Cystic fibrosis

Cystic fibrosis (CF) is correctly identified as being associated with liver cirrhosis among the options provided. CF is a genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine. It is inherited in an autosomal recessive manner, meaning that an individual must inherit two defective copies of the CFTR gene (one from each parent) to develop the disease. This condition leads to the production of thick, sticky mucus that can clog the airways and trap bacteria, leading to recurrent respiratory infections. In the liver, this mucus can block the bile ducts, leading to liver damage and, over time, cirrhosis.

Liver cirrhosis in CF patients is a result of the chronic injury and fibrosis of the liver tissue. It is a significant complication and can lead to portal hypertension, ascites, and liver failure. The management of liver involvement in CF includes regular monitoring, nutritional support, and potentially liver transplantation in severe cases.

It is important to note that CF is not diagnosed by sputum culture alone. While sputum cultures can identify bacterial infections common in CF, the diagnosis is typically made through genetic testing or sweat chloride testing, which measures the concentration of chloride that is excreted in sweat. This is a hallmark of CF, as the defective CFTR protein leads to abnormal chloride and sodium transport across epithelial cells, resulting in saltier sweat.

Regarding life expectancy, advances in medical care and treatments have significantly improved the outlook for individuals with CF. While the disease used to have a very short life expectancy, many people with CF now live into their 40s and beyond, thanks to early diagnosis, comprehensive treatment plans, and the development of new therapies aimed at the underlying cause of the disease.

In summary, cystic fibrosis is a complex, multisystem genetic disorder that can lead to severe respiratory and digestive system damage, including liver cirrhosis. It is inherited in an autosomal recessive pattern and requires comprehensive management to address its various manifestations and complications. The association with liver cirrhosis highlights the importance of monitoring liver function in CF patients and underscores the systemic nature of the disease.

Cystic fibrosis (CF) is a life-shortening genetic disorder that primarily affects the lungs and digestive system. It is caused by mutations in the CFTR gene, which leads to the production of thick, sticky mucus that can clog the airways and trap bacteria, leading to recurrent respiratory infections, and can also obstruct the pancreas and stop natural enzymes from helping the body break down and absorb food.

Rectal prolapse is indeed a recognized presentation of cystic fibrosis in children. This condition occurs when a child with CF experiences severe constipation or has to strain during bowel movements due to the thick mucus obstructing the intestines. Over time, this straining can cause the rectum to stretch and protrude from the anus. It is important to note that while rectal prolapse can be alarming for parents and caregivers, it is a treatable condition and often improves with the proper management of the child’s cystic fibrosis, including enzyme replacement therapy and nutritional support.

The other options listed, while relevant to discussions on paediatric health, are not as directly associated with cystic fibrosis as rectal prolapse. Bronchiolitis is a common lung infection in young children and infants, not specifically tied to CF. Early passage of meconium can be a sign of CF but is not as common as other digestive symptoms like rectal prolapse. Female sterility can be a complication of CF in adulthood due to thickened cervical mucus, but it is not a presentation in children. Rectal polyps, although they can occur in individuals with CF, are not as characteristic of the disease as rectal prolapse.

Cystic fibrosis (CF) is the most common lethal autosomal recessive disease of Caucasians. In the UK, there is a carrier rate of 1 in 25 leading to the disease affecting approximately 1 in 2500. CF is caused by an abnormal gene coding for the cystic fibrosis transmembrane regulator protein (CFTR), located on chromosome 7. This protein functions as a channel across the membrane. The channel transports negatively charged chloride ions into and out of cells. Cells that produce mucus, sweat, saliva, tears and digestive enzymes are all affected. The most common mutation in CF is the ΔF508 mutation, although well over a thousand different mutations have been identified. The poor transport of chloride ions and water across epithelial cells of the respiratory and pancreas exocrine glands in CF results in an increased viscosity of secretions. The range of presentations is varied, including recurrent chest infections, failure to thrive from malabsorption and liver disease. In the neonatal period, infants may present with prolonged neonatal jaundice, bowel obstruction (meconium ileus) or rectal prolapse.

The gold standard investigation for CF is the sweat test. The abnormal function of sweat glands results in the excess concentration of sodium chloride (NaCl) in sweat. Sweat is stimulated by pilocarpine iontophoresis, collected on filter paper and analyzed.

Normal sweat NaCl concentration = 10−14 mmol/L
Sweat NaCl concentration in CF = 80−125 mmol/L

At least two sweat tests should be performed as diagnostic errors and false positives are common.

Chest X-rays are frequently required in CF to monitor disease progress or during an acute infective episode but would not be diagnostic. Immunereactive trypsin (IRT) is now used as a national screening tool on the neonatal Guthrie card. A raised IRT is strongly suggestive of CF, but the diagnosis still needs to be confirmed with either genetic mutation analysis or a sweat test. Genetic mutation analyses can be used for the pre- or postnatal diagnosis of CF; however, not all mutations have been identified. Nasal potential difference is used to measure the voltage across nasal epithelium, which correlates with the transport of sodium and chloride across cell membranes.