A 6-year-old boy has recurrent sinopulmonary infections, chronic otitis media, and bronchiectasis. Examination shows dextrocardia, and imaging confirms situs inversus totalis with nasal polyps. The defect responsible for this constellation lies in:

• A CFTR chloride channel dysfunction
• B Dynein arm defects of respiratory cilia ✓
• C Alpha-1 antitrypsin deficiency
• D IgA deficiency

Explanation

Kartagener syndrome is primary ciliary dyskinesia caused by defective dynein arms producing immotile cilia. Impaired mucociliary clearance causes sinusitis, otitis media, bronchiectasis, and, because embryonic nodal cilia are also affected, situs inversus in about half of cases. CFTR defects cause cystic fibrosis without situs inversus, and alpha-1 antitrypsin deficiency causes emphysema and liver disease, neither of which explains dextrocardia.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.