Question 1: Congenital Diaphragmatic Hernia (CDH)
Stem: A neonate born at 39 weeks presents with immediate respiratory distress and a scaphoid abdomen. An urgent chest X-ray demonstrates multiple air-filled cystic structures in the left hemithorax, with displacement of the mediastinum to the right. The tip of the nasogastric (NG) tube is seen coiled within the left chest.
Question: What is the most likely diagnosis?
(A) Congenital Pulmonary Airway Malformation (CPAM) (B) Congenital Lobar Overinflation (CLE) (C) Congenital Diaphragmatic Hernia (Bochdalek) (D) Diaphragmatic Eventration (E) Congenital Cystic Adenomatoid Malformation (CCAM) Type III
Correct Answer: (C) Congenital Diaphragmatic Hernia (Bochdalek)
Explanation:
- Why (C) is correct: The clinical hallmark of CDH is a scaphoid abdomen (because the bowel is in the chest). The X-ray finding of air-filled bowel loops in the thorax and, crucially, the NG tube coiled in the chest, confirms that the stomach/bowel is herniated. Bochdalek is the most common type (posterolateral).
- Why (A) is wrong: CPAM presents as a multicystic mass, but the abdomen would be normal (not scaphoid), and an NG tube would remain in its normal sub-diaphragmatic position.
- Why (B) is wrong: CLE shows a single hyperlucent, overinflated lobe (usually LUL) causing mass effect, but no bowel-like cystic structures or abnormal NG tube position.
- Why (D) is wrong: Eventration is a focal weakness of the diaphragm. While it can cause the diaphragm to appear high, it rarely results in the entire stomach and multiple bowel loops filling the hemithorax with a scaphoid abdomen.
- Why (E) is wrong: CCAM (now called CPAM) Type III consists of microcysts that appear as a solid appearing mass on X-ray, not large air-filled bowel-like loops.
Key Points: CDH
- Location: 80-90% occur on the left side.
- Key Sign: Scaphoid abdomen + bowel loops in the chest + NG tube in the chest.
- Associations: Pulmonary hypoplasia and persistent pulmonary hypertension.
Question 2: Congenital Pulmonary Airway Malformation (CPAM)
Stem: An antenatal ultrasound identifies a cystic lung mass. A postnatal CT performed at 2 weeks of age shows a well-defined, multicystic lesion in the right lower lobe. The cysts are of varying sizes, with one large dominant cyst measuring 3 cm. There is no systemic arterial supply to the lesion.
Question: According to the Stocker classification, which type of CPAM does this represent?
(A) Type 0 (B) Type 1 (C) Type 2 (D) Type 3 (E) Type 4
Correct Answer: (B) Type 1
Explanation:
- Why (B) is correct: Type 1 CPAM is the most common (70%) and is characterized by one or more large cysts (> 2 cm).
- Why (A) is wrong: Type 0 is “acinar dysplasia,” which is extremely rare, incompatible with life, and involves the entire lung.
- Why (C) is wrong: Type 2 consists of multiple small, uniform cysts (< 2 cm).
- Why (D) is wrong: Type 3 consists of microcysts (< 0.5 cm) that appear as a solid, bulky mass on imaging.
- Why (E) is wrong: Type 4 consists of large, peripheral thin-walled cysts that look like a localized pneumothorax (and is a precursor to pleuropulmonary blastoma).
Key Points: CPAM
- Definition: A multicystic mass of non-functioning lung tissue.
- Blood Supply: Supplied by and drained by pulmonary vessels (this distinguishes it from sequestration).
- Management: Usually elective surgical resection due to risk of recurrent infection and rare malignant transformation.
Question 3: Bronchopulmonary Sequestration (BPS)
Stem: A 4-year-old child presents with recurrent pneumonia in the same location in the left lower lobe. A CT scan reveals a segment of non-aerated lung tissue. A dedicated CT angiogram demonstrates a large anomalous artery arising from the descending thoracic aorta supplying this segment.
Question: What is the most likely diagnosis?
(A) Intralobar Sequestration (B) Extralobar Sequestration (C) CPAM Type 2 (D) Scimitar Syndrome (E) Pulmonary AVM
Correct Answer: (A) Intralobar Sequestration
Explanation:
- Why (A) is correct: An Intralobar Sequestration (ILS) is the most common type (75%). It is located within the normal visceral pleura. The defining feature of all sequestrations is a systemic arterial supply (usually from the aorta). ILS classically presents later in childhood with recurrent infections.
- Why (B) is wrong: Extralobar Sequestration (ELS) has its own pleura. It typically presents in neonates with respiratory distress or associated anomalies (like CDH) and rarely gets infected because it doesn’t communicate with the bronchial tree.
- Why (C) is wrong: CPAM is supplied by pulmonary arteries, not systemic (aortic) arteries.
- Why (D) is wrong: Scimitar syndrome involves an anomalous pulmonary vein draining to the IVC, associated with a hypoplastic right lung; it’s not a focal sequestered mass.
- Why (E) is wrong: A pulmonary AVM is a high-flow communication between a pulmonary artery and a pulmonary vein, not a solid segment with aortic supply.
Key Points: Pulmonary Sequestration
- Intralobar (ILS): Shared pleura. Drains to Pulmonary Veins. Presents with infection.
- Extralobar (ELS): Own pleura. Drains to Systemic Veins (Azygos/IVC). Associated with other anomalies.
Question 4: Congenital Lobar Overinflation (CLE)
Stem: A 2-month-old infant presents with progressive respiratory distress. A chest X-ray shows a hyperlucent, hyperexpanded left upper lobe causing shift of the mediastinum to the right and compression of the adjacent left lower lobe. Vascular markings are visible within the hyperlucent area.
Question: What is the most likely diagnosis?
(A) Pneumothorax (B) Congenital Lobar Overinflation (CLE) (C) Pulmonary Hypoplasia (D) Swyer-James Syndrome (E) Bronchogenic Cyst
Correct Answer: (B) Congenital Lobar Overinflation (CLE)
Explanation:
- Why (B) is correct: CLE (formerly Congenital Lobar Emphysema) is a condition where a lobe (most commonly the LUL, followed by RML and RUL) over-inflates due to a “check-valve” bronchial obstruction. The key imaging finding is a hyperexpanded lobe with preserved vascular markings (this is vital to distinguish it from pneumothorax).
- Why (A) is wrong: A pneumothorax is a hyperlucent space but lacks vascular markings and has a visible pleural line.
- Why (C) is wrong: Pulmonary hypoplasia results in a small, opaque lung, not a hyperexpanded, lucent one.
- Why (D) is wrong: Swyer-James is an acquired post-infectious condition leading to a small, hyperlucent lung, but it occurs in older children and the lung is small, not hyperexpanded.
- Why (E) is wrong: A bronchogenic cyst is a fluid-filled, non-enhancing mass, not a hyperexpanded lobe of air.
Key Points: Congenital Lobar Overinflation (CLE)
- Most common lobe: Left Upper Lobe (LUL).
- Imaging: Hyperlucent, hyperexpanded lobe + Mass effect + Vascular markings present.
- Neonate: May appear “white” on the very first day of life due to retained fetal lung fluid, then clears to “black” (lucent).
Question 5: Respiratory Distress Syndrome (RDS)
Stem: A premature neonate born at 28 weeks gestation presents with grunting and retractions. A chest X-ray demonstrates low lung volumes and diffuse, symmetric fine granular (ground-glass) opacities bilaterally. Multiple air bronchograms are seen extending into the periphery.
Question: What is the underlying cause of this radiographic appearance?
(A) Delayed clearance of fetal lung fluid (B) Surfactant deficiency (C) Chronic lung disease of prematurity (D) Aspirated meconium (E) Group B Streptococcal infection
Correct Answer: (B) Surfactant deficiency
Explanation:
- Why (B) is correct: This is the classic description of Respiratory Distress Syndrome (RDS), or Hyaline Membrane Disease. It is caused by surfactant deficiency in premature lungs, leading to diffuse alveolar collapse (atelectasis). This manifests as low lung volumes, ground-glass opacities, and air bronchograms.
- Why (A) is wrong: This is the cause of Transient Tachypnoea of the Newborn (TTN), which typically occurs in full-term/C-section babies and shows high lung volumes and fluid in the fissures.
- Why (C) is wrong: Chronic lung disease (BPD) occurs after prolonged ventilation/oxygen therapy for RDS, appearing as bubbly/fibrotic lungs.
- Why (D) is wrong: Meconium Aspiration (MAS) occurs in full-term/post-term babies and shows “patchy” opacities and hyperinflation.
- Why (E) is wrong: GBS pneumonia can look identical to RDS, but the underlying cause of the classic ground-glass/low-volume picture in a 28-weeker is surfactant deficiency.
Key Points: RDS (Hyaline Membrane Disease)
- Patient: Premature neonates.
- X-ray Triad: 1. Low lung volumes, 2. Ground-glass opacities, 3. Air bronchograms.
- Treatment: Exogenous surfactant and positive pressure ventilation.
Question 6: Transient Tachypnoea of the Newborn (TTN)
Stem: A full-term infant born via elective Caesarean section develops mild respiratory distress shortly after birth. A chest X-ray shows normal to high lung volumes, prominent perihilar interstitial markings (vascular congestion), and fluid in the horizontal fissure. The symptoms resolve completely within 48 hours.
Question: What is the most likely diagnosis?
(A) Respiratory Distress Syndrome (RDS) (B) Transient Tachypnoea of the Newborn (TTN) (C) Meconium Aspiration Syndrome (MAS) (D) Neonatal Pneumonia (E) Pulmonary Lymphangiectasia
Correct Answer: (B) Transient Tachypnoea of the Newborn (TTN)
Explanation:
- Why (B) is correct: TTN (Wet Lung) is caused by the delayed clearance of fetal lung fluid. It is most common in full-term babies and those born via C-section (missing the “thoracic squeeze” of vaginal birth). The X-ray findings of perihilar congestion and fluid in the fissures are classic, as is the rapid clinical improvement.
- Why (A) is wrong: RDS occurs in premature infants and shows low lung volumes.
- Why (C) is wrong: MAS occurs in babies with fetal distress and shows patchy opacities, not simple fluid-clearing signs.
- Why (D) is wrong: Pneumonia usually presents with more focal consolidation and clinical signs of sepsis.
- Why (E) is wrong: This is a rare, severe congenital condition with persistent pleural effusions and a poor prognosis.
Key Points: TTN
- Risk Factors: Full-term, C-section, maternal diabetes.
- Imaging: High lung volumes, perihilar “streakiness,” and fluid in the fissures.
- Clinical: Resolves spontaneously within 24-48 hours.
Question 7: Meconium Aspiration Syndrome (MAS)
Stem: A post-term neonate (42 weeks) is born after a difficult delivery with thick, meconium-stained liquor. The infant develops severe respiratory distress. A chest X-ray reveals marked hyperinflation and diffuse, asymmetric, “patchy” areas of consolidation and atelectasis in both lungs.
Question: What is the most likely diagnosis?
(A) Respiratory Distress Syndrome (RDS) (B) Transient Tachypnoea of the Newborn (TTN) (C) Meconium Aspiration Syndrome (MAS) (D) Bronchopulmonary Dysplasia (BPD) (E) Total Anomalous Pulmonary Venous Return (TAPVR)
Correct Answer: (C) Meconium Aspiration Syndrome (MAS)
Explanation:
- Why (C) is correct: MAS occurs in full-term or post-term neonates. The aspirated meconium causes small airway obstruction (leading to hyperinflation) and a chemical pneumonitis (leading to patchy opacities).
- Why (A) is wrong: RDS has low lung volumes and ground-glass signal.
- Why (B) is wrong: TTN has clean perihilar markings and resolves quickly; it doesn’t show this “dirty,” patchy lung appearance.
- Why (D) is wrong: BPD occurs in premature infants after long-term treatment.
- Why (E) is wrong: TAPVR (Type 1 or 3) presents with pulmonary oedema and specific cardiac shapes (e.g., snowman), not patchy meconium-like consolidation.
Key Points: Meconium Aspiration Syndrome (MAS)
- Patient: Post-term neonates.
- Imaging: Hyperinflation + “Patchy” asymmetrical opacities.
- Complication: High risk of pneumothorax (due to the ball-valve effect of meconium) and persistent pulmonary hypertension.
Question 8: Round Pneumonia
Stem: A 5-year-old boy presents with fever, cough, and localized pleuritic chest pain. A chest X-ray reveals a well-defined, solitary, round 3 cm opacity in the right lower lobe. The child has no history of weight loss or night sweats.
Question: In a child of this age, this radiographic finding is most characteristic of:
(A) Bronchogenic Carcinoma (B) Round Pneumonia (C) Metastatic Wilms’ Tumour (D) Bronchogenic Cyst (E) Pleuropulmonary Blastoma (PPB)
Correct Answer: (B) Round Pneumonia
Explanation:
- Why (B) is correct: Round pneumonia is a common paediatric phenomenon. Due to underdeveloped collateral pathways (Pores of Kohn and Canals of Lambert), infections in children can stay localized in a “round” shape before spreading. It most commonly occurs in children < 8 years old and is usually caused by Streptococcus pneumoniae.
- Why (A) is wrong: Lung cancer is essentially non-existent in a healthy 5-year-old.
- Why (C) is wrong: Metastases are usually multiple and would be associated with a known primary tumour.
- Why (D) is wrong: A cyst is a fluid-filled, thin-walled lesion, not an acute consolidative opacity.
- Why (E) is wrong: PPB is a rare, aggressive malignancy that can be “round” (Type II/III), but simple infection is exponentially more common.
Key Points: Round Pneumonia
- Demographic: Children, usually < 8 years old.
- Location: Most common in the lower lobes (posteriorly).
- Management: It will resolve after a course of antibiotics; a follow-up X-ray is often performed to ensure it disappears and isn’t a rare mass.
Question 9: Foreign Body Aspiration
Stem: A 2-year-old child presents with a sudden onset of choking and a localized wheeze on the right side. An initial inspiratory chest X-ray is normal. A decubitus (side-lying) film is then performed with the right side down. The right lung fails to collapse and remains hyperlucent compared to the left.
Question: This finding is indicative of:
(A) Right-sided pneumothorax (B) Right-sided obstructive emphysema from a foreign body (C) Right-sided pulmonary hypoplasia (D) Normal physiological response (E) Right-sided pleural effusion
Correct Answer: (B) Right-sided obstructive emphysema from a foreign body
Explanation:
- Why (B) is correct: In a small child who cannot cooperate with expiratory films, decubitus views are used. Normally, the dependent lung (the one they are lying on) should collapse and become more opaque. If a foreign body causes a “ball-valve” obstruction, air can get in but not out. Therefore, the lung remains inflated (hyperlucent) even when dependent.
- Why (A) is wrong: A pneumothorax would show a pleural line and a lack of lung markings, and it wouldn’t change density like this.
- Why (C) is wrong: Hypoplasia would show a small, opaque lung, not an over-inflated lucent one.
- Why (D) is wrong: In a normal response, the down-side lung must decrease in volume.
- Why (E) is wrong: An effusion would cause opacity on the dependent side, not lucency.
Key Points: Foreign Body Aspiration
- Clinical: Sudden choking episode + localized wheeze.
- Imaging: 75% of foreign bodies are radiolucent (like a peanut) and not seen.
- Secondary Signs: Obstructive emphysema (hyperinflation that doesn’t collapse on expiration or decubitus views).
- Most common site: Right main bronchus.
Question 10: Normal Thymus
Stem: A 6-month-old infant has a chest X-ray for a suspected chest infection. The radiologist notes a wide superior mediastinum with a smooth, “sail-shaped” triangular opacity on the right, which has a wavy border that conforms to the ribs.
Question: What is the most appropriate management of this finding?
(A) CT chest to rule out Lymphoma (B) Urgent biopsy (C) No further action (Normal Thymus) (D) Follow-up X-ray in 6 weeks (E) MRI for further characterization
Correct Answer: (C) No further action (Normal Thymus)
Explanation:
- Why (C) is correct: This is a textbook description of a normal thymus. The thymus is large in infants and can be very prominent. The “Sail Sign” (triangular shape) and the “Wave Sign” (indentations from the ribs) are classic benign features. It should never be mistaken for a mass.
- Why (A), (B), (D), (E) are wrong: These are all unnecessary and would cause undue anxiety and radiation/procedure risk. A normal thymus is soft and does not displace or narrow the airway.
Key Points: The Paediatric Thymus
- Appearance: “Sail Sign” (triangular) and “Wave Sign” (wavy border).
- Consistency: Soft (it does not compress the trachea or great vessels).
- Involution: Usually becomes less prominent after age 2 and is replaced by fat in puberty.
- “Thymic Rebound”: The thymus may shrink during severe illness/chemotherapy and then “rebound” (become larger than before) during recovery.
Question 11: Scimitar Syndrome
Stem: A 10-year-old girl is investigated for a heart murmur. A chest X-ray shows a small right lung with a curving, tubular opacity that runs downwards towards the right cardiophrenic angle.
Question: What is this anomalous vessel?
(A) Anomalous pulmonary artery from the aorta (B) Anomalous pulmonary vein draining into the IVC (C) Persistent left superior vena cava (D) Pulmonary arteriovenous malformation (E) Dilated azygos vein
Correct Answer: (B) Anomalous pulmonary vein draining into the IVC
Explanation:
- Why (B) is correct: Scimitar Syndrome (a type of partial anomalous pulmonary venous return – PAPVR) consists of a hypoplastic right lung and an anomalous pulmonary vein that drains the right lung into the IVC. This vein has a characteristic curved shape resembling a Turkish sword (Scimitar).
- Why (A) is wrong: A systemic artery from the aorta is the sign of a sequestration.
- Why (C) is wrong: A PLSVC runs vertically on the left side of the mediastinum.
- Why (D) is wrong: An AVM is a tangle of vessels, not a single long, curving vein.
- Why (E) is wrong: The azygos vein is a vertical structure in the posterior mediastinum, not a curved vessel in the lung parenchyma.
Key Points: Scimitar Syndrome
- Components: 1. Hypoplastic right lung, 2. “Scimitar vein” (draining to IVC), 3. Dextroposition of the heart.
- Physiology: Results in a left-to-right shunt.
Question 12: Pleuropulmonary Blastoma (PPB)
Stem: A 2-year-old child presents with a massive, solid and cystic mass filling the entire right hemithorax. The mass is causing severe mediastinal shift and a large pleural effusion. There is no calcification seen on CT.
Question: Given the age and the aggressive nature of the mass, what is the most likely diagnosis?
(A) Pleuropulmonary Blastoma (PPB) (B) Neuroblastoma (C) Wilms’ Tumour (Metastatic) (D) Bronchogenic Carcinoma (E) Askin Tumour (Ewing’s Sarcoma)
Correct Answer: (A) Pleuropulmonary Blastoma (PPB)
Explanation:
- Why (A) is correct: PPB is a rare, highly aggressive primary mesenchymal tumour of the lung/pleura in children (usually < 5 years old). It has three types: Type I (cystic), Type II (mixed solid/cystic), and Type III (solid). A massive, aggressive mass in a toddler is highly suggestive of PPB.
- Why (B) is wrong: Neuroblastoma is a posterior mediastinal mass (paraspinal), not a primary lung mass.
- Why (C) is wrong: Wilms’ metastases are usually multiple nodules, not a single massive primary-looking mass.
- Why (D) is wrong: This is an adult malignancy.
- Why (E) is wrong: An Askin tumour is a type of Ewing’s sarcoma arising from the chest wall, not the lung parenchyma.
Key Points: Pleuropulmonary Blastoma (PPB)
- Most common primary lung malignancy of childhood.
- Association: Linked to the DICER1 mutation.
- Types: Progresses from purely cystic (Type I) to purely solid (Type III).
Question 13: Bronchogenic Cyst
Stem: A 5-year-old asymptomatic child has a chest X-ray for a pre-operative assessment. It shows a well-defined, 3 cm middle mediastinal mass located just inferior to the carina. On CT, the mass has simple fluid attenuation and does not enhance.
Question: What is the most likely diagnosis?
(A) Bronchogenic Cyst (B) Neuroblastoma (C) Thymus (D) Lymphadenopathy (E) Neurenteric Cyst
Correct Answer: (A) Bronchogenic Cyst
Explanation:
- Why (A) is correct: A bronchogenic cyst is a congenital foregut duplication cyst. Its classic location is the middle mediastinum, specifically subcarinal or paratracheal. Its appearance as a simple, non-enhancing cyst is diagnostic.
- Why (B) is wrong: Neuroblastoma is in the posterior mediastinum.
- Why (C) is wrong: The thymus is in the anterior mediastinum.
- Why (D) is wrong: Lymph nodes would be solid and enhancing.
- Why (E) is wrong: A neurenteric cyst is in the posterior mediastinum and is associated with vertebral anomalies.
Key Points: Bronchogenic Cyst
- Location: Middle Mediastinum (Subcarinal).
- Imaging: Simple water-attenuation cyst (though can be high density if proteinaceous).
- Note: It does not usually communicate with the airway (unlike CPAM).
Question 14: Cystic Fibrosis (Chest)
Stem: An 8-year-old child with known Cystic Fibrosis presents with a chronic cough. A high-resolution CT (HRCT) is performed.
Question: Which of the following is the most characteristic imaging finding of long-standing CF in the lungs?
(A) Basal-predominant UIP pattern (B) Upper-lobe predominant bronchiectasis and mucus plugging (C) Focal consolidative pneumonia (D) Pleural effusions and thickening (E) Solitary pulmonary nodule
Correct Answer: (B) Upper-lobe predominant bronchiectasis and mucus plugging
Explanation:
- Why (B) is correct: The hallmark of CF is thick, tenacious mucus leading to airway obstruction and infection. This result in upper-lobe predominant bronchiectasis and mucus plugging (“finger-in-glove” opacities).
- Why (A) is wrong: UIP is an adult fibrotic disease (basal/subpleural).
- Why (C) is wrong: While they get pneumonia, the chronic, defining feature is the underlying bronchiectasis.
- Why (D) & (E) are wrong: These are not primary or common features of CF.
Key Points: Cystic Fibrosis (Lungs)
- Hallmark: Upper-lobe predominant bronchiectasis.
- HRCT Findings: Bronchial wall thickening, mucus plugging, and “mosaic attenuation” (due to air trapping).
Question 15: Chylothorax
Stem: A 1-week-old neonate who recently underwent surgery for a coarctation of the aorta develops a large left-sided pleural effusion. Thoracocentesis is performed, and the fluid is milky-white in appearance with a high triglyceride content.
Question: What is the most likely cause of this effusion?
(A) Empyema (B) Haemothorax (C) Chylothorax (D) Simple hydrothorax (E) Oesophageal perforation
Correct Answer: (C) Chylothorax
Explanation:
- Why (C) is correct: A chylothorax is an accumulation of chyle (lymphatic fluid) in the pleural space. In neonates, it is often a complication of thoracic surgery (injury to the thoracic duct). The milky appearance and high triglycerides are diagnostic.
- Why (A) is wrong: An empyema (pus) would be associated with fever and would be “yellow/creamy,” not milky-white.
- Why (B) is wrong: A haemothorax is blood.
- Why (D) is wrong: A hydrothorax is simple serous fluid.
- Why (E) is wrong: Oesophageal perforation causes a messy, contaminated effusion with air (pneumomediastinum).
Key Points: Chylothorax
- Most common cause of a large pleural effusion in a neonate.
- Causes: 1. Congenital, 2. Post-surgical (thoracic duct injury), 3. Trauma.
- Location: Classically left-sided if the injury is high (above T4)
