Lung Infections — MCQs

10 questions

A 55-year-old woman presents with persistent cough, fever, and hemoptysis. Sputum shows branching septate hyphae. What is the likely pathogen?

Which of the following is NOT seen in an HIV patient with a CD4 count less than 100 per microliter, who has a non-productive cough?

MC cause of atypical pneumonia?

NOT a good prognostic factor for TB spine

A known case of HIV presents with cough, sputum production, and fever. Examination reveals consolidation in the right infrascapular area, and an X-ray shows right lower lobe consolidation. The patient's CD4 count is 55. What is the common cause of this presentation?

A 35-year-old woman with a long history of dyspnea, chronic cough, sputum production, and wheezing dies of respiratory failure following a bout of lobar pneumonia. She was not a smoker or an alcoholic. Which of the following underlying conditions is most likely associated with the pathologic changes shown in the lung autopsy?

Which of the following conditions characteristically causes bilateral hypertranslucency of lung fields on chest X-ray?

Which of the following congenital heart defects is least likely to cause recurrent pulmonary infections?

Shoulder pain post laparoscopy is due to:

Q10

A patient presents with recurrent lung infections, and the chest X-ray provided shows a characteristic finding. What is the most likely diagnosis?

Lung Infections Indian Medical PG Practice Questions and MCQs

Question 1: A 55-year-old woman presents with persistent cough, fever, and hemoptysis. Sputum shows branching septate hyphae. What is the likely pathogen?

A. Aspergillus fumigatus (Correct Answer)
B. Candida albicans
C. Histoplasma capsulatum
D. Mucor species

Explanation: ***Aspergillus fumigatus*** - The presence of **branching septate hyphae** in sputum, along with symptoms of **persistent cough, fever, and hemoptysis**, is highly characteristic of an *Aspergillus* infection, particularly in immunocompromised patients or those with pre-existing lung conditions. - This fungus often colonizes the respiratory tract and can cause various diseases, including **allergic bronchopulmonary aspergillosis (ABPA)**, **aspergilloma** (fungus ball), or **invasive aspergillosis**. - The hyphae branch at **acute angles (45°)** and are **septate**, which is the key distinguishing feature. *Candida albicans* - While *Candida albicans* is a common fungal pathogen, it typically presents as **yeast** or **pseudohyphae** on microscopy, not branching septate hyphae. - It usually causes **mucocutaneous infections** like thrush or candidemia, with pulmonary involvement being less common and usually presenting differently from the described symptoms. *Histoplasma capsulatum* - *Histoplasma capsulatum* is a **dimorphic fungus** that appears as **small intracellular yeast forms** within macrophages in tissue or sputum, not branching septate hyphae. - It is endemic to certain regions (e.g., Ohio and Mississippi River valleys) and typically causes **pulmonary histoplasmosis**, which can mimic tuberculosis, but microscopic findings differ significantly. *Mucor species* - **Mucor species** are characterized by **broad, ribbon-like, aseptate (non-septate) hyphae** with irregular branching at right angles, which is distinct from the branching septate hyphae described. - These fungi typically cause **mucormycosis** (zygomycosis), an aggressive infection often seen in immunocompromised individuals, especially diabetics with ketoacidosis, and can involve the rhinocerebral region, lungs, or skin.

Question 2: Which of the following is NOT seen in an HIV patient with a CD4 count less than 100 per microliter, who has a non-productive cough?

A. Mycoplasma pneumoniae (Correct Answer)
B. Pneumocystis jirovecii
C. Cryptococcal infection
D. Mycobacterium tuberculosis

Explanation: ***Mycoplasma pneumoniae*** - *Mycoplasma pneumoniae* is an atypical bacterium that causes **community-acquired pneumonia** in immunocompetent individuals. - While it can cause a non-productive cough, it is **not considered an opportunistic infection** in HIV patients with advanced immunosuppression (CD4 < 100), as its incidence is not significantly higher or more severe in this population compared to the general population. *Pneumocystis jirovecii* - **Pneumocystis pneumonia (PCP)** is a classic opportunistic infection in HIV patients, especially when the **CD4 count is below 200 cells/µL** [1]. - It commonly presents with a **non-productive cough**, fever, and dyspnea, and is a strong consideration in this clinical scenario [2]. *Cryptococcal infection* - **Pulmonary cryptococcosis**, caused by *Cryptococcus neoformans*, is an opportunistic infection in advanced HIV disease (CD4 < 100 cells/µL). - It often presents with **non-specific respiratory symptoms** including a non-productive cough, and can disseminate to the central nervous system. *Mycobacterium tuberculosis* - **Tuberculosis (TB)** is a common and serious opportunistic infection in HIV patients, particularly with **advanced immunosuppression** [1]. - Pulmonary TB can present with a **non-productive or productive cough**, fever, and weight loss, and is a significant cause of morbidity and mortality in this population [1].

Question 3: MC cause of atypical pneumonia?

A. Mycoplasma pneumoniae (Correct Answer)
B. Klebsiella pneumoniae
C. Hemophilus influenzae
D. Chlamydia

Explanation: ***Mycoplasma pneumoniae*** - *M. pneumoniae* is the most common cause of **atypical pneumonia**, often referred to as **"walking pneumonia"** due to milder symptoms compared to typical bacterial pneumonia. - It lacks a **cell wall**, making it resistant to many common antibiotics like penicillin and cephalosporins. *Klebsiella pneumoniae* - *Klebsiella pneumoniae* typically causes **lobar pneumonia**, particularly in individuals with compromised immune systems or alcoholism. - It is associated with **severe symptoms**, such as thick, "currant jelly" sputum, and often forms dense consolidated infiltrates on chest X-rays. [1] *Hemophilus influenzae* - *Haemophilus influenzae* is a common cause of **bacterial pneumonia**, especially in children and adults with underlying lung disease (e.g., COPD). - It usually presents as **typical pneumonia** with more acute and severe symptoms, rather than the milder, atypical presentation. *Chlamydia* - While *Chlamydia pneumoniae* can cause a form of atypical pneumonia, it is **less common** than *Mycoplasma pneumoniae* as the primary cause. [1] - *Chlamydia* infections can also cause other conditions, such as **urethritis** and **cervicitis**, depending on the species involved.

Question 4: NOT a good prognostic factor for TB spine

A. Young age
B. Good immunity
C. Rapid onset (Correct Answer)
D. Early diagnosis

Explanation: ***Rapid onset*** - A **rapid onset** of symptoms in TB spine can indicate aggressive disease progression and may be associated with a poorer prognosis [1]. - This suggests the infection is advancing quickly, potentially leading to more severe neurological deficits or bone destruction before effective treatment can be initiated [1]. *Young age* - **Young age** is generally considered a good prognostic factor for TB spine, as younger patients often have better bone healing capacity and immune responses. - They tend to respond more effectively to antitubercular treatment and have a lower incidence of severe complications compared to older adults. *Good immunity* - A **robust immune system** is crucial for controlling *Mycobacterium tuberculosis* infection and is a key factor in achieving a favorable outcome in TB spine. - Patients with good immunity are more likely to clear the infection, prevent widespread dissemination, and experience less severe bone and neurological damage. *Early diagnosis* - **Early diagnosis** allows for prompt initiation of appropriate antitubercular therapy, which is essential for preventing disease progression and minimizing complications. - **Timely treatment** reduces the risk of spinal deformities, neurological deficits, and the need for extensive surgical intervention, leading to a better prognosis.

Question 5: A known case of HIV presents with cough, sputum production, and fever. Examination reveals consolidation in the right infrascapular area, and an X-ray shows right lower lobe consolidation. The patient's CD4 count is 55. What is the common cause of this presentation?

A. Pneumocystis jiroveci
B. Streptococcus pneumoniae (Correct Answer)
C. Staphylococcus aureus
D. Mycoplasma pneumoniae
E. Mycobacterium tuberculosis

Explanation: ***Streptococcus pneumoniae*** * Despite a low **CD4 count** in an HIV patient, **_Streptococcus pneumoniae_** remains the most common cause of **community-acquired pneumonia (CAP)**, even in immunocompromised individuals. * The clinical presentation of **fever**, **cough**, **sputum production**, and **lobar consolidation** on X-ray is classic for bacterial pneumonia caused by this organism. *Pneumocystis jiroveci* * **_Pneumocystis jiroveci_ pneumonia (PCP)** typically presents with **diffuse interstitial infiltrates** on chest X-ray and severe **hypoxemia**, which is different from the lobar consolidation described. * It is more common when the **CD4 count is below 200**, but classic presentation differs. *Staphylococcus aureus* * **_Staphylococcus aureus_ pneumonia** is often associated with **nosocomial infections**, **influenza co-infection**, or **intravenous drug use**, which are not indicated here. * It frequently causes **necrotizing pneumonia** with **cavitation** or **abscess formation**, not typically simple lobar consolidation. *Mycoplasma pneumoniae* * **_Mycoplasma pneumoniae_** causes "**atypical pneumonia**" with a more **insidious onset** and symptoms like **headache** and **sore throat**, with **patchy infiltrates** on X-ray. * It is less likely to present with distinct lobar consolidation and significant sputum production. *Mycobacterium tuberculosis* * While **tuberculosis** is an important opportunistic infection in HIV patients with CD4 < 200, it typically presents with a more **chronic course** (weeks to months) with **night sweats**, **weight loss**, and **upper lobe involvement** or **miliary pattern**. * The **acute presentation** with **right lower lobe consolidation** is more consistent with acute bacterial pneumonia rather than TB.

Question 6: A 35-year-old woman with a long history of dyspnea, chronic cough, sputum production, and wheezing dies of respiratory failure following a bout of lobar pneumonia. She was not a smoker or an alcoholic. Which of the following underlying conditions is most likely associated with the pathologic changes shown in the lung autopsy?

A. Antibodies against type 4 collagen (associated with Goodpasture syndrome)
B. Cystic fibrosis (a genetic disorder affecting the lungs)
C. Mutation in dynein arms (associated with primary ciliary dyskinesia)
D. Alpha-1 antitrypsin deficiency (Correct Answer)

Explanation: ***Alpha 1 antitrypsin deficiency*** - This condition leads to **accumulation of abnormal protein** in the liver and lungs, resulting in emphysema, which is consistent with chronic cough and dyspnea [1]. - Patients often develop **lung pathology** similar to what is seen in smokers, making it plausible given the patient's background [1]. *Mutation in dynein arms* - This is associated with **primary ciliary dyskinesia**, which presents with recurrent respiratory infections but is not typical in non-smokers or in the context of **dyspnea with chronic cough**. - Usually linked to **situs inversus** and **recurrent infections**, neither of which is highlighted here. *Antibodies against type 4 collagen* - This condition is related to **Goodpasture syndrome**, which typically results in **hemoptysis** and **renal failure**, rather than chronic cough and sputum production. - The predominant involvement in this syndrome does not align with the clinical presentation of **chronic lung disease** noted in this patient. *Cystic fibrosis* - While it causes **chronic respiratory symptoms**, it is usually seen in younger patients and is associated with **pancreatic insufficiency** and **salty sweat**. - The age of the patient and symptom progression does not fit well with a diagnosis of cystic fibrosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 683-684.

Question 7: Which of the following conditions characteristically causes bilateral hypertranslucency of lung fields on chest X-ray?

A. Mcleod syndrome
B. Poland syndrome
C. Emphysema (Correct Answer)
D. Pneumothorax

Explanation: ***Correct: Emphysema*** - **Emphysema** causes destruction of alveolar walls, leading to enlarged air spaces and **air trapping**, making both lungs appear hypertranslucent on X-ray - This **bilateral hypertranslucency** is due to reduced lung tissue density, decreased vascular markings, and increased air volume - Classic radiographic features include flattened diaphragms, increased retrosternal space, and hyperlucent lung fields *Incorrect: Mcleod syndrome* - Also known as **Swyer–James–MacLeod syndrome**, this condition causes **unilateral** lung or lobe hyperlucency due to post-infectious obliterative bronchiolitis - The key differentiating feature is that it's **unilateral**, whereas the question asks for bilateral hypertranslucency - Affected lung shows air trapping on expiratory films *Incorrect: Pneumothorax* - A **pneumothorax** presents as a **unilateral** or focal hypertranslucent area due to air in the pleural space - Characterized by **absence of lung markings** beyond the visceral pleural line and associated lung collapse - This is a pleural space abnormality, not a bilateral parenchymal lung disease *Incorrect: Poland syndrome* - **Poland syndrome** is a congenital condition with absence or underdevelopment of the pectoralis major muscle - Can lead to **unilateral** apparent hyperlucency on the affected side due to missing chest wall muscle - This is a **chest wall anomaly**, not a parenchymal lung disease causing bilateral hypertranslucency

Question 8: Which of the following congenital heart defects is least likely to cause recurrent pulmonary infections?

A. Ventricular Septal Defect (VSD)
B. Tetralogy of Fallot (TOF) (Correct Answer)
C. Atrial Septal Defect (ASD)
D. Patent Ductus Arteriosus (PDA)

Explanation: ***Tetralogy of Fallot (TOF)*** - This is a **cyanotic heart defect** characterized by **right-to-left shunting** of blood, leading to reduced pulmonary blood flow. - Reduced pulmonary blood flow means less blood congests the lungs, thus decreasing the risk of **pulmonary edema** and subsequent infections. *Ventricular Septal Defect (VSD)* - VSD results in a **left-to-right shunt**, increasing blood flow to the pulmonary artery and causing **pulmonary overcirculation**. - This **pulmonary congestion** makes the lungs more susceptible to recurrent infections due to increased fluid and pressure in the pulmonary vasculature. *Patent Ductus Arteriosus (PDA)* - PDA also causes a **left-to-right shunt** from the aorta to the pulmonary artery, leading to **pulmonary overcirculation**. - The increased blood flow and pressure in the pulmonary system contribute to **pulmonary edema** and heightened risk of respiratory infections. *Atrial Septal Defect (ASD)* - An ASD typically causes a **left-to-right shunt** at the atrial level, increasing blood flow to the lungs and resulting in **pulmonary overcirculation**. - While generally less severe than VSD or PDA, significant pulmonary blood flow can still predispose individuals to recurrent **pulmonary infections**.

Question 9: Shoulder pain post laparoscopy is due to:

A. Subphrenic abscess
B. CO2 retention (Correct Answer)
C. Compression of the lung
D. Positioning of the patient

Explanation: ***CO2 retention*** - Shoulder pain after laparoscopy is typically referred pain caused by **diaphragmatic irritation** due to residual **carbon dioxide (CO2)** gas used for insufflation. - The **phrenic nerve**, which innervates the diaphragm, shares sensory pathways with the shoulder, leading to referred pain. *Subphrenic abscess* - While a subphrenic abscess can cause diaphragmatic irritation and shoulder pain, it is a **delayed complication** and not an immediate cause of postoperative pain. - It would also be accompanied by signs of **infection** such as fever and leukocytosis, which are not implied here. *Compression of the lung* - **Lung compression** during laparoscopy can occur due to pneumoperitoneum but primarily causes respiratory symptoms and atelectasis, not typically shoulder pain. - Lung compression itself does not directly irritate the **diaphragm** in the same manner as CO2. *Positioning of the patient* - Poor patient positioning can cause musculoskeletal pain in the neck, back, or shoulders due to **nerve compression** or **muscle strain**. - However, the classic referred shoulder pain after laparoscopy is specifically attributed to **diaphragmatic irritation** from CO2, distinguishing it from general positioning discomfort.

Question 10: A patient presents with recurrent lung infections, and the chest X-ray provided shows a characteristic finding. What is the most likely diagnosis?

A. Kartagener syndrome (Correct Answer)
B. Cystic fibrosis
C. DiGeorge syndrome
D. Down syndrome

Explanation: ***Kartagener syndrome*** - This syndrome is a subgroup of **primary ciliary dyskinesia** and is characterized by the triad of **situs inversus** (dextrocardia as seen on the chest X-ray), **chronic sinusitis**, and **bronchiectasis**. - Recurrent lung infections are a common presentation due to impaired mucociliary clearance leading to bronchiectasis. *Cystic fibrosis* - While cystic fibrosis does present with **recurrent lung infections** and **bronchiectasis**, it is not typically associated with **situs inversus** or other malformations of organ placement. - Diagnosis is usually supported by a **positive sweat chloride test** and genetic testing for CFTR mutations. *DiGeorge syndrome* - This syndrome is characterized by **T-cell immunodeficiency**, **hypocalcemia**, and **congenital heart defects**. - Recurrent infections in DiGeorge syndrome are due to immunodeficiency, not primarily due to impaired ciliary function or situs inversus. *Down syndrome* - Down syndrome is a chromosomal disorder associated with intellectual disability, distinctive facial features, and an increased risk of several health problems, including **congenital heart disease** and **immune dysfunction**. - Recurrent lung infections can occur due to weakened immune function or structural airway abnormalities, but it does not cause situs inversus or primary ciliary dyskinesia.

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