Download Phenylketonuria (PKU)

PHENYLKETONURIA (PKU)
Case Study Presentation
Cassidy Baerg
NUTR 426
OBJECTIVES
1. To recognize signs and symptoms associated with
a PKU diagnosis.
2. To gain an elementary understanding of what
causes this disease state.
3. To outline a basic intervention plan for a patient
with PKU.
WHAT IS PKU?
 PKU is an inherited amino acid
disorder in which the essential amino
acid phenylalanine is unable to be
converted into tyrosine due to a an
absence of Phenylalanine reductase or
dihydropteridine reductase.
TWO TYPES
1. Classic PKU
2. Non-variant PKU
EPIDEMIOLOGY
 According to the National Institute of Health PKU occurs
in about 1 in 10,000-15,000 newborns in the United States.
 PKU occurs more often in Caucasian and Native American
populations than in African American or Hispanic
populations.
DIAGNOSIS:
In the United States newborns are screened for
PKU approximately 48 hrs after birth.
A Guthrie or heel prick test is used to test for
PKU.
Classic PKU occurs when plasma phenylalanine
levels exceed 20 mg/dL (1200 µmol/L) without
intervention.
 http://www.youtube.com/watch?v=85f7-C4n9kY
PATIENT D.O.
 Caucasian female.
 Born at 38 weeks gestation.
 Birth weight = 5 pounds 7 oz.
 Length = 18 in.
 Head Circumference 12.6 in.
 Apgar: 5 and 6 at 1 min. and 5 min. respectively.
 Guthrie test came back positive for PKU.
 plasma phenylalanine concentration was 8.5 mg/ dL or 508 mol/ L (Normal = 0.5
mg/dL-1.7 mg/dL )
 Second Guthrie test on day 6, 22.0 mg/ dL or 1321 mol phenylalanine/ L plasma.
ASSESSMENT
Small For Gestational Age (Preterm)
No Asymmetrical Growth Retardation
Below Normal Apgar
Difficult Birth
High Phe concentrations
Positive Guthrie Test For PKU
NUTRITION RX:
Started on PKU diet at 7 Days Old.
Estimated Needs (initial):
Phe = 70mg/kg = 2.82 kg (5 # 4 oz at 6 days old)
= 197.59 mg
Pro = 3.5 g/kg = 2.82 kg x 3.5 = 9.87 g
Energy = 120 kcals/kg = 338.4
Fluid = mL/kg = 148mLx 2.82 = 417.36 mL
DIAGNOSIS: SAMPLE PES:
Excessive bioactive substances intake (too
much Phe RT excessive intake of foods high in
Phe amino acids AEB a Phe blood plasma
concentration of 26.4 mg/dL at 6 days old.
Excessive bioactive substances intake (too
much Phenylalanine) RT nutrition-related
knowledge deficit AEB increased levels of Phe
and a Guthrie test positive for PKU.
INTERVENTION
 Control Phe blood plasma concentrations by getting the
mother’s breast milk tested for Phe levels.
 Augment diet with an infant formula low in Phe such as
Periflex
 Educate parents about PKU and a diet low in Phe amino
acids.
 Discuss possible nutrient deficiencies with a low Phe diet
such as Kcals, iron, calcium, B12 and Vit D.
 Emphasize the importance of regular visits with the RD.
MONITORING AND EVALUATION
Monitor lab values for Phe/Tyr.
Monitor albumin/prealbumin.
Do a 24 hr diet recall and typical diet recall in
order to assess Ca, Vit D, and B12 status.
Evaluate the effectiveness of the nutrition
education component
FOLLOW-UP
D.O. breastfeed for 11 mo.
Phe levels within acceptable range.
Family adjusting well to low Phe diet.
Food introduction similar to normal children.
At 13 mo. Phe increased…
IN CLASS ACTIVITY
 Question?
 Why did D.O.’s Phe suddenly increase?
ANSWERS: PER 100G EDIBLE PORTION
Low
 Apple
High
 White Rice
 Egg White
 Yellow cheese
 Marshmallows
 Tofu
 Aspartame
 Sugar
 Beef
 Salmon
 Tomato
 Seaweed
 Buttermilk
 Carrot
 Peanuts
 Peaches
 Dry active
Pumpkin
seeds
 Grapefruit
 Head Lettuce
http://wholefoodcatalog.info/nutrient/phenylala
nine/confectioneries/low/
yeast
 Gelatin
 Pork
CONCLUSIONS:
 PKU is a chronic disease that requires life-long treatment
with a Phe controlled diet.
 According to the Nelms text, a study comparing Phe
concentrations to IQs demonstrated that for every
100umol/L increase in Phe above the target range IQ was
decreased 1.3-3.1 points.
 Proper nutrition is vital for people with this disease.
REFERENCES
 Nelms M, Sucher K, Lacey K, Roth SL. Nutrition Therapy and
Pathophysiology 2/e. United States: Wadsworth Cengage Learning; 2011,
2007.
 Phenylketonuria [Internet]: Federal Government Website; c2012.
Available from: http://ghr.nlm.nih.gov/condition/phenylketonuria
 Birth to 36 months: Head circumference for age and Weight for length
percentiles [internet]: National Center for Health Statistics; c2001.
Available from:
http://www.cdc.gov/growthcharts/data/set1clinical/cj41l020.pdf
 > Nutrients > Phenylalanine > Confectioneries Low in Phenylalanine:
WholeFoodCatalog; c2011. Available from:
http://wholefoodcatalog.info/nutrient/phenylalanine/confectioneries/low/