Case 26: 9wo- CF

Question 1

typical weight changes in newborn

Answer 1

immediate == <10% loss
2x weight @ 4mo (mostly fat)

formula-fed gain weight faster v. breastfed

Question 2

Failure to thrive

• define
• etiology (organic v. nonorganic)

Answer 2

• define: weight (or weight for length) <3%ile, weight loss crossing 2 major percentiles
• etiology = chronic V/D, CHF, formula allergy, imporperly prepared formula, inadequate formula volume, malabsorption, parental neglect, severe GERD, kernicterus from elevated bili, in-utero exposure to ETOH and tobacco, meconium aspiration syndrome

ORGANIC == acute/chronic d/o leading to decreased intake and/or increased expenditure/output (+ associated findings)

• congenital heart defect
• CF
• developmental delay + poor suck, swallow
• renal tubular acisosis
• milk protein allergy
• HIV
• vomiting d/t severe GERD, bowel obstruction

NONORGANIC==inadequate breast milk supply; neglect, psychological problem from parents (inadequate intake)

• poverty
• poor understanding of proper feeding / formula techniques

Question 3

if an infant has failure to thrive due to improperly mixed formula, what else might you find on exam?

Answer 3

failure to thrive
electrolyte abnormalities (hypo/hypernatremia)

Question 4

caloric requirements of healthy, full term babies

Answer 4

100-110 cal/kg/hours in first 4 months

if younger gestational age, need more calories

Question 5

Anemia in infants

• normal value in infants (birth v. infant period)
• causes:

Answer 5

• normal for newborn = 16.5
• normal for infants = 11.2 (–> “physiological anemia” d/t short t1/2 of fetal TBCs; BM stimulated to produce new RBCs @ 7-9w)
• causes: iron deficiency (microcytic), chronic dz/blood loss (normocytic, normochromic), hemolysis (decreased RBCs, damaged remaining)

Question 6

Cystic fibrosis

• inheritance pattern:
• genetic counseling:
• newborn screening:

Answer 6

• inheritance pattern: AR (most people withCF dont’ have positive family history for it)
• genetic counseling: 25% chance of another; need to determine specific CF genotype of parents (–> determines dz course and future treatment options)
• newborn screening: in all 50 states (trypsinogen test== high) + genotype testing –> leads to better nutritional status, fewer nutritional/pulm/growth complications later in life

Question 7

team for child with cystic fibrosis

Answer 7

• pulmonologists, NPs
• nutritionists
• social workers
• respiratory and physical therapists
• child psychologists
• specialists in endocrine, GI

Question 8

baby has failure to thrive. what questions should you ask?

Answer 8

• breast v. bottle-feeding (any changes since birth)
• BREAST == how long each time, one or both breasts? Mother has adequate breast milk, with healthy diet and lots of fluids
• BOTTLE == prepackaged v. prepared formula; how does she prepare it (water), any changes to formula
• thorough hx and ROS == hx of problems with feeding/feeling full
• whether he seems hungry, how long it takes him to eat
• spitting up / vomiting after feeding
• alertness, cough etc. before and after feeding
• frequency and consistencyof stools
• Unusual stressors in parents’ life

Question 9

diffdx for failure to thrive

organic

Answer 9

ORGANIC == acute/chronic d/o leading to decreased intake and/or increased expenditure/output (+ associated findings)

• congenital heart defect == difficulty feeding, respiratory distress with feeding
• milk protein allergy == intestinal blood loss, + fussiness after feeds; vomiting
• gastroenteritis == vomiting + diarrhea, fever, bloody stools (esp. giardia as chronic course)
• hypothyroidism == poor feeding, constipation
• malabsorption == poor weight gain + good feeding + loose stools

Question 10

failure to thrive

- diagnostic evaluation

Answer 10

• CBC +/- smear ==> anemia, infection
• UA ==> renal dysfx (renal tubular acidosis, hematuria, UTI)
• BUN/Cr == ?renal failure

(newborn screening)

Question 11

Evaluation: FTT

+ heart murmur

Answer 11

==> cardiology, CXR

Question 12

Evaluation: FTT

+ significant vomiting + diarrhea

Answer 12

==> electrolytes

Question 13

Evaluation: FTT+ no clear etiology

Answer 13

==> sweat chloride test for CF

Question 14

Evaluation: FTT+ hypotonia, grunting with feeding

Answer 14

==> thyroid function tests (TH deficiencyy)

Question 15

Evaluation: FTT+ abn UA, hx fever

Answer 15

==> urine culture

Question 16

sweat chloride test

• sensitivity, specificity
• when do false negatives occur?
• when do false positives occur?

Answer 16

• sensitivity = 99%, specificity = 90%
• when do false negatives occur: rare CF mutation not picked up by test
• when do false positives occur: metabolic d/o (adrenal insufficiency, hypothyroidism)

Question 17

CF management and prognosis

Answer 17

• management ==> of chronic pulmonary inflammation d/t chronic infection and underlying genetic problem
  1) nutritional management (+enzymes, vitamins, extra calories)
  2) airway clearance
  3) treatment of airway infections
• prognosis: CF mutation G511D == FDA-accepted mediation for treatment ==> resulting in normalized sweat chloride testing, improvements in nutrition and lung fx

Question 18

CF management and prognosis

Answer 18

• management ==> of chronic pulmonary inflammation d/t chronic infection and underlying genetic problem
  1) nutritional management (+enzymes, vitamins, extra calories)
  2) airway clearance
  3) treatment of airway infections
• prognosis: CF mutation G511D == FDA-accepted mediation for treatment ==> resulting in normalized sweat chloride testing, improvements in nutrition and lung fx

Question 19

What is the major underlying mechanism of failure to thrive? Select the ONE best answer from the list below.

 Multiple Choice Answer:
A		Allergy	
B		Chronic disease	
C		Endocrine disorder	
D		Genetic syndrome	
E		Inadequate calories to meet metabolic need	
F		Parental neglect	
G		Poverty

Answer 19

E

There are three means of inadequate calories:

Insufficient intake
Excessive losses
Excessive caloric need.

Question 20

physical exam in a 9mo baby with CF

Answer 20

You note his thin appearance and his lack of subcutaneous fat. He appears hungry (fussy and sucking on his fingers).

Bobby’s heart rate and respiratory rate are both at the upper limit of normal for his age. Neither suggests a major problem, but you do notice his cough and congestion, with no crackles or wheezes on chest auscultation.

He is well hydrated with moist mucous membranes and capillary refill of < 2 seconds.

He is pale, suggesting anemia, and has relative tachycardia and a grade 2/6 systolic heart murmur.

The murmur is not consistent with ventricular septal defect or atrial septal defect.
He has no diastolic murmur.
He has no evidence of congestive heart failure.

No crackles in the lungs suggestive of pulmonary edema.
His liver is not palpable.
He is in no respiratory distress.
There are no masses or other abdominal problems identified; there is no hepatosplenomegaly.

He is neurologically intact.

Question 21

cystic fibrosis management and prognosis

Answer 21

• management ==> of chronic pulmonary inflammation d/t chronic infection and underlying genetic problem
  1) nutritional management (+enzymes, vitamins, extra calories)
  2) airway clearance = prevention of airway infections
  3) treatment of airway infections
• prognosis: CF mutation G511D == FDA-accepted mediation for treatment ==> resulting in normalized sweat chloride testing, improvements in nutrition and lung fx

Question 22

physical exam in a 9mo baby with CF

Answer 22

You note his thin appearance and his lack of subcutaneous fat. He appears hungry (fussy and sucking on his fingers).

Bobby’s heart rate and respiratory rate are both at the upper limit of normal for his age. Neither suggests a major problem, but you do notice his cough and congestion, with no crackles or wheezes on chest auscultation.

He is well hydrated with moist mucous membranes and capillary refill of < 2 seconds.

He is pale, suggesting anemia, and has relative tachycardia and a grade 2/6 systolic heart murmur.

The murmur is not consistent with ventricular septal defect or atrial septal defect.
He has no diastolic murmur.
He has no evidence of congestive heart failure.

No crackles in the lungs suggestive of pulmonary edema.
His liver is not palpable.
He is in no respiratory distress.
There are no masses or other abdominal problems identified; there is no hepatosplenomegaly.

He is neurologically intact.

Question 23

lab results in CF

Answer 23

• normocytic anemia of chronic disease
• low NA,CL
• mildly elevated liver enzymes
• low serum albumin

sweat chloride >/= 60 (but will need repeat)

Question 24

Cystic fibrosis

• symptoms:
• evaluation:
• complications:
• mechanism of failure to thrive

Answer 24

• symptoms: constantly hungry; chronic cough, chronic sinusitis (+/- poor weight gain in setting of good caloric intake); abnormal “steatorrheic” stool; infertility (male - congenital absence of vas deferens)

EVALUATION

• sweat chloride test
• fecal fat analysis == malabsorption, pancreatic insufficiency
• liver function tests == biliary congestion
• complications = malabsorption, pancreatic insufficiency, biliary congestion

MECHANISM

1) malabsorption == can’t fully digest / absorb food –> loss in stool
2) increased energy expenditure == d/t trouble digesting food, trouble breathing (+/- infection)

Question 25

cystic fibrosis - followup

Answer 25

==> at accredited cystic fibrosis center by multi-disciplinary team initial monthly follow up then q3mo check for: - weight/height/head circumference gain percentile - frequency and character of stools - anemia status - prior infections / need for antibiotics.

Question 26

cystic fibrosis - followup

Answer 26

==> at accredited cystic fibrosis center by multi-disciplinary team initial monthly follow up then q3mo check for: - weight/height/head circumference gain percentile - frequency and character of stools - anemia status - prior infections / need for antibiotics.

Question 27

A 4-week-old female infant presents to clinic for a well child check. This infant had an uneventful delivery by NSVD at full term and subsequent normal neonatal screen. The nurse reports that her growth is a concern, with weight at 3.0 kg (< 3rd percentile) and weight for height at < 3rd percentile. Mom denies any drinking or drugs since before this pregnancy and says she has been breastfeeding every two to three hours and supplementing with appropriately mixed formula one to two times a day. She does report the baby seems to have issues latching and some possible gasping between suckles. There has been no diarrhea, hematochezia, vomiting, or fevers. The vital signs and exam (apart from a thin infant) are normal. The mother’s affect is flat, and she seems anxious when you ask her about her infant. What is the most likely diagnosis for this infant’s failure to thrive? ``` Single Choice Answer: Please select one answer. A Malabsorption B Gastroenteritis C Milk protein allergy D Congestive heart failure E Failure to thrive due to inadequate caloric intake ```

Answer 27

E This infant is likely not consuming adequate calories to grow. The mother or primary caregiver may neglect proper feeding of the infant because of preoccupation with the demands or care of others, her own emotional problems, substance abuse, lack of knowledge about proper feeding, or lack of understanding of the infant’s needs. It is also important to assess the mother for post-partum depression. Standardized screening tools, such as the Edinburgh, are used routinely in pediatric office settings for this purpose. Congestive heart failure is important to consider in any child with failure to thrive, but this child has no signs of CHF such as tiring with feeds, sweating, or tachypnea, tachycardia, or hepatomegaly.

Question 28

Full-term, 6-week-old baby is brought to the family physician for routine follow-up. At birth her weight, height, and head circumference were at the 50th percentile; she is now at the 5th, 10th, and 25th percentiles, respectively. She and her twin sister are exclusively breastfed; their mother has maintained a rigid every-four-hour feeding schedule since birth. Physical exam reveals a thin but otherwise healthy infant. What is the most likely cause of this infant’s failure to thrive? ``` Single Choice Answer: Please select one answer. A Congenital heart disease B Inadequate caloric intake C Cystic fibrosis D Milk protein allergy E Inborn error of metabolism ```

Answer 28

B inadequate breast milk production == should supplement with formula Inadequate caloric intake is correct because it is the most common cause of FTT. Furthermore, we have reason to believe that this particular infant is not receiving adequate calories. Breastfed infants should eat every two to three hours until 3 months of age; this infant eats every four hours and shares the milk supply with her twin. Twins can thrive on exclusive breastfeeding, but it requires that the mother consume extra fluids and calories and ensure that the twins both get enough to eat.

Question 29

On your first day rotating in the pediatric clinics, you are assigned to see a patient who is 9 weeks old and was brought into clinic by his worried mother. She states that her son has not gained weight since they left the hospital. His weight is < 5th percentile, and height and head circumference are at the 25th percentile. His mother says he drinks two ounces of milk every two to three hours, and suckling is strong without any spitting up during feeds. He poops more than 10 times a day, but it appears greasy and foul smelling. He had an unremarkable birth history and a normal newborn screen. Cardiac, pulmonary, abdominal, and neurologic exams are all normal. His mother mentions her cousin had trouble gaining weight and would get frequent “lung infections.” Which of the following is the best next step in management? ``` Single Choice Answer: Please select one answer. A Increase formula to a higher calorie mixture B Stool culture and Wright stain C Swallow study D Sweat chloride test E Echocardiogram ```

Answer 29

D steatorrheic stools FHx The patient's greasy and foul-smelling stool is characteristic of steatorrhea, or fat in the stool. This occurs in patients with cystic fibrosis due to their impaired pancreatic exocrine function. Given the stool history in the face of failure to thrive, a sweat chloride test would be indicated at tis time. Of note, the family history of poor weight gain in a cousin with frequent lung infections also suggests the possibility of cystic fibrosis–related bronchiectasis. Cystic fibrosis should still be suspected in the child who has a normal newborn screen. States differ in the type of test offered to screen for cystic fibrosis, and although great strides have been made in newborn detection, methods are not 100% sensitive.

Question 30

A 6-month-old baby boy is referred to your clinic because he has not been gaining weight appropriately. His mother denies any difficulty with feeding or reduced appetite, yet his weight has still dropped from the 30th to the 3rd percentile. Mother also complains that he has loose, malodorous stools. After a thorough workup, a diagnosis of cystic fibrosis (CF) is made. Which of the following is a TRUE statement regarding CF? Single Choice Answer: Please select one answer. A CF is an autosomal dominant disorder B CF is caused by a mutation in CFTR, resulting in defective salt balance C CF is a disease that exclusively involves the respiratory system D Gene therapy is now the primary source of CF therapy E It is important to provide calories at a lower level than recommended dietary allowance for a given age in order to prevent GI upset

Answer 30

B AR respiratory, GI therapy = nutrition, airway clearance, prevent/treat pulmonary infections INCREASE calories The mutation in CFTR gene results in defective salt balance. CF is caused by mutations in a single large gene on chromosome 7 that encodes the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Clinical disease requires disease-causing mutations in both copies of the CFTR gene.

Question 31

Casey’s parents just learned that Casey’s screening test for CF was abnormal. What other signs and symptoms might you expect this patient to develop? ``` Single Choice Answer: Please select one answer. A Bloody stools B Precordial thrill C Reflux D Greasy stools E Diaphoresis during feeds ```

Answer 31

D CF causes exocrine insufficiency and ultimately results in fat malabsorption. This causes frequent foul-smelling and greasy stools.