MEDizzy - A 51-year-old woman presents complaining of a daily cough

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Disorders of the Respiratory System and Critical Care Illness

A 51-year-old woman presents complaining of a daily cough productive of thick green sputum. The cough is worse when she first wakes in the morning. At this time, there are occasionally streaks of blood in the sputum. Her cough began about 7 years ago and has been progressively worse with the production of the increasing volume of sputum. She currently estimates that she brings up about half a cup of sputum daily. She reports frequently requiring antibiotics for both lower respiratory tract infections as well as sinus infections. Bilateral coarse crackles are heard in the lower lung zones. No clubbing is present. Pulmonary function tests demonstrate an FEV1 of 1.68 L (53.3% predicted), FVC of 3.00 L (75% predicted), and FEV1/FVC ratio of 56%. A sputum culture grows Pseudomonas aeruginosa. What test would you perform next in the evaluation of this patient?

ExplanationBronchiectasis is a common disorder that refers to an irreversible dilation of the airways that affects the lung in a focal or difuse pattern. Historically, bronchiectasis has been characterized pathologically as cylindrical, varicose, or cystic in nature. There are numerous causes of bronchiectasis including infectious, inherited, immunologic, and idiopathic causes. The most common cause of bronchiectasis worldwide is postinfectious following tuberculosis infection. However, in developed countries, other causes are more common. The most common cause in developed countries is cystic fibrosis (CF); CF patients develop clinically signifcant bronchiectasis in late adolescence or early adulthood. Most children with CF are diagnosed currently through newborn screening programs, which were introduced in all states within the past decade. However, adults may continue to present with milder forms of the disease, so clinicians should continue to have a high degree of clinical suspicion for CF when an individual presents with a new diagnosis of bronchiectasis. Epidemiologically, individuals presenting with CF bronchiectasis will typically be younger than individuals with non-CF bronchiectasis. In contrast, non-CF bronchiectasis more commonly affects nonsmoking women older than 50 years. The clinical presentation of bronchiectasis is a daily cough productive of thick tenacious sputum. Physical examination demonstrates both crackles and wheezing on examination. In CF, the disease findings are more predominant in the upper lobes, whereas in certain other causes (chronic aspiration, immunoglobulin deficiency), there is a lower lobe predominance. Clubbing is variably present and generally only seen in more advanced diseases. The diagnosis of bronchiectasis is determined by the presence of the disease on chest CT imaging. Chest radiography is not sensitive to the diagnosis of bronchiectasis, particularly early in the disease process. It may show “tram tracks” indicating dilated airway. Chest HRCT is the diagnostic modality of choice for confirming diagnosis. Findings include a demonstration of dilated, nontapering airways that may be filled with mucus. In addition, signet-ring signs may also be seen where the airway is greater than 1.5 times the size of the adjacent blood vessel. Other findings include bronchial wall thickening, inspissated secretion with a “tree-in-bud” pattern, and cysts emanating from the bronchial wall. Once bronchiectasis has been confirmed on CT imaging, other tests may be indicated in this patient to determine the etiology of the bronchiectasis. Testing should be guided by the history and physical examination and may include sputum culture for mycobacteria and fungal organisms, immunoglobulin levels, autoimmune panel, sweat chloride testing, nasal nitric oxide testing (for primary ciliary dyskinesia), bronchoscopy, and/or tests of swallow function. Despite thorough evaluation, in as many as 25%–50% of individuals referred for workup of bronchiectasis, no specific cause is ever identified.