The role genetics plays in the disease.

Cystic Fibrosis (CF) is a disease that is inherited and affects the mucus and sweat production by those glands (McCance & Huether, 2018).  How it is inherited is that parents of children with CF both have to be carriers of the cystic fibrosis transmembrane regulator (CFTR) mutation gene (McCance & Huether, 2018).  Parents do not have to have CF for their children to have CF; they just have to be carriers of the mutation gene (Tabori et al., 2017).  It is very common for people of European descent to inherit CF (McCance & Huether, 2018).

Why the patient is presenting with the specific symptoms described.

The symptoms described in the case study scenario that contributed to the CF diagnosis were thought of possible colic, baby has had many episodes of crying after eating, despite having a good appetite baby is not gaining weight (failure to thrive, FTT), baby’s belly “gets all swollen sometimes,” the baby tastes “salty” when the mother kisses the baby, and sibling has had multiple episodes of “chest congestion” and was hospitalized once for pneumonia (Abid et al., 2017).

The human body is protected against bacteria by first and second lines of defense (McCance & Huether, 2018).  Physical, mechanical, biochemical, and normal flora make up the first lines of defense (McCance & Huether, 2018).  Examples of the physical and mechanical barriers are skin and mucus membranes; antibacterial properties of mucus secretions, tears, saliva, sweat, and other secretions are examples of biochemical barriers; normal flora are good bacteria that protects the human body by preventing bad bacteria from taking over in places like the gut (McCance & Huether, 2018).

CFTR protein pushes chloride ions into secretions to help draw water into these secretions (mucus) to loosen (thin) them (McCance & Huether, 2018).  CFTR protein absence leaves excess chloride ions on the skin.  The thin and slippery mucus protects the sac that lines the lungs, stomach, tissues and organs (McCance & Huether, 2018).  The missing CFTR protein does not leave a way for the body to thin out the mucus (Abid et al., 2017), leaving the body to only make thick and sticky mucus that build up, leading to blockages, frequent infections, and damages in the affected organs (McCance & Huether, 2018).

The pancreas cannot release any digestive enzymes to the small intestine when it is blocked with thick mucus making nutrients and fat not absorbable, leading to FTT (not gaining weight despite good appetite and looking malnourished (McCance & Huether, 2018).  Other gastrointestinal symptoms include fatty stools (McCance & Huether, 2018), abdominal pain after eating due to poor intestinal malabsorption (Tabori et al., 2017), abdominal bloating, constipation, and flatulence (McCance & Huether, 2018).  CFTR also helps the skin regulate sodium ions and fluid absorption; so, in someone with CF, there is less fluid absorption to dilute the sodium ions, leaving the salty taste on the skin (McCance & Huether, 2018).

The second line of defense is the body’s response to damage known as inflammation (McCance & Huether, 2018).  Symptoms are redness, swelling, pain, and heat, collection of fluid at the site, leukocytosis and fever (McCance & Huether, 2018).  In the presence of CF, inflammation causes damage to lungs and pancreas in particular, but other organs as well (McCance & Huether, 2018).  A child or young adult, or their sibling, with a history of severe and recurrent bronchitis, pneumonia, pancreatitis, and hemoptysis is suspect for further CF testing.