Fatal Nonhepatic Hyperammonemia in ICU Setting: A Rare but Serious Complication following Bariatric Surgery

UK National audit of the measurement of ammonia

BACKGROUND

Severe hyperammonaemia is associated with significant morbidity and mortality. Rapid analysis and reporting of ammonia results is essential to prevent patient harm. The aim was to investigate the laboratory sample acceptance criteria, ammonia analysis and the reporting of ammonia results.

METHODS

A questionnaire was distributed to clinical biochemistry laboratories in the United Kingdom. The results were collated and compared to updated best practice guidelines on hyperammonaemia issued by the Metabolic Biochemistry Network (MetBio.net).

RESULTS

Seventy-six laboratories responded to the audit questionnaire. Although 83% laboratories are aware of the updated MetBio.net hyperammonaemia guidelines, most laboratories continue to reject samples for ammonia that are 'too old' for analysis (64%), haemolysed (72%) or not sent on ice (24%). Rapid ammonia analysis is available in 96% laboratories and all laboratories offer ammonia analysis on a 24/7 basis. Nearly all laboratories had implemented critical phoning limits for ammonia.

CONCLUSIONS

Laboratories are rejecting samples for ammonia analysis that have not been collected/transported in an optimal manner. Laboratories should review their sample acceptance criteria for ammonia and accept all samples in order to avoid delaying the diagnosis and management of hyperammonaemia.

Non-hepatic Hyperammonemia: A Potential Therapeutic Target for Sepsis-associated Encephalopathy

Sepsis-Associated Encephalopathy (SAE) is a common complication in the acute phase of sepsis, and patients who develop SAE have a higher mortality rate, longer hospital stay, and worse quality of life than other sepsis patients. Although the incidence of SAE is as high as 70% in sepsis patients, no effective treatment is available for this condition. To develop an effective treatment for SAE, it is vital to explore its pathogenesis. It is known that hyperammonemia is a possible factor in the pathogenesis of hepatic encephalopathy as ammonia is a potent neurotoxin. Furthermore, our previous studies indicate that non-hepatic hyperammonemia seems to occur more often in sepsis patients; it was also found that >50% of sepsis patients with non-hepatic hyperammonemia exhibited encephalopathy and delirium. Substatistical analyses indicate that non-hepatic hyperammonemia is an independent risk factor for SAE. This study updates the definition, clinical manifestations, and diagnosis of SAE; it also investigates the possible treatment options available for non-hepatic hyperammonemia in patients with sepsis and the mechanisms by which non-hepatic hyperammonemia causes encephalopathy.

Russian Consensus “Hyperammonemia in Adults” (Version 2021)

Justification Given the large number of reports on the peculiarities of liver lesions during the Sars-Cov-2 infection [1], a team of experts who participated in the 23rd Congress of the Scientific Society of Gastroenterologists of Russia and 15 National Congress of Therapists of November 19, 2020 decided to make additions to the Russian Consensus of “Hyperammonemia in Adults” published early 2020 [2, 3].

Prognostic Role of Ammonia in Critical Care Patients Without Known Hepatic Disease

Background and Aims: Hyperammonemia usually develops because of hepatic disease, but it may occur in patients with non-hepatic hyperammonemia (NHH). But, studies on the prognosis and possible risk factors of this disorder are lacking. The aim of this study was to find possible prognostic and risk factors for NHH in critically ill patients.

Methods: Data were extracted from MIMIC III Database. Survival was analyzed by the Kaplan-Meier method. Univariate and multivariate analyses were performed to identify prognostic factors.

Results: Valproic acid, carbamazepine, corticosteroids, recent orthopedic surgery, epilepsy, disorders of urea cycle metabolism, and obesity were found to be risk factors for NHH. Patients in the hyperammonemia group had a higher 30 day mortality than those in the non-hyperammonemia group. After final regression analysis, ammonia was found to be independent predictors of mortality.

Conclusion: Ammonia was an independent prognostic predictor of 30 day mortality for critical care patients without liver disease.

Postbariatric Surgery Hyperammonemia: A Rare Cause of Encephalopathy

Hyperammonemic encephalopathy is an under-recognized and potentially fatal complication of Roux-en-Y gastric bypass surgery. We present a case of a 42-year-old woman with no known history of liver disease who experienced worsening encephalopathy 1 year after bariatric surgery. She presented with elevated ammonia and severe encephalopathy requiring intubation. A complete workup led to the diagnosis of a urea cycle disorder. The patient was managed with lactulose, ammonia scavenging agents, and nutritional supplementation with a favorable outcome. We report this case to increase awareness of this condition and urge providers to maintain a high clinical suspicion in the appropriate setting.

Treatment of Severe Protein Malnutrition After Bariatric Surgery

BACKGROUND

Severe protein malnutrition, with a serum albumin < 25 g/L, is one of the complications that may develop after bariatric surgery. It is associated with increased morbidity and mortality and requires timely diagnosis and appropriate treatment to prevent rapid clinical deterioration. However, evidence-based recommendations for a specific treatment approach are currently not available. The present study describes the efficacy of a newly developed treatment regimen for post-bariatric patients presenting with severe hypoalbuminemia.

METHODS

A single-centre, retrospective analysis of eleven post-bariatric patients presenting with severe hypoalbuminemia, treated with continuous 24 h nasal-jejunal tube feeding of a medium chain triglyceride (MCT) formulation in combination with pancreatic enzyme supplementation every 3 h.

RESULTS

Duration of tube feeding ranged from 25 to 156 days (median 64 days) and pancreatic enzyme was supplemented for 22-195 days (median 75 days). An increase in serum albumin levels of 5 g/L and 10 g/L was achieved after a median period of 20 (range 6-26 days) and 36 days (range 21-57 days), respectively. Albumin levels were > 35 g/L after a median period of 58 days (range 44-171 days).

CONCLUSION

In this case series, a continuous 24-h nasal-jejunal MCT tube feed combined with frequent pancreatic enzyme supplementation was effective in all patients presenting with severe post-bariatric hypoalbuminemia and was not associated with adverse effects.

Features of Adult Hyperammonemia Not Due to Liver Failure in the ICU

OBJECTIVES

To evaluate the epidemiology of hyperammonemia unrelated to liver failure in the critical care setting.

DESIGN

Retrospective case series.

SETTING

Critically ill patients admitted to ICUs at Mayo Clinic, Rochester, MN (medical ICU, two mixed medical-surgical ICUs, coronary care unit, or the cardiosurgical ICU) between July 1, 2004, and October 31, 2015.

PATIENTS

Adult critically ill patients with hyperammonemia not related to acute or chronic liver failure. We excluded patients with diagnosis of moderate or severe liver disease, hyperbilirubinemia, and patients who denied the use of their medical records.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 3,908 ICU patients with hyperammonemia, 167 (4.5%) had no evidence of acute or chronic liver failure. One-hundred one patients (60.5%) were male with median age of 65.7 years (interquartile range, 50-74.5 yr) and median serum ammonia level of 68 µg/dL (interquartile range, 58-87 µg/dL). Acute encephalopathy was present in 119 patients (71%). Predisposing conditions included malnutrition 27 (16%), gastric bypass six (3.6%), total parenteral nutrition four (2.4%); exposure to valproic acid 17 (10%); status epilepticus 11 (6.6%), high tumour burden 19 (11.3%), and renal failure 82 (49.1%). Urea cycle defects were diagnosed in seven patients (4.1%). Hospital mortality was high (30%), and median ammonia level was higher among the nonsurvivors (74 vs 67 µg/dL; p = 0.05). Deaths were more likely in hyperammonemic patients who were older (p = 0.016), had greater illness severity (higher Acute Physiology and Chronic Health Evaluation III score, p < 0.01), malignancy (p < 0.01), and solid organ transplantation (p = 0.04), whereas seizure disorder was more common in survivors (p = 0.02). After adjustment, serum ammonia level was not associated with increased mortality.

CONCLUSIONS

Hyperammonemia occurs in a substantial minority of critically ill patients without liver failure. These patients have a poor prognosis, although ammonia level per se is not independently associated with mortality. Serum ammonia should be measured when risk factors are present, such as nutritional deficiencies and protein refeeding, treatment with valproic acid, high tumour burden, and known or suspected urea cycle abnormalities.

An overview of complications affecting the Central Nervous System following bariatric surgery

Bariatric surgery has been considered as an effective treatment for morbid obesity. Apart from procedures related complications, a broad spectrum of neurological disorders affecting any part of neuraxis has been reported following BS. Central nervous system complications, although less common than peripheral nervous system complications, carry significant morbidity and potential mortality. Encephalopathy, behavioral and psychiatric disorders, myelopathy and optic neuropathy are the most frequently reported CNS complications. Early detection and prompt management may improve or completely reverse these neurological complications. It is essential that the treating physicians must be aware of their clinical manifestations and management, so early diagnosis and treatment can prevent patients from suffering significant neurological deficits and even death. This review discusses the clinical manifestations of these complications in detail which will help concerned physician in earlier recognition and hence prevent the delay in specific treatment.

Late presentation of fatal hyperammonemic encephalopathy after Roux-en-Y gastric bypass

Worldwide, there have been <25 reported cases of hyperammonemic encephalopathy associated with Roux-en-Y gastric bypass surgery in the absence of cirrhosis. We describe a 42-year-old woman who presented with subacute but progressive neurological decline late in her postoperative course, which deteriorated despite multiple conservative and aggressive measures, including hemodialysis, in an attempt to reduce measured plasma ammonia levels. This syndrome of hyperammonemic encephalopathy represents a serious, underrecognized, and potentially treatable complication after Roux-en-Y gastric bypass.

5-FU-induced leukoencephalopathy with reversible lesion of splenium of corpus callosum in a patient with colorectal cancer

5-Fluorouracil (5-FU), a commonly used antimetabolite and antineoplastic agent, has been approved for treatment of various cancers. Neurotoxicities are considered extremely rare side effects of 5-FU. We present a case of 5-FU-induced encephalopathy with diffusion-restricted reversible lesion of the splenium of the corpus callosum in a patient with colorectal cancer. The patient presented with confusion, dysarthria and agitation after 5-FU infusion. The prognosis of this toxic effects of 5-FU is usually good if recognised and treated in time. Emergency physicians, general practitioners and oncologists should be aware of this rare side effects of 5-FU chemotherapy and its diagnosis and treatment.

Hyperammonemia: What Urea-lly Need to Know: Case Report of Severe Noncirrhotic Hyperammonemic Encephalopathy and Review of the Literature

Purpose. A 66-year-old man who presented with coma was found to have isolated severe hyperammonemia and diagnosed with a late-onset urea-cycle disorder. He was treated successfully and had full recovery. Methods. We report a novel case of noncirrhotic hyperammonemia and review the literature on this topic. Selected literature for review included English-language articles concerning hyperammonemia using the search terms “hyperammonemic encephalopathy”, “non-cirrhotic encephalopathy”, “hepatic encephalopathy”, “urea-cycle disorders”, “ornithine transcarbamylase (OTC) deficiency”, and “fulminant hepatic failure”. Results. A unique case of isolated hyperammonemia diagnosed as late-onset OTC deficiency is presented. Existing evidence about hyperammonemia is organized to address pathophysiology, clinical presentation, diagnosis, and treatment. The case report is discussed in context of the reviewed literature. Conclusion. Late-onset OTC deficiency presenting with severe hyperammonemic encephalopathy and extensive imaging correlate can be fully reversible if recognized promptly and treated aggressively.