Cystic Fibrosis Flashcards
How common is being a CF carrier?
1 in 25
What gene type is CF?
Autosomal recessive
What is the incidence of CF?
1 in 2000-2500
How many different mutations of the CF gene are there?
2000
Which chromosome is the CF gene on?
Long arm of chromosome 7
What systems are affected by CF?
Respiratory - airway epithelial cells Pancreatic - insufficiency and diabetes Liver - disease, hypertension, gallstones Intestines Bones - osteoporosis Reproductive
Why are males with CF usually infertile?
Congenital absence of vas deferens
Which gene is mutated and what does it code for?
Cystic fibrosis transmembrane conductance regulator (CFTR)
Codes for an apical membrane protein that regulates the hydration of sweat, digestive juices, airways, mucus
Does bronchiectasis occur often?
Yes
What cells are lost in the pancreas and what does this cause?
Islets of Langerhans - responsible for making insulin so CF related diabetes occurs
How is mucus affected?
Abnormally viscous, cilia can’t clear it
Why is sweat salty?
Sweat is secreted with high Na+ and CL-, but the duct is impermeable to water absorption so sweat has a high salt content
Why are there thick viscous secretions?
Thick mucous
High levels of extra cellular DNA are released from degenerating neutrophils and accumulate in airways in response to infection/inflammation
Prior events to CF
Family history Symptoms often appear in infancy Bowel obstruction in newborn Thick, sticky mucus Frequent chest infection
What is the median age of death?
25.6 years
predicted survival 35-40
What do most CF sufferers die from?
Respiratory failure
What medication is given?
Nebulised antibiotics IV antibiotics DNase Dietary supplements - vitamins Pancreatic enzymes Insulin Physiotherapy
Symptoms
coughing sputum productions shortness of breath chronic lung infection repeated chest exacerbations abnormal bowel motions reduced vision weight loss
Why is a chest x ray useful?
Lobe of lung may have collapsed due to thick secretions
Clinical signs
salt skin poor growth poor weight gain Increased cough Poor absorption of nutrients coughing up blood finger clubbing fatty stools crackles
Why do patients lose weight?
infection and pancreatic malabsorption
What causes loss of vision?
Vitamin A deficiency - fat soluble vitamin
Primary and secondary prevention
Genetic counselling antenatally
Proactive treatment f airway infection
Encouragement of good nutrition and active lifestyle
cure for 2-4% patients
