CLIPP case 26. 9 week-old with FTT and CF

Question 1

9 week-old boy presents with FTT. Despite good caloric intake, his weight gain and weight for length have both fallen from the 25th percentile at birth to less than the 3rd percentile today. He has loose, “stinky” stools without blood or mucus. Physical exam is unremarkable. Labs reveal elevated sweat chloride.

Answer 1

• CF: sweat chloride ≥60 on two tests
• Hemolytic anemia 2/2 vitamin E deficiency
• DDx:
• Malabsorption
• Formula allergy
• Improperly prepared formula
• Psychosocial failure to thrive
• Inadequate formula volume
• Congestive heart failure

Question 2

Newborn weight, HR, RR

Answer 2

3.5kg, 100-160, 30-60

Question 3

6 month-old weight, HR, RR

Answer 3

7kg, 110-160, 24-38

Question 4

1yo weight, HR, RR

Answer 4

9kg, 90-150, 22-30

Question 5

3yo weight, HR, RR

Answer 5

14kg, 80-125, 22-30

Question 6

5yo weight, HR, RR

Answer 6

18kg, 70-115, 20-24

Question 7

10yo weight, HR, RR

Answer 7

33kg, 60-100, 16-22

Question 8

12yo weight, HR, RR

Answer 8

40kg, 60-100, 16-22

Question 9

14yo weight, HR, RR

Answer 9

50kg, 60-100, 14-20

Question 10

Assessing weight gain

Answer 10

*Most sensitive indicator of nutritional status.
*Up to 10% wt loss in first week
*20–30 grams per day wt gain in first 4 months
*Doubles by 5 months, triples by 12
*Formula-fed gain weight faster
*Reduced linear growth usually indicates more severe, prolonged malnutrition.
*Reduced growth in head circumference occurs late and indicates very severe or
longstanding malnutrition

Question 11

FTT

Answer 11

*FTT= lack of physiologic growth and development:
-Weight or wt-for-length < 3rd percentile
-Rate of growth slows, crossing two or more
major percentiles downward
*Organic versus non-organic cause

Question 12

FTT organic causes

Answer 12

*Other disorder resulting in inadequate nutrient intake, malabsorption of nutrients, or
increased energy requirements
-Chronic diarrhea
-Formula allergy
-Congenital heart defects
-Cystic fibrosis
-Developmental delay with poor suck and swallow
-Renal tubular acidosis
-Vomiting from severe GERD or obstruction

Question 13

FTT non-organic causes

Answer 13

• Nearly 90% of FTT. Inadequate caloric intake NOT resulting from an underlying disease:
• Poverty
• Poor understanding of feeding techniques
• Improperly prepared formula
• Inadequate supply of breast milk
• Neglect of the infant (lack of food)
• Less commonly, psychological basis in which stimulation is lacking because caregiver depressed, has poor parenting skills, or is responding to real or perceived external stresses.

Question 14

Physiologic anemia

Answer 14

*Decrease in hemoglobin because fetal RBCs have a short half-life. In full-term newborns the marrow is not stimulated to produce new RBCs until the hemoglobin reaches its nadir of about 11 g/dL at 7–9 weeks of age, after which the hemoglobin rises

Question 15

CF pathophysiology

Answer 15

CFTR mutation -> disturbed salt balance and buildup of mucus -> pancreas and lung dz -> GI malabsorption and chronic infection and inflammation of the lungs

Question 16

CF symptoms

Answer 16

*Chronic cough, recurrent bronchitis, or sinusitis
*85-90% have pancreatic insufficiency and
present with steatorrhea and malabsorption
*Vast majority identified by NBS: abnormal trypsinogen?

Question 17

CF inheritance

Answer 17

AR

Question 18

CF diagnosis

Answer 18

• Sweat chloride test is the main diagnostic test, but may be false positive in CAH and congenital hypothyroidism
• Genotyping is adjunctive: Supports the diagnosis of CF but is generally not sufficient for diagnosis alone. Important because new methods of treatment for CF may correct specific gene mutations

Question 19

Malabsorption history FTT

Answer 19

• History of poor weight gain with good caloric intake and loose stools
• Can be malabsorption due to CF

Question 20

Formula allergy FTT

Answer 20

*True milk-protein allergy typically causes intestinal blood loss (either gross or occult). *Infants are usually fussy and may vomit. *Poor weight gain as an isolated finding is unusual.

Question 21

Psychosocial FTT

Answer 21

*Inadequate caloric intake may result from poverty, poor understanding of feeding techniques, improperly prepared formula, or inadequate supply of breast milk. It occasionally reflects neglect of the infant (lack of food).

Question 22

CHF FTT

Answer 22

*Important to consider in any child with failure to thrive. History would likely include difficulty feeding and respiratory distress.

Question 23

CF management

Answer 23

*Genetic counseling, nutritional (extra calories, pancreatic enzyme, fat-soluble vitamins ADEK), treat airway inflammation and infection