Cystic Fibrosis Flashcards
What is the inheritance pattern of Cystic Fibrosis?
Autosomal Recessive
What is Cystic Fibrosis?
- Multisystem disease although respiratory problems are usually the most prominent.
- Vicious cycle of mucus stasis, inflammation and infection leads to respiratory failure, and death in majority of patient.
- Most patients also have pancreatic insufficiency
- Median survival is around 36 years.
What is the pathophysiology of Cystic Fibrosis of the lungs?
- Mutation of gene leads to abnormalities in production of CTFR protein which is expressed on apical membrane of epithelial cells and acts as chloride channel.
- In lungs, CFTR dysfunction leads to dehydrated airway surface liquid, mucus stasis, airway inflammation and recurrent infection.
- Process originates in small airways, leading to progressive airway obstruction and bronchiectasis
Where is the CF gene located?
CF gene is located on long arm of Chromosome 7.
What are clinical features of Respiratory Cystic Fibrosis?
- Breathlessness
- Nasal Polyps
- Haemoptysis
- Pneumothorax
- Chronic daily cough ad sputum production
- Recurrent Sinusitis and Respiratory Infection
What are clinical features of Gastrointestinal Cystic Fibrosis?
- Meconium Ileus in infancy
- Intestinal Malabsorption
- Distal Intestinal Obstruction syndrome
- Steatorrhea
How is Cystic Fibrosis Screened?
- Screening at birth.
- Test involves measuring immunoreactive trypsinogen at time of neonatal heel prick test.
- If concentration is raised, formal testing is performed
- Test involves measuring immunoreactive trypsinogen at time of neonatal heel prick test.
What are the formal testing criteria for Cystic Fibrosis?
- History of CF in a sibling and
- CFTR functional testing. Sweat test measures chloride concentration and test routinely performed. Normal range is <30 mmol/L and borderline at 3—60 mmol/L OR
- Confirmatory genetic testing OR
- Demonstration of abnormal nasal epithelial ion transportation
What are complications of Cystic Fibrosis?
- Respiratory Infections
- Pancreatic Insufficiency
- Failure to thrive in infancy and low BMI in adults
- Distal Intestinal Obstruction Syndrome (DIOS)
- CF related Diabetes
- CF-related Liver Disease and Cirrhosis
- Respiratory Failure and Cor Pulmonale
- Increased Risk of Gastrointestinal malignancy
- Osteoporosis, Arthropathy
- Male infertility
How are respiratory infection managed in Cystic Fibrosis?
- Needs aggressive therapy with physiotherapy and antibiotics
- Prophylactic antibiotics often given to maintain health
How is Pancreatic Insufficiency managed in cystic Fibrosis?
Needs careful monitoring
- Pancreatic insufficiency can lead to failure to thrive in infamy or Low BMI in adults
- In these patients give pancreatic enzyme replacement therapy
How does DIOS compare to constipation?
- Faecal obstruction in ileocaecum vs Whole bowel
- Due to intestinal contents in distal ileum and proximal colon. Faeces are typically thick and dehydrated
How does DIOS typically occur?
- Most often due to insufficient prescription of pancreatic enzymes or non-compliance.
- Also salt deficiency/hot weather
How is DIOS diagnosed?
Symptoms: Palpable Right Iliac Fossa Mass
AXR: Demonstrates faecal loading at junction of small and large bowel
How is Cystic fibrosis managed?
- Seen every 3 months and annual review.
- Lung function and BMI should be record at every appointment
- Antibiotics for exacerbations
- Mucolytics can be given such as Dornase alfa
- Pancreatic enzyme replacement, Fat soluble vitamin supplements, Urosdeoxylic acid for impaired liver function
