Breathe Easy in 2026: Ace the Respiratory CAS Test with Confidence!

The key idea is impaired mucociliary clearance due to dysfunctional motile cilia, which leads to chronic sinusitis and recurrent lower airway infections that can progress to bronchiectasis. When this ciliary dysfunction is present with abnormal left-right body symmetry (situs inversus), the classic presentation is Kartagener’s syndrome, a subset of primary ciliary dyskinesia.

In a child with recurrent sinus infections and bronchiectasis, Kartagener’s syndrome fits best because the combination of chronic upper airway disease and bronchiectasis accompanied by situs inversus (dextrocardia or reversed organ positioning) is highly characteristic. This distinguishes it from other causes: cystic fibrosis commonly has gastrointestinal features like pancreatic insufficiency and growth issues; alpha-1 antitrypsin deficiency tends to cause early emphysema rather than a sinusitis/bronchiectasis pattern in children; primary immunodeficiencies cause recurrent infections but don’t typically present with situs inversus.