Foundations · Year 1 · from Foundations
Case 2: Primary Ciliary Dyskinesia (Cytoskeleton Disorder)
Clinical Image
Source: Radiopaedia - Kartagener syndrome - CC BY-NC-SA 3.0
Case Presentation
A 12-year-old boy presents with a history of chronic productive cough, recurrent sinusitis, and multiple episodes of pneumonia since infancy. His mother mentions that his heart was found to be on the right side during a routine checkup. Physical examination reveals dextrocardia on auscultation and bronchial breath sounds in the lower lung fields. Chest X-ray confirms situs inversus totalis with dextrocardia and bronchiectasis. Nasal nitric oxide levels are markedly reduced. Electron microscopy of nasal cilia brushings shows absence of outer dynein arms, confirming primary ciliary dyskinesia (Kartagener syndrome). The ciliary defects impair mucociliary clearance, leading to chronic respiratory infections. The situs inversus occurs because nodal cilia, which normally establish left-right body asymmetry during embryogenesis, are non-functional. Management includes airway clearance techniques, prompt antibiotic treatment of infections, and monitoring for progressive bronchiectasis.
Key Learning Points
- Primary ciliary dyskinesia results from defects in dynein motor proteins or other ciliary components, demonstrating the importance of cytoskeletal motor proteins
- The triad of situs inversus, chronic sinusitis, and bronchiectasis defines Kartagener syndrome (50% of PCD cases)
- Cilia are microtubule-based structures whose beating requires dynein motors - the same proteins that drive intracellular transport