Severe hyperammonaemia in adults not explained by liver disease

Annals of Clinical Biochemistry
Valerie Walker

Abstract

Ammonia is produced continuously in the body. It crosses the blood-brain barrier readily and at increased concentration it is toxic to the brain. A highly integrated system protects against this: ammonia produced during metabolism is detoxified temporarily by incorporation into the non-toxic amino acid glutamine. This is transported safely in the circulation to the small intestine, where ammonia is released, carried directly to the liver in the portal blood, converted to non-toxic urea and finally excreted in urine. As a result, plasma concentrations of ammonia in the systemic circulation are normally very low (<40 μmol/L). Hyperammonaemia develops if the urea cycle cannot control the ammonia load. This occurs when the load is excessive, portal blood from the intestines bypasses the liver and/or the urea cycle functions poorly. By far, the commonest cause is liver damage. This review focuses on other causes in adults. Because they are much less common, the diagnosis may be missed or delayed, with disastrous consequences. There is effective treatment for most of them, but it must be instituted promptly to avoid fatality or long-term neurological damage. Of particular concern are unsuspected inherited defects of the urea cycle an...Continue Reading

Citations

Oct 10, 2013·Journal of Anaesthesiology, Clinical Pharmacology·Tanmoy GhatakArmin Ahmed
Jul 9, 2013·Medicina clínica·Luis Téllez VillajosVíctor Moreira Vicente
Jan 27, 2015·Journal of Hepatology·Fabrizio A PradoJair A de Oliveira
May 5, 2016·Case Reports in Critical Care·Gyanendra AcharyaHarmanjot Kaur
Jan 18, 2014·BMC Neuroscience·Jeng-Rung ChenTsyr-Jiuan Wang
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Dec 29, 2020·World Journal of Gastroenterology : WJG·Zhi-Peng YaoHong-Liang Wang

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Methods Mentioned

BETA
deamidation
biopsy
amidation
biopsies
deamination
electrophoresis

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