Acute Respiratory Distress Syndrome — MCQs

10 questions

In acute respiratory distress syndrome (ARDS), which type of cell is primarily damaged?

A 48F, COPD history is admitted with increasing dyspnea and cyanosis. Blood gas analysis reveals pH 7.32, PaCO2 60 mmHg, and PaO2 50 mmHg. Most appropriate management step?

Which of the following statements about the ABCDE approach in pediatric Advanced Life Support (PALS) is incorrect?

In which of the following conditions is Positive end-expiratory pressure (PEEP) beneficial?

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:

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

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?

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

Which of the following presents as mediastinal enlargement?

Q10

What is the most common complication of blood transfusion that can lead to death?

Acute Respiratory Distress Syndrome Indian Medical PG Practice Questions and MCQs

Question 1: In acute respiratory distress syndrome (ARDS), which type of cell is primarily damaged?

A. Type 2 pneumocytes
B. Type 1 pneumocytes (Correct Answer)
C. Alveolar macrophages
D. Bronchial epithelial cells

Explanation: ***Type 1 pneumocytes*** - These cells form an **extensive network of thin cells** that cover approximately 95% of the alveolar surface and are primarily responsible for **gas exchange** [4]. - Their thinness and large surface area make them particularly vulnerable to injury during the **initial inflammatory phase of ARDS**, leading to increased permeability and alveolar edema [1]. *Type 2 pneumocytes* - While important for producing **surfactant** and differentiating into Type 1 pneumocytes during repair, Type 2 cells are generally **more resistant to acute injury** than Type 1 cells [2]. - They play a role in the **repair phase** of ARDS, regenerating damaged alveolar epithelium [2]. *Alveolar macrophages* - These are **immune cells** that reside in the alveoli, primarily responsible for **phagocytosis** of foreign particles and initiating immune responses [3]. - While they are activated and contribute to the inflammation in ARDS, they are not the primary cells damaged in the early stages as the epithelial barrier cells are [1]. *Bronchial epithelial cells* - These cells line the airways (bronchi and bronchioles) and are involved in **mucociliary clearance** [3]. - While severe lung injury can extend to these areas, the hallmark of ARDS is damage primarily to the **alveolar-capillary membrane**, not the larger airways.

Question 2: A 48F, COPD history is admitted with increasing dyspnea and cyanosis. Blood gas analysis reveals pH 7.32, PaCO2 60 mmHg, and PaO2 50 mmHg. Most appropriate management step?

A. Administer intravenous antibiotics
B. Initiate NIPPV (Correct Answer)
C. Provide high-flow oxygen therapy
D. Immediate intubation and mechanical ventilation

Explanation: ***Initiate NIPPV*** - The patient's **pH 7.32 (acidemia)**, **PaCO2 60 mmHg (hypercapnia)**, and **PaO2 50 mmHg (hypoxemia)** indicate **acute hypercapnic respiratory failure** in the context of COPD exacerbation [1], [2]. - **Non-invasive positive pressure ventilation (NIPPV)**, such as BiPAP, is the cornerstone of managing acute exacerbations of COPD with respiratory acidosis, as it improves gas exchange and reduces work of breathing without the risks of intubation. *Administer intravenous antibiotics* - While infections are a common trigger for COPD exacerbations and antibiotics may be indicated, treating **respiratory failure** with antibiotics alone is insufficient and does not address the immediate life-threatening gas exchange abnormality. - Antibiotics are a supportive measure, but not the **most appropriate initial management step** for this degree of respiratory acidosis and hypoxemia. *Provide high-flow oxygen therapy* - Administering **high-flow oxygen** in a patient with COPD and **hypercapnic respiratory failure** may worsen hypercapnia by blunting the hypoxic drive and increasing V/Q mismatch [3], [4]. - While supplemental oxygen is necessary to treat hypoxemia, aggressive oxygen therapy without ventilatory support in this context can be detrimental if not closely monitored for CO2 retention [3]. *Immediate intubation and mechanical ventilation* - **Immediate intubation** is an invasive procedure with associated risks and is typically reserved for patients who fail NIPPV, have contraindications to NIPPV, or present with severe, life-threatening respiratory distress (e.g., altered mental status, hemodynamic instability, severe acidosis unresponsive to initial measures). - Given the patient's current ABG, **NIPPV** should be trialed first as it is a less invasive and often effective intervention for this presentation [1].

Question 3: Which of the following statements about the ABCDE approach in pediatric Advanced Life Support (PALS) is incorrect?

A. Dehydration is a component of the ABCDE approach. (Correct Answer)
B. Airway management is essential in PALS.
C. Breathing assessment is part of the ABCDE approach.
D. Circulation is a critical component of the ABCDE approach.

Explanation: ***Dehydration is a component of the ABCDE approach.*** - The **ABCDE approach** in PALS focuses on **Airway, Breathing, Circulation, Disability, and Exposure**, which are immediate life threats. - While dehydration is a crucial clinical concern in children, it's a **diagnostic consideration** and management target, not a primary component of the initial rapid assessment categories (A, B, C, D, E) themselves. - Dehydration may affect circulation (C) but is not itself a separate component of the ABCDE framework. *Airway management is essential in PALS.* - **Airway** is the first step in the ABCDE approach, focusing on ensuring a **patent and protected airway** to allow for effective ventilation. - **Airway management** is critical in pediatric resuscitation to prevent respiratory arrest and optimize oxygen delivery. *Breathing assessment is part of the ABCDE approach.* - **Breathing** is the second step, involving the assessment of **respiratory rate, effort, breath sounds, and oxygen saturation**. - Effective breathing is vital for adequate **oxygenation and ventilation**, and addressing breathing problems is a key part of PALS. *Circulation is a critical component of the ABCDE approach.* - **Circulation** is the third step, involving the assessment of **heart rate, blood pressure, capillary refill time, and peripheral perfusion**. - **Circulatory assessment** helps identify shock or cardiac arrest, which require immediate intervention. - The complete ABCDE also includes **Disability** (neurological status assessment using AVPU or GCS) and **Exposure** (full examination while preventing hypothermia).

Question 4: In which of the following conditions is Positive end-expiratory pressure (PEEP) beneficial?

A. Pneumonia
B. Pulmonary edema
C. Chronic Obstructive Pulmonary Disease (COPD)
D. Acute Respiratory Distress Syndrome (ARDS) (Correct Answer)

Explanation: ***Acute Respiratory Distress Syndrome (ARDS)*** - PEEP is crucial in ARDS to prevent **alveolar collapse** at end-expiration, improving oxygenation and reducing the risk of **ventilator-induced lung injury**. - It helps by **recruiting collapsed alveoli** and maintaining them open, thus increasing the functional residual capacity. *Pneumonia* - While pneumonia can cause hypoxemia, PEEP's benefit is less pronounced unless it progresses to **ARDS** or causes significant **atelectasis**. - Excessive PEEP can lead to barotrauma if lung compliance is relatively normal or if only a limited portion of the lung is affected. *Pulmonary edema* - PEEP can be helpful in **cardiogenic pulmonary edema** by reducing venous return and thus **preload**, as well as improving oxygenation. - However, it's not the primary or most universally beneficial intervention compared to its role in ARDS. *Chronic Obstructive Pulmonary Disease (COPD)* - PEEP must be used cautiously in COPD due to the risk of **dynamic hyperinflation** and **auto-PEEP**, which can increase air trapping. - While it might be cautiously applied to improve oxygenation or reduce work of breathing, it's generally not considered broadly beneficial and can be detrimental if not carefully managed.

Question 5: 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 6: 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 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: 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 9: Which of the following presents as mediastinal enlargement?

A. T-cell Acute Lymphoblastic Leukemia
B. Hodgkin lymphoma (Correct Answer)
C. Primary mediastinal large B-cell lymphoma
D. Chronic Myeloid Leukemia

Explanation: ***Hodgkin lymphoma*** - **Hodgkin lymphoma** frequently presents with **mediastinal involvement**, particularly the **nodular sclerosis subtype**, leading to mediastinal enlargement [1]. - This enlargement is often detected on chest X-rays and can cause symptoms due to compression of nearby structures [1]. *T-cell Acute Lymphoblastic Leukemia* - While T-cell ALL can cause a **mediastinal mass**, it is a **leukemia** typically characterized by widespread bone marrow involvement and circulating blast cells, not primarily a solid mediastinal enlargement. - The mediastinal involvement is usually a manifestation of **thymic infiltration** by leukemic cells, but the primary disease is systemic. *Primary mediastinal large B-cell lymphoma* - This is a distinct subtype of **diffuse large B-cell lymphoma (DLBCL)** that **primarily arises in the mediastinum** and presents as a large mediastinal mass. - It is histologically and clinically distinct from Hodgkin lymphoma, though both can cause mediastinal enlargement [1]. *Chronic Myeloid Leukemia* - **CML** is a myeloproliferative neoplasm characterized by the **Philadelphia chromosome** and primarily affects the bone marrow and spleen. - While extramedullary hematopoiesis can occur, mediastinal enlargement is not a typical or common presentation of CML.

Question 10: What is the most common complication of blood transfusion that can lead to death?

A. Hyperkalemia
B. Citrate toxicity
C. T.R.A.L.I (Correct Answer)
D. Hypothermia

Explanation: ***T.R.A.L.I*** - **Transfusion-Related Acute Lung Injury (TRALI)** is the leading cause of transfusion-related mortality, characterized by sudden onset of **non-cardiogenic pulmonary edema** within 6 hours of transfusion [1]. - It is thought to be mediated by **donor antibodies** that activate recipient neutrophils in the pulmonary vasculature, leading to capillary leakage [1]. *Hyperkalemia* - Can occur, especially in massive transfusions or rapid infusion of stored blood, but it is less common and typically less lethal than TRALI [1]. - Often manageable with interventions to shift potassium intracellularly or remove it from the body. *Citrate toxicity* - Associated with **massive transfusions** or in patients with **liver dysfunction**, as the liver metabolizes citrate. - Leads to **hypocalcemia** due to citrate chelating calcium, but is rarely fatal and reversible with calcium administration. *Hypothermia* - Can occur with rapid infusion of large volumes of cold blood products, particularly in trauma or surgical settings. - While it can exacerbate coagulopathy and arrhythmias, it is generally preventable with blood warmers and rarely a direct cause of death compared to TRALI.

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