Cystic Fibrosis Flashcards
What type of genetic disease is cystic fibrosis?
Cystic fibrosis is an autosomal recessive disease.
What is the prevalence of cystic fibrosis in the white population?
Cystic fibrosis is the most common genetically inherited disease in the white population, with an incidence of 1 in 2500 newborns.
What is the underlying abnormality in cystic fibrosis?
Cystic fibrosis is characterized by abnormal chloride and bicarbonate transport due to pathogenic mutations in the CF transmembrane conductance regulator (CTFR) gene.
Which chromosome is the CFTR gene located on?
The CFTR gene is located on chromosome 7.
How do mutations in the CFTR gene contribute to clinical symptoms and signs?
Mutations in the CFTR gene lead to the production of abnormally viscous mucus and secretions in the lungs, bile and pancreatic ducts, and intestines. These obstructions in the lumens result in the clinical symptoms and signs of cystic fibrosis.
What investigations can be done for gastro-oesophageal reflux disease (GORD) in cystic fibrosis?
Blood tests
Oesophagogastroduodenoscopy (OGD) or upper GI tract endoscopy
Why is GORD common in cystic fibrosis?
GORD is common in cystic fibrosis and can present with symptoms such as heartburn, regurgitation, dysphagia (stricture/malignancy), oesophagitis, stricture, and Barrett’s oesophagus, which can lead to malignancy.
What is the management approach for GORD?
Conservative measures: Lifestyle changes such as having smaller meals, chewing food well, leaving 2-3 hours between the last meal and bedtime, raising the head of the bed, avoiding tight-fitting clothing, and avoiding precipitant foods.
Medical management: Proton-pump inhibitors, H2-antagonists (e.g., Famotidine).
Surgical management: Anti-reflux procedures such as fundoplication or Linx procedure.
What are the pancreatic disorders associated with cystic fibrosis?
Pancreatic exocrine insufficiency (PEI)
Pancreatitis
Malignancy
What is pancreatic exocrine insufficiency (PEI)?
Pancreatic exocrine insufficiency is a deficiency of the exocrine pancreatic enzymes, resulting in the inability to properly digest food, leading to malnutrition. It is present in about 2/3 of CF patients and is predominantly characterized by fat malabsorption
What are the symptoms of pancreatic exocrine insufficiency?
Steatorrhea: Frequent, bulky, foul-smelling stools that are difficult to flush or float.
Failure to thrive
Weight loss
Deficiency of fat-soluble vitamins (A, D, E, and K), leading to coagulopathy and bleeding tendencies.
What is the treatment for pancreatic exocrine insufficiency?
Pancreatic Enzyme Replacement Therapy (PERT) with Creon: Typically, 25,000 units with snacks and 50,000 units with main meals.
Proton-pump inhibitors (PPIs) to reduce gastric acid secretion.
Supplementation of fat-soluble vitamins (A, D, E, and K).
What are the consequences of progressive pancreatic damage in cystic fibrosis?
Progressive pancreatic damage can lead to acute or recurrent pancreatitis. Key markers for pancreatic damage include elevated amylase (3 times the upper limit of normal), urinary amylase, and lipase (considered the gold standard). In cases where blood tests are inconclusive, a CT scan can be performed.
How does cystic fibrosis affect the endocrine function of the pancreas?
Dysfunction of the endocrine pancreas in cystic fibrosis can lead to impaired glucose tolerance and CF-related diabetes.
What hepatobiliary diseases are associated with cystic fibrosis?
Hepatobiliary diseases associated with cystic fibrosis include cirrhosis, steatosis, gallstones, and cholangiocarcinoma (although rare). Liver failure can also occur, albeit infrequently.
