Cystic fibrosis
Completed
In progress
Reviewed
What is cystic fibrosis?
Inherited autosomal recessive disorder affecting the CFTR (cystic fibrosis
transmembrane conductance regulator) gene
CFTR gene is located on chromosome 7
The CFTR protein is a gated ion channel protein that allows (negative ions) mainly
Cl- ion movement into and out of cells into the surrounding mucus
This mediates the movement of sodium and water
Clinical features and effects of cystic fibrosis
💨 Chronic airway infection/inflammation resulting in bronchiectasis
(abnormal dilatation of airway from bronchial tissue destruction) and
advancing airway obstruction (sputum overproduction)
Airway surface liquid (ASL): thin layer of mucus which enables the full
extension and wafting motion of cilia (that removes irritants/pathogens
trapped in the mucus) in the airways
Optimal depth of ASL is 7 um
Height and mucus hydration mediated by Na+ absorption and Cl- secretion
Mucus plug formation may occur
Normal Cl- efflux restricts how much Na+ comes into the epithelial
cells
Cl- cannot be transported out of the epithelial cells effectively,
resulting in Na+ hyper-absorption = osmosis of water into the
Cystic fibrosis 1
, epithelial cells (ASL becomes dry (surface dehydration), mucus has
increased viscosity and reduces mucus clearance)
Results in accumulation of bacteria and irritants = infections
and inflammation in airway
A common infection in CF patients is P. aeruginosa
Some bacterial infections make CF patients ineligible for a lung
transplant
🍽 Impaired intestinal and hepatic function
🍬 Pancreatic insufficiency
Loss of more than 90% pancreatic function
About 90% of adult CF patients develop pancreatic insufficiency
Results in steatorrhoea (excess fat excretion in the stool)
Vessels transporting digestive enzymes out of the pancreas become blocked
with mucus, so food is not digested efficiently for absorption
Bicarbonate (a negatively charged digestive enzyme) cannot be properly so
it stays in the pancreas and damages/digests the pancreas
Reduced/ absent exocrine secretion = poor digestion of starch, fat and
protein
Cystic fibrosis-related diabetes may occur from scarring/inflammation of
pancreas = reducing effective insulin production
😰 Abnormal sweat gland function
Individuals with CF can become dehydrated upon physical exertion or being in
a warm environment
Cystic fibrosis 2
Completed
In progress
Reviewed
What is cystic fibrosis?
Inherited autosomal recessive disorder affecting the CFTR (cystic fibrosis
transmembrane conductance regulator) gene
CFTR gene is located on chromosome 7
The CFTR protein is a gated ion channel protein that allows (negative ions) mainly
Cl- ion movement into and out of cells into the surrounding mucus
This mediates the movement of sodium and water
Clinical features and effects of cystic fibrosis
💨 Chronic airway infection/inflammation resulting in bronchiectasis
(abnormal dilatation of airway from bronchial tissue destruction) and
advancing airway obstruction (sputum overproduction)
Airway surface liquid (ASL): thin layer of mucus which enables the full
extension and wafting motion of cilia (that removes irritants/pathogens
trapped in the mucus) in the airways
Optimal depth of ASL is 7 um
Height and mucus hydration mediated by Na+ absorption and Cl- secretion
Mucus plug formation may occur
Normal Cl- efflux restricts how much Na+ comes into the epithelial
cells
Cl- cannot be transported out of the epithelial cells effectively,
resulting in Na+ hyper-absorption = osmosis of water into the
Cystic fibrosis 1
, epithelial cells (ASL becomes dry (surface dehydration), mucus has
increased viscosity and reduces mucus clearance)
Results in accumulation of bacteria and irritants = infections
and inflammation in airway
A common infection in CF patients is P. aeruginosa
Some bacterial infections make CF patients ineligible for a lung
transplant
🍽 Impaired intestinal and hepatic function
🍬 Pancreatic insufficiency
Loss of more than 90% pancreatic function
About 90% of adult CF patients develop pancreatic insufficiency
Results in steatorrhoea (excess fat excretion in the stool)
Vessels transporting digestive enzymes out of the pancreas become blocked
with mucus, so food is not digested efficiently for absorption
Bicarbonate (a negatively charged digestive enzyme) cannot be properly so
it stays in the pancreas and damages/digests the pancreas
Reduced/ absent exocrine secretion = poor digestion of starch, fat and
protein
Cystic fibrosis-related diabetes may occur from scarring/inflammation of
pancreas = reducing effective insulin production
😰 Abnormal sweat gland function
Individuals with CF can become dehydrated upon physical exertion or being in
a warm environment
Cystic fibrosis 2
