Respiratory Diseases Practice Questions

Q: In cystic fibrosis, which is the second most common organism to cause infection?

Staphylococcus aureus. **Explanation:** In **Cystic Fibrosis (CF)**, the thick, inspissated mucus in the airways provides a nidus for recurrent bacterial infections. The prevalence of specific pathogens is highly **age-dependent**, which is a frequent focus of NEET-PG questions. * **Staphylococcus aureus (Correct):** It is the **second most common** organism overall and the **most common** organism isolated from the respiratory tract of children and infants with CF. As patients age, its prevalence is eventually surpassed by *Pseudomonas*. * **Pseudomonas aeruginosa:** This is the **most common** organism overall across the entire lifespan of a CF patient and the leading cause of chronic colonization and lung function decline in adults. **Why the other options are incorrect:** * **Streptococci & Pneumococci (A & C):** While *Streptococcus pneumoniae* can cause community-acquired pneumonia in CF patients, it is not a characteristic or predominant pathogen associated with the pathophysiology of CF bronchiectasis. * **Klebsiella (B):** This is a common cause of gram-negative pneumonia in the general population (especially in diabetics or alcoholics) but is not a primary pathogen specific to the CF airway. **High-Yield Clinical Pearls for NEET-PG:** 1. **Age-wise dominance:** * Infancy/Childhood: *Staphylococcus aureus* (Most common). * Adulthood: *Pseudomonas aeruginosa* (Most common). 2. **Burkholderia cepacia:** Its presence is a poor prognostic sign ("Cepacia syndrome") and is often a contraindication for lung transplantation. 3. **Haemophilus influenzae:** Also a common early colonizer in young children with CF. 4. **Treatment:** For *S. aureus*, use Methicillin-sensitive (MSSA) or MRSA-targeted antibiotics; for *Pseudomonas*, inhaled Tobramycin or Colistin is often used.

Q: An infant has a positive newborn screening test for cystic fibrosis. What cutoff of sweat chloride concentration confirms cystic fibrosis?

Sweat chloride > 60 mEq/L. **Explanation:** The diagnosis of Cystic Fibrosis (CF) is primarily confirmed using the **Quantitative Pilocarpine Iontophoresis Test (QPIT)**, commonly known as the Sweat Chloride Test. In CF, a defect in the CFTR protein prevents the reabsorption of chloride in the sweat ducts, leading to abnormally high concentrations of salt in the sweat. **1. Why Option D is Correct:** According to the current clinical guidelines (Cystic Fibrosis Foundation), a **sweat chloride concentration of ≥ 60 mmol/L (or mEq/L)** on two separate occasions is considered diagnostic for Cystic Fibrosis in individuals of all ages, including infants identified via newborn screening. **2. Analysis of Incorrect Options:** * **Option A (< 30 mEq/L):** This is considered the **normal** range. CF is highly unlikely at this level. * **Option B & C (30–59 mEq/L):** This range is classified as **Intermediate (Borderline)**. It is not diagnostic of CF but requires further evaluation, such as repeat sweat testing or CFTR genetic mutation analysis (extended sequencing). **3. High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** Sweat Chloride Test (QPIT) remains the gold standard for diagnosis. * **Newborn Screening:** Usually involves testing for **Immunoreactive Trypsinogen (IRT)**. If elevated, it is followed by DNA testing or sweat testing. * **False Positives:** Conditions like Adrenal Insufficiency, Ectodermal Dysplasia, Nephrogenic Diabetes Insipidus, and Malnutrition can occasionally cause elevated sweat chloride. * **Genetics:** CF is an Autosomal Recessive disorder; the most common mutation is **ΔF508** on Chromosome 7. * **Clinical Triad:** Chronic sinopulmonary disease, pancreatic insufficiency (steatorrhea), and high sweat chloride levels.

Q: A 1-month-old infant presents with cough and sneezing, a respiratory rate of 40 per minute, and no chest indrawing. What is the most appropriate management?

Frequent breastfeeding. This question tests your ability to classify and manage acute respiratory infections (ARI) in young infants based on the **IMNCI (Integrated Management of Neonatal and Childhood Illness)** guidelines. ### **Explanation** According to IMNCI guidelines, a child aged **0–2 months** with a cough and cold is evaluated based on respiratory rate and signs of distress. * **Normal Respiratory Rate:** In an infant <2 months, a rate of **<60 breaths per minute** is considered normal. * **Signs of Severity:** The absence of fast breathing (≥60 bpm), chest indrawing, or "danger signs" (lethargy, convulsions, persistent vomiting, or inability to feed) classifies this case as **"No Pneumonia: Cough or Cold."** For "No Pneumonia," the management is supportive. **Frequent breastfeeding** is the priority to prevent dehydration, provide immunological support, and soothe the throat. Mothers are advised to keep the nose clear and return if symptoms worsen. ### **Why Other Options are Incorrect** * **A & B (Urgent referral/IV antibiotics):** These are indicated for "Very Severe Disease" (e.g., chest indrawing, grunting, or danger signs). This infant is hemodynamically stable with a normal respiratory rate. * **D (Oral antibiotic syrup):** Antibiotics are indicated for "Pneumonia" (fast breathing). Since this infant's rate is 40 bpm (normal), antibiotics are unnecessary and contribute to resistance. ### **High-Yield Clinical Pearls for NEET-PG** * **IMNCI Cut-offs for Fast Breathing:** * <2 months: ≥60 bpm * 2–12 months: ≥50 bpm * 12 months–5 years: ≥40 bpm * **Chest Indrawing:** In infants <2 months, mild chest indrawing is common; only **severe** chest indrawing is a sign of serious illness. * **Key Management:** For simple cough/cold, avoid over-the-counter cough suppressants in infants; focus on hydration and warmth.

Q: What is the recommended treatment for chlamydial pneumonia?

Erythromycin. **Explanation:** **Chlamydial pneumonia** (caused by *Chlamydia trachomatis*) typically presents in infants aged 1–3 months with a characteristic "staccato cough," tachypnea, and hyperinflation on X-ray, often preceded by neonatal conjunctivitis. **1. Why Erythromycin is Correct:** *Chlamydia trachomatis* is an obligate intracellular bacterium, meaning it lacks a traditional peptidoglycan cell wall. Therefore, it is highly susceptible to **Macrolides**, which inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit. **Erythromycin** (50 mg/kg/day for 14 days) is the traditional drug of choice. It effectively clears the nasopharyngeal carriage and treats the pneumonia. **2. Why the Other Options are Incorrect:** * **Ceftriaxone (B) and Penicillin (C):** These are Beta-lactam antibiotics that act by inhibiting cell wall synthesis. Since *Chlamydia* lacks a typical cell wall, these drugs are entirely ineffective. * **Sulphonamide (D):** While some older texts mention sulfonamides for certain chlamydial infections, they are not the first-line treatment for pneumonia in infants due to the risk of kernicterus and lower efficacy compared to macrolides. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad:** Afebrile illness + Staccato cough + Peripheral eosinophilia (≥400 cells/mm³). * **Association:** About 50% of infants with chlamydial pneumonia have a history of neonatal conjunctivitis (inclusion blennorrhea). * **Alternative:** Azithromycin is increasingly used due to a shorter course and better GI tolerance. * **Caution:** Systemic Erythromycin in infants <2 weeks old is associated with an increased risk of **Infantile Hypertrophic Pyloric Stenosis (IHPS)**; patients should be monitored for symptoms of projectile vomiting.

Q: An infant develops cough and fever. Chest X-ray is suggestive of broncho-pneumonia. Which of the following viruses is NOT a common causative agent?

Mumps virus. **Explanation:** The correct answer is **D. Mumps virus**. **1. Why Mumps virus is the correct answer:** Mumps is a member of the *Paramyxoviridae* family, but it primarily exhibits tropism for glandular tissues (especially the parotid glands) and the central nervous system. While it is a respiratory virus in terms of transmission (droplets), it is **not** a recognized cause of lower respiratory tract infections like bronchopneumonia or bronchiolitis in infants. **2. Analysis of Incorrect Options:** * **Respiratory Syncytial Virus (RSV):** This is the **most common** cause of bronchiolitis and pneumonia in infants and young children worldwide. It frequently presents with the "bronchopneumonia" pattern on X-ray. * **Parainfluenza viruses:** Specifically types 1, 2, and 3, these are major causes of Croup (Laryngotracheobronchitis) and are the second most common cause of lower respiratory infections in infants after RSV. * **Influenza virus A:** This virus is a significant cause of viral pneumonia across all age groups, including infants, often leading to secondary bacterial pneumonia. **3. NEET-PG Clinical Pearls:** * **Most common cause of Bronchiolitis:** RSV. * **Most common cause of Croup:** Parainfluenza virus Type 1. * **X-ray findings in Viral Pneumonia:** Typically show bilateral, diffuse interstitial infiltrates or bronchopneumonia patterns (patchy opacities), unlike the lobar consolidation seen in bacterial pneumonia (e.g., *S. pneumoniae*). * **Mumps complications:** Orchitis (most common post-pubertal complication), Oophoritis, Pancreatitis, and Aseptic Meningitis. It does not cause pneumonia.

Q: Which of the following is NOT an indication for admission in a patient with pneumonia?

Fever of 39°C. In pediatric practice, the decision to admit a child with pneumonia is based on the assessment of severity and the risk of respiratory failure or dehydration. **Explanation of the Correct Answer:** **A. Fever of 39°C:** Fever, regardless of the degree, is a common symptom of pneumonia but is **not** an independent indication for hospitalization. High fever alone does not correlate directly with the severity of lung parenchymal involvement or the need for oxygen therapy. Management of fever is typically supportive (antipyretics) and can be handled in an outpatient setting unless accompanied by "danger signs." **Explanation of Incorrect Options:** * **B. Cyanosis:** This is a sign of severe hypoxemia and indicates "Very Severe Pneumonia" according to WHO/IMCI guidelines. It necessitates immediate admission for oxygen supplementation and parenteral antibiotics. * **C. Chest retraction:** Subcostal or intercostal retractions signify increased work of breathing and respiratory distress. In the IMCI classification, chest indrawing categorizes the illness as "Severe Pneumonia," requiring inpatient care. * **D. Poor feeding:** Inability to drink or feed is a "General Danger Sign." It indicates that the child is either too breathless to coordinate sucking/swallowing or is systemically toxic, posing a high risk for dehydration and exhaustion. **NEET-PG High-Yield Pearls:** * **WHO Classification (Revised):** * **Pneumonia:** Fast breathing and/or chest indrawing (Treat with oral Amoxicillin at home). * **Severe Pneumonia:** Pneumonia with any "Danger Sign" (Cyanosis, inability to feed, lethargy, convulsions). Requires IV antibiotics (Ampicillin + Gentamicin). * **Fast Breathing Cut-offs:** <2 months: ≥60/min; 2–12 months: ≥50/min; 12–60 months: ≥40/min. * **Pulse Oximetry:** An SpO2 <90–92% is a definitive indication for admission.

Q: A 2-year-old boy presents with a history of sudden onset respiratory difficulty and stridor. On auscultation, there are decreased breath sounds and wheezing on the right side. An X-ray shows a right opaque hemithorax. What is the most likely diagnosis?

Foreign body aspiration. ### Explanation **Correct Answer: D. Foreign body aspiration** **Why it is correct:** The clinical triad of **sudden onset** respiratory distress, **stridor**, and **unilateral** findings (decreased breath sounds/wheezing) in a toddler is classic for foreign body aspiration (FBA). In children, the right main bronchus is more vertical, making it the most common site for aspirated objects. The "opaque hemithorax" on X-ray indicates **obstructive atelectasis** (collapse). When a foreign body completely occludes a bronchus, the air distal to the obstruction is absorbed, leading to lung collapse and a radio-opaque appearance. **Why incorrect options are wrong:** * **Pneumothorax:** This would present with sudden distress, but the X-ray would show **hyperlucency** (increased darkness) and absent lung markings, not an opaque hemithorax. * **Acute Epiglottitis:** While it causes sudden stridor, it is characterized by high fever, drooling, and a "tripod position." It is a supraglottic airway obstruction and would not cause unilateral lung findings or an opaque hemithorax. * **Massive Pleural Effusion:** While this causes an opaque hemithorax, the onset is typically **gradual** (associated with pneumonia or malignancy), not sudden. It also usually causes a mediastinal shift *away* from the opacification, whereas collapse (FBA) shifts it *towards* the lesion. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Right main bronchus. * **Most common age:** 1–3 years (toddlers). * **X-ray findings:** Can vary from normal (most common) to obstructive emphysema (check-valve effect) or collapse (stop-valve effect). * **Gold Standard Diagnosis & Management:** Rigid Bronchoscopy (Emergency). * **Key sign:** "Holzknecht sign" (mediastinal swing towards the affected side during inspiration on fluoroscopy).

Question 1

In cystic fibrosis, which is the second most common organism to cause infection?

Accepted Answer

Staphylococcus aureus

Answer

Streptococci

Answer

Klebsiella

Answer

Pneumococci

Question 2

An infant has a positive newborn screening test for cystic fibrosis. What cutoff of sweat chloride concentration confirms cystic fibrosis?

Accepted Answer

Sweat chloride > 60 mEq/L

Answer

Sweat chloride > 30 mEq/L

Answer

Sweat chloride > 40 mEq/L

Answer

Sweat chloride > 50 mEq/L

Question 3

Pneumatoceles often develop in children after pneumonia due to which of the following organisms?

Accepted Answer

Staphylococcus aureus

Answer

Klebsiella

Answer

Streptococcus

Answer

Haemophilus influenzae

Question 4

A 1-month-old infant presents with cough and sneezing, a respiratory rate of 40 per minute, and no chest indrawing. What is the most appropriate management?

Accepted Answer

Frequent breastfeeding

Answer

Urgent referral to hospital

Answer

Intravenous antibiotics

Answer

Oral antibiotic syrup

Question 5

What is the recommended treatment for chlamydial pneumonia?

Accepted Answer

Erythromycin

Answer

Ceftriaxone

Answer

Penicillin

Answer

Sulphonamide

Question 6

A 5-year-old girl presents with recurrent, intermittent episodes of fever and respiratory distress over the past 1.5 years, including cough, wheezing, and dyspnea lasting for 3-4 days. Hemoptysis is present with every episode. She was diagnosed with right lower lobe pneumonia which improved with treatment. On physical examination, the patient is pale and icteric with digital clubbing. Which of the following is the most appropriate next investigation?

Accepted Answer

Bronchoalveolar lavage

Answer

Modified barium swallow study to evaluate for aspiration

Answer

Nasal swab for viral culture

Answer

Incentive spirometry

Question 7

A seven-week-old child presents with cough and a respiratory rate of 48/min. The child is otherwise normal. What is the most likely diagnosis?

Accepted Answer

The child has pneumonia.

Answer

Antibiotics are not indicated.

Answer

The child does not require resuscitation.

Answer

Fever should be treated.

Question 8

An infant develops cough and fever. Chest X-ray is suggestive of broncho-pneumonia. Which of the following viruses is NOT a common causative agent?

Accepted Answer

Mumps virus

Answer

Parainfluenza viruses

Answer

Influenza virus A

Answer

Respiratory syncytial virus

Question 9

Which of the following is NOT an indication for admission in a patient with pneumonia?

Accepted Answer

Fever of 39°C

Answer

Cyanosis

Answer

Chest retraction

Answer

Poor feeding

Question 10

A 2-year-old boy presents with a history of sudden onset respiratory difficulty and stridor. On auscultation, there are decreased breath sounds and wheezing on the right side. An X-ray shows a right opaque hemithorax. What is the most likely diagnosis?

Accepted Answer

Foreign body aspiration

Answer

Pneumothorax

Answer

Acute epiglottitis

Answer

Massive pleural effusion

Respiratory Diseases — MCQs

Respiratory Diseases — MCQs

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