Cystic Fibrosis Flashcards
What is cystic fibrosis?
Inherited autosomal recessive disease (genetic)
Result of gene mutation - single gene defect on chromosome 7
Chromosome 7 is responsible for encoding the cystic fibrosis membrane conductance regulator, a transmembrane protein involved in ion transport called cystic fibrosis transmembrane regulating protein (CTFR)
Defect leads to compromise in ion transport called- impairs transport of chloride ions and also affects sodium levels and water in the cell
Affected several organs causing ducts to become obstructed with muscus, leading to inflammation and replacement of damaged cells with connective tissue tissue (scarring)
CTFR protein role -
Cystic fibrosis transmembrane regulating protein
It is a channel proteins (sits within membrane controlling movement of H20 and chloride ions)
When the structure is changed, passage of molecules and ions is blocked
This is the MOST COMMON pathology of cystic fibrosis
There are many more… over 1500 mutations of CTFR gene that produce dif variations of CTFR protein
Defect in CTFR, pathology:
Respiratory disease -
Reps disease - abnormally concentrated fluid in the lungs, leads to viscous secretions in the airways, due to dehydrated airways mucus is not cleared, which predisposes patients to disease and infection.
- can lead to lung scarring
Defect in CTFR, pathology:
High sodium sweat -
Chloride ions not absorbed leading to prevention of sodium absorption
- blood slat level is low, leading to risk of dehydration
Defect in CFTR, pathology:
Pancreatic insuffiency -
Production of enzymes is normal but abnormal ion transport leads to dehydration of pancreatic secretions, and therefore leads to stagnation in pancreatic duct.
Can cause diabetes later in life
Defect in FTR, pathology:
Biliary disease -
Abnormal ion transport reduces water movement in the lumen resulting in concentrated bile which can damage walls of the lumen
Defect in CFTR, pathology:
Infertility-
Male CF patients are often infertile due to absence of vas deferns (tube that transports sperm from testes to urthera)
Females - cervical mucous can be thicker, therefore affecting fertility
Defect in CFTR, pathology:
Cirrhosis of the liver -
Due to abnormality in ion transport
Defect in CFTR, pathology:
Gastrointestinal disease -
Intraluminal water deficiency causes problems with bowel movement - can become constipated for example
Prevalence:
Two carriers have a 1 in 4 chance of having an affected baby, and a 1 in 2 chance that their baby will be a carrier
1 in every 2 Caucasians
Claims 2 lives a week
1 in 2,500 babies are born with CF
Diagnosis of CF
Genetic testing -
History of CF in fam, a partner with CF or child with the condition, they may choose to get carrier testing
Simple mouthwash or blood test can determine if someone is a gene carrier
Often done for people who are thinking of starting a family
Diagnosis of CF
Heal prick test -
Since 2007 in uk all babies born have been screened for CF using this test
Extract a little blood
As a result most children with CF are diagnosed shortly after birth
Diagnosis of CF
Sweat test -
If a baby is suspected to have CF, sweat test can be down as part of follow up.
Due to problems with ion transport, CF patients will have higher concentration of chloride (as salt) ions in sweat.
Sweat test measures this concentration and is done by collecting small amount of sweat from arm or leg.
Symptoms
At birth -
Around 10% babies are born with serious bowel obstruction (meconium ileus)
Meconium is thick, black substance, it is normally passed out in a day or two.
However, CF babies, this is too thick to be passed so causes a blockage in the bowels, surgery often needed to clear this
Some babies show signs of jaundice which are yellowing of the skin eyes and mucus membrane
Symptoms
Lungs -
Persistent cough
Coughing fits
Inflammation in the lungs - wheezing, SOB, difficulties breathing (esp after exercise)
Recurring chest and lung infections
Cross infections - between CF patients
Impaired diaphragm from englarged liver
Symptoms
Digestive system -
Large smelly stool
Malnutrition/poor weight gain/stunted growth
- mucous blocks ducts in pancreas, therefore not enough digestive enzymes reach to digest food, and therefore done gain nutrients due to decreased digestive enzymes
Other symptoms of CF -
Diabetes
Sinusitis
Nasal polyps (fleshy swellings that grow from lining of nose/sinuses)
Arthritis
Osteoporosis
Infertility
Liver failure (tiny bile ducts get blocked by mucus)
Urinary incontinence
Insipiratory muscle atrophy
Delayed puberty
Kyphosis of spine resulting in neck and back pain
Treatment
Medication -
Bronchodilators
Hypertonic saline nets
Antibiotics
Mucolytic (DNAse)
Steroids
Routine vaccinations
Digestive enzymes (Creon)
Treatment
Other treatments (not meds or physio) -
Dietary advice
Education
Exercise
Lung transplant
Psychological support
Patients MUST stay up to date with vaccinations!!!!!
Treatment
Physio -
PD
Percussion, vibes/shakes
ACBT
AD
Adjuncts
Mobilisation/exercise
Suction (ITU)
Prognosis -
No cure or prevention
Currently, half of people with CF with live past age 40
Lung complications are normally the cause of death
Specific QOL depends on specific protein mutation (1500 types) and environmental and development factors
What is gastrointestinal disease?
Intraluminal water deficiency causes problems with bowel movement
Mucolytic such as DNase role -
Used to treat CF patients to help breakdown their thick secretions
