Hyperammonemia: Difference between revisions
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==Background== | ==Background== | ||
===Pathophysiology=== | |||
*Acquired: liver failure results in shunting of blood from the liver to the inferior vena cava, decreased filtration of blood and removal of nitrogen-containing toxins by the liver, and then hyperammonemia. | |||
*Congenital: Defect in one of the enzymes of the urea cycle, which leads to lower production of urea from ammonia. | |||
===Types=== | |||
====Primary vs. secondary==== | |||
*Primary | |||
**Caused by several [[inborn errors of metabolism]] | |||
**Characterized by reduced activity of urea cycle enzymes | |||
*Secondary | |||
**Caused by inborn errors of intermediary metabolism (i.e. reduced activity of enzymes that are not part of the urea cycle) | |||
***Normally from acute or chronic [[liver failure]] | |||
====Acquired vs. congenital==== | |||
*Acquired | |||
**Diseases that result in [[liver failure]] | |||
**Medications (e.g. [[valproic acid]] overdose) | |||
*Severe dehydration (from small intestinal bacterial overgrowth) | |||
*Glycine toxicity (CNS symptoms and nausea) | |||
*Congenital | |||
**Genetic | |||
====Specific types==== | |||
The following list includes such examples: | |||
* {{OMIM|311250}} - hyperammonemia due to [[ornithine transcarbamylase deficiency]] | |||
* {{OMIM|606762}} - [[hyperinsulinism-hyperammonemia syndrome]] ([[glutamate dehydrogenase 1]]) | |||
* {{OMIM|238970}} - [[hyperornithinemia-hyperammonemia-homocitrullinuria]] | |||
* {{OMIM|237310}} - hyperammonemia due to [[N-acetylglutamate synthetase deficiency]] | |||
* {{OMIM|237300}} - hyperammonemia due to [[carbamoyl phosphate synthetase I deficiency]] ([[carbamoyl phosphate synthetase I]]) | |||
* {{OMIM|238750}} - [[hyperlysinuria]] with hyperammonemia (genetics unknown) | |||
* [[Methylmalonic acidemia]] | |||
* [[Isovaleric acidemia]] | |||
* [[Propionic acidemia]] | |||
* [[Carnitine palmitoyltransferase II deficiency]] | |||
* [[Transient hyperammonemia of the newborn]], specifically in the preterm | |||
==Clinical Features== | ==Clinical Features== | ||
Revision as of 10:23, 18 July 2020
Background
Pathophysiology
- Acquired: liver failure results in shunting of blood from the liver to the inferior vena cava, decreased filtration of blood and removal of nitrogen-containing toxins by the liver, and then hyperammonemia.
- Congenital: Defect in one of the enzymes of the urea cycle, which leads to lower production of urea from ammonia.
Types
Primary vs. secondary
- Primary
- Caused by several inborn errors of metabolism
- Characterized by reduced activity of urea cycle enzymes
- Secondary
- Caused by inborn errors of intermediary metabolism (i.e. reduced activity of enzymes that are not part of the urea cycle)
- Normally from acute or chronic liver failure
- Caused by inborn errors of intermediary metabolism (i.e. reduced activity of enzymes that are not part of the urea cycle)
Acquired vs. congenital
- Acquired
- Diseases that result in liver failure
- Medications (e.g. valproic acid overdose)
- Severe dehydration (from small intestinal bacterial overgrowth)
- Glycine toxicity (CNS symptoms and nausea)
- Congenital
- Genetic
Specific types
The following list includes such examples:
- Template:OMIM - hyperammonemia due to ornithine transcarbamylase deficiency
- Template:OMIM - hyperinsulinism-hyperammonemia syndrome (glutamate dehydrogenase 1)
- Template:OMIM - hyperornithinemia-hyperammonemia-homocitrullinuria
- Template:OMIM - hyperammonemia due to N-acetylglutamate synthetase deficiency
- Template:OMIM - hyperammonemia due to carbamoyl phosphate synthetase I deficiency (carbamoyl phosphate synthetase I)
- Template:OMIM - hyperlysinuria with hyperammonemia (genetics unknown)
- Methylmalonic acidemia
- Isovaleric acidemia
- Propionic acidemia
- Carnitine palmitoyltransferase II deficiency
- Transient hyperammonemia of the newborn, specifically in the preterm