Acute Respiratory Distress Syndrome — MCQs

10 questions

Following tests are done for assessing fetal lung maturity. Which of the following test results does not indicate adequate fetal lung maturity?

Which of the following parameters is most critical for maintaining optimal oxygenation?

All of the following may lead to pneumatocele formation except which of the following?

Best management for an inhaled foreign body in an infant is?

With reference to Respiratory Distress Syndrome (RDS), which of the following statements is false?

All of the following are direct causes of acute lung injury, except which of the following?

A patient with a known case of acute pancreatitis develops breathlessness and bilateral basal crepitations on day 4. What is the most likely diagnosis based on the chest radiography image?

A neonate delivered at 36-week gestation develops respiratory distress soon after birth. CXR is as shown. Likely diagnosis?

A child presents with respiratory distress. A vascular ring is suspected. Investigation of choice is -

Q10

X-ray chest in a neonate may show 'ground glass' haziness in all the following conditions EXCEPT:

Acute Respiratory Distress Syndrome Indian Medical PG Practice Questions and MCQs

Question 1: Following tests are done for assessing fetal lung maturity. Which of the following test results does not indicate adequate fetal lung maturity?

A. Foam stability index greater than 47
B. Presence of phosphatidylglycerol
C. Lecithin/sphingomyelin ratio less than 2 (Correct Answer)
D. Optical density at 650 nm less than 0.15

Explanation: ***Lecithin/sphingomyelin ratio less than 2*** - A **lecithin/sphingomyelin (L/S) ratio** of **less than 2:1** indicates a higher risk of respiratory distress syndrome (RDS) due to insufficient **surfactant** production. - Surfactant is crucial for reducing surface tension in the alveoli, preventing their collapse at the end of expiration. - An L/S ratio **≥2:1** is considered indicative of fetal lung maturity. *Foam stability index greater than 47* - A **foam stability index (FSI) greater than or equal to 47** indicates the presence of sufficient **surfactant** to create stable foam, suggesting **fetal lung maturity**. - This test is based on the ability of surfactant to reduce surface tension in amniotic fluid when mixed with ethanol. *Presence of phosphatidylglycerol* - The **presence of phosphatidylglycerol (PG)** in the amniotic fluid is a strong indicator of **fetal lung maturity**. - PG is a mature **surfactant** component that appears later in gestation and signifies a very low risk of respiratory distress syndrome (RDS). *Optical density at 650 nm less than 0.15* - An **optical density (OD) at 650 nm of less than 0.15** in the amniotic fluid indicates **fetal lung maturity**. - This test measures the turbidity of amniotic fluid, with lower values indicating the presence of mature surfactant and clear fluid.

Question 2: Which of the following parameters is most critical for maintaining optimal oxygenation?

A. FiO2
B. Respiratory rate
C. PEEP (Correct Answer)
D. Tidal volume

Explanation: ***PEEP*** - **Positive End-Expiratory Pressure (PEEP)** is crucial for maintaining optimal oxygenation because it prevents **alveolar collapse** at the end of expiration, thereby increasing the **functional residual capacity** and improving gas exchange. - By keeping alveoli open, PEEP increases the number of available alveoli for ventilation, preventing **atelectasis** and optimizing the **venous admixture** from non-ventilated lung units. *FiO2* - While **Fraction of Inspired Oxygen (FiO2)** is essential for providing sufficient oxygen, simply increasing FiO2 without proper alveolar recruitment and patency (often achieved with PEEP) can be less effective and potentially harmful due to **oxygen toxicity**. - High FiO2 can improve oxygenation in cases of **hypoxemia**, but it doesn't address underlying problems like **alveolar collapse** or **ventilation-perfusion mismatch** as directly as PEEP does. *Respiratory rate* - **Respiratory rate** primarily affects **carbon dioxide elimination** (PaCO2) and, to some extent, alveolar ventilation. - While an adequate respiratory rate is necessary for overall gas exchange, it is not the most direct or critical parameter for optimizing **oxygenation** compared to PEEP's role in maintaining alveolar patency. *Tidal volume* - **Tidal volume** also primarily affects **carbon dioxide elimination** and plays a role in overall minute ventilation. - Excessive tidal volume can lead to **ventilator-induced lung injury (VILI)**, while insufficient tidal volume can reduce minute ventilation, but it does not directly optimize oxygenation by preventing **alveolar collapse** in the same way PEEP does.

Question 3: All of the following may lead to pneumatocele formation except which of the following?

A. Staphylococcal pneumonia
B. Positive pressure ventilation
C. Hydrocarbon inhalation
D. ARDS (Correct Answer)

Explanation: ***ARDS*** - **Acute Respiratory Distress Syndrome (ARDS)** is primarily characterized by **inflammatory lung injury**, leading to **alveolar edema**, but does not typically cause pneumatocele formation [1]. - Pneumatoceles are more likely associated with infections or mechanical ventilation, not with ARDS itself. *Staphylococcal pneumonia* - **Staphylococcal pneumonia** can lead to pneumatocele formation due to **necrotizing pneumonia**, where the formation of air-filled cysts occurs from lung tissue damage. - This type of pneumonia is associated with **Staphylococcus aureus** and can cause cavitary lesions. *Positive pressure ventilation* - **Positive pressure ventilation** can increase the risk of barotrauma, leading to the formation of pneumatocele through excess air entering lung tissue. - It is often used in cases of respiratory distress but can inadvertently contribute to pneumatocele development. *Hydrocarbon inhalation* - **Hydrocarbon inhalation** is linked to pneumonitis and can cause lung injury, leading to the formation of **pneumatoceles** as a result of **lung inflammation**. - Such inhalation can create **alveolar damage**, allowing for air-filled spaces to develop.

Question 4: Best management for an inhaled foreign body in an infant is?

A. IPPV
B. Tracheostomy
C. Corticosteroids
D. Bronchoscopy (Correct Answer)

Explanation: ***Bronchoscopy*** - **Bronchoscopy** is the definitive and most effective procedure for both diagnosing and removing an inhaled foreign body in an infant. - It allows direct visualization of the airways and the precise retrieval of the foreign object, preventing complications like **atelectasis** or **pneumonia**. *Tracheostomy* - **Tracheostomy** is an emergency procedure to create a surgical airway, usually reserved for severe upper airway obstruction that cannot be managed by less invasive means. - It is not the primary line of treatment for removing an inhaled foreign body, which is typically found further down in the **bronchial tree**. *Corticosteroids* - **Corticosteroids** are used to reduce inflammation and edema in the airways, but they do not remove the foreign body itself. - While they might be used as an adjunct in managing airway inflammation after removal, they are not the definitive treatment for the foreign body. *IPPV* - **Intermittent Positive Pressure Ventilation (IPPV)** is a method of respiratory support used for patients with respiratory failure. - It does not address the physical obstruction caused by an inhaled foreign body and may even push the object further into the airway or cause **pneumothorax**.

Question 5: With reference to Respiratory Distress Syndrome (RDS), which of the following statements is false?

A. Leads to respiratory distress in premature infants
B. Is less common in babies born to diabetic mothers (Correct Answer)
C. Is treated by administering surfactant therapy
D. Usually occurs in infants born before 34 weeks of gestation

Explanation: ***Is less common in babies born to diabetic mothers*** - Babies born to **diabetic mothers** are at an **increased risk** of Respiratory Distress Syndrome (RDS) due to delayed lung maturation caused by **hyperinsulinemia.** - Insulin inhibits the production of **surfactant**, a substance critical for reducing surface tension in the alveoli and preventing lung collapse. - This statement is **FALSE** - RDS is actually **MORE common** in infants of diabetic mothers. *Leads to respiratory distress in premature infants* - RDS is primarily a disease of **prematurity**, resulting from a deficiency of **surfactant** in the immature lungs. - This deficiency leads to widespread **atelectasis** (lung collapse), which causes breathing difficulties immediately or shortly after birth. - This statement is **TRUE**. *Is treated by administering surfactant therapy* - **Surfactant therapy** is a cornerstone of RDS treatment, often delivered via an **endotracheal tube**. - It works by replacing the deficient natural surfactant, thereby improving **lung compliance** and reducing the work of breathing. - This statement is **TRUE**. *Usually occurs in infants born before 34 weeks of gestation* - RDS predominantly affects infants born **before 34 weeks of gestation**, as their lungs are typically not mature enough to produce sufficient surfactant. - The risk **decreases significantly** with increasing gestational age, with full-term infants rarely developing the condition. - This statement is **TRUE**.

Question 6: All of the following are direct causes of acute lung injury, except which of the following?

A. Aspiration
B. Lung contusion
C. Cardiopulmonary bypass with heart-lung machine (Correct Answer)
D. Toxic gas inhalation

Explanation: ***Cardiopulmonary bypass with heart-lung machine*** - While **cardiopulmonary bypass** can lead to acute lung injury (ALI)/ARDS in some patients, it is considered an **indirect cause**. [1] - The systemic inflammatory response triggered by bypass rather than direct lung insult typically mediates the injury. [1] *Aspiration* - **Aspiration of gastric contents** is a classic **direct cause** of acute lung injury. [1] - The acidic and particulate matter directly irritates and damages the alveolar epithelial and endothelial cells. *Toxic gas inhalation* - Inhaling **toxic gases** directly causes injury to the airway and alveolar lining. [2] - This direct damage can lead to inflammation and compromise gas exchange, precipitatingALI. [2] *Lung contusion* - **Lung contusion** is a **direct traumatic injury** to the lung tissue. - This physical damage causes hemorrhage and edema within the alveolar spaces, directly impairing lung function.

Question 7: A patient with a known case of acute pancreatitis develops breathlessness and bilateral basal crepitations on day 4. What is the most likely diagnosis based on the chest radiography image?

A. Bilateral pneumonia
B. Carcinogenic Pulmonary Embolism
C. Lung collapse (atelectasis)
D. Acute Respiratory Distress Syndrome (ARDS) (Correct Answer)

Explanation: ***Acute Respiratory Distress Syndrome (ARDS)*** - The chest radiograph shows **bilateral patchy infiltrates** and **diffuse alveolar opacities** consistent with ARDS, especially in the context of **acute pancreatitis** as a known risk factor. - The development of **breathlessness** and **bilateral basal crepitations** (rales) on day 4 further supports ARDS due to fluid accumulation in the lungs. *Bilateral pneumonia* - While pneumonia can cause bilateral infiltrates, the **symmetrical and widespread distribution** seen on this radiograph, combined with the context of acute pancreatitis, makes ARDS a more likely diagnosis. - Pneumonia typically presents with fever, productive cough, and lung consolidation, which are not specifically highlighted as primary symptoms over the breathlessness. *Carcinogenic Pulmonary Embolism* - Pulmonary embolism typically manifests with **sudden onset dyspnea**, pleuritic chest pain, and sometimes hemoptysis, and chest X-rays are often normal or show subtle findings like a **Westermark sign** or Hampton's hump. - The widespread bilateral infiltrates seen in the image are **not characteristic of pulmonary embolism**. *Lung collapse (atelectasis)* - Atelectasis usually appears as a ** localised area of increased opacification**, often with volume loss (e.g., tracheal deviation, elevated hemidiaphragm), and is often unilateral or segmental. - The **diffuse, bilateral, and often fluffy infiltrates** seen in this image are not consistent with typical atelectasis.

Question 8: A neonate delivered at 36-week gestation develops respiratory distress soon after birth. CXR is as shown. Likely diagnosis?

A. Meconium Aspiration Syndrome
B. Respiratory Distress Syndrome (Correct Answer)
C. Transient Tachypnea of Newborn
D. Neonatal Pneumonia

Explanation: ***Respiratory Distress Syndrome*** - The chest X-ray shows classic features of RDS, including a diffuse **reticulogranular pattern** (ground-glass appearance) and prominent **air bronchograms**, indicative of widespread alveolar atelectasis. - This condition is primarily caused by **surfactant deficiency** in preterm infants (like this 36-week neonate), leading to increased surface tension, alveolar collapse, and respiratory distress shortly after birth. ***Transient Tachypnea of Newborn*** - This is caused by delayed clearance of **fetal lung fluid** and is more common in term infants delivered by Caesarean section. - The chest X-ray typically shows **perihilar streaking**, fluid in the interlobar fissures, and hyperinflation, which are not the primary findings in the provided image. ***Neonatal Pneumonia*** - While it can present with respiratory distress, neonatal pneumonia typically shows **asymmetrical patchy infiltrates**, consolidation, or pleural effusions on chest X-ray. - The diffuse, symmetrical ground-glass appearance seen here is less characteristic of an infectious process like pneumonia, which is often more localized. ***Meconium Aspiration Syndrome*** - This condition occurs in term or post-term infants following aspiration of **meconium-stained amniotic fluid**, which is not mentioned in the history. - The characteristic X-ray findings are coarse, patchy opacities, **hyperinflation**, and potential air-leak syndromes (e.g., pneumothorax), which differ from the image.

Question 9: A child presents with respiratory distress. A vascular ring is suspected. Investigation of choice is -

A. Angiography
B. MRI (Correct Answer)
C. CT
D. PET

Explanation: ***MRI/MRA*** - **Magnetic Resonance Imaging (MRI) with MR Angiography** provides excellent visualization of the **aortic arch** and its branches without ionizing radiation, making it ideal for pediatric patients with suspected **vascular rings**. - MRI clearly delineates **vascular anatomy, tracheal and esophageal compression**, confirming the diagnosis and guiding surgical planning. - Particularly preferred when **radiation-free imaging** is prioritized in children. *CT Angiography* - **CT Angiography (CTA) with 3D reconstruction** provides excellent vascular imaging and is widely used for vascular ring diagnosis in many centers. - **Advantage**: Faster acquisition time, less need for sedation, excellent anatomical detail with 3D reconstruction. - **Disadvantage**: Involves **ionizing radiation** exposure, which is a concern in pediatric patients when equally diagnostic radiation-free alternatives exist. - Both MRI and CTA are considered appropriate first-line investigations; choice depends on institutional expertise and clinical context. *Conventional Angiography* - **Catheter angiography** is invasive, involves radiation, and has been largely replaced by non-invasive cross-sectional imaging (MRI/CT). - May be reserved for cases requiring intervention or when non-invasive imaging is inconclusive. *PET* - **Positron Emission Tomography (PET)** detects metabolic activity and is used for cancer or inflammation, not for **anatomical vascular anomalies**. - Not indicated for vascular ring diagnosis.

Question 10: X-ray chest in a neonate may show 'ground glass' haziness in all the following conditions EXCEPT:

A. Left-to-right shunt (Correct Answer)
B. Obstructed TAPVC
C. Staphylococcal pneumonia
D. Hyaline membrane disease

Explanation: ***Left-to-right shunt*** - A **left-to-right shunt** in a neonate typically causes an increase in pulmonary blood flow, leading to vascular congestion and possibly **cardiomegaly**, not ground-glass haziness. - While prolonged significant shunting can lead to pulmonary edema, classic "ground glass" haziness is more characteristic of diffuse lung pathology. *Obstructed TAPVC* - **Obstructed total anomalous pulmonary venous connection (TAPVC)** leads to severe pulmonary venous congestion, resulting in **pulmonary edema** and a classic **ground-glass appearance** on chest X-ray. - This condition is a surgical emergency due to severe respiratory distress and lung opacification. *Staphylococcal pneumonia* - **Staphylococcal pneumonia** in neonates can cause extensive **pulmonary inflammation** and **exudate formation**, leading to a diffuse alveolar filling pattern that appears as ground-glass opacities. - This is a severe form of pneumonia that can rapidly progress. *Hyaline membrane disease* - **Hyaline membrane disease (respiratory distress syndrome)** is characterized by surfactant deficiency, leading to diffuse **atelectasis** and **pulmonary edema**, which manifests as a **ground-glass appearance** on chest X-ray. - This condition commonly affects premature infants and is associated with air bronchograms.

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free