1. INBORN ERRORS OF METABOLISM
Soumya Ranjan Parida
Basic B.Sc. Nursing 4th
year
Sum Nursing College
2. INBORN ERRORS OF METABOLISM
Introduction –
Inborn errors of metabolism are a group of metabolic disorders
caused by deficiency of an enzyme required for the formation of a
protein or for catalyzing a biochemical reaction in body.
IEM are divided into six subgroups –
1 Aminoacidurias
a) Disorders of aminoacid metabolism
b) Urea cycle defects
c) Disorders of fatty acid oxidation
d) Disorders of organic acids
2 Disorders of carbohydrate metabolism
3 Lysosomal storage defects
4 Peroxisomal disorders
5 Endocrine disorders
6 Miscellaneous diseases
3. Diagnostic approach to neurometabolic disorders
When to suspect IEM
History of unexplained deaths in the neonatal period
Parental consanguinity
In the neonatal period –
Lethargy, poor feeding, persistent vomiting, intractable seizures,
tachypnea, floppyness, unusual body/ urine odor, failure to thrive
Always r/o sepsis and HIE
On examination –
Skin and hair changes,
Hepatomegaly,
Jaundice,
Hypotonia,
Unexplained neurological signs and coma,
Ambiguous genitalia
4. Diagnostic approach to neurometabolic disorders
Older children –
- Recurrent episodes of sensorial derangement,
- Vomiting, hypotonia,
- Hypoglycemia and acidosis
- Unexplained development delay with or without seizures,
- Mental retadation,
- Organomegaly,
- Coarse facies,
- Cataract,
- Dislocated lenses,
- Chronic skin lesions,
- Abnormal hair and urine color,
- FTT
13. Blood ph, HCO3
Acidosis No acidosis
Obtain
organic acids
Obtain plasma
Amino acidosis
Specific amino
acid elevation
No specific amino
acic elevation
Obtain urine
orotic acid
High Normal or low
Obtain plasma citruline
Low Normal or elevated
Organic
acidemia
Citrullinemia Argininemia Arginosuccinic
acidemia
HHH
syndrome
OTC
deficiency CPS or NAG
synthase deficiency
Than
Clinical apprach to Hyperammonia
14. Treatment of hyperammonemia
• Provide adequate calories, fluid and electrolytes
• Give priming dose of following –
• To be added to 20 ml/kg of 10% glucose and infuse with in 1-2
hours
Sodium benzoate 250mg/kg
Sodium phenylacetate250mg/kg
Arginine hydrochloride 200-600mg/kg
• These compounds are prepared as 1-2% solution for IV use
• Higher doses are needed for Citrullinemia and argininsuccinic
aciduria
• Continue infusion of above following the priming doses
• Initiate peritonial or hemodialysis if above treatment fails