Cystic Fibrosis Flashcards
What is it?
Autosomal recessive mutation in CFTR gene
What does CFTR do?
Chloride channel
What happens in CF?
What are people with CF prone to? - 2
CFTR dysfunction leads to reduced fluid flow into airways hence the failure of mucus to be cleared as it is really thick.
Recurrent pneumonia and bronchiectasis
What happens in the pancreas?
Pancreatic interlobular ducts become clogged with mucus leading to impaired secretion of digestive enxymes and eventually pancreatic destruction.
What about sweat?
Sweat glands have impaired chloride removal therefore the sweat is salty.
Presentation:
Neonatal problems:
- The main feature of children with CF
- Why do neonates with CF suffer from neonatal meconium ileus?
Respiratory:
- List symptoms
- Why are CF patients at risk of a pneumothorax?
Failure to thrive
Cystic fibrosis causes intestinal secretions to be abnormally thick and sticky, and the secretions stick to the lining of the intestine, causing an obstruction of the small intestine.
Cough
Wheeze
Recurrent bronchiectasis - ALL DUE TO THICK MUCUS CLOGGING LUNGS
Structural impairment and altered airflow dynamics in the lungs of CF patients are considered as the main predisposing factors but also inhaled medications and non-invasive positive pressure ventilation (NIPPV) could increase the risk of pneumothorax.
GI:
- Why do they get steatorrhoea?
- Why do they get DM?
- Why do they get cirrhosis?
Thick mucus also clogs the pancreas and hinders the release of digestive enzymes. About 90 percent of people with cystic fibrosis also develop exocrine pancreatic insufficiency (EPI).
In people with CF, the thick, sticky mucus that is characteristic of the disease causes scarring of the pancreas. This scarring prevents the pancreas from producing normal amounts of insulin; so, like people with type 1 diabetes, they become insulin deficient.
Bile produced by the liver cells becomes stickier than normal and begins to block the small bile ducts. This causes damage and scarring to the surrounding liver tissue (called biliary fibrosis).
GI:
- Why do they get rectal prolapse?
- Why do they get small bowel obstruction?
- Other GI symptoms - 2
Frequent coughing or hard-to-pass stools can occasionally cause rectal prolapse. This means that part of the rectum protrudes, or sticks out, through the anus. About 20% of kids with cystic fibrosis experience this. In some cases, rectal prolapse is the first noticeable sign of cystic fibrosis.
Though the exact mechanism cannot be definitively delineated, we speculate that the increased viscosity and prolonged intestinal transit time, characteristic of CF, resulted in inspissated fecal content in the proximal small bowel, which then acted as a lead point for obstruction.
GORD
PUD
Other signs:
Why do they get nasal sinusitis and polyps?
Why do they get clubbing?
It is the respiratory epithelium that is affected by cystic fibrosis, and that leads to the inflammation and infection that causes harm. Most patients with CF suffer from pansinusitis, inflammation and infection of all the sinuses.
The exact cause of nasal polyps is unknown but allergy, infections, and chronic congestion often play a key role.
Poor lung function causes clubbing in people with CF. When the lungs aren’t working well, the body has trouble pushing enough oxygen through the body, so the areas farthest from the trunk, the fingers, and toes, may become deprived of oxygen.
Other signs:
Why do men become infertile?
Why do they have a higher chance of developing osteoporosis due to Vit D deficiency?
A blockage or absence of the sperm canal, known as the congenital bilateral absence of the vas deferens (CBAVD).
It is a fat soluble vitamin - they can’t absorb fats remember.
Differentials
Immunocomprimised - congenital, HIV
TB
Other cause of bronchiectasis
Investigations:
2 tests specific for CF?
Bedside:
- What bedside test is done to check extent of disease?
- What may be collected for culture?
Bloods: Why do the following: - FBC - U&E - LFT - Clotting - Vitamins ADEK - Glucose tolerance test
Genetic testing showing 2 disease causing mutations
Sweat test
Pulmonary function test (PFT) - spirometry - shows low FEV2/FVC ratio
Sputum culture ========= FBC - WBC in infection U&E - baseline LFT - cirrhosis Clotting - liver damage Vitamins ADEK - malabsorption Glucose tolerance test - pancreatic insufficiency
Investigations:
Why is a CXR done? - 2
What imaging can be used to look for abdominal pathology (e.g. fatty liver, cirrhosis, chronic pancreatitis)?
Looking for hyperinflation due to obstructive nature - Barrel chest
Evidence of bronchiectasis
USS
Management:
Members of the MDT involved?
Consultants Nurses Physiotherapists Dieticians Social workers Psychologists
Management - Respiratory:
Mucus clearance - 2
What about recurrent infections? - 2
What about inflammation? - 2
Targeted therapy that helps lung function and exacerbation frequency - 2
What if all else fails? - 1
What is used to monitor disease and how often?
Long term azithromycin or ibuprofen
Chest physio - postural drainage
Nebulized mucolytics - hypertonic saline
Prophylactic inhaled tobramycin
Long term AB’s
Ivacaftor and lumacaftor - CFTR modulators
Bilateral lung transplant
CXR annually
