Cystic Fibrosis Flashcards
What is cystic fibrosis?
An inherited disease affecting multiple organs.
A genetic mutation results in thickened secretions which commonly leads to recurrent respiratory infections.
Epidemiology
CF is the most common inherited disease in Caucasians.
In the UK there are around 10,600 cases, whereas worldwide there are thought to be around 100,000.
What is the inheritance pattern in CF?
Autosomal recessive
What mutation causes CF?
Chromosome 7 in the CF transmembrane conductance regulator (CFTR) gene.
The most common mutation found in Caucasians is delta-F508 (DF508).
What is the impact of the mutation on chromosome 7 in CF?
CFTR allows efflux of chloride and inhibits influx of sodium.
This keeps sodium and chloride in the lumen, out of the cells.
In CF, increased sodium absorption and abnormal chloride secretion leads to thicker mucus impairing the function of cilia.
What is a risk factor of CF?
Family history
Clinical Features
CF has effects on multiple systems but most commonly presents with respiratory effects.
Present at any age but usually found in new born screening
What does CF cause?
Thickened secretions from lungs
Reduce mucociliary clearance from the bronchi and increased salt concentration leads to impaired bacterial defences.
Subsequently, bacterial colonisation and lung inflammation increases, which can present as recurrent lower respiratory tract infections and bronchiectasis.
Neonatal features
Failure to thrive
Meconium Ileus - bowel obstruction
Rectal prolapse
Respiratory features
Chronic Sinusitis
Nasal Polyps - painless soft growths inside your nose
Symptoms including cough, wheeze, haemoptysis
Recurrent lower respiratory tract infections
Bronchiectasis
Pneumothorax
Cor pulmonale
Respiratory failure
Reproductive features
Male infertility
Diagnosis
Neonatal heel prick day between day 5 and day 9
Sweat test: measure chloride concentration >60mmol/L is abnormal
Faecal elastase: this can provide evidence for abnormal pancreatic exocrine function.
Genetic screening: This can identify CF mutations
History
Respiratory: frequency of infections, cough, sputum (colour, amount), haemoptysis, breathlessness
Pancreatic function: failure to thrive, steatorrhoea, thirst, polyuria
Gastrointestinal: abdominal pain, bloating, vomiting
Difficulty conceiving and irregular menstruation
Medical management
Infective exacerbations
Antibiotics, although for patients with recurrent chest infections prophylactic long-term antibiotics may be prescribed.
Nebulised mucolytics (Dornase Alfa)
Bronchodilators (Inhaled corticosteroids or B2-agonists)
Worsening progressive lung disease is treated with:
Oxygen
Non invasive ventilation
Diuretics if signs of cor pulmonale
Clinical examination
Peripheral signs: finger clubbing, cyanosis
Chest signs: coarse crackles over areas of bronchiectasis
Conservative management
Education about the condition
Fertility and genetic counselling
Dietician
Psychosocial counselling
Chest physiotherapy: postural drainage and active cycle breathing techniques
Screening for complications of Cystic Fibrosis such as osteoporosis
Treatment for progressive respiratory decline
Oxygen
Nocturnal NIV
Lung transplant
Treatment for mucus obstruction
Airway clearance via physiotherapy
Mucolytics
Bronchodilators
Treatment for lung infection
Antibiotics
Treatment for increased inflammation
Azithromycin - antibiotic shown to improve lung function and reduce the number of pulmonary exacerbations in patients with cystic fibrosis
Treatment of pancreatic insufficiency
Replace enzymes
High energy diet
Fat soluble vitamin + mineral supplements
Treatment for type 2 diabetes
Insulin
What is a modulator drug for CF?
Kaftrio - combination of 3 meds,
Common cause of respiratory tract infections in a patient with cystic fibrosis
Pseudomonas, Staphylococcus aureus and Haemophilus influenzae
Vitamin deficiency in cystic fibrosis
Vitamin A, D, E and K
Treatment for pancreatic insufficiency secondary to Cystic Fibrosis
Replacement of enzymes (Creon)
