A 56-year-old woman with a history of asthma comes to the emergency department due to shortness of breath. The patient's asthma was previously well controlled with inhaled albuterol, but she has had increasing dyspnea over the past several weeks. The symptoms became more severe today, and the patient is coughing up dark-colored sputum. Other medical conditions include hypertension and type 2 diabetes mellitus. The patient has never smoked and drinks alcohol occasionally. Temperature is 37.5 C (99.5 F), blood pressure is 130/74 mm Hg, pulse is 92/min, and respirations are 18/min. Pulse oximetry is 93% on room air. The patient speaks in short sentences and is using accessory muscles of respiration. On physical examination, the trachea is deviated to the right, and there is dullness to percussion on the right. Scattered rhonchi are present bilaterally, and breath sounds are diminished over the right lower lung. Which of the following best explains this patient's physical examination findings?

Question

A 56-year-old woman with a history of asthma comes to the emergency department due to shortness of breath.  The patient's asthma was previously well controlled with inhaled albuterol, but she has had increasing dyspnea over the past several weeks.  The symptoms became more severe today, and the patient is coughing up dark-colored sputum.  Other medical conditions include hypertension and type 2 diabetes mellitus.  The patient has never smoked and drinks alcohol occasionally.  Temperature is 37.5 C (99.5 F), blood pressure is 130/74 mm Hg, pulse is 92/min, and respirations are 18/min.  Pulse oximetry is 93% on room air.  The patient speaks in short sentences and is using accessory muscles of respiration.  On physical examination, the trachea is deviated to the right, and there is dullness to percussion on the right.  Scattered rhonchi are present bilaterally, and breath sounds are diminished over the right lower lung.  Which of the following best explains this patient's physical examination findings?

Quizplus · Accepted Answer

11ec25c8_d2a9_24b6_bc81_b11dd5a91e20_MD0003_00 This patient most likely has an asthma exacerbation complicated by mucus plugging and large-volume, right-sided atelectasis. Asthma exacerbations can be associated with mucus hypersecretion (eg, dark-colored sputum), which can result in formation of a mucus plug in the airways. The resultant airway obstruction causes distal air trapping and prevents additional air from entering that portion of the lungs. The trapped air molecules eventually diffuse into the bloodstream, creating a vacuum that leads to alveolar collapse (ie, atelectasis). As the lung collapses, the trachea and other mediastinal structures are pulled toward the side of the atelectasis. Because collapsed lung has a greater density than air-filled lung, dullness to percussion is also present. In addition, the lack of air flow leads to absent or markedly decreased breath sounds and decreased tactile fremitus. Chest x-ray in large-volume atelectasis typically shows opacification of the affected lung area with ipsilateral mediastinal shifting and rib space narrowing. (Choice B) Bacterial pneumonia typically causes localized lung consolidation with increased density compared to normal air-filled lung. Dullness to percussion is expected. However, because sound conducts more quickly and efficiently through high-density media, the air passing through consolidated lung creates increased-intensity (rather than decreased) breath sounds. (Choice C) Lung hyperinflation, such as occurs with severe emphysema, typically leads to hyperresonance to percussion and decreased breath sounds due to impaired air movement. (Choice D) A large pleural effusion would cause dullness to percussion ipsilateral to the effusion but mediastinal shifting (eg, tracheal deviation) contralateral to the effusion (displacement away from space-occupying pathology), unlike what is seen in this patient. (Choice E) Left-sided tension pneumothorax can cause right tracheal deviation. However, hyperresonance to percussion is expected on the opposite side of the mediastinal displacement. Educational objective: Large-volume atelectasis can result from airway obstruction (eg, mucus plug) and lead to mediastinal displacement toward the side of alveolar collapse. Dullness to percussion and decreased or absent breath sounds are expected over the area of atelectasis.

A 56-Year-Old Woman with a History of Asthma Comes to the Emergency