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MAPLE SYRUP URINE DISEASE
Brittany Taylor
Rebecca Linstead
Overview of Disorder

The body is unable to process leucine, isoleucine
and valine because at least one of the four genes
that code for the enzyme responsible for breaking
down these amino acids has a mutation.
Four Forms of MSUD


Enzyme activity = <2%
Classic neonatal form:
 Most
common; most severe
 Absence or significant decrease in function of the
enzyme branched-chain ketoacid dehydrogenase,
which is needed to break down the branched-chain
amino acids
 Infants don’t show symptoms until days four to seven of
life
Intermediate Form



Enzyme activity = 3-30%
A higher level of enzyme is present than in the
classical form, therefore allowing a higher tolerance
of leucine
Management is the same in both intermediate and
classical forms of MSUD
Intermittent Form





Enzyme activity = 5-20%
Mild form of MSUD
Greater amount of enzyme activity is present
An affected child will not show symptoms until
around 12-24 months of age
Symptoms are usually brought on by a surge in
protein intake or illness
Thiamine-Responsive Form



Enzyme activity = 2-40%
Most rare form
A child with this form may take large doses of
thiamine to increase their enzyme activity
Diagnosis



Suspect of MSUD results from the characteristic
odor of maple syrup in the urine
Confirmed diagnosis with abnormal amounts of keto
acids and amino acids in blood and urine
Serum alanine levels may also be depressed
Genetic Inheritance

Autosomal recessive
 Each
parent carries one normal copy and one mutated
copy of the gene but does not show symptoms
themselves
Signs and Symptoms






Poor appetite
Irritability
Maple smelling urine
Mental retardation
Seizures
Coma and death if
left untreated

Infants will…
 Lose
their sucking
reflex
 Become limp with
episodes of rigidity
Incidence


In the US = 1 in 185,000 births
The Mennonite population in Lebanon and Lancaster
counties of Pennsylvania have an incidence of 1 in
176 newborns
 Founder’s
effect?
Prognosis



Overall very poor if left undetected/untreated
With treatment and proper dietary management,
the prognosis is good
However, severe stress and illness can cause a surge
of certain amino acids
Medical Management of MSUD

Long-term management via diet
 Restriction


of leucine, isoleucine and valine
Treatment of acute metabolic decompensation
Liver transplant may be an option but is associated
with other consequences (transplant mediations for
life)
Goal of Nutritional Management

Ultimate goal is to restrict branched-chain amino
acids while avoiding impairment of growth and
intellectual development
 Maintain
normal levels of branched-chain amino acids,
particularly leucine
General Nutritional Management


Lifelong nutrition support via formulas and foods
with minimal (if any) branched-chain amino acids
Leucine intake is carefully monitored and calculated
following the measurement of plasma branchedchain amino acids
Nutritional Management during Acute
Illness

Situational stress and illness may result in metabolic
decompensation
 Initiate
IV glucose to promote anabolism
 Stop intake of branched-chain amino acids; resume
when levels normalize
 If possible, continue additional dietary support
including lipids and formulas free of branched-chain
amino acids
 Hemodialysis may be necessary to remove toxic
metabolites
Supplements, Formulas and
Medications

Powdered protein supplements that are similar to
whey protein
 Leucine,
isoleucine and valine removed
 Major source of protein for patient


Ketonex makes an infant formula in powdered and
liquid forms that are suitable for infants with MSUD
No medications available for specific treatment of
MSUD
 Isoleucine
diet
and valine may be supplemented back into
Case Study

Anthropometrics:
 Born
full term
 Born 7 lb 3 oz, 19 inches
 Age: 3 years, 1 month
 Height: 94 cm (37 in)  50th percentile
 Weight: 14.3 kg (31.5 lb) 50th percentile
 Length for weight: 75-90th percentile
 Growth patterns have been consistently normal
Family and Social History



Patient lives with mother, step father, two older
sisters (13 and 14 years of age) and three stepsiblings (14 y/o male, two 12 y/o females)
Family receives WIC services and had an
appointment scheduled with Early Intervention as of
last visit
Insurance coverage through Medicaid; Children’s
Special Services provides low protein foods and
helps cover medical expenses if not covered by
Medicaid
Family and Social History

Family seems to care for patient very well
 Dad
is literate and understands ROSS Family Guide
booklet as well as need for diet changes
 Feeds patient through G-tube
 Mother
attends G-tube clinic and changes is G-tube
 Grandparents


assist in care
Patient is enrolled in HeadStart
Receptive language increasing; says approximately
six words
Prenatal History

Normal Pregnancy!
 Prenatal
vitamin and iron supplement
 Visited doctor regularly
 Gained 30 lbs
 No family hx of DM, heart disease or food allergies
Health History

Had problems with poor suckling and electrolyte
imbalances
 Received
breast milk and Ketonex via NG tube due to
his poor suck
 Initiated thickened liquids and some solid foods but was
not obtaining enough nutrients
 PEG tube was placed to provide patient with nutrients
due to dysphagia
 As of most recent visit, mother reports dysphagia has
resolved but no notation of latest swallow test; patient
now with some PO intake but still with EN via PEG
Health History (cont)



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
No food allergies
8 teeth on both top and bottom row
Current medications: isoleucine and valine
No mention of smoking or alcohol abuse in home
Activity level: cannot ride a tricycle; is able to
partially dress himself; goes up and down the stairs;
No lifestyle modifications needed at this time as
patient is at appropriate height and weight
Feeding Skills and Behavior



Will feed himself with his fingers but will not use a
fork or spoon – there may be some fine-motor
delay; may also have a language delay
Has full range of motion
Parenting skills are good
 Advanced
formula preparation
Eating Habits


Good appetite
Eating more solid foods but is still dependent on
PEG tube
 Enjoys
cereal, oatmeal and pizza
Present Intake

Last food record:
 Captain
Crunch, Kool-aide, chicken nuggets, fruit rollup, apple juice, grape soda, cheese pizza, oatmeal

Evaluation of intake:
 100%
of kcal, 402% of protein, 148% of CHO
 Isoleucine: 326 mg (165-325 mg/day)100%
 Leucine: 593 mg (275-535 mg/day)111%
 Valine: 396 (190-400 mg/day) 100%
Biochemical Information

Most recent data:
 Prealbumin:
18 mg/dl
 Glucose: 68 mg/dl
 Bicarb: 28 mEq/L

All normal!
Findings

ICD-9 Codes
 270.3=
MSUD
 V44.1= G-Tube


Inadequate oral intake related to dysphagia and
feeding difficulties as evidenced by majority of
nutritional needs met through enteral feedings
Altered nutrient utilization related to inborn error of
metabolism-MSUD as evidenced by hx of elevated
leucine with restrictions needed to keep within range
Recommendations


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Continue with current regimen of 125 g of Ketonex1, 55 g of Ketonex-2 and 32 g of Good Start, 3 ml
of isoleucine and 6 ml of valine with water to total
40 ounces
Administer 5-8oz feedings throughout the day into
PEG tube
Encourage low protein PO intake
Presenting Information to Family

No barriers noted in chart regarding literacy or
ability to care for patient
 All
their ducks are in a row
Role of MNT

Rationale for recommendations:
 Dietary
restrictions will limit branched-chain amino
acids, specifically leucine
 Prevention
of toxic build-up of these amino acids and their
metabolites
 Enteral
nutrition continued as we are unsure of
dysphagia status and patient still has difficulty feeding
himself
 Maintain adequate calorie and protein intake to
promote growth
Role of RD


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To provide family and patient with support and
recommendations regarding MNT
To modify the diet as needed to keep amino acids
within target ranges
To act as a resource
References
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http://ghr.nlm.nih.gov/condition/maple-syrup-urine-disease

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2044.1996.tb12568.x/pdf
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http://emedicine.medscape.com/article/946234-medication#2
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http://newenglandconsortium.org/for-professionals/acute-illness-protocols/organic-aciddisorders/maple-syrup-urine-disease-msud
http://www.wvdhhr.org/nbms/diseases/Maple_Syrup_Urine_Disease.asp
http://www.uic.edu/classes/phar/phar332/Clinical_Cases/aa%20metab%20cases/MSUD/
Diagnostics_of_MSUD.html
http://www.newbornscreening.info/Parents/aminoaciddisorders/MSUD.html