Beyond Tuberculosis: Late Diagnosis of Cystic Fibrosis in an Adolescent with Bronchiectasis and Recurrent Pseudomonas aeruginosa Isolation: A Case Report

Background and Clinical Significance: Cystic fibrosis may remain undiagnosed until adolescence, when recurrent respiratory infections and bronchiectasis are attributed to a previous severe infection. Case Presentation: We report the case of a male adolescent in whom approximately five years elapsed between microbiologically confirmed pulmonary tuberculosis in July 2021 and recognition of cystic fibrosis in August 2026. Archived records documented two sputum specimens that were acid-fast bacilli smear-positive (1+) and culture-positive (1+) for Mycobacterium tuberculosis complex. During adolescence, persistent bronchiectasis, recurrent Gram-negative respiratory infections, digital clubbing, and repeated Pseudomonas aeruginosa isolation prompted etiologic reassessment. A single documented sweat chloride concentration was 114 mmol/L. CFTR analysis of blood collected on 18 August 2026, reported on 16 September 2026, identified homozygous c.1521_1523delCTT (p.Phe508del; F508del), providing molecular confirmation. Spirometry showed FEV1 2.69 L (79.6% predicted), FVC 3.73 L (91.56% predicted), and FEV1/FVC 72.01% (z-score −2.58), consistent with airflow obstruction; without total lung capacity measurements, restriction or a mixed ventilatory defect could not be confirmed. The previously recorded azithromycin regimen was 500 mg orally three times weekly. Tobramycin inhalation solution 300 mg/5 mL was prescribed as one ampoule twice daily for 28 days, followed by 28 days off, with three planned cycles and salbutamol 15 min before administration. Management of cystic fibrosis also included airway-clearance therapy, dornase alfa 2.5 mg once daily, a high-calorie diet, pancreatic enzyme replacement, and vitamin supplementation. Longitudinal post-treatment spirometry, anthropometry, and validated quality-of-life measurements were not available. Conclusions: Previous pulmonary tuberculosis should not terminate etiologic investigation when bronchiectasis, repeated Pseudomonas aeruginosa isolation, digital clubbing, or progressive structural lung disease persists. Earlier recognition may permit earlier coordinated cystic fibrosis care and genotype-appropriate CFTR-modulator assessment.