Robert Giusti, MD
CF Center of Long Island College Hospital
Brooklyn, NY
Robert Karp, MD
Avi Gurwitz, MPH
SUNY-Downstate Medical Center
Brooklyn, NY
Pre-Test:
Q1. True or False: All patients with the diagnosis of Cystic Fibrosis have some degree of pancreatic insufficiency.
Q2. True or False: Patients with Cystic Fibrosis gain weight and grow to their genetic potential with the normal diet as long as they use pancreatic enzymes.
Q3. Best answer: Infants diagnosed with Cystic Fibrosis require which pair of therapies to improve their nutritional status:
a. Hydrolysate formula and MCT oil
b. MCT oil and Enzymes prior to each breast or bottle feed
c. Enzymes prior to each breast or bottle feed and Increased sodium during warm weather
d. All are required
Q4. Patients with Cystic Fibrosis need the following monitored yearly:
a. Fat-soluble vitamins (ADEK), CBC, LFT's & glucose after age ten-years.
b. Pre-albumin, LFT's & electrolytes
c. 72-hour fecal fat test.
d. All are required
Q5. True or False: Approximately 85% of patients with Cystic Fibrosis have pancreatic insufficiency.
Q6. True or False: Calorie and protein intake in patients with Cystic Fibrosis increases to 150% of the RDA for calories and 200% of the RDA for protein.
Q7. True or False: Adequate nutrition therapy will counter the former problem of sterility in men.
OBJECTIVES
On completion of this module, the resident will:
1. Appreciate the diverse pathophysiologic consequences of inheriting two mutant copies of the Cystic Fibrosis gene.
2. Identify the diagnostic procedures for Cystic Fibrosis including:
a. Sweat chloride testing
b. Genotyping
c. Newborn screening (elevated IRT)
d. Prenatal diagnosis
3. List the common presenting symptoms of Cystic Fibrosis.
4. Recognize the impact of CF on nutritional status and, consequently, outcome.
5. Provide nutritional support appropriate for age of patients with CF to:
a. Improve weight gain and growth
b. Improve pulmonary health and
c. Promote longevity
FACILITATOR'S PREPARATION
These articles are suggested as a primer on CF nutrition.
Milla CE, Association of nutritional issues and pulmonary function in children with cystic fibrosis Curr Opin Pulm Med 2004;20:505-9
Moskowitz SM, Gibson RL, Sternen D, et al. CFTR-Related Disorders. Gene Reviews (2005) to be found at:
Pencharz PB, Durie Pr Pathogenesis of malnutrition in Cystic Fibrosis, and its treatment. Clin Nutr 200;19:387-94
Schibli S, Durie PR, Tullis ED Proper usage of pancreatic enzymes. Curr Opin Pulm Med 2002;8:542-6
INTRODUCTION
Cystic fibrosis is an autosomal recessive disease of the chloride channels in glands that mainly affects the lungs and digestive system, causing progressive disability and for many, early death.
History: There was a time in the not too distant past when cystic fibrosis (CF) was unknown. First mention of "fibrocystic disease of the pancreas" was by Landsteiner in 1907. The remarkable Dr. Fanconi picked up on it in the 1930s with common appreciation, from the work of Anderson in the 1940s.
Infants usually died in infancy without the cause being recognized although even then there would be occasional adults presenting with a triad of sinusitis, pulmonary disease and malabsorbtion. In the 1940s, when infant mortality dropped below 40/1000 live births, CF, which affects 1 in 1,600 infants of European ancestry, was identified. Most infants who died with a meconium ileus also had fibrous cysts in the pancreas, which occurred because the exocrine pancreatic duct was obstructed and the digestive enzymes remained in the gland to harmful effect. Over the course of these 70 years, a diagnosis of CF in a child has gone from a death sentence in early life, to a diagnosis that left the children themselves aware of their own short life, to what we have now. With early recognition and support, much of which is nutritional, CF children are surviving to adulthood with many of the characteristics of chronic but not necessarily lethal disease. The best rates of mortality show a life expectancy to 35 to 45 years, with the average being around 37 years. For some children, however, CF is associated with co-morbidities and earlier death.
Pathophysiology: The name Fibrocystic Disease which was localized to the pancreas was changed to Cystic Fibrosis as the basic metabolic defect was discovered to affect every secreting gland in the body, including sweat glands. CF is caused by defects in the gene for cystic fibrosis transmembrane conductance regulator (CFTR), which encodes for a protein that functions as a chloride channel and is regulated by cyclic adenosine monophosphate (cAMP). Mutations in the gene for CFTR (CFTR) result in abnormalities of cAMP-regulated chloride transport across epithelial cells on mucosal surfaces. Defective CFTR results in decreased secretion of chloride and increased reabsorption of sodium and water across epithelial cells. Resultant reduced height of epithelial lining fluid and decreased hydration of mucus results in mucus that is stickier to bacteria, which results in infection and inflammation. These abnormalities result in viscid secretions in the respiratory tract, pancreas, gastrointestinal tract, sweat glands, and other exocrine tissues. Increased viscosity of these secretions makes them difficult to clear.
Genetics: CF is so common in European ancestry families that a balanced selective advantage to CF has been suggested. With 1 in 2,500 Caucasians affected, 1 in 25 persons would be a carrier, (See module on in born errors for more on genetics on autosomal recessive traits).
Early diagnosis: The diagnosis of cystic fibrosis (CF) is based on typical pulmonary and/or gastrointestinal tract manifestations, a family history, and positive results on sweat test.
Sweat test: Several methods are used to conduct a sweat test. Performed properly, the quantitative pilocarpine iontophoresis test (QPIT) to collect sweat and perform a chemical analysis of its chloride content is currently considered to be the only adequately sensitive and specific type of sweat test. For reliable results, collect at least 50 mg or, preferably, 100 mg of sweat. Current macroduct collection methods allow adequate analysis with smaller volumes of sweat. The normal sweat chloride reference value is less than 40 mEq/L, and a value of more than 60 mEq/L of chloride in the sweat is consistent with a diagnosis of CF. The sweat test must be performed at least twice in each patient, preferably several weeks apart. Values of 40-60 mEq/L are considered borderline, and the test must be repeated because these values have been found to be consistent with the diagnosis in some patients with typical features. Repeat a sweat test with negative results if clinical features suggestive of CF are present. Some patients with genetically documented CF and typical symptoms have consistently negative results on sweat tests.
Genotyping: More than 1300 CF mutations have been identified. In the commercially available CF gene sequencing method, the entire coding region, splice junction sites, and promoter region of the CFTR gene are amplified from genomic DNA by polymerase chain reaction (PCR) and subjected to nucleotide sequence analysis on an automated capillary DNA sequencer. This test can detect more than 98% of disease-causing mutations. The detection rate is lower in African American, Hispanic, and Asian populations; therefore, failure to find 2 abnormal genes does not exclude the disease.
A finding of 2 CFTR mutations in association with clinical symptoms is diagnostic, but negative results on genotype analysis do not exclude the diagnosis.
Nutrition support through childhood: In general, a normal diet with additional energy and unrestricted fat intake is recommended. A high-energy and high-fat diet, in addition to vitamin (especially fat soluble) and mineral supplementation, is recommended to compensate for malabsorption and the increased energy demand of chronic inflammation. In children, because of a variety of physical activities and eating habits, base assessment and modification of energy requirements on growth and weight gain. Special consideration is given to female patients with a potential for delayed puberty because of malnutrition, patients with diabetes mellitus, and patients with liver disease. Nutritional supplements in the form of either high-energy oral preparations (eg, Scandishake) or enteral feeds (eg, elemental formulas, high-fat mixtures) via nasogastric tube or gastrostomy may be indicated in some patients
Keys to Nutitional Support:
A. Early identification leads to preventive measures
B. On going assessment - nutrient and enzyme enhances intervention
C. Nutritional support permits interventions for patients with severe disease
The three case presentations illustrate these issues.
Case # 1:
Mrs. Giammatis is 7 months pregnant with her first child. The Obstetrician had referred her to the CF clinic after a prenatal test showed a positive result for the condition. She arrives with her husband for counseling. In taking the history you find that they do not know of any biologic relationship, but their families emigrated from the same region of Italy.
For the Facilitator: For these cases, have the residents break into groups where one person will be the physician, one the nutritionist and one or two be the parents. Shift roles through the module. Once again, no gender stereotyping is allowed in role-play.
Q1. What are the nutritional advantages of Prenatal and Newborn Screening in Cystic Fibrosis?
A1. Good nutritional status has been correlated with improved pulmonary status and longevity. Studies done in patient populations already having implemented Newborn Screening show that starting nutritional therapies early (enzymes, fat-soluble vitamins, increased caloric density) has positive outcomes in terms of weight-gain, growth and head circumference of these babies. Nutritional rehabilitation in an older infant or toddler diagnosed secondary to clinical presentation rather than Newborn Screening can reverse some of the sequelae of malnutrition, but is expensive, time intensive and may take months to years for the child's nutritional status to return to baseline.
Q2. How would you introduce CF to the family?
A2. Team delivered care is the essence of caring for CF just as it is in most if not all-chronic illnesses. It is important that the physician work closely with a Registered Dietician, a Social Worker, Psychologist, and if possible a Health Educator. The physician and RD are the "point people" on the team
A brief, factual overview of CF is needed. It need not be morbid (from the history given above), but it is inappropriate to give an overly rosy picture either. The model suggested is the 4 "E's":
TABLE 1. The 4 E's of engaging a family in the care of a chronically ill child
Empathy
Engagement
Education, and
Enrollment or (Encouraging Adherence)
TEACHING CAPTION: Note that "Adherence" is used to describe the patient role rather than "compliance." The more the patient shares in the plans, the better the adherence.
One must let the parents express their concerns. Often parents feel that they did something wrong or that they are being punished. Perhaps the Giammatis will find that they are actually 3rd cousins. How will they react? They are likely to have experienced a "colony effect," where the gene pool is relatively small. How will they feel? One asks the parents to "Tell me more…".The nutrition issues to be addressed in the first meeting include the need for pancreatic enzyme therapy, the need to monitor fat-soluble vitamin levels and to provide additional micronutrients.
Q3. Are there elements of support that might best be deferred?
A3. This is not the time to address CF-Related Diabetes, nutrition support with G-tube feedings, or other major nutritional or infectious complications of CF. Questions should always be answered honestly. The Giammatis have almost certainly searched the Internet and found that CF patients are sterile.
Q4. What recommendations would you present to the Giammatis?
A4. They have already been introduced to the team-care concept and members of the team. Children with CF, even when stable, are seen at three-month intervals with the possibility of increased frequency when problems arise. Don't forget the financial as well as the social and psychological strains on CF families. Medicaid in most states will assume care for families within "SCHP" limits (about 2.7 times the poverty level for the family which equates to about $45,000 a year for a four person family based on a poverty level of $17,000/year). In many states, a child can be put on "straight Medicaid" to avoid the constant need for prior approvals from categorical SCHIP. Moreover, other children in CF families may be ignored as all energy is given to the "fragile child." This discussion will follow in Case 2.
Repeated infections, especially those affecting the lungs, has been the major cause for morbidity and mortality. It is necessary to review the recent advances in inhaled antibiotics.
Q5. Once again, what recommendations would not be made to parents or the cooperating primary care pediatrician for follow-up immediately after birth?
A5. Children with CF can be breast fed with supplements or be offered an infant formula so long as their growth and electrolyte status is carefully monitored. They do not need a hydrolysate formula. Nor is it necessary to do an extensive evaluation such as sending stool sample for fecal elastase.
Case # 2:
William Briggs is an eight-year-old boy with Cystic Fibrosis diagnosed at 4 years of age. He is pancreatic insufficient, has symptoms of sinus disease (chronic sinusitis) and mild malnutrition. On presentation at 4 years of age, he weighed 13kg and was 93cm tall. You have linear measures from then to now.
Q6. Describe some presenting symptoms of Cystic Fibrosis in traditional diagnosis (vs. Newborn Screening).
A6. The most common presenting symptoms in young children with Cystic Fibrosis include symptoms of malabsorption (large, bulky, greasy, foul-smelling stools), malnutrition and Failure-To-Thrive despite a ravenous appetite and intake, and chronic pulmonary symptoms in a young child. Other presenting symptoms less overt can be nasal polyps in a young child, which are uncommon, hyponatremia and metabolic alkalosis at any age, especially in hot weather. Hyponatremia and secondary edema in undiagnosed breast-fed infants can also be a presenting factor. Meconium ileus at birth is also the presenting symptom in 15% of people with Cystic Fibrosis.
Q8. How would you go about classifying his nutritional status? [See modules on Failure to Thrive and Assessing Nutritional status]
A8. First, take a look at him. Does he have signs of weight loss? Is there a wasting at the zygomatic arch? Is there a demarcation at the deltoid insertion on the humerus? Did you chart his dynamic of growth? Do you have early childhood measures? Has he ever had a weight or length below the 5th percentile? What about his BMI? What does the progression look like? Remember weight falls before height so the weight to height (before 2 years of age) or BMI may seem to normalize when linear growth ceases.
You would examine carefully looking for signs of vitamin or mineral deficiencies. Lack of fat-soluble vitamin A will lead to a dry scaly skin.
You then begin a laboratory assessment to be described below.
The case continues
The resident serving as his primary care physician notices that there has been a plateau in his weight gain. He reports increasing symptoms of sinus disease, including nasal polyps and an increase in number, size and consistency of his stools.
Facilitator: Have the residents list the observations and provide diagnostic tests and therapies for each: Nasal polyps, failure to gain weight, and fat malabsorption.
Q9. What work up(s) would you recommend?
A9.
Sinusitis: Williams needs an ENT evaluation. Chronic sinusitis can be an intractable problem for CF patients given the likelihood that sinus drainage will be poor.
Growth Failure: Engage the dietician. William needs a careful assessment of intake with a 3-day (72 hours)diet history. Caloric needs increase in proportion to the malabsorption that occurs. It is not necessary to do a 72-hour fecal fat study.
Adherence: The most likely cause for the fat malabsorption is an unwillingness to maintain therapy with intestinal enzymes. Let's find out how William and his family are coping with the CF regimen. A Social Work evaluation will help clarify enzyme therapy adherence.
The case continues:
As it turns out, William hates Scandishakes (R), Pediasure, (R) and the other drinks offered for nutrition supplementation. The engagement of an RD with the family is essential. She will help them adjust the commercial formulaes available as well as monitor intake and augment his diet with home prepared food.
Q10. Why do patients with Cystic Fibrosis, particularly patients with pancreatic insufficiency, need increased caloric-density to gain weight? What did William need at diagnosis?
A10. One theory initially was that the Cystic Fibrosis genetic defect itself included hypermetabolism. More recent theories include the fact that chronic infection, no matter how minor, can increase caloric requirement as in any chronic infection (not only CF). Often colonization with Pseudomonas Aeruginosa can first express itself as a weight velocity deceleration in the absence of decreased appetite, intake or increased activity level.
Pancreatic enzymes only correct malabsorption up to 85-90% so some calories in the form of fat and protein continue to be lost in the stool. Also, the concern of obesity in the general non-CF population makes purchase of foods with high fat content challenging. Often families would prefer to buy one kind of milk - not whole milk for the patient with CF and 2% for the rest of the family. Budgetary constraints may restrict families with several children from purchasing higher calorie foods their one child with Cystic Fibrosis. The Social Worker can help the family obtain necessary resources though public and private channels.
The caloric needs are approximately 1.5 times the basic caloric need of 100 cal for the first 10 kg; 50 cal/kg for the next 10 kg, and 10 calories for each subsequent kg of body weight. Protein needs are doubled to about 1.5 to 2 gm/kg. William needs 1,800 calories and 20 to 25 grams of protein each day on diagnosis.
Q11. How would you go about evaluating the problem of food refusal?
A11. Children with chronic illness often have a food culture unique to themselves. It is a result, in part, of being vulnerable to malnutrition and "fragile" as seen by their parents. Prevention of this phenomenon requires attention to the foods that are offered, how they are prepared and served. As much as possible, the child's eating should be integrated with that of the rest of the family.
Inappropriate or disturbed parental care, in the form of neglect or overprotection with an inability to set limits or expectations is often expressed around food issues. The response of the child to his or her restriction can range from over-acceptance to non-acceptance. By easy acceptance of limitations, the child does not have to confront disapproval by parent or physician. This sort of passive acceptance may be easier for parents and health care providers, but it is developmentally inappropriate as the child grows. Yes, some resistance is a good sign!
In a child struggling with identity as well as chronic illness, early passivity can result in a maladaptive resistance to therapy even at the cost of remarkable success in promoting nutritional status. One needs to prescribe a dietary regimen, but the more opportunity for child integration into decision making the better the long-term outcome. One wants to avoid adolescent rebellion working against the plans made for successful care.
TABLE 2. Shows the elements of a "food culture of chronic poverty" and how to maintain normality.
Foods consumed Encourage a broad variety
Means of Preparation Resist excessive commercial products
Flavors used Maintain family traditions
Social setting Always include affected child
TEACHING CAPTION: Resist at all costs segregating the patent from the rituals of family eating. From Karp, Bachrach and Moskowitz, 1980 derived from the work on food future of Elizabeth and Paul Rozin. [See module on Handicapped children]
Q12. What would you recommend?
Facilitator: Let the students for physician/patient pairs and see hpow well they negotiate the increased caloric intake.
A12. William will need:
1. A list of high calorie beverages the family can make from ingredients at home.
2. A breakdown of calories required per meal for three meals and per snack for three snacks.
3. A handout of ways to increase caloric-density of meals and snacks, and
4. A trial of alternative commercial supplementation products.
TEACHING CAPTION: Note that multiple ways are suggested. Let the family and especially the patient, make decisions. Decisions that they agree to will be used. Directed choices will not.
Q13. How would adherence with nutritional recommendations be evaluated?
A13. Ask that a daily diary sheets be kept and brought or sent to thr clinic's Registered Dietitian. Furthermore, have an open discussion with the family, patient and social worker on impediments to adherence. These could include school schedule, supervision, behavioral issues, or finances. This is a good opportunity to include a home visit by a Public Health Nurse experienced with similar issues of impediments to adherence. It is not, however, necessary to refer to a psychologist unless it is clear that the patient or family is creating obstacles to care.
Q14. Should the RD suggest a low fat or high fat diet?
A14. The traditional treatment of CF through the 1990s was to put children on low fat diets. Studies in Toronto, however, showed great advantage to be had from using a higher fat regimen with adequate enzyme support. As a result of these studies, CF centers encourage increasing caloric intake with all available resources except isolated high sugar boosts (e.g., soda, juice, and "drinks").
Case # 3 - Nutritional Support
Shirley Lu is a fourteen year old girl (diagnosed at age three months with pancreatic insufficiency, lung infection, and Failure-To-Thrive) who used gastrostomy tube feedings during toddler and primary school years, and since then has had the gastrostomy tube removed secondary to a BMI in the 60th percentile. She now presents to CF Clinic with weight loss, increased cough and sputum production, decrease in BMI percentile, electrolytes indicative of mild dehydration and a random blood glucose of 382.
Q15. What work-up would you recommend for Shirley?
A15. Shirley needs a more extensive evaluation than suggested for the earlier patients. This will include looking for CF associated Diabetes Mellitus. Order a Fasting glucose, fasting insulin, and Hgb A1C. This is type 1 DM so the insulin to glucose ratio will be low. It is likely that there is a super infection in the lung. Referral to Endocrinology is warranted. Order a sputum culture. Pulmonary function tests are needed, too.
The case continues
Your evaluation and endocrinology consult suggest a diagnosis of Cystic Fibrosis Related Diabetes (CFRD). You ask the endocrinology group (pediatrician and Registered Dietician) to provide more information
The endocrinologist describes CFRD as follows:
In the CF patient, fibrosis causes scarring and destruction of the pancreas. Many, but not all, of the insulin-producing pancreatic islets are destroyed. This leads to abnormally low levels of insulin secretion. Insulin resistance may also play a role in the development of CFRD, especially during acute infection.
The majority of non-diabetic CF patients, in their usual state of health, appear to be insulin sensitive. During bouts of infection, however, they may become insulin resistant. Treatment with glucocorticoid drugs (like prednisone) or pregnancy are another reasons why some CF patients without diabetes become insulin resistant. Because insulin doesn't work well in the body when one is insulin resistant, more insulin is required to achieve the same effect. If the pancreas is unable to make the extra insulin, blood sugar levels become elevated.
There is a continuum of glucose tolerance in CF ranging from normal glucose tolerance, to increasingly severe abnormal glucose intolerance, to diabetes.
Q16. What nutrition education follow-up would you recommend for CFRD?
A16. The patient and family need substantial education on a carbohydrate counting diet for Cystic Fibrosis Related Diabetes. This will provide continued increased calories, adequate sodium and fat. She will require routine appointments with Endocrine and Cystic Fibrosis Clinic with a review of her diabetes log book at each visit. It will be necessary to monitor her nutritional status (weight, growth and BMI) very carefully to be sure that the dynamic of normal growth is maintained.
The most important change in diet will be an elimination of regular soda, candy as well as "stand alone" snacks. It is not necessary to eliminate all highly concentrated carbohydrate snacks or accept less-than-optimal weight gain and BMI pattern. Do not change from whole milk to skim because these calories are needed.
Q17. Shirley has heard that people with Cystic Fibrosis are always sterile. She asks if good nutrition will enable her to bear children
A17. Good nutrition will do many things, but for boys, it will not affect the inherent sterility that comes with blocked vas deferens. Women can and do become pregnant, but these are inherently high-risk pregnancies. An immediate referred to an adult center with an Obstetrician with such experience is needed. The end result of high quality care is a high quality adult life.
Q18. Would you suggest a regimen of Nutrition Support for Shirley?
A18. Gastrostomy Tube (G-tube): The G-tube is inserted through the skin of the abdomen directly into the stomach with a small portion of the tube left outside of the body.
Nasogastric (NG) Tube: The NG tube is inserted into one of the nostrils and passed down the esophagus and into the stomach. Unlike the G-tube, the NG tube can be inserted in evening and removed in the morning, allowing for feeding to commence during the night when it is least obtrusive to the person with cystic fibrosis.
Benefits of Tubefeeding are as follows:
- Provides the necessary nutrients
- Allows for tracking and ensuring of caloric intake
- Ensures natural growth
- Increases energy
- Improves lung function
- Adds fighting power during infections
Many parents who have a child with cystic fibrosis find that tubefeeding relieves the pressures of trying to get their child to eat. They have also indicated that their child has become more energetic, and in some cases, seem to enjoy eating again.
Tubefeeding usually begins with low intake volumes and slowly progresses to that set by a cystic fibrosis dietician - usually within a one week timeframe. How quickly the tubefeeding volume will be increased depends on how the feeding is going. Many people receiving tubefeeding may experience nausea, abdominal pain or diarrhea until their body gets accustom to the tubefeeding.
Within a couple of weeks of tubefeeding there will be weight gain. The initial weight gain may be substantial, but it will eventually taper off as the patient nears weight goal.
SUMMARY
In the 100 years since Landsteiner first recognized the pathology of Cystic Fibrosis we have brought a truly remarkable change in the outlook for infants given this diagnosis. Without wearing the rose tinted glasses of researchers certain that the next treatment will provide a permanent cure, it is apparent that early diagnosis and nutritional support within a team of committed professionals, parents and child can work wonders. Children and adults with CF now function well with productive and fulfilling lives.
REFERENCES
Aris R, Lester G, Ontjes D (2004) Treatment of bone disease in cystic fibrosis. Curr Opin Pulm Med 10:524-30.
Consensus Document for Pediatric Nutrition (CF Foundation)
Consensus Document for Cystic Fibrosis-Related Diabetes
Gibson RL, Burns JL, Ramsey BW (2003) Pathophysiology and management of pulmonary infections in cystic fibrosis. Am J Respir Crit Care Med 168:918-951
Karp RJ, Bachrach SJ, Moskowitz S. Malnutrition in Chronic Illness of Childhood with Special Reference to Pulmonary Disease. Clinics in Chest Medicine. 1980;1:375-383.*
Moran A (2002) Endocrine complications of cystic fibrosis, Adolesc Med 13:145-59, vii-viii
Milla CE, (2004) Association of nutritional issues and pulmonary function in children with cystic fibrosis Curr Opin Pulm Med 10: 505-9
Moskowitz SM, Gibson RL, Effmann EL (2005) Cystic fibrosis lung disease: genetic influences, microbial interactions, and radiological assessment. Pediatr Radiol. 2005 May 3 (Epub ahead of print) PMID 15868140.
Pencharz PB, Durie Pr (2000) Pathogenesis of malnutrition in Cystic Fibrosis, and its treatment. Clin Nutr 19:387-94
Schibli S, Durie PR, Tullis ED (2002) Proper usage of pancreatic enzymes. Curr Opin Pulm Med 8:542-6
Wagener JS, Sontag MK, Sagel SD, Accurso FJ (2004) Update on newborn screening for cystic fibrosis Curr Opin Pulm Med 10:500-4
Annotated Answers:
A1. This is False: Approximately 15 percent of patients with the diagnosis of Cystic Fibrosis are pancreatic sufficient. There are some specific CFTR mutations that are associated with pancreatic sufficiency.
A2. This is False: Patients with Cystic Fibrosis need up to 150% of the RDA for calories times their ideal body weight (if they are underweight). They also need up to 200% of the RDA for protein. Caloric requirements are increased because enzyme replacement does not completely ameliorate pancreatic insufficiency, chronic infection increases caloric expenditures and caloric intake may be decreased due to post-tussive emesis or signs and symptoms of pancreatic insufficiency itself.
A3. The answer is C: Most infants with Cystic Fibrosis whose mothers want to breastfeed them are able to do so successfully when given pancreatic enzymes prior to each feeding. They may need some increased caloric-density with formula powder added to expressed breast milk. Since breast milk is lower in sodium than infant formula and patients with Cystic Fibrosis lose more salt in their sweat, approximately 1/8 teaspoon per day (not per feeding!) is often recommended in warmer climates and hot weather. Older children are instructed on choosing salty snacks such as pretzels and beverages containing electrolytes to take in adequate sodium in warmer climates and weather.
A4. The answer is A: The Cystic Fibrosis Foundation has recommended that basic lab tests be measured annually. The other tests depend on clinical picture.
A5. The answer is True: Most CF patients have pancreatic insufficiency. There are however, a minority of about 15% of patients whose pancreatic disease is minimal and symptoms are primary pulmonary.
A6. The answer is True: The principle nutritional interventions are to increase calorie and protein intake. One must also supplement sodium to replace loss in sweat and body secretions.
A7. The answer is False: The underlying problem of obstructed exocrine ducts continues. Men are universally sterile. This consequence is unaffected by treatment.
