hyperammonemia


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hyperammonemia

 [hi″per-am″mo-ne´me-ah]
elevated levels of ammonia or its compounds in the blood. A congenital form occurs in two types: Type 1, due to deficiency of the enzyme ornithine carbamoyltransferase, is marked by vomiting, lethargy, coma, and hepatomegaly; symptoms are aggravated by protein ingestion. Type 2, due to deficiency of the enzyme carbamoyl phosphate synthetase (ammonia), is marked by vomiting, lethargy, and flaccidity and by elevated plasma and urinary levels of glycine. Hyperammonemia may also occur in nongenetic diseases such as severe liver disease.

am·mo·ne·mi·a

, ammoniemia (am'ō-nē'mē-ă, am'ō-ne-ē'mē-ă),
The presence of ammonia or some of its compounds in the blood, thought to be formed from the decomposition of urea; it usually results in subnormal temperature, weak pulse, gastroenteric symptoms, and coma.
Synonym(s): hyperammonemia
[ammonia + G. haima, blood]

hyperammonemia

/hy·per·am·mo·ne·mia/ (-am″o-ne´me-ah) a metabolic disturbance marked by elevated levels of ammonia in the blood.

hyperammonemia

[hī′pəram′ōnē′mē·ə]
Etymology: Gk, hyper + (ammonia), haima, blood
abnormally high levels of ammonia in the blood. Ammonia is produced in the intestine, absorbed into the blood, and detoxified in the liver. It is also generated as a by-product of protein metabolism. An increased production of ammonia or a decreased ability to detoxify it increases the blood levels of ammonia. The disorder is controlled by low-protein diets, including essential amino acid mixtures. Untreated, the condition leads to hepatic encephalopathy, characterized by asterixis, vomiting, lethargy, coma, and death.

hyperammonemia

Metabolism A heterogeneous group of five largely AR inborn errors of metabolism; each has a defect in a urea cycle enzyme–arginase, argininosuccinase, argininosuccinic acid synthetase, carbamyl phosphate synthetase, ornithine transcarbamylase; all begin in late infancy or childhood, except arginase deficiency, which is neonatal Clinical Accumulation of urea precursors–eg, ammonia, glutamine causes progressive lethargy, hyperthermia, apnea, hyperammonemia Diagnosis may be established in utero by restriction fragment–RFLP analysis Treatment Restrict dietary protein; activate alternate pathways of waste nitrogen excretion–eg, sodium benzoate or dietary supplementation with arginine

hyperammonemia, hyperammoniemia

1. the presence of ammonia in excess of the normal range of concentration of ammonia in the blood.
2. a metabolic disorder marked by elevated levels of ammonia or ammonium ion in the blood. One of the effects of severe hepatic dysfunction. May cause hepatic encephalopathy.
References in periodicals archive ?
Synlogic announced the presentation of the expanded clinical data set from its first-in-human Phase 1 study of SYNB1020, a Synthetic Biotic medicine being developed for the treatment of hyperammonemia associated with urea cycle disorders, or UCDs, and cirrhosis.
Ingestion of Lactobacillus strain reduces anxiety and improves cognitive function in the hyperammonemia rat.
OCR-002 is an ammonia scavenger and has been granted orphan drug designation and fast track status by the US Food and Drug Administration for the treatment of hyperammonemia and resultant hepatic encephalopathy in patients with acute liver failure and acute-on-chronic liver disease.
The higher BCAA dose promoted hyperammonemia, which explains the reduction in performance.
Ocera's developmental product OCR-002, with intravenous and oral formulations, is being studied for treatment of hepatic encephalopathy, a neuropsychiatric syndrome related to hyperammonemia (excess ammonia in the blood), a complication of acute or chronic liver disease.
SYNB1020, is a novel, first-in-class, synthetic biotic medicine that is orally delivered and designed to treat elevated blood ammonia levels, or hyperammonemia, in genetic urea cycle disorders (UDDs) or in chronic liver disease.
Ocera's developmental product OCR-002, an ammonia scavenger, is being studied for treatment of hepatic encephalopathy, a neuropsychiatric syndrome associated with hyperammonemia, a complication of acute or chronic liver disease.
Serum sodium less than 120 mg/dL, hyperammonemia, and electrocardiogram changes (wide QRS, elevated ST, inverted T wave) may be identified (Collins, 2016; Feng et al.
7 mg/dL), hyperammonemia (19-60 mg/dL), increased AST-ALT level (AST >40 U/L, ALT >41 U/L) were also recorded.
Urea cycle disorders are a group of diseases associated with hyperammonemia, which causes severe neurological sequelae, seizures and psychomotor retardation.
The neuronal dysfunction of HE is due to hyperammonemia, which is a consequence of impaired metabolic capacity of the urea cycle in the liver and intra- and extrahepatic portosystemic shunting of blood related to portal hypertension.
When researchers induced hyperammonemia in cirrhotic patients, an increase in ADC in brain white matter was observed, supporting excess ammonia in the blood as a mechanism driving cerebral edema (Mardini et al.