Getting the Diagnosis

Now that cystic fibrosis has become much more understood in the medical world, the importance of testing for this disease at a very young age has also been recognized. All states in the US, therefore, screen all newborns for CF. Typically, this is done with a genetic test and/or a blood test. The genetic test is able to determine if the newborn's CFTR genes are working properly and the blood test is able to check the function of the pancreas.

If either one of these tests suggest that the newborn may have cystic fibrosis, your healthcare provider will then want to confirm this by using a sweat test. This is one of the most accurate ways to get a confirmation of a cystic fibrosis diagnosis. The provider will try and get the newborn to sweat in a small patch on either their arm or leg by rubbing a sweat-producing chemical on an area of skin. Once the newborn has begun sweating, they will apply an electrode which will cause a mild electrical current to run through the skin, which helps get the medication into the skin and initiate sweating. The provider will then collect and analyze a small sample of the sweat. Specifically, they will be measuring the amount of salt in the sweat. If high levels of salt are observed, this can confirm the diagnosis for cystic fibrosis.

At this point, the provider may want to order a series of other tests. There may be more genetic tests to determine the exact type of CFTR gene mutation, which can help the patient and caregivers understand what the progression of their type of CF may look like. A chest X-ray can also be beneficial to look at the inflammation level in the lungs (since this is the most common problem with CF). A sinus X-ray may also be ordered to check the level of sinus infections, another common CF complication. Lung function tests can help your provider see how well the lungs are providing oxygen to the blood. Finally, a sputum culture (where the provider will take a sample of spit/mucus) will help determine whether or not there is bacteria present in the lungs (especially Pseudomonas aeruginosa). If this bacteria is present, it indicates that the cystic fibrosis has advanced and that a more aggressive treatment will be needed.

Cystic fibrosis can also be detected during pregnancy through prenatal testing. This will include amniocentesis and chorionic villus sampling. In amniocentesis, a small hollow tube will be inserted into the uterus through the abdomen. They will then take a sample of some of the amniotic fluid surrounding the baby to test for CFTR gene mutations. With chorionic villus sampling, a small tube is inserted up through the vagina and past the cervix into the placenta. A small piece of placenta will be taken and tested for CFTR gene mutations.

Finally, if you are worried that you may be a carrier for cystic fibrosis, you can be tested by a genetics counselor. They will take either a blood or saliva sample and can determine if you carry the malfunctioning CFTR gene.

References:
How Is Cystic Fibrosis Diagnosed? (2013, December 26). Retrieved January 31, 2015, from http://www.nhlbi.nih.gov/health/health-topics/topics/cf/diagnosis

Cystic fibrosis. (2012, June 13). Retrieved January 31, 2015, from http://www.mayoclinic.org/diseases-conditions/cystic-fibrosis/basics/tests-diagnosis/con-20013731

What's Happening Inside the Body

Cystic fibrosis can be a difficult disease to understand; it is not uncommon to be completely overwhelmed by all of the medical jargon and have a difficult time understanding exactly what is happening to you or a loved one. However, all of the problems that occur with CF come down a mutation in a single gene: the cystic fibrosis gene. This gene is responsible for the protein transmembrane conductance regulator (CFTR) gene. When the CF gene can't function properly, neither can the CFTR gene. Most of the problems seen with CF arise from this CFTR gene not working correctly. However, just because it can be identified that somebody has a defect with their CF gene and their CFTR gene does not mean we can tell what their disease will look like. All CFTR gene mutations look very different, which is one of the reasons why no two cystic fibrosis cases are exactly alike. So far, there have been 1,893 different CFTR mutations identified.

When the CFTR gene is not working like it should, there will be problems with chloride-transport across the surface of cells (specifically mucosal cells). This decreased secretion of chloride leads to an increased reabsorption of sodium and water, which leaves the mucus much more sticky than normal. This sticky mucus can attract bacteria which makes the person prone to infection and inflammation. This stickiness of the mucus is also what makes it so difficult to clear from the body.

The two most common complications experienced by cystic fibrosis patients are lung disease and intestinal disease. Typically, it is the severity of these two diseases that determine how long an individual can live with CF. Typically, with lung disease it will progress from bronchitis, to bronchiolitis, to bronchiectasis. This will eventually lead to cor pulmonale (abnormal enlargement of the right side of the heart) and end-stage lung disease. The cause of death is usually respiratory failure or cor pulmonale in an individual with cystic fibrosis.

References: 

Sharma, G. (2014). Cystic Fibrosis. Medscape. 

Cystic Fibrosis in the United States

According to the Cystic Fibrosis Foundation, about 1,000 new cases of CF are diagnosed each year (around 1 in every 3,500 births). Additionally, 10 million people (about 1 in every 31 Americans) are symptomless carriers for CF. More than 75% of these diagnoses are in patients under the age of 2 years. Currently in the US, about 40% of the CF population is age 18 or older. Right now, it is estimated that 30,000 people in the United States suffer from cystic fibrosis. This statistic makes it the most common lethal genetic disorder among the Caucasian population. The median age of predicted survival of those with CF is in the early 40s.  Half of the population with CF no liver longer than 28 years.

The bacteria most commonly involved in respiratory tract infections in those with CF is Pseudomonas aeruginosa. 52.5% of patients with CF contained P. aeurginosa in their sputum.  The group of patients infected with P. auerginosa includes those age 1 and younger and those between the ages of 2 and 5. P auerginosa is also one of the most deadly strains of bacteria that those with CF can become infected with. Initial signs of infection can be intermittent and multiple other strains may be involved. However, the P. auerginosa will dominate and chronic infection will occur. Once this happens, the complete eradication of the pulmonary infection is usually impossible.

References:
Cystic Fibrosis Foundation - Home. (n.d.). Retrieved January 18, 2015, from http://www.cff.org/

Genes and human disease. (n.d.). Retrieved January 18, 2015, from http://www.who.int/genomics/public/geneticdiseases/en/index2.html#CF

Lipuma, J. (2010). The Changing Microbial Epidemiology in Cystic Fibrosis. Clinical Microbiology Reviews, 23, 299-323. Retrieved January 18, 2015.

Folkesson, A., Jelsbak, L., Yang, L., Johansen, H., Ciofu, O., Høiby, N., & Molin, S. (2012). Adaptation of Pseudomonas aeruginosa to the cystic fibrosis airway: An evolutionary perspective. Nature Reviews Microbiology,841-851. Retrieved January 24, 2015.

The Basics of Cystic Fibrosis

Cystic Fibrosis (CF) is an autosomal recessive genetic disorder. It mainly affects the lungs; however, it can also affect the kidneys, pancreas, liver, and intestines. It can cause severe damage to both the lungs and the intestines. Some of the most common symptoms include a persistent cough (with thick mucus production), wheezing, shortness of breath, persistent lung infections, a stuffy nose, foul-smelling stool, delayed weight gain/growth, and constipation.

Cystic Fibrosis elicits harm by targeting specific cells of the body that produce mucus, sweat, and digestive juices.  Normally, all of these fluids are vey thin and slippery. However, the defective gene in those with CF causes these fluids to become very thick and sticky. In this manner, the fluids are no longer able to circulate through and exit the body as effectively. Instead, they will begin to block varying tubes and passageways (especially in the lungs and pancreas).

Unfortunately, there is no cure for Cystic Fibrosis. However, improvements have been made and many people who receive this diagnosis are now able to live into their 20s and 30s. CF is diagnosed in early childhood (usually by age 2) and is more common in Caucasians of Northern European ancestry. You should consult a doctor if your child is not growing properly despite adequate nutrition, has a persistent cough with mucus production, is suffering from lung/sinus infections, or has frequent foul-smelling stools that are sticky and greasy.

If you know that Cystic Fibrosis runs in your family, prenatal screening and genetic testing are great options to obtain an early diagnosis and to begin discussing treatment options.

References:
Cystic Fibrosis Foundation - Home. (n.d.). Retrieved January 10, 2015, from http://www.cff.org/

Cystic fibrosis. (n.d.). Retrieved January 10, 2015, from http://www.mayoclinic.org/diseases-conditions/cystic-fibrosis/basics/definition/con-20013731

What Is Cystic Fibrosis? (n.d.). Retrieved January 11, 2015, from http://www.nhlbi.nih.gov/health/health-topics/topics/cf