Description
Kartagener syndrome (KS), also known as immotile cilia syndrome, is a rare, autosomal recessive disorder characterised by the triad of situs inversus, chronic sinusitis, and bronchiectasis. It is a type of primary ciliary dyskinesia, where defects in the structure and function of cilia lead to impaired mucociliary clearance.
Pathogenesis
The primary defect in Kartagener syndrome lies in the dynein arms of the cilia, which are responsible for ciliary movement. Mutations in several genes, including DNAI1 and DNAH5, have been associated with KS. These mutations result in abnormalities in cilia structure and function, leading to impaired mucociliary clearance and characteristic clinical features.
Epidemiology, Risk Factors & Associations
- Prevalence is estimated to be approximately 1 in 30,000 individuals.
- It is an autosomal recessive disorder, so both parents must be carriers of a mutation for a child to be affected.
- No known associations with other conditions or risk factors, beyond genetic predisposition.
Clinical Features
- Chronic sinusitis: Persistent inflammation of the sinuses leading to nasal congestion, rhinorrhoea, and sinus pain.
- Bronchiectasis: Chronic cough, dyspnoea, and recurrent chest infections due to impaired clearance of mucus from the bronchi.
- Situs inversus: Organs on the opposite side of the body than usual; often asymptomatic but can occasionally lead to confusion in diagnosis of abdominal or thoracic conditions.
- Infertility in males due to immotile sperm and subfertility in females due to impaired transport of the ovum.
Complications
Potential complications include recurrent respiratory infections leading to progressive lung damage, hearing loss due to chronic middle ear infections, and infertility.
Subtypes
As a subtype of primary ciliary dyskinesia, there are no further subtypes of Kartagener syndrome.
Pathological Features
Morphology
Microscopic examination of respiratory epithelium may show reduced or absent cilia.
Histopathology
In cases of bronchiectasis, expect to see dilated and thickened bronchi with chronic inflammatory changes.
Biochemistry/Genetics
Mutations in genes such as DNAI1 and DNAH5 disrupt the formation and function of cilia.
Radiological Features
Chest X-ray/CT
- Evidence of bronchiectasis and situs inversus. CT may show more detailed features of bronchiectasis such as bronchial wall thickening and dilatation.
Abdominal Ultrasound/CT
- Situs inversus with ‘mirror-image’ positioning of abdominal organs.
Grading and Staging
There is no specific grading or staging system for Kartagener syndrome.
Differential Diagnosis
The differential diagnosis includes other causes of bronchiectasis such as cystic fibrosis and non-tuberculous mycobacterial infection, other causes of sinusitis, and conditions that can mimic situs inversus such as congenital diaphragmatic hernia.
Management
Management primarily focuses on symptom relief and prevention of complications. This may include physiotherapy and postural drainage to aid mucus clearance, regular sinus irrigation, antibiotics for infection management, and hearing aids or cochlear implants for hearing loss. In severe cases of bronchiectasis, lung transplantation may be considered. Genetic counselling is advised for affected individuals and their families.