Management of hepatic encephalopathy. Curr Treat Options Neurol. 2014;16:297. [PMID: 24807164 DOI: 10.1007/s11940-014-0297-2]

Postoperative hyperammonemic encephalopathy due to unexpected constipation in a patient with hyperornithinemia-hyperammonemia-homocitrullinuria syndrome: a case report

BACKGROUND

Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is a rare autosomal recessive urea cycle disorder associated with a high risk of exacerbation of hyperammonemia during the perioperative period. Here, we describe an adult patient with HHH syndrome who developed hyperammonemic encephalopathy secondary to postoperative constipation.

CASE PRESENTATION

A 52-year-old patient with HHH syndrome underwent intrathecal baclofen pump insertion for lower limb spasticity under general anesthesia. The surgery was uneventful, without any increase in serum ammonia levels. However, after surgery, he was constipated, and on postoperative day (POD) 3, he fell into a coma with an exacerbation of hyperammonemia (894 µg/dL). After administering a glycerin enema, he defecated, leading to a rapid decrease in serum ammonia levels to 165 µg/dL. He regained consciousness, and serum ammonia levels remained stable as long as he defecated.

CONCLUSIONS

We suggest strict management of defecation during the perioperative period to prevent hyperammonemia in patients with HHH syndrome.

Drug-induced hyperammonaemia

Hyperammonaemia (HA) as a consequence of numerous primary or secondary causes, gives rise to clinical manifestations due to its toxic effects on the brain. The neurological consequences broadly reflect the ammonia level, duration and age, with paediatric patients being more susceptible. Drug-induced HA may arise due to either decreased ammonia elimination or increased production. This is associated most frequently with use of valproate and presents a dilemma between ongoing therapeutic need, toxicity and the possibility of an alternative cause. As there is no specific test for drug-induced HA, prompt discussion with a metabolic physician is recommended, as the neurotoxic effects are time-dependent. Specific guidelines for managing drug-induced HA have yet to be published and hence the treatment approach outlined in this review reflects that outlined in relevant urea cycle disorder guidelines.

Normalization of lipid oxidation defects arising from hypoxia early posthepatectomy prevents liver failure in mouse

Surgical liver failure (SLF) develops when a marginal amount of hepatic mass is left after surgery, such as following excessive resection. SLF is the commonest cause of death due to liver surgery; however, its etiology remains obscure. Using mouse models of standard hepatectomy (sHx) (68%, resulting in full regeneration) or extended hepatectomy (eHx) (86%/91%, causing SLF), we explored the causes of early SLF related to portal hyperafflux. Assessing the levels of HIF2A with or without oxygenating agent inositol trispyrophosphate (ITPP) indicated hypoxia early after eHx. Subsequently, lipid oxidation (PPARA/PGC1α) was downregulated and associated with persisting steatosis. Mild oxidation with low-dose ITPP reduced the levels of HIF2A, restored downstream PPARA/PGC1α expression along with lipid oxidation activities (LOAs), and normalized steatosis and other metabolic or regenerative SLF deficiencies. Promotion of LOA with L-carnitine likewise normalized the SLF phenotype, and both ITPP and L-carnitine markedly raised survival in lethal SLF. In patients who underwent hepatectomy, pronounced increases in serum carnitine levels (reflecting LOA) were associated with better recovery. Lipid oxidation thus provides a link between the hyperafflux of O₂-poor portal blood, the metabolic/regenerative deficits, and the increased mortality typifying SLF. Stimulation of lipid oxidation-the prime regenerative energy source-particularly through L-carnitine may offer a safe and feasible way to reduce SLF risks in the clinic.

Narrative review of migraine management in patients with renal or hepatic disease

OBJECTIVES/BACKGROUND

Treatment of migraine in the setting of either renal or hepatic disease can be daunting for clinicians. Not only does the method of metabolism have to be considered, but also the method of elimination/excretion of the parent drug and any active or toxic metabolites. Furthermore, it is difficult to think about liver or kidney disease in isolation, as liver disease can sometimes contribute to impaired renal function and renal disease can sometimes impair hepatic metabolism, through the cytochrome P450 system.

METHODS

A detailed search for terms related to liver disease, renal disease, and migraine management was performed in PubMed, Ovid Medline, Embase, and the Cochrane Library.For each medication, product labels were retrieved and reviewed using the US FDA website, with additional review of IBM Micromedex, LiverTox, and the Renal Drug Handbook.

RESULTS

This manuscript provides an overview of migraine drug metabolism and how it can be affected by liver and renal impairment. It reviews the standard terminology recommended by the US Food and Drug Administration for the different stages of hepatic and renal failure. The available evidence regarding the use of abortive and preventative medicines in the setting of organ failure is discussed in detail, including more recent therapies such as lasmiditan, gepants, and calcitonin gene-related peptide antibodies.

CONCLUSIONS

For acute therapy, the use of NSAIDS should be limited, as these carry risk for both severe hepatic and renal disease. Triptans can be selectively used, often with dose guideline adjustments. Ubrogepant may be used in severe hepatic disease with dose adjustment and lasmiditan can be used in end stage renal disease. Though non-medicine strategies may be the most reasonable initial approach, many preventative medications can be used in the setting of hepatic and renal disease, often with dose adjustment. This review provides tables of guidelines, including reduced dosing recommendations, for the use of abortive and preventative migraine medications in hepatic and renal failure.

Acute Liver Failure

Acute liver failure (ALF) is a rare but life-threatening disease process that can result in rapidly progressive encephalopathy, elevated intracranial pressure, and multiorgan failure. In the United States, the 2 most common causes of ALF in the intensive care unit (ICU) are acetaminophen overdose and hypoxic-ischemic hepatopathy. Less common causes of ALF include alcoholic hepatitis, nonacetaminophen drug-induced liver injury, acute viral hepatitis, Wilson's disease, autoimmune hepatitis, and acute fatty liver of pregnancy. Unfortunately, there are many cases in which the cause of liver failure is indeterminate. ALF is an ICU emergency that requires close monitoring, extensive workup to determine etiology, frequent support of hemodynamic, respiratory, and renal function, administration of targeted therapies depending on the cause, utilization of N-acetylcysteine if appropriate, and consideration for liver transplant in select cases. The primary objective of this article is to define, diagnose, and detail the management of ALF in an ICU setting.

Acetyl-L-carnitine for patients with hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy is a common and devastating neuropsychiatric complication of acute liver failure or chronic liver disease. Ammonia content in the blood seems to play a role in the development of hepatic encephalopathy. Treatment for hepatic encephalopathy is complex. Acetyl-L-carnitine is a substance that may reduce ammonia toxicity. This review assessed the benefits and harms of acetyl-L-carnitine for patients with hepatic encephalopathy.

OBJECTIVES

To assess the benefits and harms of acetyl-L-carnitine for patients with hepatic encephalopathy.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE Ovid, Embase Ovid, LILACS, and Science Citation Index Expanded for randomised clinical trials. We sought additional randomised clinical trials from the World Health Organization Clinical Trials Search Portal and ClinicalTrials.gov. We performed all electronic searches until 10 September 2018. We looked through the reference lists of retrieved publications and review articles, and we searched the FDA and EMA websites.

SELECTION CRITERIA

We searched for randomised clinical trials in any setting, recruiting people with hepatic encephalopathy. Trials were eligible for inclusion if they compared acetyl-L-carnitine plus standard care (e.g. antibiotics, lactulose) versus placebo or no acetyl-L-carnitine plus standard care. We are well aware that by selecting randomised clinical trials, we placed greater focus on potential benefits than on potential harms.

DATA COLLECTION AND ANALYSIS

We selected randomised clinical trials, assessed risk of bias in eight domains, and extracted data in a duplicate and independent fashion. We estimated risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes. We measured statistical heterogeneity using I² and D² statistics. We subjected our analyses to fixed-effect and random-effects model meta-analyses. We assessed bias risk domains to control systematic errors. We assessed overall quality of the data for each individual outcome by using the GRADE approach.

MAIN RESULTS

We identified five randomised clinical trials involving 398 participants. All trials included only participants with cirrhosis as the underlying cause of hepatic encephalopathy. Trials included participants with covert or overt hepatic encephalopathy. All trials were conducted in Italy by a single team and assessed acetyl-L-carnitine compared with placebo. Oral intervention was the most frequent route of administration. All trials were at high risk of bias and were underpowered. None of the trials were sponsored by the pharmaceutical industry.None of the identified trials reported information on all-cause mortality, serious adverse events, or days of hospitalisation. Only one trial assessed quality of life using the Short Form (SF)-36 scale (67 participants; very low-quality evidence). The effects of acetyl-L-carnitine compared with placebo on general health at 90 days are uncertain (MD -6.20 points, 95% confidence interval (CI) -9.51 to -2.89). Results for additional domains of the SF-36 are also uncertain. One trial assessed fatigue using the Wessely and Powell test (121 participants; very low-quality evidence). The effects are uncertain in people with moderate-grade hepatic encephalopathy (mental fatigue: MD 0.40 points, 95% CI -0.21 to 1.01; physical fatigue: MD -0.20 points, 95% CI -0.92 to 0.52) and mild-grade hepatic encephalopathy (mental fatigue: -0.80 points, 95% CI -1.48 to -0.12; physical fatigue: 0.20 points, 95% CI -0.72 to 1.12). Meta-analysis showed a reduction in blood ammonium levels favouring acetyl-L-carnitine versus placebo (MD -13.06 mg/dL, 95% CI -17.24 to -8.99; 387 participants; 5 trials; very low-quality evidence). It is unclear whether acetyl-L-carnitine versus placebo increases the risk of non-serious adverse events (8/126 (6.34%) vs 3/120 (2.50%); RR 2.51, 95% CI 0.68 to 9.22; 2 trials; very low-quality evidence). Overall, adverse events data were poorly reported and harms may have been underestimated.

AUTHORS' CONCLUSIONS

This Cochrane systematic review analysed a heterogeneous group of five trials at high risk of bias and with high risk of random errors conducted by only one research team. We assessed acetyl-L-carnitine versus placebo in participants with cirrhosis with covert or overt hepatic encephalopathy. Hence, we have no data on the drug for hepatic encephalopathy in acute liver failure. We found no information about all-cause mortality, serious adverse events, or days of hospitalisation. We found no clear differences in effect between acetyl-L-carnitine and placebo regarding quality of life, fatigue, and non-serious adverse events. Acetyl-L-carnitine reduces blood ammonium levels compared with placebo. We rated all evidence as of very low quality due to pitfalls in design and execution, inconsistency, small sample sizes, and very few events. The harms profile for acetyl-L-carnitine is presently unclear. Accordingly, we need further randomised clinical trials to assess acetyl-L-carnitine versus placebo conducted according to the SPIRIT statements and reported according to the CONSORT statements.

The Measurement of Ammonia in Human Breath and its Potential in Clinical Diagnostics

Ammonia is an important component of metabolism and is involved in many physiological processes. During normal physiology, levels of blood ammonia are between 11 and 50 µM. Elevated blood ammonia levels are associated with a variety of pathological conditions such as liver and kidney dysfunction, Reye's syndrome and a variety of inborn errors of metabolism including urea cycle disorders (UCD), organic acidaemias and hyperinsulinism/hyperammonaemia syndrome in which ammonia may reach levels in excess of 1 mM. It is highly neurotoxic and so effective measurement is critical for assessing and monitoring disease severity and treatment. Ammonia is also a potential biomarker in exercise physiology and studies of drug metabolism. Current ammonia testing is based on blood sampling, which is inconvenient and can be subject to significant analytical errors due to the quality of the sample draw, its handling and preparation for analysis. Blood ammonia is in gaseous equilibrium with the lungs. Recent research has demonstrated the potential use of breath ammonia as a non-invasive means of measuring systemic ammonia. This requires measurement of ammonia in real breath samples with associated temperature, humidity and gas characteristics at concentrations between 50 and several thousand parts per billion. This review explores the diagnostic applications of ammonia measurement and the impact that the move from blood to breath analysis could have on how these processes and diseases are studied and managed.

Endozepine-4 levels are increased in hepatic coma

AIM

To evaluate the serum levels of endozepine-4, their relation with ammonia serum levels, the grading of coma and the severity of cirrhosis, in patients with hepatic coma.

METHODS

In this study we included 20 subjects with Hepatic coma, 20 subjects with minimal hepatic encephalopathy (MHE) and 20 subjects control. All subjects underwent blood analysis, Child Pugh and Model for End - stage liver disease (MELD) assessment, endozepine-4 analysis.

RESULTS

Subjects with hepatic coma showed significant difference in endozepine-4 (P < 0.001) and NH3 levels (P < 0.001) compared both to MHE and controls patients. Between NH3 and endozepine-4 we observed a significant correlation (P = 0.009; Pearson correlation 0.570). There was a significant correlation between endozepine-4 and MELD (P = 0.017; Pearson correlation = 0.529). In our study blood ammonia concentration was noted to be raised in patients with hepatic coma, with the highest ammonia levels being found in those who were comatose. We also found a high correlation between endozepine-4 and ammonia (P < 0.001). In patients with grade IV hepatic coma, endozepine levels were significantly higher compared to other groups.

CONCLUSION

This study suggests that an increased level of endozepine in subjects with higher levels of MELD was observed. In conclusion, data concerning involvement of the GABA-ergic system in HE coma could be explained by stage-specific alterations.