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The Follow-Up Metabolic Medicine Hospital Consultation
Published in Michael M. Rothkopf, Jennifer C. Johnson, Optimizing Metabolic Status for the Hospitalized Patient, 2023
Michael M. Rothkopf, Jennifer C. Johnson
The administration of amino acids may drive the additional production of ammonia. The added burden of processing the amino acid–derived ammonia may worsen the condition of the already compromised hepatocytes and raise ammonia levels. In this setting, specialized high branched chain amino acid formulations may be useful. On occasion, we have discovered undiagnosed disorders of the urea cycle in patients with persistent hyperammonemia. Such cases are rare but can be very fulfilling for the astute metabolist. It demonstrates the depth of our metabolic understanding and comprehension.
Inborn Errors of Metabolism
Published in Praveen S. Goday, Cassandra L. S. Walia, Pediatric Nutrition for Dietitians, 2022
Surekha Pendyal, Areeg Hassan El-Gharbawy
Newborn infants appear normal at birth and may be asymptomatic in the first 24–48 hours but then become lethargic, irritable, feed poorly, and vomit. These symptoms can progress rapidly resulting in a hyperammonemic crisis, seizures, coma, and death if not treated immediately. Hyperammonemia is the hallmark of UCDs with peak ammonia concentrations >500 μmol/L in most neonatal patients at presentation. Individuals with partial enzyme activity may not be diagnosed with a UCD until faced with a high protein load, growth spurt, puberty, menarche, a catabolizing illness, or surgery. Infants and children diagnosed late can present with malnutrition, chronic neurological symptoms, and episodic encephalopathy with lethargy, ataxia, and seizures. Adolescents and adults can present with chronic neurological or psychiatric problems, episodes of disorientation, or lethargy. Late-onset diagnosis is particularly common in female carriers of OTC deficiency.
Introduction to hyperammonemia and disorders of the urea cycle
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
The treatment of the patient with hyperammonemia has many common features relevant to states of elevated ammonia, regardless of cause. Therapy must not be delayed because coma duration of less than 1.5 days [8] and timely start of treatment are the most important determinants of outcome. Specialized pediatric hospitals should have first-line medications, consensus-based treatment-protocols and should act according or similar to the following principles of a recently published guideline [9]: Nothing by mouth. Stop protein intake. Immediately start infusion of 10% glucose.Tailor i.v. fluid and glucose substitution (see Table 25.1).Start first-line medication (see Table 25.2).Collect plasma and urine for diagnostic purposes without delaying therapy.
Preclinical and clinical developments in enzyme-loaded red blood cells: an update
Published in Expert Opinion on Drug Delivery, 2023
Marzia Bianchi, Luigia Rossi, Francesca Pierigè, Sara Biagiotti, Alessandro Bregalda, Filippo Tasini, Mauro Magnani
Hyperammonemia is mostly caused by chronic liver diseases and congenital defects in the urea cycle’s enzymes. As reviewed in Rossi et al. [8], the excessive ammonium blood concentration is neurotoxic, producing many neurological complications, such as hepatic encephalopathy, convulsions, up to coma and death, and currently available medications are not completely successful. Erythrocyte-bioreactors, containing enzymes that process ammonium, have been proposed to remove this byproduct of many reactions from the blood [11,12,13]; the most promising ones were engineered to co-encapsulate glutamate dehydrogenase (GDH) and alanine aminotransferase (ALT) (Figure 2), thus creating a metabolic pathway where α-ketoglutarate and L-glutamic acid were produced and consumed cyclically [55]. However, the low encapsulation rate of a commonly employed bovine liver GDH made the clinical use of this approach unfeasible. Recently, in Borsakova et al. [56], new bioreactors containing ALT and a non-aggregating new bacterial GDH enzyme from Proteus species at higher loading were produced, and the efficacy of these erythrocytes was demonstrated in vitro. The ammonium consumption rate increased linearly with an increase in encapsulated GDH activity and in accordance with alanine production, which indicated the joint functioning of both encapsulated enzymes. These preliminary results defined the most promising conditions to achieve therapeutic efficacy of such bioreactors and for their future clinical use as treatment to reduce ammonia levels.
Phytochemical constituents and protective efficacy of Schefflera arboricola L. leaves extract against thioacetamide-induced hepatic encephalopathy in rats
Published in Biomarkers, 2022
Ali M. El-Hagrassi, Abeer F. Osman, Mostafa E. El-Naggar, Noha A. Mowaad, Sahar Khalil, Manal A. Hamed
Hepatic encephalopathy (HE) is one of the most dangerous side effects of liver diseases. It is a neuropsychiatric syndrome that develops as a result of acute or chronic liver failure. Anxiety, shorter attention span, sleep problems, personality change, impaired consciousness levels that eventually progresses to coma may appear as a result of HE and depending on the original cause of the existing liver injury (Lopez-Franco et al. 2021). Patients with HE have an exceedingly high death rate, ranging from 50 to 90% (Allampati and Mullen 2019). The pathophysiology of HE is complicated and the variables that link hepatic and neural system damage are still unknown (Wijdicks 2016). Hyperammonemia, on the other hand, is widely accepted as the cause of HE’s clinical, pathological, and neurochemical alterations. Others have suggested that HE development is influenced by inflammation (Sun et al. 2020) and oxidative stress (Montes-Cortes et al. 2018). Therefore, finding and testing effective techniques to treat and protect against acute liver and brain injury is a challenge.
Hyperammonemia in the setting of Roux-en-Y gastric bypass presenting with osmotic demyelination syndrome
Published in Journal of Community Hospital Internal Medicine Perspectives, 2021
Carly Rosenberg, Michael Rhodes
Hyperammonemia is most commonly associated with liver disease. It can cause a multitude of neurotoxic effects such as cerebral edema, brain herniation and ultimately death. Multiple case reports have now shown that Roux-en-Y gastric bypass (RYGB) can be a causative factor of hyperammonemia in the absence of liver disease [1–4]. The exact underlying mechanism is not entirely clear, but due to alteration of the gut microbiome in association with nutritional deficiencies, these are thought to be the two main reasons for increased ammonia level [1]. Although more commonly hyperammonemia neurotoxicity would be expected to cause cerebral edema, we present a case of a patient with a history of RYGB who unfortunately developed osmotic demyelination syndrome. Osmotic demyelination syndrome was speculated to be secondary to hyperammonemia. Few case reports have made this association previously; however, there is a possible underlying relationship between the two [5,6].