Hyperammonemia

Hyperammonemia
Classification and external resources

Ammonia
ICD-10 E72.2
ICD-9 270.6
DiseasesDB 20468
eMedicine neuro/162 ped/1057
MeSH D022124

Hyperammonemia (or hyperammonaemia) is a metabolic disturbance characterised by an excess of ammonia in the blood. It is a dangerous condition that may lead to encephalopathy and death. It may be primary or secondary.

Ammonia is a substance that contains nitrogen. It is a product of the catabolism of protein. It is converted to the less toxic substance urea prior to excretion in urine by the kidneys. The metabolic pathways that synthesize urea are located first in the mitochondria and then into the cytosol. The process is known as the urea cycle, which comprises several enzymes acting in sequence.

Contents

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Types

Primary vs. secondary

Specific types

The following list includes such examples:

Treatment

Treatment centers on limiting intake of ammonia and increasing its excretion. Dietary protein (a source of ammonium) is restricted and caloric intake is provided by glucose and fat. Intravenous sodium phenylacetate and sodium benzoate are pharmacologic agents commonly used as adjunctive therapy to treat hyperammonemia in patients with urea cycle enzyme deficiencies.[1] Sodium phenylacetate and sodium benzoate can serve as alternatives to urea for the excretion of waste nitrogen. Phenylacetate conjugates with glutamine to form phenylacetylglutamine, which is excreted by the kidneys. Similarly, sodium benzoate reduces ammonia content in the blood by conjugating with glycine to form hippuric acid, which is rapidly excreted by the kidneys.[2] A preparation containing sodium phenylacetate and sodium benzoate is available under the trade name Ammonul. Acidification of the intestinal lumen using lactulose can decrease ammonia levels by protonating ammonia and trapping it in the stool. This is a treatment for hepatic encephalopathy.

Sequelae

Hyperammonemia is one of the metabolic derangements that contribute to hepatic encephalopathy.

See also

References

  1. ^ eMedicine - Hyperammonemia : Article by Kazi Imran Majeed
  2. ^ Ammonul (Sodium Phenylacetate and Sodium Benzoate Injection) clinical pharmacology - prescription drugs and medications at RxList

External links