Inborn errors of metabolism: Difference between revisions
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*Must rule-out sepsis (more common in these pts) | *Must rule-out sepsis (more common in these pts) | ||
== | ==Clinical Features== | ||
Exam and history: | Exam and history: | ||
* Lethargic (2/2 hyperammonia encephelopathy) | * Lethargic (2/2 hyperammonia encephelopathy) | ||
* Nausea/vomiting | *[[Nausea]]/[[vomiting]] | ||
* Difficulty feeding | * Difficulty feeding | ||
* Seizure | * [[Seizure]] | ||
* Unusual odors | * Unusual odors | ||
* Hypotonia | * Hypotonia | ||
*Encephalopathy | *Encephalopathy | ||
*Hypoglycemia | *[[Hypoglycemia]] | ||
*Hepatic dysfunction | *Hepatic dysfunction | ||
== | ==Differential Diagnosis== | ||
{{Sick neonate DDX}} | |||
==Diagnosis== | |||
*Glucose level | |||
*Ammonia | *Ammonia | ||
** | **Should be <200 in normal neonate (higher suggests urea cycle disorders) | ||
*Lactate | |||
*Chemistry | *Chemistry | ||
**Anion gap a/w organic acidemias | |||
**May see hypoglycemia, metabolic acidosis | **May see hypoglycemia, metabolic acidosis | ||
*UA (ketones) | *UA (ketones) | ||
*LFT | *LFT | ||
*VBG | *VBG | ||
== | ==Management== | ||
''Must stop catabolism and acculmulation of toxins/ammonia'' | |||
*[[Normal saline]] 20 mL/kg boluses | |||
**Once rehydrated switch to IVF with dextrose at 1-1.5x maintenace | |||
* IVF with | |||
**Increase renal excretion of toxic metabolites | **Increase renal excretion of toxic metabolites | ||
*Keep NPO | *Keep NPO | ||
| Line 62: | Line 45: | ||
***(Na phenylacetate & Na benzoate) 250mg/kg in D10 over 90min; then 250 mg/kg/d infusion | ***(Na phenylacetate & Na benzoate) 250mg/kg in D10 over 90min; then 250 mg/kg/d infusion | ||
***Arginine 210mg/kg IV/IO in D10 over 90min; then 210 mg/kg/d infusion | ***Arginine 210mg/kg IV/IO in D10 over 90min; then 210 mg/kg/d infusion | ||
**> | **>500 | ||
***Dialysis | ***Dialysis | ||
* NaBicarb if acidotic | |||
*Cerebral edema | *Cerebral edema | ||
**Hyperammonemia is risk factor | **Hyperammonemia is risk factor | ||
***Give mannitol 0.5gm/kg IV/IO | ***Give mannitol 0.5gm/kg IV/IO | ||
***Do not give steroids (worsens hyperammonemia) | ***Do not give steroids (worsens hyperammonemia) | ||
*If seizing: consider Vitamin B6 (pyroxidine) | |||
* Consider L-carnitine in conjuction with specialist, as some diseases may respond (but has side effects) | |||
==See Also== | ==See Also== | ||
*[[Neonatal Resuscitation]] | *[[Neonatal Resuscitation]] | ||
==References== | |||
[[Category:Peds]] | [[Category:Peds]] | ||
[[Category:Endo]] | [[Category:Endo]] | ||
Revision as of 17:14, 10 May 2015
Background
- Suspect in any sick neonate
- Newborn screening varies by state
- May present as late as early childhood
- Clinical manifestations are due to accumulation of toxic metabolites
- Must rule-out sepsis (more common in these pts)
Clinical Features
Exam and history:
- Lethargic (2/2 hyperammonia encephelopathy)
- Nausea/vomiting
- Difficulty feeding
- Seizure
- Unusual odors
- Hypotonia
- Encephalopathy
- Hypoglycemia
- Hepatic dysfunction
Differential Diagnosis
Sick Neonate
THE MISFITS [1]
- Trauma
- Heart
- Congenital heart disease
- Hypovolemia
- Endocrine
- Metabolic
- Sodium
- Calcium
- Glucose
- Inborn errors of metabolism
- Seizure
- Formula / feeding problems
- Intestinal Disasters
- Toxin
- Sepsis
Diagnosis
- Glucose level
- Ammonia
- Should be <200 in normal neonate (higher suggests urea cycle disorders)
- Lactate
- Chemistry
- Anion gap a/w organic acidemias
- May see hypoglycemia, metabolic acidosis
- UA (ketones)
- LFT
- VBG
Management
Must stop catabolism and acculmulation of toxins/ammonia
- Normal saline 20 mL/kg boluses
- Once rehydrated switch to IVF with dextrose at 1-1.5x maintenace
- Increase renal excretion of toxic metabolites
- Keep NPO
- Removes potential inciting metabolic substrates
- Provide D10 at 2x usual maintenance rates
- Hyperammonemia
- <500
- (Na phenylacetate & Na benzoate) 250mg/kg in D10 over 90min; then 250 mg/kg/d infusion
- Arginine 210mg/kg IV/IO in D10 over 90min; then 210 mg/kg/d infusion
- >500
- Dialysis
- <500
- NaBicarb if acidotic
- Cerebral edema
- Hyperammonemia is risk factor
- Give mannitol 0.5gm/kg IV/IO
- Do not give steroids (worsens hyperammonemia)
- Hyperammonemia is risk factor
- If seizing: consider Vitamin B6 (pyroxidine)
- Consider L-carnitine in conjuction with specialist, as some diseases may respond (but has side effects)
See Also
References
- ↑ Brousseau T, Sharieff GQ. Newborn emergencies: the first 30 days of life. Pediatr Clin North Am. 2006 Feb;53(1):69-84, vi.