Autosomal recessive
1 in 2 500 – 3 300 live births
1 in 19 carry the gene in
heterozygous form
70% of cases caused by the F508 mutation on the long arm of
chromosome 7
Cystic fibrosis transmembrane regulator (CFTR) gene
Abnormal regulation of sodium and chloride channels
Chloride movement seems most important in aetiology
700 other mutations account for 30% of cases
Carrier screening is available
Exocrine gland dysfunction
Excessive sodium chloride secretion by sweat glands
Blockages caused by secretion accumulation
Increased viscosity of pancreatic and lung secretions
Viscid mucous plugs in the pancreatic ducts cause atrophy
and secondary fibrosis of the pancreas
Failure of pancreatic secretions
Respiratory sputum is viscid and difficult to cough up
Patchy areas of bronchial obstruction
Stasis – infection
Anterior-posterior diameter of chest increased
Widespread emphysema
Reduced air entry
Expiration prolonged
Crepitations
Possible bronchospasm
Small areas of consolidation due to bronchopneumonia
Diffuse bronchiectasis – chronic dilation and
destruction of the bronchial walls
Eventual cor pulmonale
Bile ducts may become plugged by viscous secretions of bile
Biliary cirrhosis
Portal hypertension
Thicker and more viscous than normal
Duodenal secretions will show reduced or absent pancreatic
secretions
A form of intestinal obstruction in the newborn
Causes by a viscous meconium plug in the small bowel
Caused by the absence of trypsin which normally digests and
softens the meconium
Occurs in children of all ages
Gumlike masses in the caecum can obstruct the bowel causing
nausea, vomiting and pain
90% of sufferers have a malabsorption syndrome
Caused by lack of pancreatic secretions
Bulky, pale, greasy, foul smelling stools several times
daily
Progressive wasting
Appetite may be increased
Prolapse of the rectum occurs in 25% of patients, usually in
the first 3 years of life
Frequent coughing
Cyanosis
Dyspnoea
Finger clubbing
Recurrent respiratory infections
Infections may begin in early infancy or later at 2 –
3 years
Blood streaking in mucus usually indicates infection
Pneumothorax may occur in advanced disease
Progressive disability due to respiratory insufficiency
May be dry with predisposition to infections
Retarded growth
Delayed puberty
Ongoing partial intestinal obstruction due to tenacious
faeces
Diabetes mellitus may develop from pancreatic fibrosis
Depends very much on treatment
There is a variation in level of severity
Death may occur from GI obstruction shortly after birth
98% of males are sterile due to blockage of the vas deferens
Women have sub-fertility due to thick cervical secretions
Prompt and aggressive treatment of infections
Intravenous and aerosolised antibiotics
Staphylococcus aureus and H. influenze Pseudomonas
aeruginosa are common organisms
Aerosols of mucolytics – recombinant human
deoxyribonuclease (DNase)
Humidified oxygen during acute episodes
Note - many of these children retain CO2
Daily ibuprofen slows rate of decline in pulmonary function
Do not nurse two together
Transplantations
Pancreatin, powdered or in tablets or
capsules - Titrated dose
Reduced appetite is often a sign of improved digestion
Well balanced high protein, high calorie – but
possibly reduced fat
150% of RDA is often needed for normal growth
Vitamin supplements may be needed
Treat constipation and obstruction with osmotic and other
laxatives
Prevent constipation / obstruction with a stool softener,
bulky diet and mild stimulant
Give adequate salt to prevent hypochloraemic and
hyponatraemic alkalosis
Plenty of salt in hot weather or when febrile
Cystic fibrosis society and local groups