SESSION TYPE: Infectious Disease Student/Resident Case Report Posters II
PRESENTED ON: Tuesday, October 23, 2012 at 01:30 PM - 02:30 PM
INTRODUCTION: The association of mucoid Pseudomonas aeruginosa community-acquired pneumonia (CAP) and cystic fibrosis (CF) is well established, and its presence has been described as pathognomonic of CF. To our knowledge, however, few clinical examples exist in the literature of atypical CF presentations and concurrent infection with this encapsulated subspecies. Here we present the case of a 34-year-old woman with mucoid-variant P. aeruginosa CAP who is a CFTR-ΔF508 carrier.
CASE PRESENTATION: A 34-year-old Caucasian female presents with increasing shortness of breath over the past two weeks, cough, pleuritic chest pain, and subjective fevers. Her past medical history includes previous smoking, multiple pneumonias in her 20s, and non-tuberculous (TB) mycobacterium infection with inconclusive work-up for chronic lung diseases. Upon admission, chest x-ray demonstrated ill-defined opacities involving the right infrahilar region with scattered nodular opacities bilaterally. CT scan showed bronchiectasis, bronchial wall thickening, and ground-glass and nodular opacities in the right middle and right lower lobes. TB and other causes of bronchiectasis were ruled out. Sputum and bronchoalveolar lavage cultures grew mucoid variant Pseudomonas aeruginosa. Subsequent testing revealed heterozygosity for the CFTR-ΔF508 gene. Intravenous tobramycin and cefepime, chest physiotherapy, breathing treatments, and flutter valve therapy were initiated. The patient improved over the next week. Also, the patient had undetectable levels of tobramycin at supratherapeutic doses of 12 mg/kg/day, furthering suspicion for variant CF. The patient was discharged home on intravenous tobramycin for two weeks and oral Azithromycin thrice weekly. Outpatient sweat chloride values were 21 and 24 mmol/L (reference range 0-39).
DISCUSSION: Our patient had carrier status of a common CFTR mutation and unconvincing sweat chloride test, but the presence of a P. aeruginosa encapsulated subtype, raises suspicion of a non-classical presentation. CF diagnosed in adults is more likely to present with Pseudomonas infection than those at younger ages. Adult diagnosed CF is less likely to be distinguished by genetic analysis or sweat testing. Additionally, adult diagnosed CF is more likely heterozygous for ΔF508 with less pulmonary involvement and lower sweat chloride levels. Based on the features above, our case is a plausible non-classical presentation of CF.
CONCLUSIONS: While most cases of CF are confirmed with homozygous CFTR-ΔF508 mutation and elevated sweat chloride levels, a small minority of adult diagnoses are non-classical and demonstrated by other clinical attributes. The high incidence of mucoid P. aeruginosa in confirmed CF justifies clinical suspicion for CF when this pulmonary infection is present.
1) Keating C, Liu X, DiMango E. Classic Respiratory Disease but Atypical Diagnostic Testing Distinguishes Adult Presentations of Cystic Fibrosis. Chest 2010; 137:1157-1163.
DISCLOSURE: The following authors have nothing to disclose: Michael Scott, Nathan Hicks, Patton Thompson, Tanya Wiese, Mohamed Saad
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