Overnight glucose infusion suppresses renal ammoniagenesis and reduces hyperammonaemia induced by a simulated bleed in cirrhotic patients

Severe hyperammonemia from intense skeletal muscle activity: A rare case report and literature review

RATIONALE

Adult hyperammonemia is most often the result of hepatic dysfunction. Hyperammonemia in the setting of normal hepatic function is a much less common phenomenon and has usually been associated with medications and certain disease states. Here, we present an unusual case of severe hyperammonemia caused physiologically by intense muscle activity in a patient lacking any evidence of liver disease.

PATIENT CONCERNS

A 36-year-old woman was brought to the emergency department for a suicide attempt after being found covered in Lysol and Clorox germicidal bleach. She was noted to be in a state of violent psychosis with extreme agitation and had to be sedated and intubated for airway protection.

DIAGNOSIS AND INTERVENTIONS

Initial labs revealed hyperammonemia, lactic acidosis, and anion gap metabolic acidosis. Aminotransferases, bilirubin, and creatine kinase (CK) were normal. Renal function, prothrombin time, activated partial thromboplastin time, and international normalized ratio were also unremarkable and remained so at 24 hours. Ethyl alcohol, acetaminophen, salicylate, and valproic acid were all undetectable in blood. She received 2 doses of lactulose overnight, with a subsequent bowel movement. Next day, her mentation, serum ammonia level, and lactic acid level were back to normal, and she was extubated. Aminotransferases and CK levels were elevated but improved with supportive care. A detailed history and relevant biochemical investigations were unremarkable for any other etiology of hyperammonemia including the common inborn errors of metabolism (IEM). The combination of clinical findings of extreme skeletal muscle activity along with hyperammonemia and lactic acidosis, and subsequently rhabdomyolysis in the setting of unremarkable history and otherwise normal hepatic function strongly suggest the myokinetic origin of hyperammonemia in the patient.

OUTCOME

The patient recovered well with supportive care and was discharged on day 5.

LESSONS

This unique case illustrates the important role of skeletal muscle in the human metabolism of ammonia. In our discussion, we also elucidate the underlying pathophysiology, with the objective of improving clinician understanding of various differential diagnoses.

Repeated Measures of Blood and Breath Ammonia in Response to Control, Moderate and High Protein Dose in Healthy Men

Ammonia physiology is important to numerous disease states including urea cycle disorders and hepatic encephalopathy. However, many unknowns persist regarding the ammonia response to common and potentially significant physiologic influences, such as food. Our aim was to evaluate the dynamic range of ammonia in response to an oral protein challenge in healthy participants. We measured blood and breath ammonia at baseline and every hour for 5.5 hours. Healthy men (N = 22, aged 18 to 24 years) consumed a 60 g protein shake (high dose); a subset of 10 consumed a 30 g protein shake (moderate dose) and 12 consumed an electrolyte drink containing 0 g protein (control). Change in blood ammonia over time varied by dose (p = 0.001). Difference in blood ammonia was significant for control versus high (p = 0.0004) and moderate versus high (p = 0.03). Change in breath ammonia over time varied by dose (p < 0.0001). Difference in breath ammonia was significant for control versus moderate (p = 0.03) and control versus high (p = 0.0003). Changes in blood and breath ammonia were detectable by fast, minimally-invasive (blood) or non-invasive (breath) point-of-care ammonia measurement methods. These pilot data may contribute to understanding normal ammonia metabolism. Novel measurement methods may aid research into genetic and metabolic ammonia disorders.

Progress in treatment of hepatic encephalopathy

Hepatic encephalopathy (HE) is a common complication of severe liver disease and a common cause of mortality. Clinical features range from clinically imperceptible symptoms in minimal HE which require neuropsychological testing to identify, to abnormal behavior, mental deterioration, and even coma or death. It is a reversible progressive neuropsychiatric disorder that is associated with a decrease in quality of life and an increase in rate of hospitalization and consequent costs because patients are at risk for recurrence. Unfortunately, the prevalence of HE continues to rise for several reasons. For one, patients with viral hepatitis are now developing cirrhosis. Additionally, we are currently in the midst of a global obesity epidemic, which fuels the metabolic syndrome and nonalcoholic fatty liver disease, and these patients are now presenting in larger numbers with complications of chronic liver disease such as HE. The high morbidity and mortality combined with the costs underline the importance to search the effective treatment for HE. This article reviews the progress in the treatment of HE.

Dietary management of hepatic encephalopathy revisited

PURPOSE OF REVIEW

The burden of hepatic encephalopathy on health services is increasing, and some degree of consensus in relation to drug therapy and prophylaxis has been reached. This review focuses on the role of nutritional interventions in the management of hepatic encephalopathy.

RECENT FINDINGS

A number of relatively new pieces of evidence are emerging in relation to nutrition and hepatic encephalopathy as follows: first, reduction of protein intake is not useful for hepatic encephalopathy, but protein selection should be considered; second, oral supplementation with branched chain amino acids has a role not only for its nutritional effect in cirrhosis per se, but also for its effect in reducing the risk of recurrence of hepatic encephalopathy; third, alterations in gut microbiota develop in parallel with decompensation of cirrhosis, and modulation of gut microbiota may be effective for treating and preventing hepatic encephalopathy; fourth, prebiotics and probiotics are potentially useful in this aim, thus further research or trials on prebiotics and probiotics are required; fifth, micronutrient deficiency, which is common in end-stage liver disease, has adverse effects on the brain and may either directly cause encephalopathy per se, or interact with the mechanisms leading to hepatic encephalopathy.

SUMMARY

Properly performed nutritional interventions are likely to be useful for patients with hepatic encephalopathy, but well conducted clinical trials are required.

VIDEO ABSTRACT

http://links.lww.com/COCN/A7.

Hepatic encephalopathy is related to anemia and fat-free mass depletion in liver transplant candidates with cirrhosis

BACKGROUND

Although muscle wasting may lead to decreased ammonia detoxification in cirrhosis, the potential role of lean mass depletion in hepatic encephalopathy (HE) has not been explored. Anemia, hormonal abnormalities, and psychological distress may contribute to cognitive dysfunction, but data on their potential relation to HE are limited.

METHODS

Data on 108 cirrhotic liver transplant candidates enrolled in a prospective study on fatigue were retrospectively analyzed. HE was assessed clinically and with the number connection tests (NCT) A and B. Psychosocial distress was assessed with a validated questionnaire. Fasting serum glucose, insulin, ammonia, and the glomerular filtration rate (GFR) were measured. Fat and fat-free mass was evaluated with dual-energy X-ray absorptiometry. Serum cortisol, testosterone, dehydroepiandrosterone, thyroid function tests, interleukin-6, and tumor necrosis factor-α (TNF-α) were measured in a subgroup of 80 patients.

RESULTS

A total of 28% of patients had (overt or minimal) HE. Anemia was present in 59%, diabetes in 29%, renal impairment in 16%, and fat-free mass depletion in 14%. In multivariate analysis, fat-free mass depletion was an independent predictor of HE and NCT-A; renal impairment of NCT-A and -B; and anemia of NCT-B (p < 0.05 for all). HE was also independently related to international normalized ratio and TNF-α (p < 0.05 for both), but not to other hormonal abnormalities or psychological distress. Plasma ammonia was independently associated to anemia (beta = 15.24, p = 0.049), fasting insulin (beta = 0.26, p < 0.05), and GFR (beta = -0.43, p = 0.003).

CONCLUSIONS

Anemia and fat-free mass depletion are predictors of HE in cirrhotic liver transplant candidates along with liver failure, renal impairment, and systemic inflammation.