CONTEXT Idiopathic hyperammonemia is characterized by elevated serum ammonia associated with neurological deterioration of no other obvious etiology associated with relatively normal liver function tests and normal amino-acid levels. CASE REPORT We report a case of a 32-year-old woman who presented with acute mental status changes with a pelvic abscess approximately a year following her total...

Hyperammonemia is commonly encountered in active liver disease. Evaluation of patients having hyperammonemia with normal liver function is difficult. We present a case referred to us as undiagnosed hyperammonemic coma with normal liver function, who was subsequently diagnosed to have Hashimoto's encephalopathy. In patients with hyperammonemia without hepatic dysfunction, one must search for the...

Hyperammonemia is considered the main responsible for the neurological alterations found in liver disease and hepatic encephalopathy, including decreased intelectual and cognitive function. Ammonia affects both excitatory and inhibitory synaptic transmission in the mammalian brain by a variety of mechanisms. LTP is impaired in hyperammonemia and this may contribute to the impairment of cognitiv...

PURPOSE Valproic acid (VPA), which is widely used to treat epilepsy, migraine, and bipolar disorder, can causes severe hyperammonemia. However, the mechanism responsible for this adverse effect is not readily apparent. We previously reported that phenytoin coadministration is a strong risk factor for the development of hyperammonemia during VPA-based therapy. In this study, we focused on glutam...

The effect of hyperammonemia of varying degree and duration on the gamma-glutamyl-transpeptidase (GGT) activity was studied in the homogenates and capillaries of different brain regions of the rat. "Acute" hyperammonemia (750 and 600 mg of ammonium acetate per kg b.w. were injected i.p. at 30 min interval, and the animals were decapitated immediately), in which blood ammonia was increased 14-fo...

The Abernethy malformation is a rare congenital malformation defined by the presence of an extrahepatic portosystemic shunt. Although most patients are asymptomatic, clinical encephalopathy is present in 15% of cases. We present a patient with type 2 Abernethy malformation, hyperammonemia, and encephalopathy. Shunt closure was performed successfully using interventional angiography; however, hy...

Valproic acid is used in the treatment of multiple disorders. Adverse effects from valproic acid include hepatotoxicity, hypotension, metabolic acidosis, and decreased mental status. Valproic acid also causes hyperammonemia. Many physicians assume that this is due to a supratherapeutic valproic acid concentration; when in fact, it can occur with therapeutic valproic acid concentrations. This is...

Citrin deficiency (neonatal-onset type II citrullinemia), is an autosomal recessive metabolic disorder, caused by a mutation of the SLC25A13 gene. The defective transport between the mitochondria and the cytosol, leads to insufficient substrate for argininosuccinate synthetase (ASS) and secondary functional deficiency of ASS activity [1]. Infants with citrin deficiency, have transient intrahepa...

Life-threatening hyperammonemia is uncommon in patients with mitochondrial disorders (MDs).When present, it is usualy due to TMEM70 deficiency [1] and only rarely is it noted in other MDs [2]. Hyperammonemia was documented in patients with Barth syndrome [2], maternally inherited Leigh syndrome (MILS) [3], pyruvate dehydrogenase deficiency [4], pyruvate carboxylase deficiency [5], complex III d...