A 29-year-old man presents for the evaluation of infertility. He has a history of recurrent lower respiratory tract infections, productive cough, abdominal pain, and diarrhea. Physical examination reveals clubbing and bilateral crackles on chest auscultation. Chest X-ray reveals increased pulmonary markings and peripheral bronchi with a ‘tram track’ appearance. Which of the following pathophysiologies is responsible for the patient’s condition?

Fibrosis of the lung parenchyma

A 28-year-old man presents to his primary care provider because of shortness of breath, cough, and wheezing. He reports that in high school, he occasionally had shortness of breath and would wheeze after running. His symptoms have progressively worsened over the past 6 months and are now occurring daily. He also finds himself being woken up from sleep by his wheeze approximately 3 times a week. His medical history is unremarkable. He denies tobacco use or excessive alcohol consumption. His temperature is 37.1°C (98.8°F), blood pressure is 121/82 mm Hg, and heart rate is 82/min. Physical examination is remarkable for expiratory wheezing bilaterally. Spirometry shows an FEV1 of 73% of predicted, which improves by 19% with albuterol. In addition to a short-acting beta-agonist as needed, which of the following is the most appropriate therapy for this patient?

A low-dose inhaled corticosteroid and a long-acting beta-agonist

A high-dose inhaled corticosteroid and a long-acting beta-agonist

A long-acting beta-agonist alone

A low-dose inhaled corticosteroid alone

A medium-dose inhaled corticosteroid and a long-acting beta-agonist

A 52-year-old man comes to the physician because of a 6-month history of shortness of breath and nonproductive cough. He has smoked 1 pack of cigarettes daily for 15 years. Cardiopulmonary examination shows fine inspiratory crackles bilaterally. There is clubbing present in the fingers bilaterally. Pulmonary function tests (PFTs) show an FVC of 78% of expected and an FEV1/FVC ratio of 92%. A CT scan of the chest is shown. Which of the following is the most likely underlying diagnosis?

Chronic obstructive pulmonary disease

A 51-year-old woman is brought to the emergency department because of an aggressive cough with copious amounts of thick, foamy, yellow-green sputum. She says she has had this cough for about 11 years with exacerbations similar to her presentation today. She also reports that her cough is worse in the morning. She was evaluated multiple times in the past because of recurrent bouts of bronchitis that have required treatment with antibiotics. She is a non-smoker. On physical examination, the blood pressure is 125/78 mm Hg, pulse rate is 80/min, respiratory rate is 16/min, and temperature is 36.7°C (98.0°F). Chest auscultation reveals crackles and wheezing over the right middle lobe and the rest of her physical examinations are normal. The chest X-ray shows irregular opacities in the right middle lobe and diffuse airway thickening. Based on this history and physical examination, which of the following is the most likely diagnosis?

Chronic obstructive pulmonary disease

Bronchiectasis for USMLE Step 2 CK: High-Yield Internal Medicine Lessons

Pathophysiology & Etiology - Vicious Cycle of Damage

Core Mechanism: A self-perpetuating cycle of inflammation, infection, and airway injury.
Primary Causes:
- Cystic Fibrosis: Most common cause in the US (~50% of cases).
- Post-Infectious: H. influenzae, Pseudomonas, NTM, Aspergillus, viral.
- Immune Defects: Allergic Bronchopulmonary Aspergillosis (ABPA), hypogammaglobulinemia.
- Congenital: Primary Ciliary Dyskinesia (e.g., Kartagener syndrome).
- Airway Obstruction: Tumor, foreign body.

⭐ In non-CF patients, infection is the most frequent underlying cause of bronchiectasis.

CT Chest: Bronchiectasis with signet ring sign

Clinical Features & Diagnosis - The Telltale Cough

Persistent, productive cough: The hallmark feature. Produces copious, purulent, often foul-smelling sputum daily for months to years.
Other common findings: Dyspnea, rhinosinusitis, fatigue, and intermittent, sometimes massive, hemoptysis. Digital clubbing may be seen in severe disease.
Diagnosis: High-resolution CT (HRCT) is the gold standard imaging test.
- Key HRCT signs: ↑ broncho-arterial ratio >1 ("signet ring" sign), and lack of airway tapering ("tram tracks").
Pulmonary Function Tests (PFTs): Typically show an irreversible obstructive pattern (↓ FEV1/FVC ratio <0.7).

⭐ Prognostic Pearl: Sputum cultures are crucial. Chronic colonization with Pseudomonas aeruginosa is associated with more frequent exacerbations, accelerated lung function decline (↓FEV1), and increased mortality.

Management - Clearing the Airways

Goal: Break the vicious cycle of mucus stasis → infection → inflammation.
Airway Clearance Therapy (ACT): Cornerstone of daily management.
- Perform 1-2 times daily; increase frequency during exacerbations.
- Methods: Chest physiotherapy (postural drainage, percussion), oscillating positive expiratory pressure (OPEP) devices, or high-frequency chest wall oscillation (HFCWO) vests.
Pharmacologic Adjuncts:
- Bronchodilators (SABA): Administer before ACT to open airways.
- Mucoactive Agents: Inhaled hypertonic saline (3-7%) to thin mucus.

⭐ Routine inhaled corticosteroid use is NOT recommended without comorbid asthma/COPD, due to an increased risk of nontuberculous mycobacterial (NTM) infection.

High‑Yield Points - ⚡ Biggest Takeaways

Bronchiectasis is an irreversible, permanent dilation of the bronchi, most commonly caused by cystic fibrosis in the US.

Other key causes include allergic bronchopulmonary aspergillosis (ABPA) and Kartagener syndrome.

Presents with a chronic cough producing large volumes of purulent, foul-smelling sputum; hemoptysis is frequent.

High-resolution CT (HRCT) is the diagnostic gold standard, revealing "tram tracks" and the "signet ring" sign.

Management focuses on airway clearance and treating underlying infections.

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Bronchiectasis