Cystic fibrosis Flashcards
What is the carrier rate of CF
1 in 25
What is the inheritance pattern of CF?
Autosomal recessive
How is it diagnosed in the newborn?
Heel-prick bloodspot - Guthrie
How does it present in infancy?
- Meconium ileus
- Prolonged neonatal jaundice
- FTT
- Recurrent chest infections
- Malabsorption and steatorrhoea
What is the pathophysiology behind CF
- Mutation on chromosome 7 which results in defective CFTR protein
- Leads to defective Cl-
airway secretion and increased Na+ absorption causing increased H2O absorption across the epithelium into cells 3. Thickened secretions in a number of organs
What does CFTR stand for
Cystic fibrosis transmembrane regulator
What is the commonest mutation?
F508 deletion mutation
What lung disease does CF ultimately lead to and why?
BRONCHIECTASIS due to recurrent infections and narrowed airways
What are the most common causative organisms of chest infections?
Chronic infections - pseudomonas aeruginosa
What are the resp sx
Cough Wheeze Recurrent inf Bronchiectasis Pneumothorax Haemoptysis Resp failure Cor pulmonale
What are the main features of CF
- Pancreatic insufficiency - DM, steatorrhoea
- Poor weight gain
- Big appetite
- Chronic sinusitus + polyps
- Clubbing
- Male infertility
- Distal intestinal obstruction syndrome
- GORD
What investigations can u do
- Sweat test - Cl >60mmol/L
- Genetic testing
- CXR - hyperinflation, bronchiectasis
- Spirometry - obstructive
- Sputum culture
- GTT, vit levels
How does CF lead to malabsorption?
pancreatic enzyme deficiency due to pancreatic ducts being blocked by thick secretions
What are the main principles of resp management?
- monitor lung function e.g. spirometry and FEV1
- physio - clear secretions
- Abx
- Nebulised DNAse or hypertonic saline to decrease viscosity of sputum
- lung transplant
What types of abx treatment is there for CF?
Continuous and prophylactic
Nebulised antipseudomonal abx for chronic pseudomonas inf.
azithromycin to reduce respiratory exacerbations
