Respiratory Diseases — MCQs
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What is true about chest radiographs of children with foreign body aspiration?
A 1-year-old female infant is hospitalized for pneumonia. Bacterial cultures of the sputum have grown Pseudomonas aeruginosa. She has had two prior hospitalizations for severe respiratory infections. Her mother has noted that when she kisses her child, the child tastes 'salty.' The child has had weight loss that the mother attributes to frequent vomiting and diarrhea with bulky, foul-smelling fatty stools. The child is small for her age. Which of the following critical proteins is altered in this condition?
A 3-hour-old preterm baby develops respiratory grunting. The X-ray shows a reticulonodular pattern. What is the most likely diagnosis?
A 12-year-old boy presents with a productive cough and large volumes of foul-smelling sputum. Three years prior, he was diagnosed with pancreatic insufficiency, evidenced by recurrent gastrointestinal symptoms of steatorrhea. Sputum culture reveals colorless, oxidase-positive colonies with a fruity aroma. The function of which of the following proteins is most likely inhibited by the bacteria responsible for this boy's infection?
What is the most common cause of ARDS in children?
A child with a three-day history of upper respiratory tract infection presents with stridor that decreases on lying down. What is the most probable diagnosis?
Acute onset of cough, stridor, and respiratory distress in the absence of fever is suggestive of what condition?
In an exhausted child with severe bronchiolitis, for every 10 mm Hg increase in PCO2, how many mEq of bicarbonate will increase?
A 2-month-old child has a respiratory rate of 45/minute. The child has not been accepting feeds for the last 4 days and shows signs of dehydration. Which type of pneumonia is this?
Hecht's pneumonia is a complication of which condition?
Respiratory Diseases Indian Medical PG Practice Questions and MCQs
Question 211: What is true about chest radiographs of children with foreign body aspiration?
- A. Always abnormal
- B. May show hyperinflation of one lung field (Correct Answer)
- C. Always show antibody
- D. Will always present with pneumothorax
Explanation: **Explanation:** Foreign body aspiration (FBA) is a common pediatric emergency. The radiological presentation depends on the size, nature, and location of the object, as well as the degree of airway obstruction. **Why Option B is correct:** The most common radiological finding in FBA is **obstructive emphysema (hyperinflation)**. This occurs due to a **"ball-valve" mechanism**: the foreign body allows air to enter during inspiration (when bronchi dilate) but prevents it from leaving during expiration (when bronchi constrict). This leads to air trapping and hyperinflation of the affected lung, often seen as increased radiolucency and a mediastinal shift away from the affected side. **Why the other options are incorrect:** * **Option A:** Up to **15–25% of children** with FBA have a **normal chest X-ray**, especially in the early stages. A normal X-ray does not rule out FBA if clinical suspicion is high. * **Option C:** This is medically irrelevant. "Antibodies" are proteins found in blood/plasma and are not visible or relevant findings on a chest radiograph for FBA. * **Option D:** While pneumothorax is a possible complication of FBA (due to alveolar rupture from air trapping), it is rare. It is certainly not a constant or "always" present finding. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Rigid Bronchoscopy (both diagnostic and therapeutic). * **Most Common Site:** Right main bronchus (due to it being wider, shorter, and more vertical). * **Classic Triad:** Sudden onset of coughing, wheezing, and diminished breath sounds. * **Radiographic Tip:** If a standard X-ray is inconclusive, obtain **decubitus films** or **expiratory films**. The affected lung will fail to deflate (remain hyperinflated) on the dependent side.
Question 212: A 1-year-old female infant is hospitalized for pneumonia. Bacterial cultures of the sputum have grown Pseudomonas aeruginosa. She has had two prior hospitalizations for severe respiratory infections. Her mother has noted that when she kisses her child, the child tastes 'salty.' The child has had weight loss that the mother attributes to frequent vomiting and diarrhea with bulky, foul-smelling fatty stools. The child is small for her age. Which of the following critical proteins is altered in this condition?
- A. Cystic fibrosis transmembrane conductance regulator (Correct Answer)
- B. Dystrophin
- C. alpha-1,4-Glucosidase
- D. alpha-L-Iduronidase
Explanation: ### Explanation The clinical presentation of recurrent pneumonia (specifically with **Pseudomonas aeruginosa**), failure to thrive, and **steatorrhea** (bulky, foul-smelling stools) in an infant is classic for **Cystic Fibrosis (CF)**. The pathognomonic sign mentioned—the mother noticing the child **tastes "salty"**—points directly to an abnormality in sweat chloride levels. **1. Why the Correct Answer is Right:** Cystic Fibrosis is caused by a mutation in the **CFTR (Cystic Fibrosis Transmembrane Conductance Regulator)** gene on chromosome 7. The CFTR protein is a cAMP-regulated chloride channel. In the lungs and pancreas, defective CFTR leads to thick, dehydrated secretions that obstruct airways (leading to infections) and pancreatic ducts (leading to malabsorption and steatorrhea). In sweat glands, it fails to reabsorb chloride, resulting in high salt concentration on the skin. **2. Why Incorrect Options are Wrong:** * **B. Dystrophin:** Mutations here cause Duchenne or Becker Muscular Dystrophy, characterized by progressive muscle weakness, not respiratory infections or malabsorption. * **C. alpha-1,4-Glucosidase (Acid Maltase):** Deficiency causes Pompe disease (GSD II), presenting with cardiomegaly and hypotonia. * **D. alpha-L-Iduronidase:** Deficiency causes Hurler Syndrome (MPS I), characterized by corneal clouding, hepatosplenomegaly, and coarse facial features. **3. NEET-PG High-Yield Pearls:** * **Most common mutation:** $\Delta$F508 (deletion of phenylalanine). * **Diagnosis:** Sweat Chloride Test (>60 mEq/L on two occasions) is the gold standard. * **Microbiology:** *S. aureus* is the most common lung pathogen in early childhood; *P. aeruginosa* becomes dominant in older children/adults. * **Associated findings:** Meconium ileus (newborns), nasal polyps, and bilateral absence of vas deferens (infertility in males).
Question 213: A 3-hour-old preterm baby develops respiratory grunting. The X-ray shows a reticulonodular pattern. What is the most likely diagnosis?
- A. Hyaline membrane disease (Correct Answer)
- B. Transient tachypnea of the newborn
- C. Meconium aspiration syndrome
- D. All of the above
Explanation: **Explanation:** The clinical presentation and radiological findings point directly to **Hyaline Membrane Disease (HMD)**, also known as Respiratory Distress Syndrome (RDS). **1. Why Hyaline Membrane Disease is correct:** HMD is primarily a disease of **preterm infants** caused by a deficiency of **surfactant**. Surfactant deficiency leads to widespread alveolar collapse (atelectasis). * **Clinical Presentation:** Symptoms like grunting, tachypnea, and chest retractions typically appear within the first few hours of life. * **Radiology:** The classic X-ray finding is a **diffuse reticulonodular pattern** (often described as a "ground-glass appearance") with **air bronchograms** due to the contrast between air-filled bronchi and collapsed alveoli. **2. Why other options are incorrect:** * **Transient Tachypnea of the Newborn (TTN):** Usually occurs in term or late-preterm babies, often following Cesarean sections. X-ray shows **perihilar streaking** and fluid in the fissures (wet lung), not a reticulonodular pattern. * **Meconium Aspiration Syndrome (MAS):** Typically affects **post-term or term** infants with a history of meconium-stained liquor. X-ray shows **patchy opacities** and areas of hyperinflation (coarse mottling). **Clinical Pearls for NEET-PG:** * **Risk Factors:** Prematurity (most common), Maternal Diabetes, Cesarean section without labor. * **L/S Ratio:** A Lecithin/Sphingomyelin ratio of **<2:1** in amniotic fluid indicates fetal lung immaturity. * **Management:** The definitive treatment is **Exogenous Surfactant** replacement and respiratory support (CPAP/Ventilation). * **Prevention:** Antenatal corticosteroids (e.g., Betamethasone) given to the mother 24–48 hours before preterm delivery significantly reduce the risk.
Question 214: A 12-year-old boy presents with a productive cough and large volumes of foul-smelling sputum. Three years prior, he was diagnosed with pancreatic insufficiency, evidenced by recurrent gastrointestinal symptoms of steatorrhea. Sputum culture reveals colorless, oxidase-positive colonies with a fruity aroma. The function of which of the following proteins is most likely inhibited by the bacteria responsible for this boy's infection?
- A. A CFTR protein lacking a phenylalanine at position 508 in exon 10
- B. A GTP-binding protein involved in the elongation step of protein synthesis (Correct Answer)
- C. A GTP-binding protein coupled with α2-adrenergic receptors
- D. A GTP-binding protein coupled with β-adrenergic receptors
Explanation: ### Explanation **Clinical Correlation & Diagnosis** The patient has **Cystic Fibrosis (CF)**, suggested by the combination of pancreatic insufficiency (steatorrhea) and chronic productive cough. In CF patients, the most common cause of severe pulmonary infection is ***Pseudomonas aeruginosa***. The description of "colorless, oxidase-positive colonies with a fruity aroma" on culture is pathognomonic for *Pseudomonas*. **Why Option B is Correct** *Pseudomonas aeruginosa* produces **Exotoxin A**, which functions identically to the Diphtheria toxin. It catalyzes the ADP-ribosylation of **Elongation Factor-2 (EF-2)**. EF-2 is a GTP-binding protein essential for the translocation step of protein synthesis on ribosomes. By inactivating EF-2, the toxin inhibits host cell protein synthesis, leading to cell death and tissue necrosis. **Why Other Options are Wrong** * **Option A:** While a mutation in the **CFTR protein** (specifically ΔF508) is the *underlying cause* of Cystic Fibrosis, the question asks for the protein inhibited by the **infecting bacteria**, not the protein causing the genetic disease. * **Option C:** Inhibition of G-proteins coupled with α2-receptors is associated with **Pertussis toxin**, which causes "Whooping cough," not the foul-smelling sputum seen in CF. * **Option D:** Activation (not inhibition) of G-proteins coupled with β-receptors is the mechanism of **Cholera toxin**, leading to secretory diarrhea. **NEET-PG High-Yield Pearls** * ***Pseudomonas* Pigments:** Produces Pyocyanin (blue-green) and Pyoverdin (fluorescent yellow-green). * **Culture:** Grows on MacConkey agar as a **non-lactose fermenter** (colorless). * **Toxin Mechanism:** Exotoxin A (Pseudomonas) and Diphtheria toxin both target **EF-2**. * **CF Microbiology:** *S. aureus* is the most common pathogen in early childhood; *P. aeruginosa* becomes dominant in adolescence and adulthood.
Question 215: What is the most common cause of ARDS in children?
- A. Aspiration
- B. Injury
- C. Severe pneumonia with sepsis (Correct Answer)
- D. DIC
Explanation: **Explanation:** Acute Respiratory Distress Syndrome (ARDS) is a clinical syndrome characterized by acute onset of non-cardiogenic pulmonary edema and hypoxemia. In the pediatric population, the etiology is broadly categorized into direct (pulmonary) and indirect (extrapulmonary) lung injuries. **Why Option C is Correct:** According to the **Pediatric Acute Lung Injury Consensus Conference (PALICC)**, **severe pneumonia** is the most common cause of direct lung injury, while **sepsis** is the most common cause of indirect lung injury leading to ARDS in children. When combined, pneumonia-related sepsis accounts for the majority of pediatric ARDS cases globally. The underlying mechanism involves a massive inflammatory surge (cytokine storm) that increases alveolar-capillary permeability, leading to protein-rich fluid accumulation in the alveoli. **Why Other Options are Incorrect:** * **A. Aspiration:** While a significant cause of direct lung injury (especially gastric acid aspiration), it is statistically less frequent than infectious pneumonia. * **B. Injury (Trauma):** Physical trauma or pulmonary contusions can trigger ARDS, but these are more common in adolescents and adults rather than the general pediatric population. * **D. DIC:** Disseminated Intravascular Coagulation is typically a *complication* or a co-morbidity of sepsis rather than the primary inciting event for ARDS. **High-Yield Clinical Pearls for NEET-PG:** * **Definition:** Pediatric ARDS (PARDS) is defined by the **PALICC criteria**, which uses the **Oxygenation Index (OI)** or Oxygenation Saturation Index (OSI) instead of the PaO2/FiO2 ratio used in the adult Berlin criteria. * **Radiology:** Requires new infiltrates consistent with acute pulmonary parenchymal disease (not fully explained by heart failure or fluid overload). * **Management:** Lung-protective ventilation (low tidal volume: 3–6 mL/kg) and maintaining plateau pressures <28 cm H2O.
Question 216: A child with a three-day history of upper respiratory tract infection presents with stridor that decreases on lying down. What is the most probable diagnosis?
- A. Acute Epiglottitis
- B. Laryngotracheobronchitis (Correct Answer)
- C. Foreign body aspiration
- D. Retropharyngeal abscess
Explanation: ### Explanation **Laryngotracheobronchitis (Croup)** is the most common cause of acute upper airway obstruction in children (typically 6 months to 3 years). It is usually preceded by a prodrome of upper respiratory infection (URI) symptoms like rhinorrhea and low-grade fever. The characteristic **barking cough** and **inspiratory stridor** occur due to subglottic narrowing. A key clinical feature is that the stridor often **decreases when the child is lying down or resting** (as agitation increases respiratory effort and turbulence), though it classically worsens at night. **Why other options are incorrect:** * **Acute Epiglottitis:** This is a medical emergency characterized by a rapid onset, high fever, and the "4 Ds": Drooling, Dysphagia, Distress, and Dysphonia. Patients prefer the "tripod position" and stridor **worsens** when lying supine due to the epiglottis falling back over the glottis. * **Foreign Body Aspiration:** This typically presents with a sudden, choking episode in a previously healthy child without a viral prodrome (no 3-day history of URI). * **Retropharyngeal Abscess:** While it presents with stridor and fever, it is distinguished by severe sore throat, neck stiffness (torticollis), and muffled "hot potato" voice. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Most common virus is **Parainfluenza type 1**. * **Radiology:** The classic X-ray finding is the **"Steeple Sign"** (subglottic narrowing) on the Anteroposterior (AP) view of the neck. * **Management:** Mild cases are managed with oral Dexamethasone. Severe cases (stridor at rest) require **Nebulized Adrenaline** and steroids. * **Westley Croup Score** is used to assess severity.
Question 217: Acute onset of cough, stridor, and respiratory distress in the absence of fever is suggestive of what condition?
- A. Foreign body aspiration (Correct Answer)
- B. Acute asthma
- C. Aspiration pneumonia
- D. Primary complex
Explanation: ### Explanation **Correct Answer: A. Foreign Body Aspiration (FBA)** The hallmark of Foreign Body Aspiration is the **sudden, acute onset** of respiratory symptoms (cough, choking, stridor, or wheezing) in a previously healthy child. The **absence of fever** is a critical clinical differentiator, as it points toward a mechanical obstruction rather than an infectious process like croup or epiglottitis. In children aged 1–3 years, the "penetration syndrome" (sudden choking episode) is highly suggestive of FBA. **Why the other options are incorrect:** * **B. Acute Asthma:** While asthma causes respiratory distress and cough, it typically presents with recurrent episodes of expiratory wheezing rather than inspiratory stridor. It is often preceded by viral triggers or allergen exposure. * **C. Aspiration Pneumonia:** This is an inflammatory/infectious process resulting from the inhalation of gastric contents or oropharyngeal flora. It usually presents with **fever**, productive cough, and constitutional symptoms, rather than an instantaneous onset of stridor. * **D. Primary Complex:** This refers to the initial focus of pulmonary Tuberculosis. It is a chronic condition characterized by low-grade fever, weight loss, and a persistent cough, rather than acute respiratory distress. **NEET-PG High-Yield Pearls:** * **Most common site:** Right main bronchus (due to it being wider, shorter, and more vertical than the left). * **Most common age group:** 1 to 3 years (toddlers). * **Radiological sign:** "Check-valve" obstruction leading to **obstructive emphysema** (hyperlucency) on the affected side. * **Gold Standard Management:** Rigid Bronchoscopy (both diagnostic and therapeutic). Flexible bronchoscopy is preferred only for distal foreign bodies.
Question 218: In an exhausted child with severe bronchiolitis, for every 10 mm Hg increase in PCO2, how many mEq of bicarbonate will increase?
- A. 2
- B. 4
- C. 8
- D. 1 (Correct Answer)
Explanation: **Explanation:** The question tests the understanding of acid-base compensation in **Acute Respiratory Acidosis**. Bronchiolitis in an "exhausted child" indicates impending respiratory failure, leading to the rapid accumulation of $CO_2$. **1. Why Option D (1) is Correct:** In **Acute Respiratory Acidosis**, the body relies on immediate chemical buffering (primarily by hemoglobin and intracellular proteins) because the kidneys take 24–72 hours to mount a significant metabolic response. * **Rule of Thumb:** For every **10 mm Hg rise in $PaCO_2$**, the Bicarbonate ($HCO_3^-$) increases by **1 mEq/L**. * In this scenario, the child is acutely exhausted, meaning the compensation is in the acute phase, making 1 mEq/L the correct physiological response. **2. Why Other Options are Incorrect:** * **Option B (4):** This represents the compensation for **Chronic Respiratory Acidosis** (e.g., COPD or chronic neuromuscular weakness). In chronic states, the kidneys have had time to retain more bicarbonate. For every 10 mm Hg rise in $PaCO_2$, $HCO_3^-$ increases by **3.5 to 4 mEq/L**. * **Options A (2) and C (8):** These do not correspond to standard physiological compensation ratios for respiratory acidosis. **3. NEET-PG High-Yield Pearls:** * **Acute Respiratory Acidosis:** $\Delta HCO_3 = 1$ for every $10 \uparrow PaCO_2$. * **Chronic Respiratory Acidosis:** $\Delta HCO_3 = 3.5 - 4$ for every $10 \uparrow PaCO_2$. * **Clinical Sign:** In bronchiolitis, a "normal" $PaCO_2$ (40 mm Hg) in a child with increased work of breathing is a **danger sign** of impending respiratory failure; it should normally be low due to hyperventilation. * **Management:** If a child is "exhausted" with rising $PCO_2$, they require immediate respiratory support (CPAP or Intubation).
Question 219: A 2-month-old child has a respiratory rate of 45/minute. The child has not been accepting feeds for the last 4 days and shows signs of dehydration. Which type of pneumonia is this?
- A. No pneumonia
- B. Pneumonia
- C. Severe pneumonia (Correct Answer)
- D. Very severe pneumonia
Explanation: ### Explanation The classification of pneumonia in children is based on the **WHO Integrated Management of Neonatal and Childhood Illness (IMNCI)** guidelines. **Why "Severe Pneumonia" is correct:** According to IMNCI guidelines for a child aged 2 months to 5 years, the presence of any **"General Danger Sign"** automatically classifies the condition as **Severe Pneumonia**. These signs include: 1. Inability to drink or breastfeed (as seen in this patient). 2. Persistent vomiting. 3. Convulsions. 4. Lethargy or unconsciousness. 5. Presence of chest indrawing. Even though the child’s respiratory rate (45/min) is technically normal for a 2-month-old (threshold for tachypnea is $\geq$ 50/min), the **inability to feed** is a critical danger sign that mandates hospitalization and parenteral antibiotics, categorizing it as Severe Pneumonia. **Analysis of Incorrect Options:** * **No Pneumonia:** Classified if there is no fast breathing AND no general danger signs. * **Pneumonia:** Classified if there is fast breathing ($\geq$ 50/min for 2–12 months) but **no** general danger signs and **no** chest indrawing. * **Very Severe Pneumonia:** This term was used in older WHO classifications. Under current IMNCI guidelines, "Severe Pneumonia" and "Very Severe Disease" are often grouped to simplify treatment protocols (referring to those requiring IV antibiotics). **NEET-PG High-Yield Pearls:** * **Tachypnea Cut-offs (IMNCI):** * < 2 months: $\geq$ 60/min * 2–12 months: $\geq$ 50/min * 12 months–5 years: $\geq$ 40/min * **Treatment:** Severe pneumonia requires **Injectable Ampicillin and Gentamicin** (or Ceftriaxone) as first-line therapy. * **Key Indicator:** In a child < 2 months, even "Chest Indrawing" is classified as Severe Disease/Pneumonia.
Question 220: Hecht's pneumonia is a complication of which condition?
- A. Measles (Correct Answer)
- B. Mumps
- C. AIDS
- D. Mycoplasma
Explanation: **Explanation:** **Hecht’s Pneumonia**, also known as **Giant Cell Interstitial Pneumonia**, is a severe and often fatal complication of **Measles (Rubeola)**. It typically occurs in immunocompromised children (e.g., those with leukemia or HIV) who fail to develop the characteristic measles rash due to impaired T-cell immunity. 1. **Why Measles is Correct:** The measles virus causes the fusion of infected cells, leading to the formation of **Warthin-Finkeldey giant cells** (multinucleated giant cells with eosinophilic intranuclear and intracytoplasmic inclusion bodies) in the lymphoid and pulmonary tissues. In Hecht’s pneumonia, these giant cells infiltrate the alveolar walls, leading to progressive respiratory failure. 2. **Why Other Options are Incorrect:** * **Mumps:** Primarily involves the parotid glands and testes; respiratory complications are rare and do not manifest as Hecht’s pneumonia. * **AIDS:** While patients with AIDS are at high risk for Hecht’s pneumonia if they contract measles, the pneumonia itself is specifically etiologically linked to the measles virus, not HIV. * **Mycoplasma:** Causes "Walking Pneumonia" characterized by interstitial infiltrates and cold agglutinins, but does not produce multinucleated giant cells. **High-Yield Clinical Pearls for NEET-PG:** * **Warthin-Finkeldey Cells:** Pathognomonic for Measles; found in nasal secretions, tonsils, and lung tissue. * **Koplik Spots:** The hallmark prodromal sign of measles (found opposite the lower second molars). * **Vitamin A:** Supplementation is recommended for all children with acute measles to reduce morbidity and mortality. * **SSPE (Subacute Sclerosing Panencephalitis):** A late neurological complication occurring years after a primary measles infection.
Practice by Chapter
Upper Respiratory Tract Infections
Practice Questions
Lower Respiratory Tract Infections
Practice Questions
Asthma Management
Practice Questions
Cystic Fibrosis
Practice Questions
Bronchiolitis
Practice Questions
Foreign Body Aspiration
Practice Questions
Sleep-Disordered Breathing
Practice Questions
Congenital Lung Malformations
Practice Questions
Pleural Diseases
Practice Questions
Tuberculosis in Children
Practice Questions
Chronic Lung Disease in Premature Infants
Practice Questions
Pulmonary Function Testing
Practice Questions
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