A 22-year-old woman comes to the office due to worsening cough. The patient has been coughing every day for the past several months, but over the last 4 weeks, the cough has worsened, with increased amounts of thick sputum and shortness of breath. Streaks of blood have been present in the sputum on several occasions. The patient also has a history of chronic sinusitis and repeated hospitalizations for airway infections. She takes pancreatic enzyme supplements for chronic diarrhea. She does not use tobacco, alcohol, or illicit drugs. Physical examination reveals nasal polyps, a barrel-shaped chest, bilateral coarse lung crackles, and digital clubbing. Chest x-ray shows hyperinflated lungs and dilated, thickened airways. Sputum culture from this patient is most likely to yield which of the following organisms?

Question

A 22-year-old woman comes to the office due to worsening cough.  The patient has been coughing every day for the past several months, but over the last 4 weeks, the cough has worsened, with increased amounts of thick sputum and shortness of breath.  Streaks of blood have been present in the sputum on several occasions.  The patient also has a history of chronic sinusitis and repeated hospitalizations for airway infections.  She takes pancreatic enzyme supplements for chronic diarrhea.  She does not use tobacco, alcohol, or illicit drugs.  Physical examination reveals nasal polyps, a barrel-shaped chest, bilateral coarse lung crackles, and digital clubbing.  Chest x-ray shows hyperinflated lungs and dilated, thickened airways.  Sputum culture from this patient is most likely to yield which of the following organisms?

Quizplus · Accepted Answer

Cystic fibrosis (CF) is a progressive, fatal illness characterized by the development of thick, viscous, clogging secretions in a multitude of organs. Young adults with CF typically have several manifestations of the disorder, including pancreatic insufficiency (eg, diarrhea), chronic sinusitis, nasal polyps, and chronic bronchitis (eg, long-standing productive cough, hyperinflated lungs, barrel chest). However, persistent lower respiratory tract infection is the major source of morbidity and death. Early in the course of the disease, thick airway secretions obstruct mucociliary clearance and lead to the colonization of the lower respiratory tract with pathogenic bacteria. Although Haemophilus influenzae and Staphylococcus aureus are seen in children with CF, Pseudomonas aeruginosa is the major pathogen in adults. This organism forms a biofilm and switches to a mucoid phenotype to prevent its full elimination (even with antibiotics). Neutrophils respond by releasing elastase, myeloperoxidase, and reactive oxygen species, but these compounds are insufficient to clear the infection and progressively destroy the walls of the airway, leading to bronchiectasis and respiratory decline. (Choice A) Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity reaction to Aspergillus fumigatus that primarily manifests with asthma-like symptoms. Although ABPA can occur in patients with CF, it is far less common than Pseudomonas lower respiratory infections. (Choice B) Moraxella catarrhalis is an upper respiratory pathogen that frequently causes otitis media, sinusitis, bronchitis, and laryngitis. Although this organism is a common cause of exacerbations of chronic obstructive pulmonary disease, it is not a frequent colonizer of patients with CF. (Choice C) Mycobacterium tuberculosis infections can cause coughing for several weeks or months and, occasionally, hemoptysis. However, thick sputum production is uncommon. In addition, chest x-ray typically reveals cavitary lesions in the upper lobes. (Choice E) Streptococcus pneumoniae is the leading cause of community-acquired pneumonia and a frequent underlying pathogen in sinusitis, bronchitis, and otitis media. It is not a typical cause of persistent infection in patients with CF. Educational objective: In patients with cystic fibrosis, pathogenic bacteria colonize the respiratory tract early in the disease course. The leading pathogen in adults is Pseudomonas aeruginosa, which forms a thick biofilm to prevent its full elimination from the body.

A 22-Year-Old Woman Comes to the Office Due to Worsening