MEDICAL MYSTERY FOR CHAPTER 2: Maddy
Her mother noticed that Maddy was not eating well and seemed to be sick more often than her brothers. She had more than her share of respiratory infections, and despite all the antibiotics, these conditions persisted. Maddy’s mother noticed that her stools sometimes smelled bad, but their general practitioner said that this was probably due to a change in her diet. Despite regular visits to the doctor, Maddy’s chest was always congested. Recently, the doctor found some polyps in her nose and said that Maddy had developed an allergy that was the most likely reason for all her symptoms. Her mother was not satisfied and became worried because Maddy was not gaining weight and was very lethargic. Even during simple play with her brothers, she was always out of breath. Finally, Maddy’s mother decided to seek out a pediatric specialist.
When I saw Maddy at our outpatient clinic at the children’s hospital, I noticed that she was underweight and looked ill. She also appeared dehydrated, so I decided to admit her for inpatient care. Her mother said that Maddy was the only sickly child in the family and that there was nothing unusual in their family history. A chest x-ray revealed that Maddy has had recurrent lung infections, so I ordered additional x-rays of her thoracic cavity. I decided to also evaluate the amount of salt in the sweat on Maddy’s skin. While I waited for these results, I also decided to do some genetic tests on a sample of Maddy’s blood. When these test results came back, I asked that the other children in the family be evaluated using the sweat test. Their results did not reveal unusually high levels of salt.
I had the difficult task of telling Maddy’s mother that her daughter has cystic fibrosis (CF). An inherited condition, CF affects the cells that produce mucus, sweat, saliva, and digestive juices. Normally, these secretions are thin and slippery, but in CF, a defective gene causes the secretions to be thick and sticky. Instead of acting as a lubricant, the secretions plug up tubes, ducts, and passageways, especially in the pancreas and lungs. Difficulty in breathing is the most common presentation, along with excess salt in the sweat and foul-smelling, greasy stools.
Both of Maddy’s parents turned out to be carriers of the CF gene. Because the gene is recessive, it can only produce the disease if a child receives the gene from each parent. Maddy was unlucky enough to have this happen.
Although CF shortens the life span of those it affects, early diagnosis and a comprehensive treatment plan can improve both survival rate and quality of life. I told Maddy’s mother that her daughter would need antibiotics for her lung infections and physical therapy to help her cough up the thick secretions. In addition, I prescribed some medications that would make her breathing easier. I recommended that the mother give Maddy special enzymes to allow her to absorb food better, and encouraged her to give Maddy a high-calorie diet. I told her that Maddy must be regularly seen in the CF clinic and that other treatment options would be discussed in due time.
When I saw Maddy again 6 months later, both she and her mother were still learning to live with her condition and with her daily medical regimen. Maddy continues to be small for her age, but is not shy about expressing her opinions. Her older brothers have become very protective of their little sister now that they realize how vulnerable she is to lung infections. Although only about half of those diagnosed with CF as infants or young children live beyond their late twenties, this percentage is rising as an increasing number of patients survive into adult life. It is possible that in the future, she will be a candidate for a lung transplantation, which might extend her life considerably.
Cystic fibrosis is a genetic disorder. What does this mean?
Can you name two other genetic disorders?
The doctor requested x-rays of Maddy’s thoracic cavity. What is this?
The CF gene is recessive. What does this mean?