KMU Past Paper Practice

Question:

A 58-year-old man has complete obstruction of a segmental bronchus by an intraluminal lesion. The distal lung gradually loses its air without accumulation of pleural fluid. Which process is responsible for the resulting atelectasis?

Options:

Correct Answer: Removal of distal gas into the bloodstream

Explanation: Complete bronchial obstruction prevents replacement of distal air; continued absorption of that gas into blood makes the affected alveoli progressively collapse.

Question:

Two patients develop lung collapse. One has an obstructed bronchus, while the other has a large collection of fluid in the pleural cavity. Which feature best distinguishes the mechanism in the second patient?

Options:

Correct Answer: The lung is compressed despite an open airway

Explanation: Pleural fluid produces compression atelectasis by exerting pressure from outside; unlike resorption atelectasis, bronchial obstruction is not required.

Question:

A patient has chronic fibrotic thickening involving the lung and pleura. Imaging demonstrates persistent reduction in expansion of the affected region. Which feature makes this form of atelectasis different from collapse caused by a temporary bronchial obstruction?

Options:

Correct Answer: Scarring mechanically limits re-expansion

Explanation: Contraction atelectasis results from fibrosis of lung or pleura; the scar physically restricts expansion rather than merely removing air from patent alveoli.

Question:

A patient develops widespread acute pulmonary injury. Despite ventilation, many alveoli become unstable and collapse. Damage to which cell population contributes most directly to the surfactant abnormality responsible for this component of the disease?

Options:

Correct Answer: Type II pneumocytes

Explanation: Type II pneumocytes produce surfactant. Their injury in ARDS reduces surfactant activity, increasing alveolar instability and contributing to collapse.

Question:

A 47-year-old patient develops severe acute respiratory failure after a major inflammatory insult. Histology shows endothelial and epithelial injury with leakage of protein-rich fluid into alveoli. Which subsequent change most directly makes the lungs difficult to expand?

Options:

Correct Answer: Edema with alveolar collapse

Explanation: Alveolar edema together with surfactant dysfunction and collapse makes the ARDS lung stiff and poorly compliant, increasing the pressure needed for expansion.

Question:

Microscopy from the lung of a patient in the acute phase of ARDS shows capillary congestion, interstitial edema and intra-alveolar fluid. Which additional finding would most strongly support the characteristic pathological pattern?

Options:

Correct Answer: Eosinophilic lining of damaged alveoli

Explanation: Hyaline membranes appear as eosinophilic material lining injured alveoli and are a characteristic morphological feature of diffuse alveolar damage.

Question:

A patient with ARDS survives the initial exudative injury. Several days later, alveolar epithelial regeneration is evident. Which finding represents an appropriate reparative response rather than continuing acute injury?

Options:

Correct Answer: Proliferation of type II pneumocytes

Explanation: Surviving type II pneumocytes proliferate during recovery to restore the damaged alveolar epithelial lining; the other changes indicate ongoing injury.

Question:

Two patients recover from the acute phase of ARDS. One regains near-normal pulmonary function, whereas the other has persistent stiff lungs. Which pathological event most likely occurred in the second patient?

Options:

Correct Answer: Organization of injury with fibrosis

Explanation: Organization of the inflammatory exudate with interstitial fibrosis can follow ARDS and leaves the lung persistently less compliant.

Question:

In experimental acute lung injury, activated neutrophils are prevented from releasing their major damaging products. Which component of ARDS pathogenesis would be most directly reduced?

Options:

Correct Answer: Protease and oxidant-mediated tissue injury

Explanation: Activated neutrophils amplify ARDS by releasing proteases and reactive oxygen species that injure alveolar epithelium and pulmonary endothelium.

Question:

An adult with severe ARDS and a premature newborn with respiratory distress both have unstable alveoli. Which statement best distinguishes the role of surfactant in these two conditions?

Options:

Correct Answer: Dysfunction is secondary in ARDS but primary in neonatal RDS

Explanation: Adult ARDS begins with acute alveolar-capillary injury and secondary surfactant impairment; neonatal RDS centers on inadequate surfactant production in immature lungs.

Question:

Two newborns are delivered on the same day. One is markedly premature and the other is full term. The premature infant develops progressive respiratory difficulty soon after birth. Which developmental factor best explains the difference in risk?

Options:

Correct Answer: Surfactant production increases with fetal maturation

Explanation: Surfactant production rises as the fetal lungs mature, so premature delivery may occur before sufficient surfactant is available to maintain alveolar stability.

Question:

A premature newborn develops tachypnea and marked chest retractions shortly after birth. Which physiological sequence best explains the increased respiratory effort?

Options:

Correct Answer: Reduced surfactant → higher surface tension → lower compliance

Explanation: Surfactant deficiency increases alveolar surface tension, promotes collapse and reduces compliance, so greater inspiratory effort is required to expand the lungs.

Question:

A premature infant is tachypneic with nasal flaring and intercostal retractions. The infant begins grunting during expiration. Which change is the infant attempting to achieve through this maneuver?

Options:

Correct Answer: Higher pressure at the end of expiration

Explanation: Expiratory grunting helps maintain positive end-expiratory pressure, limiting collapse of surfactant-deficient alveoli between breaths.

Question:

A 31-week newborn develops respiratory distress. Continuous bedside monitoring shows reduced oxygen saturation, but the clinical team also needs to assess ventilation and acid-base disturbance. Which investigation provides the required additional information?

Options:

Correct Answer: Blood gas analysis

Explanation: Blood gas analysis assesses oxygenation together with carbon dioxide and acid-base status, providing information that pulse oximetry alone cannot supply.

Question:

A premature newborn has respiratory distress and diffuse reduction in lung aeration. Chest radiography shows a fine reticulogranular appearance. Which additional radiological finding would support the same underlying process?

Options:

Correct Answer: Air bronchograms within poorly aerated lungs

Explanation: Neonatal RDS can produce diffuse fine reticulogranular or ground-glass opacity with air bronchograms because the alveoli are poorly expanded while larger airways remain air filled.

Question:

A preterm infant with surfactant deficiency remains spontaneously breathing but has recurrent end-expiratory alveolar collapse. Which treatment principle most directly counteracts this mechanical problem without replacing surfactant itself?

Options:

Correct Answer: Maintaining continuous positive airway pressure

Explanation: CPAP provides positive pressure that helps keep unstable alveoli open at end-expiration, directly reducing repeated collapse.

Question:

A premature infant receives exogenous surfactant. Soon afterward, less inspiratory pressure is required to expand the lungs. Which physiological change best explains this response?

Options:

Correct Answer: Reduced surface tension with improved compliance

Explanation: Exogenous surfactant lowers alveolar surface tension, stabilizes alveoli and improves compliance, so less pressure is required to inflate the lungs.

Question:

A preterm newborn with respiratory distress is receiving supplemental oxygen but develops worsening respiratory effort and inadequate gas exchange. Which management step is most appropriate when basic support is no longer sufficient to maintain ventilation?

Options:

Correct Answer: Mechanical ventilatory support when required

Explanation: Severe neonatal respiratory failure may require mechanical ventilation when adequate gas exchange cannot be maintained with less intensive respiratory support.

Question:

A premature newborn with respiratory distress is placed in a thermally controlled environment while respiratory support is arranged. What is the main rationale for this component of supportive management?

Options:

Correct Answer: It limits unnecessary metabolic and oxygen demand

Explanation: Maintaining thermal stability is part of supportive neonatal care because unnecessary heat loss increases metabolic activity and oxygen requirements.

Question:

A student reviews three patients: one has bronchial obstruction with distal lung collapse, another has inflammatory alveolar-capillary injury with protein-rich edema, and a third is a premature newborn with unstable alveoli. Which sequence correctly matches the principal mechanism in each patient?

Options:

Correct Answer: Distal gas absorption → permeability injury → surfactant deficiency

Explanation: Obstructive atelectasis follows absorption of trapped distal gas, ARDS centers on permeability injury, and neonatal RDS primarily results from inadequate surfactant.