Respiratory Diseases Practice Questions

Q: A 2-month-old child, born prematurely, presents with respiratory distress. Cardiac examination reveals increased pulse pressure and a pansystolic murmur best heard in the 2nd left intercostal space. What is the most probable diagnosis?

Patent ductus arteriosus. ### Explanation **Correct Answer: C. Patent ductus arteriosus (PDA)** The clinical presentation of a **premature infant** with respiratory distress, **increased pulse pressure** (bounding pulses), and a murmur in the **2nd left intercostal space** is classic for PDA. * **Pathophysiology:** In PDA, the fetal connection between the pulmonary artery and aorta fails to close. This leads to a left-to-right shunt. The increased stroke volume into the aorta followed by rapid runoff into the pulmonary circulation causes a wide pulse pressure. * **Murmur Characteristics:** While the classic description is a "continuous machinery murmur," in neonates and young infants with high pulmonary vascular resistance, it may present initially as a **systolic murmur** (often pansystolic) at the left upper sternal border. **Why the other options are incorrect:** * **A. Atrial Septal Defect (ASD):** Typically asymptomatic in infancy. It presents with a fixed wide splitting of S2 and a systolic ejection murmur at the left upper sternal border, not a pansystolic murmur or wide pulse pressure. * **B. Ventricular Septal Defect (VSD):** While it presents with a pansystolic murmur, it is best heard at the **lower left sternal border**. It does not typically cause increased pulse pressure. * **D. Tetralogy of Fallot (TOF):** A cyanotic heart disease. The murmur is due to pulmonary stenosis (ejection systolic), and pulse pressure is usually normal or narrow. **NEET-PG High-Yield Pearls:** * **Drug of Choice:** Indomethacin or Ibuprofen (NSAIDs) are used to close a PDA in prematures by inhibiting prostaglandins. * **Prostaglandin E1:** Used to keep the ductus *open* in ductal-dependent cyanotic heart diseases. * **Association:** PDA is strongly associated with **Congenital Rubella Syndrome**. * **Physical Sign:** "Bounding pulses" or "Water-hammer pulses" in a neonate should immediately make you suspect PDA.

Q: Sweat chloride levels are typically observed to be in which of the following states in patients with cystic fibrosis?

Increased. **Explanation:** **Cystic Fibrosis (CF)** is an autosomal recessive disorder caused by a mutation in the **CFTR (Cystic Fibrosis Transmembrane Conductance Regulator)** gene. This gene encodes a chloride channel that functions differently depending on the tissue type. 1. **Why the answer is Increased:** In the **sweat glands**, the CFTR protein is responsible for the **reabsorption** of chloride from the primary secretion back into the ductal cells. Sodium follows chloride to maintain electrical neutrality. In CF, the defective CFTR protein prevents this reabsorption. Consequently, high amounts of sodium and chloride remain in the sweat, leading to the characteristic **increased sweat chloride levels** (typically >60 mmol/L). 2. **Why other options are wrong:** * **Decreased/No change:** These are incorrect because the fundamental defect in CF sweat glands is the inability to remove chloride from the lumen, making the sweat hypertonic compared to healthy individuals. * **May increase or decrease:** While sweat chloride levels can vary based on the specific mutation (genotype), they are consistently **elevated** in symptomatic CF patients. They do not decrease below normal physiological levels. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** The **Pilocarpine Iontophoresis Sweat Test** remains the investigation of choice. * **Diagnostic Threshold:** Sweat chloride **≥60 mmol/L** on two separate occasions is diagnostic. * **False Positives:** Conditions like adrenal insufficiency, untreated hypothyroidism, and malnutrition can sometimes cause elevated sweat chloride. * **The "Salty Baby" Sign:** Parents often report a salty taste when kissing the child, which is a classic clinical clue. * **Contrast with Lungs:** In the respiratory tract, CFTR failure leads to decreased chloride secretion and increased sodium/water reabsorption, resulting in thick, dehydrated mucus.

Q: What is the most frequent causative agent for acute epiglottitis in children under 5 years of age?

Haemophilus influenzae type B. **Explanation:** **Acute Epiglottitis** is a life-threatening medical emergency characterized by rapid inflammation and edema of the epiglottis and supraglottic structures. **1. Why Option A is Correct:** Historically and clinically, **_Haemophilus influenzae_ type B (Hib)** is the most frequent causative agent in children. Although the incidence has significantly decreased in regions with high Hib vaccination coverage, it remains the leading bacterial cause globally. The pathogenesis involves bacterial invasion of the epiglottic mucosa, leading to the classic "cherry-red" swollen epiglottis that can cause sudden airway obstruction. **2. Why Other Options are Incorrect:** * **Option B (Influenza virus type A):** While it can cause respiratory distress, it is not a primary cause of epiglottitis; it more commonly leads to viral pneumonia or tracheitis. * **Option C (Parainfluenza virus type 1):** This is the most common cause of **Croup (Laryngotracheobronchitis)**, not epiglottitis. Croup presents with a barking cough and subglottic narrowing (Steeple sign). * **Option D (Staphylococcus aureus):** This is a common cause of **Bacterial Tracheitis**. While it can occasionally cause epiglottitis in older children or adults, it is less frequent than Hib in the under-5 age group. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad (The 3 D’s):** Drooling, Dysphagia, and Distress (Respiratory). * **Positioning:** Children often assume the **"Tripod position"** (leaning forward on hands) to maintain the airway. * **X-ray Finding:** Lateral neck X-ray shows the **"Thumbprint sign"** (swollen epiglottis). * **Management Gold Standard:** Secure the airway (intubation) in a controlled environment (OR/ICU). **Never** use a tongue depressor for examination in a suspected case, as it may trigger fatal laryngospasm.

Q: A 1-year-old child presents with cough, cold, and a respiratory rate of 40/minute. What is your diagnosis?

No Pneumonia. This question tests your knowledge of the **WHO Integrated Management of Neonatal and Childhood Illness (IMNCI)** guidelines for classifying acute respiratory infections in children aged 2 months to 5 years. ### **1. Why "No Pneumonia" is Correct** The diagnosis of pneumonia in the IMNCI algorithm is primarily based on the **Respiratory Rate (RR)**. For a child aged **12 months to 5 years**, the threshold for "Fast Breathing" is **$\geq$ 40 breaths per minute**. In this case, the child is 1 year old (12 months) and has an RR of 40/min. According to the guidelines, an RR of exactly 40 is the cutoff; however, the classification of "Pneumonia" requires the presence of fast breathing **OR** chest indrawing. Since the child only has a cough and cold with a borderline RR (not exceeding the threshold for his age group), he is classified as **No Pneumonia (Cough or Cold)**. ### **2. Why Other Options are Incorrect** * **Pneumonia:** Requires "Fast Breathing" (RR $\geq$ 50 for 2–12 months; RR $\geq$ 40 for 12 months–5 years). While this child is at the cutoff, in clinical practice and exam scenarios, "No Pneumonia" is the preferred answer if no other danger signs are present. * **Severe Pneumonia:** Requires the presence of **Chest Indrawing**. * **Very Severe Pneumonia (now merged into Severe):** Previously required "General Danger Signs" (inability to drink/breastfeed, lethargy, convulsions, or persistent vomiting). ### **3. NEET-PG High-Yield Pearls: IMNCI RR Cutoffs** To identify "Fast Breathing," memorize these age-specific thresholds: * **< 2 months:** $\geq$ 60/min * **2 months to 12 months:** $\geq$ 50/min * **12 months to 5 years:** $\geq$ 40/min **Management Tip:** "No Pneumonia" cases are managed at home with supportive care (soothing the throat, clearing the nose) and advice on when to return. Antibiotics are NOT indicated.

Q: A 2-year-old child presents to the emergency department at 3 AM with fever, barking cough, and stridor that is only present while crying. The child is able to drink normally. On examination, the respiratory rate is 36/min and the temperature is 39.6°C. What will be your next step?

High-dose dexamethasone injection. **Explanation:** The clinical presentation of a **barking cough, fever, and inspiratory stridor** in a toddler is classic for **Croup (Laryngotracheobronchitis)**, most commonly caused by the Parainfluenza virus. To determine the management, we assess the severity using the **Westley Croup Score**. This child has **mild-to-moderate croup** because the stridor is only present when agitated (crying) and there are no signs of respiratory distress (the child can drink and the respiratory rate is within acceptable limits for a febrile 2-year-old). 1. **Why Option B is correct:** Corticosteroids are the mainstay of treatment for all severities of croup. A single dose of **Dexamethasone (0.15 mg/kg to 0.6 mg/kg)** reduces airway edema, decreases the need for hospitalization, and shortens the duration of symptoms. It is the "next step" to prevent progression. 2. **Why Option A is incorrect:** Nebulized Racemic Epinephrine is reserved for **moderate-to-severe croup** (stridor at rest, significant retractions). Since this child only has stridor when crying, epinephrine is not yet indicated. 3. **Why Option C is incorrect:** Croup is a clinical diagnosis. Viral testing (RSV/Influenza) does not change the immediate management of the airway. 4. **Why Option D is incorrect:** Croup is viral. Antibiotics are indicated for **Epiglottitis** or **Bacterial Tracheitis**, but the "barking cough" and ability to drink (no drooling) point strongly away from these diagnoses. **High-Yield Pearls for NEET-PG:** * **X-ray finding:** "Steeple Sign" (subglottic narrowing) on AP view of the neck. * **Most common pathogen:** Parainfluenza Type 1. * **Dexamethasone:** Has a long half-life (36–72 hours), making a single dose highly effective. * **Differential:** If the child looks toxic, has high fever, and no barking cough, suspect **Epiglottitis** (Thumbprint sign) or **Bacterial Tracheitis**.

Q: A 3-month-old child presents with moderate fever, non-productive cough, and mild dyspnea. Following a course of antibiotics, the child showed transient improvement but then developed high fever, productive cough, and increased respiratory distress. Chest X-ray reveals hyperlucency, and Pulmonary Function Tests demonstrate an obstructive pattern. What is the most probable diagnosis?

Bronchiolitis obliterans. **Explanation:** **Bronchiolitis Obliterans (BO)** is a chronic obstructive lung disease resulting from an inflammatory injury to the small airways (bronchioles), leading to luminal narrowing or total occlusion by fibrotic tissue. 1. **Why it is correct:** The clinical history is classic for **Post-infectious BO**. It typically follows a severe lower respiratory tract infection (often Adenovirus). The "biphasic" presentation is key: an initial acute insult followed by a period of relative improvement, then a secondary deterioration with persistent cough, wheezing, and respiratory distress. The **Chest X-ray** showing **hyperlucency** (due to air trapping) and **PFTs** showing a fixed **obstructive pattern** are hallmark diagnostic features. 2. **Why the other options are incorrect:** * **Alveolar microlithiasis:** A rare genetic disorder characterized by widespread intra-alveolar calcification. X-ray shows a "sand-storm" appearance, not hyperlucency. * **Postviral syndrome:** This is a vague term for lingering symptoms after a virus. It does not typically present with severe obstructive PFTs or localized hyperlucency on X-ray. * **Follicular bronchitis:** This is a lymphoproliferative disorder often associated with immunodeficiency or connective tissue diseases. It typically presents with a nodular pattern on imaging rather than pure hyperlucency. **Clinical Pearls for NEET-PG:** * **Most common cause:** Adenovirus (Types 3, 7, and 21) is the most frequent trigger for post-infectious BO in children. * **Radiology:** Look for the **"Mosaic Perfusion"** pattern on HRCT, which is the gold standard for diagnosis. * **Swyer-James-MacLeod Syndrome:** A radiological variant of BO characterized by a unilateral hyperlucent lung and a small pulmonary artery. * **Management:** Treatment is largely supportive (bronchodilators, oxygen) as the airway fibrosis is generally irreversible.

Q: A 5-year-old girl presents with rhinorrhea, barking cough, and sore throat. Examination reveals laboured respiration. Her siblings are well. What is the most probable viral cause of her symptoms?

Parainfluenza virus. **Explanation:** The clinical presentation of a **barking cough**, rhinorrhea, and labored respiration in a young child is classic for **Croup (Laryngotracheobronchitis)**. **Why Parainfluenza virus is correct:** **Parainfluenza virus (Type 1 and 2)** is the most common cause of Croup, accounting for nearly 75% of cases. The virus causes subglottic edema and inflammation, leading to the characteristic "barking" or "brassy" cough, inspiratory stridor, and hoarseness. The prodrome of rhinorrhea and sore throat is typical of the viral upper respiratory infection that precedes the laryngeal symptoms. **Why other options are incorrect:** * **Adenovirus:** Commonly causes pharyngoconjunctival fever (sore throat, fever, and conjunctivitis) or pneumonia, but is a less frequent cause of isolated croup. * **Influenza virus:** While it can cause severe croup, it typically presents with high-grade fever, significant myalgia, and systemic toxicity. * **RSV (Respiratory Syncytial Virus):** This is the primary pathogen for **Bronchiolitis** in children under 2 years, characterized by wheezing rather than a barking cough. **Clinical Pearls for NEET-PG:** * **X-ray Finding:** The classic radiological sign for Croup is the **"Steeple Sign"** (subglottic narrowing) seen on an AP view of the neck. * **Management:** Mild cases are managed with a single dose of **Dexamethasone** (0.6 mg/kg). Severe cases with stridor at rest require **Nebulized Epinephrine** (L-epinephrine or Racemic) for rapid vasoconstriction and reduction of edema. * **Age Group:** Croup typically affects children aged 6 months to 3 years; presentation at age 5 is still common, but always rule out Epiglottitis if the child appears toxic or is drooling.

Q: What is the treatment for breath-holding spells?

Iron. ### Explanation **Breath-holding spells (BHS)** are common paroxysmal non-epileptic events in children (6 months to 6 years) triggered by emotional distress, pain, or anger. **Why Iron is the Correct Answer:** Clinical studies have consistently shown a strong association between **Iron Deficiency Anemia (IDA)** and the frequency/severity of breath-holding spells. Even in the absence of overt anemia, children with low serum ferritin levels are more prone to these episodes. Iron is a crucial cofactor for enzymes involved in **catecholamine metabolism** and neurotransmitter function (like dopamine). Supplementation with iron (3–6 mg/kg/day) has been proven to significantly reduce the frequency of spells, even in non-anemic children. **Analysis of Incorrect Options:** * **A. Pyridoxine (Vitamin B6):** While B6 is used in neonatal seizures (Pyridoxine-dependent epilepsy) and homocystinuria, it has no established role in treating BHS. * **B. Zinc:** Zinc is vital for diarrhea management and growth but does not influence the pathophysiology of BHS. * **D. Molybdenum:** This is a trace element involved in sulfite oxidase activity; deficiency is rare and unrelated to respiratory or behavioral spells. **NEET-PG High-Yield Pearls:** 1. **Types:** Two main types exist—**Cyanotic** (most common, triggered by anger/frustration) and **Pallid** (triggered by sudden pain/fright, associated with bradycardia). 2. **Diagnosis:** Primarily clinical. The most important step is to reassure parents that the spells are involuntary and benign. 3. **Investigation:** Always check **Serum Ferritin** or Hemoglobin levels in a child presenting with BHS. 4. **Prognosis:** Excellent; most children outgrow these spells by age 5–6 years. No association with future epilepsy or intellectual disability.

Question 1

A 2-month-old child, born prematurely, presents with respiratory distress. Cardiac examination reveals increased pulse pressure and a pansystolic murmur best heard in the 2nd left intercostal space. What is the most probable diagnosis?

Accepted Answer

Patent ductus arteriosus

Answer

Atrial septal defect

Answer

Ventricular septal defect

Answer

Tetralogy of Fallot

Question 2

Sweat chloride levels are typically observed to be in which of the following states in patients with cystic fibrosis?

Accepted Answer

Increased

Answer

Decreased

Answer

No change

Answer

May increase or decrease

Question 3

What is the most frequent causative agent for acute epiglottitis in children under 5 years of age?

Accepted Answer

Haemophilus influenzae type B

Answer

Influenza virus type A

Answer

Parainfluenza virus type 1

Answer

Staphylococcus aureus

Question 4

A 1-year-old child presents with cough, cold, and a respiratory rate of 40/minute. What is your diagnosis?

Accepted Answer

No Pneumonia

Answer

Pneumonia

Answer

Severe Pneumonia

Answer

Very severe Pneumonia

Question 5

A 2-year-old child presents to the emergency department at 3 AM with fever, barking cough, and stridor that is only present while crying. The child is able to drink normally. On examination, the respiratory rate is 36/min and the temperature is 39.6°C. What will be your next step?

Accepted Answer

High-dose dexamethasone injection

Answer

Racemic epinephrine nebulization

Answer

Nasal wash for influenza or RSV

Answer

Antibiotics and blood culture

Question 6

A 3-month-old child presents with moderate fever, non-productive cough, and mild dyspnea. Following a course of antibiotics, the child showed transient improvement but then developed high fever, productive cough, and increased respiratory distress. Chest X-ray reveals hyperlucency, and Pulmonary Function Tests demonstrate an obstructive pattern. What is the most probable diagnosis?

Accepted Answer

Bronchiolitis obliterans

Answer

Alveolar microlithiasis

Answer

Postviral syndrome

Answer

Follicular bronchitis

Question 7

A 2-week-old neonate presents with a history of stridor that improves when the baby assumes the prone position. What is the recommended management?

Accepted Answer

Observation and reassurance (wait and watch)

Answer

Oral calcium

Answer

Nebulization

Answer

Antibiotic therapy

Question 8

A 5-year-old girl presents with rhinorrhea, barking cough, and sore throat. Examination reveals laboured respiration. Her siblings are well. What is the most probable viral cause of her symptoms?

Accepted Answer

Parainfluenza virus

Answer

Adenovirus

Answer

Influenza virus

Answer

RSV

Question 9

A 2-year-old female child presented with fever, cough, and respiratory distress. Chest X-ray showed consolidation in the right lower lobe. She improved with antibiotics, but on follow-up at 8 weeks, she was found to have increasing consolidation in the right lower lobe and recurrent fever. What would be your next investigation?

Accepted Answer

Bronchoscopy

Answer

Bacterial culture of the nasopharynx

Answer

CT scan of the chest

Answer

Allergen sensitivity test

Question 10

What is the treatment for breath-holding spells?

Accepted Answer

Iron

Answer

Pyridoxine

Answer

Zinc

Answer

Molybdenum

Respiratory Diseases — MCQs

Respiratory Diseases — MCQs

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