Solve this mcq with reason as I am preparing for fcps part 1 anesthesiology
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Answer: B) Primary Ciliary Dyskinesia (Kartagener Syndrome)
The Classic Triad
The question presents the Kartagener triad, which is a subset of Primary Ciliary Dyskinesia (PCD):
| Feature | This Patient |
|---|---|
| Situs inversus | ✅ |
| Recurrent sinusitis | ✅ |
| Bronchiectasis | ✅ |
This is a textbook-perfect presentation of Kartagener syndrome — all three defining features are present simultaneously in a young patient.
Pathophysiology (Why This Happens)
PCD/Kartagener syndrome is caused by absent or defective dynein side arms on the A-tubules of cilia and flagella. Dynein is the motor protein that drives ciliary beating.
- Without functional dynein → cilia are immotile or dyskinetic
- Immotile cilia → failure of mucociliary clearance → recurrent sinusitis and bronchiectasis
- During embryogenesis, normal ciliary beating at the embryonic node determines left-right body asymmetry. Defective cilia → random (50%) chance of situs inversus
- Inheritance: autosomal recessive (mutations in DNAI1, DNAH5, and others)
- Men are also often infertile due to immotile spermatozoa (flagella share the same dynein defect)
Why the Other Options Are Wrong
A) Cystic Fibrosis (CF)
- CF causes bronchiectasis and sinusitis, but does NOT cause situs inversus — this is the disqualifying feature
- CF is caused by CFTR chloride channel mutation, not a ciliary defect
- CF has pancreatic insufficiency, high sweat chloride, and GI involvement — none mentioned here
C) Alpha-1 Antitrypsin Deficiency
- Causes emphysema/COPD (panacinar) and liver disease
- Can occasionally cause bronchiectasis, but never situs inversus
- Typically presents later in life with airflow obstruction
D) Allergic Bronchopulmonary Aspergillosis (ABPA)
- Associated with asthma or CF
- Causes central bronchiectasis but never situs inversus
- Has eosinophilia, elevated IgE, positive Aspergillus serology
High-Yield Mnemonic for FCPS
Kartagener = KSB → Kartagener = Situs inversus + Bronchiectasis + Sinusitis Caused by absent dynein arms → immotile cilia → "everything goes wrong"
The key discriminator in this question is situs inversus — this feature immediately locks in Kartagener/PCD and excludes all other options.
— K.J. Lee's Essential Otolaryngology; Goldman-Cecil Medicine
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