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Don’t be overwhelmed knowing/memorizing each inborn error of metabolism. The basic approach is actually quite easy!!!

Inborn Errors of Metabolism (IEM)

  • Almost always result in one of the following three clinical abnormalities
    • Buildup of toxins
      • Ammonia
        • To test for this, obtain an ammonia level
    • Buildup of acids
      • Methylmalonic acidemia
        • To test for this, obtain electrolyte panel and look for decrease CO2
    • Shortage of glucose
      • Glycogen storage disorders
        • To test for this, obtain a blood glucose level

Congenital Adrenal Hyperplasia (CAH)

  • Decreased 21-hydroxylase enzyme
  • Physiologic abnormalities
    • Decreased aldosterone
      • Low sodium (hyponatremia)
      • High potassium (hyperkalemia)
    • Decreased cortisol
      • Low glucose level
      • Hyperpigmentation
    • INCREASED sex hormone (androgens)
      • Fused labia
      • Partial male genitalia

Additional Reading