Case Presentation: A 37-year-old male with a past medical history of chronic sinusitis, gastrointestinal dysmotility, and right upper lobe cavitary pneumonia presented with one week of fevers, five-pound weight loss, and new left-sided chest pain. The patient was using an aerosolized nasal saline spray for chronic sinusitis prior to presentation. Review of systems was positive for cough, acid reflux, nausea, and anorexia, but no sputum production or hemoptysis. On presentation, vital signs were 98F, 125 BPM, BP 108/70, and saturating 97%. The physical exam was notable for cachexia with bitemporal wasting, tachycardia, and coarse breath sounds in the left upper lobe. Initial labs were significant for a leukocytosis to 23.9 K/µL with 87.8% neutrophils, and potassium of 3.1 mmol/L. A chest CT revealed a left upper lobe cavitary pneumonia and the patient was started on vancomycin 750 mg IV every 12 hours, ceftazidime 2g IV every 8 hours, and metronidazole 500mg orally every 12 hours given prior resistance patterns. Nasal endoscopy found no active sinus infection. Bronchoscopy cultures grew resistant Pseudomonas aeruginosa. Antibiotics were adjusted to meropenem 1g IV every 8 hours and azithromycin 500mg orally daily. AFB cultures were positive for Mycobacterium abscessus, though therapy was deferred. The patient completed a 4 week course of meropenem with airway clearance therapy. He remained on both a proton pump inhibitor and anti-histamine for acid-suppression, with outpatient GI referral for further evaluation. Given his chronic sinus infections, repeated cavitary lung infections, and gastrointestinal issues with malnutrition, cystic fibrosis was considered. Sweat chloride testing was positive with chloride concentrations of 76 mmol/L left arm and 69 mmol/L right arm. Genetic testing revealed heterozygous CFTR intron 9 TG/T repeats 11TG/7T : 10TG/7T, previously unreported variants.
Discussion: Cystic fibrosis is caused by mutations in the CFTR gene, leading to impaired chloride absorption, electrolyte imbalance, and thickened secretions. Typically a pediatric disease, 10% of CF cases are now identified in adulthood. Symptoms are similar in the pediatric and adult populations, but phenotypes are typically more mild in adult cases, leading to missed diagnoses. CF is difficult to recognize in adults as symptoms overlap with more common pulmonary, autoimmune, or infectious etiologies. Presentation includes recurrent sinopulmonary infections, often with pseudomonas and non-tuberculous mycobacteria. Gastrointestinal issues, including pancreatic insufficiency, are also common, and can lead to malnutrition.Sweat chloride testing is the screening tool, and when positive genetic testing is pursued. Early recognition of CF has long term implications due to the advent of CFTR modulator therapies, which can drastically alter the disease course. In this patient, the combination of chronic sinus infections, multiple cavitary pneumonias due to Pseudomonas, and chronic GI dysmotility with malnutrition raised suspicion for CFTR dysfunction.
Conclusions: Cystic fibrosis is not exclusive to the pediatric population. Adults with recurrent respiratory infections, chronic sinusitis, or gastrointestinal dysmotility may have atypical CF presentations due to partial CFTR function. Early suspicion and genetic testing are essential, as timely diagnosis allows access to CFTR modulator therapy, which can markedly improve outcomes and quality of life even when treatment is started during adulthood.