Download 4/18/14 - ERS 4 KIDS

ED Board Questions
 Tamara Gayle, MD
 PGY-1
A 4 year old girl who has the classic form of Maple
Syrup Urine Disease is brought to the emergency
department. She recently started pre-K and has
had a temperature of 39.5 since this morning with
continuous episodes of vomiting. In the ED she
appears very lethargic and is now very difficult to
arouse on exam. She also has crackles heard in the
right lower base.
Of the following the best NEXT step in
management is:
A. Check electrolytes
B. Obtain blood culture
C. CXR
D. CT
E. Start hydration
A. Check electrolytes
B. Obtain blood culture
C. CXR
D. CT
E. Start hydration
What is Maple Syrup Urine
Disease?
 Autosomal recessive
 Due to defect in the Branched Chain Ketoacid
Dehydrogenase (BCKD) enzyme, which catalyzes the
breakdown of branched chain ketoacids
 These ketoacids form from breakdown of branched
chain amino acids: leucine, isoleucine, and valine
 These amino acids accumulate in the blood
 Accumulation of leucine and isoleucine cause
characteristic smell in the urine
Back to the question..
 A metabolic crisis is typically caused by a
stressor such as illness, trauma, etc.
 Management includes:
 Stop all protein intake
 Provide hydration with high caloric
supplementation
 Correct metabolic abnormalities
 Eliminate toxic metabolites
 Treat precipitating factor (s)
 Provide cofactor supplementation
 Prevent associated sequale
Cerebral edema
 “Leucine encephalopathy”
 Increased concentrations of leucine are toxic
 Consider if neurologic signs such as vomiting,
clonus, lethargy, etc develop
 If suspected obtain a CT or MRI
 If confirmed, infuse mannitol at 1-2 grams/kg
over 30-40 minutes
 Add IV lasix for diuresis by carefully monitor
serum sodium
 Most common cause of death in MSUD
You are evaluating a 7mo old male who has Maple
Syrup Urine Disease in the emergency
department. He has not been feeding well for the
past two days, because his parents feel he is
coming down with a flu-like illness and is now
going into metabolic crisis.
Which of the following electrolyte abnormalities
are you MOST likely to find:
A. Metabolic alkalosis and
hypernatremia
B. Metabolic acidosis and hyponatremia
C. Metabolic alkalosis and
hyponatremia
D. Metabolic acidosis and
hypernatremia
E. Respiratory alkalosis and
hyponatremia
A. Metabolic alkalosis and
hypernatremia
B. Metabolic acidosis and hyponatremia
C. Metabolic alkalosis and
hyponatremia
D. Metabolic acidosis and
hypernatremia
E. Respiratory alkalosis and
hyponatremia
Pathophysiology breakdown
 Catabolic stress->endogenous protein breakdown
 Increase in the branched chain amino acids (leucine,
isoleucine, and valine)
 Also occurs with an excessive amount of protein ingestion
 Increased ketoacids and glucose utilization
ketosis

metabolic acidosis
Metabolic acidosis 101
 Slowly correct with rehydration and high caloric
intake
 If serum bicarb is below 14 meq/L and blood pH
<7.2, give IV bolus NaHC03 as 2.5 meq/kg over 30
minutes, then 2.5 meq/kg/day until serum bicarb
is 24-28 meq/L
 Goals:
 Serum bicarb level over 24 mew/L
 Asence of ketones in urine
Sodium management
 Maintain serum sodium at 140-145 meq/L
 Monitor urine sodium loss an replacement
requirement
 As sodium apporaches 140-145meq/L, reduce IV
fluids to D10 1/2NS and monitor sodium closely
 After 24 hours adjust sodium intake to provide
4meq/kg/day
References
 New England Consortium of Metabolic Programs
 Current Diagnosis and Treatment. Pediatrics. Sondheimer et. al. Lange.
 Up to date
 Pediatric Care Online