Acute Respiratory Distress Syndrome — MCQs

10 questions

In a preterm baby with respiratory distress syndrome, which type of cell is deficient?

Patient of pneumonia on ventilator with wt. 50 kg. RR 14/min, bicarbonate - 18, pH 7.3, pCO2 48 mmHg, pO2 110 mmHg, PEEP 12 cm H2O, tidal volume 420 mL, SpO2 - 100% with FiO2 90%. What is next step in management?

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

What is to be addressed first in case of polytrauma -

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

A 3-month-old child presents with indrawing of the chest and a respiratory rate of 52 breaths per minute. This condition can be classified as:

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?

Most common cause of death in Rheumatoid Arthritis?

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

Q10

The following are true of Mendelson's syndrome –

Acute Respiratory Distress Syndrome Indian Medical PG Practice Questions and MCQs

Question 1: In a preterm baby with respiratory distress syndrome, which type of cell is deficient?

A. Type 2 alveolar cell (Correct Answer)
B. Type 1 alveolar cell
C. Alveolar capillary endothelial cell
D. Bronchial mucosal epithelial cell

Explanation: ***Type 2 alveolar cell*** - **Type 2 alveolar cells** (pneumocytes) are responsible for producing and secreting **surfactant**. - A deficiency in these cells, common in preterm infants, leads to insufficient surfactant, causing alveolar collapse and respiratory distress syndrome. *Type 1 alveolar cell* - **Type 1 alveolar cells** are primarily involved in **gas exchange** due to their thin, flat structure. - While essential for respiration, their deficiency is not the primary cause of respiratory distress syndrome in preterm infants. *Alveolar capillary endothelial cell* - **Alveolar capillary endothelial cells** form the walls of the capillaries surrounding the alveoli, facilitating the transfer of gases between the alveoli and blood. - They do not produce surfactant, and their deficiency is not the direct cause of respiratory distress syndrome. *Bronchial mucosal epithelial cell* - **Bronchial mucosal epithelial cells** line the airways and are involved in mucus production and ciliary clearance. - While important for respiratory function, their primary role is not in preventing alveolar collapse in respiratory distress syndrome.

Question 2: Patient of pneumonia on ventilator with wt. 50 kg. RR 14/min, bicarbonate - 18, pH 7.3, pCO2 48 mmHg, pO2 110 mmHg, PEEP 12 cm H2O, tidal volume 420 mL, SpO2 - 100% with FiO2 90%. What is next step in management?

A. Increase PEEP
B. Increase tidal volume
C. Decrease fio2 (Correct Answer)
D. Decrease RR

Explanation: **Decrease FiO2** - The patient has an **SpO2 of 100% with a FiO2 of 90%**, indicating **hyperoxia** induced by excessive oxygen delivery. - Decreasing FiO2 is the appropriate next step to prevent **oxygen toxicity** (e.g., absorption atelectasis, free radical damage) while maintaining adequate oxygenation. *Increase PEEP* - The patient's **PaO2 of 110 mmHg** is already well within the normal to high range, suggesting that oxygenation is adequate. - Increasing PEEP would be considered if the patient had **refractory hypoxemia**, not hyperoxia. *Increase tidal volume* - The current tidal volume of **420 mL for a 50 kg patient (8.4 mL/kg)** is already at the higher end of lung-protective ventilation (typically 6-8 mL/kg). - Increasing tidal volume further could lead to **ventilator-induced lung injury** (VILI) due to volutrauma, especially in a patient with pneumonia. *Decrease RR* - The patient has a **pCO2 of 48 mmHg** and a **pH of 7.3**, indicating **respiratory acidosis** (hypoventilation). - Decreasing the respiratory rate would further exacerbate the acidosis by reducing minute ventilation and increasing pCO2, which is inappropriate.

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: What is to be addressed first in case of polytrauma -

A. Circulation
B. Neurology
C. Blood Pressure
D. Airway (Correct Answer)

Explanation: ***Airway*** - Maintaining a **patent airway** is the absolute first priority in polytrauma management according to the **ATLS (Advanced Trauma Life Support)** protocol. - Failure to secure an airway can lead to **hypoxia** and **brain damage** within minutes, regardless of other injuries. *Circulation* - While critical, addressing **circulation** (C in ABCDE) comes after establishing a secure airway and adequate breathing (A and B). - Uncontrolled hemorrhage would be the focus of circulation management, but only after guaranteeing proper oxygenation. *Neurology* - Neurological assessment (D in ABCDE for Disability) follows the primary survey of airway, breathing, and circulation. - Initial neurological evaluation focuses on **level of consciousness** using the **GCS (Glasgow Coma Scale)**. *Blood Pressure* - **Blood pressure** is an indicator of circulatory status but is not the first thing to be addressed. - It falls under the "C" for circulation in the ATLS protocol, which is secondary to airway and breathing.

Question 5: 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 6: A 3-month-old child presents with indrawing of the chest and a respiratory rate of 52 breaths per minute. This condition can be classified as:

A. SIRS
B. Respiratory distress (Correct Answer)
C. Tachypnoea
D. ARDS

Explanation: ***Respiratory distress*** - **Indrawing of the chest** is a classic sign of increased work of breathing, indicating the child is struggling to oxygenate. - A respiratory rate of **52 breaths per minute in a 3-month-old** is significantly elevated and, combined with indrawing, points to respiratory distress. - According to **WHO IMCI guidelines**, chest indrawing in a child with fast breathing is classified as **pneumonia/respiratory distress** requiring immediate treatment. *SIRS* - **Systemic Inflammatory Response Syndrome (SIRS)** criteria are typically more comprehensive and include fever or hypothermia, tachycardia, tachypnea, and abnormal white blood cell count. - While tachypnea is present, the other defining features of SIRS are not fully met by the information provided, nor does indrawing directly classify as SIRS. *Tachypnoea* - **Tachypnoea** refers specifically to an elevated respiratory rate, which is present (52 breaths per minute). - However, the presence of **chest indrawing** indicates more than just rapid breathing; it signifies significant respiratory effort and compromise. - The classification must capture both the elevated rate and the increased work of breathing. *ARDS* - **Acute Respiratory Distress Syndrome (ARDS)** is a severe form of lung injury characterized by widespread inflammation, hypoxemia, and bilateral infiltrates on chest imaging. - While respiratory distress is a feature of ARDS, the given information is insufficient to diagnose ARDS, which requires specific criteria relating to oxygenation and radiological findings.

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: Most common cause of death in Rheumatoid Arthritis?

A. Hepatic failure
B. ARDS
C. Pulmonary fibrosis
D. Ischemic heart disease (Correct Answer)

Explanation: ***Ischemic heart disease*** - Patients with **rheumatoid arthritis (RA)** have a significantly increased risk of developing **cardiovascular diseases**, including ischemic heart disease. [1] - This heightened risk is due to chronic systemic inflammation, accelerated atherosclerosis, and potential side effects of RA treatments contributing to **endothelial dysfunction**. [1] *Hepatic failure* - While certain medications used to treat RA, such as **methotrexate**, can cause liver toxicity, hepatic failure is not the most common cause of death in RA patients. [2] - Regular **liver enzyme monitoring** helps in detecting and managing medication-induced liver issues. *ARDS* - **Acute Respiratory Distress Syndrome (ARDS)** can occur in severely ill patients, but it is not a direct or most common complication of rheumatoid arthritis nor a primary cause of death. [2] - RA can affect the lungs (e.g., interstitial lung disease), but ARDS is typically a severe, acute event triggered by other conditions like **sepsis** or trauma. *Pulmonary fibrosis* - **Interstitial lung disease (ILD)**, including pulmonary fibrosis, is a known extra-articular manifestation of RA and can be a significant cause of morbidity and mortality. [2] - However, **cardiovascular events**, particularly ischemic heart disease, still surpass pulmonary fibrosis as the leading cause of death in RA patients.

Question 9: 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.

Question 10: The following are true of Mendelson's syndrome –

A. Steroids have been shown to improve outcome
B. Critical volume of aspirate is 50 mls
C. Critical pH of gastric aspirate is 1.5
D. Onset of symptoms generally occurs within 30 minutes (Correct Answer)

Explanation: ***Onset of symptoms generally occurs within 30 minutes*** - Mendelson's syndrome refers to **chemical pneumonitis** resulting from pulmonary aspiration of sterile gastric contents. - Symptoms like **bronchospasm**, **dyspnea**, and **tachycardia** typically manifest rapidly, often within minutes to 30 minutes post-aspiration. *Steroids have been shown to improve outcome* - **Corticosteroids** are generally **not recommended** for the treatment of Mendelson's syndrome or chemical pneumonitis caused by gastric aspiration. - Their use can potentially increase the risk of **secondary bacterial pneumonia** due to immunosuppression, without significant clinical benefit in improving lung injury. *Critical volume of aspirate is 50 mls* - The critical volume of aspirate associated with Mendelson's syndrome is generally considered to be **25 mL** or **0.3 mL/kg** of gastric contents. - Aspiration of volumes greater than this threshold significantly increases the risk of developing **severe pneumonitis**. *Critical pH of gastric aspirate is 1.5* - The critical pH of gastric aspirate associated with Mendelson's syndrome is generally considered to be **less than 2.5**. - A pH below this value indicates highly acidic gastric contents, which cause **severe chemical burns** to the tracheobronchial tree and lung parenchyma.

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