eosinophilic granuloma
D. Bronchopulmonary Aspergillosis (Correct Answer)

Explanation: ***Bronchopulmonary Aspergillosis*** - Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity reaction to *Aspergillus* species, primarily causing **bronchospasm**, **mucus plugging**, and **bronchiectasis**, rarely leading to pneumothorax [1]. - While it can cause significant lung damage, **pneumothorax** is not a characteristic or common complication, unlike the other conditions listed. *Marfan syndrome* - Patients with **Marfan syndrome** have connective tissue abnormalities, including those affecting the pleura and lung parenchyma. - This predisposition can lead to the formation of **apical blebs and bullae**, which are prone to rupture and cause **spontaneous pneumothorax** [2]. *Assisted ventilation* - **Positive pressure ventilation**, especially with high pressures or volumes, can cause barotrauma or volutrauma to the lungs [2]. - This can lead to alveolar rupture, resulting in **pneumothorax**, particularly in patients with pre-existing lung disease or those requiring high ventilatory support. *Eosinophilic granuloma* - Also known as **pulmonary Langerhans cell histiocytosis**, this condition involves the infiltration of the lungs by Langerhans cells. - It often leads to the formation of **cysts and nodules**, which can rupture and cause recurrent **spontaneous pneumothorax**.

Question 8: Which of the following statements about tuberculosis (TB) of the uterus is NOT true?

A. Increase incidence of ectopic pregnancy
B. Involvement of endosalpinx
C. Most common is ascending infection (Correct Answer)
D. Mostly secondary

Explanation: ***Most common is ascending infection*** - Uterine tuberculosis is overwhelmingly due to **hematogenous spread** from a primary site, often the lungs, rather than an ascending infection from the lower genital tract. - Tuberculosis typically reaches the female genital tract by the **bloodstream**, with the fallopian tubes being the most common initial site of involvement. *Mostly secondary* - Genital tuberculosis, including uterine involvement, is almost always a **secondary infection**, meaning it results from the spread of Mycobacterium tuberculosis from another primary site in the body, most commonly the lungs. - The initial infection establishes elsewhere, and then the bacteria **disseminate hematogenously** to the reproductive organs. *Increase incidence of ectopic pregnancy* - Tubal damage and scarring caused by tuberculosis, particularly in the fallopian tubes (**salpingitis**), disrupt the normal passage of the ovum. - This anatomical alteration significantly **increases the risk** of the fertilized egg implanting outside the uterus, leading to ectopic pregnancy. *Involvement of endosalpinx* - The **fallopian tubes (endosalpinx)** are the most common site of genital tuberculosis, with eventual spread to the uterus through the lymphatic system or direct extension. - Tubal involvement can lead to **salpingitis isthmica nodosa** and hydrosalpinx, contributing to infertility and ectopic pregnancy.

Question 9: Gram stain shows branching filaments. Culture shows sulfur granules and grows in CO2. Which organism?

A. Aspergillus
B. Nocardia
C. Actinomyces (Correct Answer)
D. Streptomyces

Explanation: ***Actinomyces*** - The presence of **branching filaments** on Gram stain and the formation of **sulfur granules** in culture are classic pathological findings for *Actinomyces* infection, specifically **actinomycosis**. - Its requirement for **CO2** (capnophilic growth) further supports *Actinomyces* as the causative organism. *Aspergillus* - *Aspergillus* is a **mold** that forms **septate hyphae with acute angle branching**, not branching filaments on Gram stain readily seen in bacterial infections. - It does not produce **sulfur granules** and is a fungus, not a bacterium. *Nocardia* - *Nocardia* also shows **branching filaments** and is an aerobic organism, but it typically stains **acid-fast** or partially acid-fast. - While it can cause abscesses, it does not form the characteristic **sulfur granules** seen with *Actinomyces*. *Streptomyces* - *Streptomyces* are also **filamentous bacteria** that resemble fungi, but they are generally **soil organisms** and significant human pathogens are less common. - They do not typically produce the **sulfur granules** that are a hallmark of *Actinomyces* infections.

Question 10: What is a likely diagnosis for a patient with persistent fever after treatment for pneumonia?

A. Fungal pneumonia
B. Bronchogenic carcinoma
C. Lung abscess
D. Empyema (pleural effusion with infection) (Correct Answer)

Explanation: ***Empyema (pleural effusion with infection)*** - **Empyema** is a collection of pus in the pleural space, often a complication of pneumonia, and can cause **persistent fever** despite appropriate antibiotic treatment for the initial pneumonia [1]. - The continued presence of infection in the pleural space, which is not directly targeted by standard pneumonia treatment, can lead to prolonged inflammatory symptoms [1]. *Fungal pneumonia* - While fungal pneumonia can cause persistent fever, it typically does not develop *after* treatment for bacterial pneumonia unless the patient is immunocompromised or has specific environmental exposures . - It would usually be considered if initial bacterial treatment failed or if there were specific risk factors for fungal infection. *Bronchogenic carcinoma* - This is a long-term, chronic condition that can cause fever, but it is unlikely to present as a *persistent fever immediately after treatment* for an acute pneumonia episode. - Fever associated with malignancy often has a different pattern and is usually accompanied by other systemic symptoms like weight loss. *Lung abscess* - A **lung abscess** is a pus-filled cavity within the lung parenchyma, which can cause persistent fever. - However, fever from a lung abscess often responds partially to antibiotics, and the diagnosis is usually made earlier during the initial pneumonia course or when treatment fails to resolve the infiltrates.

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