Hyperammonemic syndrome after Roux-en-Y gastric bypass

Severe non-hepatic hyperammonaemic encephalopathy in an immunocompromised adolescent with enterocolitis

Non-hepatic causes of hyperammonaemia are uncommon relative to hepatic aetiologies. An adolescent female was admitted to the hospital with a diagnosis of very severe aplastic anaemia. During her treatment with immunosuppressive therapy, she developed neutropenic enterocolitis, pseudomonal bacteraemia and hyperammonaemia. A combination of intermittent haemodialysis and high-volume continuous veno-venous haemodiafiltration (CVVHDF) was required to manage the hyperammonaemia. Despite a thorough investigation, there were no hepatic, metabolic or genetic aetiologies identified that explained the hyperammonaemia. The hyperammonaemia resolved only after the surgical resection of her inflamed colon, following which she was successfully weaned off from the renal support. This is a novel case report of hyperammonaemia of non-hepatic origin secondary to widespread inflammation of the colon requiring surgical resection in an immunocompromised patient. This case also highlights the role of high-volume CVVHDF in augmenting haemodialysis in the management of severe refractory hyperammonaemia.

Nonhepatic hyperammonemic encephalopathy following bariatric surgery: A systematic review

BACKGROUND

Nonhepatic Hyperammonemic encephalopathy (NHAE) following Bariatric Surgery (BS), mainly Roux-en-Y Gastric Bypass (RYGB) and Biliopancreatic Diversion (BPD) is a potentially devastating condition if not diagnosed and managed promptly.

METHODS

A literature review was performed using PRISMA guidelines. Eighteen studies and 3 conference abstracts with a total of 33 patients were included in this review.

RESULTS

Majority (28 patients, 84.8 %) had RYGB. Seven patients (21.2 %) had associated metabolic disorders. 60 % of patients presented with neurological symptoms or signs such as confusion, cognitive and/or psychomotor changes, and decreased reflexes. Two patients presented with status epilepticus. In 30 of the 33 patients an elevated serum ammonia levels was reported (90.9 %). The overall mortality was 39.3 %.

CONCLUSION

NHAE is a rare condition following bariatric surgery (in particular bypass procedures), carrying a high mortality rate. The signs and symptoms are predominantly neurological and may be mistaken for Wernicke's encephalopathy or other more common neurological conditions. Serum ammonia levels should be checked in those who present with these symptoms and signs. Prompt treatment might be life saving in patients with NHAE.

Hyperammonemia Encephalopathy due to Urea Cycle Disorder Precipitated by Gastrointestinal Bleed in the Setting of Prior Bariatric Surgery

The urea cycle is a metabolic pathway that excretes nitrogenous waste products from the body. Urea cycle disorders (UCDs) result from enzymatic deficiencies within this pathway, which can lead to life-threatening hyperammonemia. Gastric bypass-related hyperammonemia in patients who have undergone Roux-en-Y gastric bypass surgery has been previously reported. UCDs have been implicated as a cause of gastric bypass-related hyperammonemia. In this report, we present the case of a patient with a history of bariatric surgery who experienced severe hyperammonemia encephalopathy triggered by a gastrointestinal bleed due to an undiagnosed UCD.

Hyperammonaemic encephalopathy: a remarkably rare complication after bariatric surgery

Hyperammonaemia is a metabolic disorder with elevated blood ammonia levels. Here we describe a case of hyperammonaemia associated encephalopathy as an incredibly rare, potentially fatal and treatable complication associated with bariatric surgery. This case highlights the importance of longer-term follow-up after bariatric surgery.

Extrahepatic portosystemic shunts as an unusual but treatable cause of hyperammonemic encephalopathy in a noncirrhotic patient - a case report

We report a case of hyperammonemic encephalopathy due to extrahepatic portosystemic shunts in a noncirrhotic patient. A 79-year-old woman suffered from episodic confusion, disorientation, dysphasia and fluctuating level of consciousness. Electroencephalography (EEG) showed encephalopathic changes and serum levels of ammonia were elevated. Further investigation revealed mesenterorenal and mesenterocaval shunts, which had possibly evolved after pancreatic surgery 5 years ago. After shunt obliteration, the symptoms completely resolved, ammonia levels dropped to the normal range and EEG findings normalized. Clinicians should be aware of this rare but treatable cause of encephalopathy in noncirrhotic patients.

Hyperammonaemic encephalopathy following bariatric surgery: A case of a potentially life-threatening delayed complication

Hyperammonaemia is a life-threatening condition with numerous aetiologies and a variable presentation. It is increasingly associated with bariatric weight-loss procedures and significant mortality despite treatment. Symptoms often occur long after surgery and at times in association with other trigger illnesses. Patients can present to general medicine, general practice and intensive care as well as surgical and anaesthetic teams. We present the case of a male patient who underwent a sleeve gastrectomy with subsequent weight loss and suffered from hyperammonaemic encephalopathy on multiple occasions. His delayed postoperative complication was likely to be multifactorial in nature, and this is outlined in the case. We discuss presentation, investigation, management and patient outcomes.

MiR-200c-3p Regulates DUSP1/MAPK Pathway in the Nonalcoholic Fatty Liver After Laparoscopic Sleeve Gastrectomy

AIM

Non-alcoholic fatty liver disease (NAFLD) is a health burden worldwide, which is closely related to obesity. The effect of sleeve gastrectomy (SG) on NAFLD is efficient, and the underlying mechanism remains unknown. Our study sought to investigate the mechanism of dual-specificity protein phosphatase 1 (DUSP1) expression regulation following the SG procedure in NAFLD patients and C57BL/6J mice via miR-200c-3p.

METHODS

The serum was extracted from NAFLD patients who underwent laparoscopic sleeve gastrectomy (LSG) and volunteers. Next, the correlation between miR-200c-3p and DUSP1 was identified in vitro. NAFLD mice were modelled by high-fat diets (HFD). The hepatic tissue expression levels of miR-200c-3p, DUSP1, phospho-extracellular regulated protein kinases1/2 (p-ERK1/2), phospho -p38 mitogen-activated protein kinases (p-p38), and phospho-c-Jun N-terminal kinases (p-JNK) induced by SG procedure were evaluated.

RESULTS

The SG procedure contributed to significant weight loss, reduced lipids in NAFLD patients and mice. The increased expression level of miR-200c-3p and reduced expression of DUSP1 were observed in NAFLD patients and mice (p<0.05). The reduced expression levels of miR-200c-3p and increased expression of DUSP1 were observed in patients and mice with NAFLD who underwent SG procedure. DUSP1 is a potential target of miR-200c-3p.

CONCLUSIONS

A novel mechanism was identified in which miR-200c-3p regulates the MAPK-dependent signals that are linked to the promotion of hepatosteatosis via DUSP1 after sleeve gastrectomy. The findings suggested that miR-200c-3p should be further explored as a potential target for the treatments of NAFLD.

The effect of weight reduction surgery on the efficacy and tolerability of epilepsy pharmacotherapy

BACKGROUND

Bariatric surgery is an increasingly utilized procedure among patients with obesity-related medical complications. The impact of bariatric surgery on seizure frequency and antiseizure drug (ASD) levels are not well described.

METHODS

We conducted a retrospective chart review of adult patients with a history of epilepsy or seizures undergoing bariatric surgery for morbid obesity from September 1997-September 2019. The median follow-up was 60 months [range 9-220 months].

RESULTS

Forty-six patients with a history of seizures were identified (38 female); 44 patients had recurrent and unprovoked seizures. Seventeen sets of pre- and post-surgery drug concentrations from 14 patients were reviewed. The median age at surgery was 44 years (range, 19-68). Thirty-three patients were prescribed ASDs at the time of bariatric surgery (median 1 drug [range, 1-3]). Laparoscopic Roux-en-Y was performed in 40 patients, and sleeve gastrectomy in 6 patients. Median pre-surgery weight was 120.75 kg (range, 71-230) and BMI 44.4 kg/m2 (range, 34-77.6). Six months following surgery the median weight was 89.5 kg (range, 58.2-202) and BMI 34.2 kg/m2 (range, 24.5-61.9). Nine patients (19.6%) had a worsening of seizure control on long-term follow-up (median 60, range 9-220 months) following bariatric surgery, including five (10.8%) who suffered seizures within 6 months of bariatric surgery. Five patients developed ASD-associated side effects following bariatric surgery including irritability in two patients (levetiracetam and phenytoin) and one patient each suffering from somnolence (phenytoin), hyperammonemic encephalopathy (sodium valproate), and nausea and vomiting (carbamazepine). Subtherapeutic post-surgery drug concentrations were identified in 5 patients and supratherapeutic concentrations in one patient. In the initial 6 months following surgery, ASD doses were increased in five patients and reduced in five.

CONCLUSIONS

The majority of patients with epilepsy who undergo bariatric surgery have no change in seizure frequency. However, a significant minority of patients may experience medication side effects or an increase in seizure tendency due to the impact of bariatric surgery on ASD drug absorption and metabolism leading. Pre- and post-surgical serum concentrations should be measured in patients with seizures or epilepsy receiving ASDs.

Nonhepatic hyperammonemic encephalopathy complications following bariatric surgery: a case report and review of the literature

Background

Hyperammonemic encephalopathy, a rare but fatal condition, is increasingly being reported as a possible complication of bariatric surgery. Here, we present a case of hyperammonemic encephalopathy, focusing on the clinical presentation, diagnostic measures, and our treatment methods, which resulted in a rare favorable outcome, emphasizing the unique role of renal replacement treatment. We also provide a detailed discussion of the mechanism through which hyperammonemia occurs secondarily to bariatric surgery.

Case presentation

A 44-year-old Moroccan Jew woman with a history of obesity presented in the hospital with urea cycle disorder that manifested after bariatric surgery. A rapid diagnostic process, together with conservative treatment with lactulose, nutritional supplementation, dietary protein restriction, and ammonia scavengers did not result in adequate improvement. Therefore, hemofiltration was performed, which yielded a favorable outcome.

Conclusions

The case findings indicate an association between hyperammonemic encephalopathy and bariatric surgery, and support early treatment with ammonia scavengers, as currently accepted. Nevertheless, if rapid improvement is not seen, it is advisable to consider hemodialysis or hemofiltration as early invasive strategies.

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].

Clinical utility of brain MRS imaging of patients with adult-onset non-cirrhotic hyperammonemia

Adult-onset non-cirrhotic hyperammonemia (NCH) is a rare, but often fatal condition that can result in both reversible and irreversible neurological defects. Here we present five cases of adult-onset non-cirrhotic hyperammonemia wherein brain magnetic resonance spectroscopy (MRS) scans for cerebral glutamine (Gln) and myo-inositol (mI) levels helped guide clinical management. Specifically, we demonstrate that when combined with traditional brain magnetic resonance imaging (MRI) scans, cerebral Gln and mI MRS can help disentangle the reversible from irreversible neurological defects associated with hyperammonemic crisis. Specifically, we demonstrate that whereas an elevated brain MRS Gln level is associated with reversible neurological defects, markedly low mI levels are associated with a risk for irreversible neurological defects such as central pontine myelinolysis. Overall, our findings indicate the utility of brain MRS in guiding clinical care and prognosis in patients with adult-onset non-cirrhotic hyperammonemia.

A retrospective study of adult patients with noncirrhotic hyperammonemia

Adult-onset noncirrhotic hyperammonemia (NCH) is poorly understood and has a high morbidity and mortality. To elucidate the etiology and management of NCH, we performed a retrospective analysis of 23 adults (median age 51) with NCH treated between 2014 and 2020 at two academic medical centers. Hyperammonemia was diagnosed in all cases during the evaluation of altered mental status, with 22% presenting with seizures. Peak ammonia levels were >200 μmol/L in 70% of cases. Defects in ammonia metabolism were assessed using urea cycle biochemical testing, germline genetic testing, and testing for urease-producing infectious agents. Ammonia metabolism defects in these cases appear attributable to four major sources: (a) infection with urease-producing organism (n = 5); (b) previously undiagnosed inborn errors of metabolism (IEMs) (n = 4); (c) clinical exposures causing acquired urea cycle dysfunction (n = 6); and (d) unexplained acquired urea cycle dysfunction (uaUCD) (n = 8), as evidenced by biochemical signatures of urea cycle dysfunction without a genetic or clinical exposure. Severe protein malnutrition appeared to be a reversible risk factor for uaUCD. Overall, 13% of our cohort died prior to resolution of hyperammonemia, 26% died after hyperammonemia resolution, 57% survived after having reversible neurological changes, and 4% survived with irreversible neurological changes. Renal replacement therapy for ammonia clearance was often utilized for patients with an ammonia level above 250 μmol/L and patients were frequently empirically treated with antibiotics targeting urea-splitting organisms. Our study demonstrates that acquired urea cycle dysfunction, IEMs and urease-producing infections are major sources of adult-onset NCH and highlights successful management strategies for adult-onset NCH.

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.

Characteristics and outcomes of critically ill patients with severe hyperammonemia

PURPOSE

To determine the etiology and outcomes of critically ill patients with severe hyperammonemia.

MATERIALS AND METHODS

Retrospective observational study of adults (18 years or older) admitted to a MICU from 2007 to 2016 who had a serum ammonia level >180 μmol/L (3 times the upper limit of normal).

RESULTS

The 78 patients (45 male, 32 female) had a median age of 52 (interquartile range [IQR] 46-58) years. Hyperammonemia occurred most often with acute-on-chronic liver failure (ACLF) (49 %) or decompensated cirrhosis (27 %) and less often as a consequence of prior gastric bypass (9%), acute hepatic failure (6%), or valproic acid (3%). Median serum ammonia level was 201 μmol/L (IQR 126-265, range 18-736) on admission, with peak value of 245 μmol/L (IQR 205-336, range 185-842). Fifty (64%) patients died during the hospitalization. Cerebral edema was documented in 8 (10%) patients, only one of whom survived. Six of the 8 patients with cerebral edema had hyperammonemia related to ACLF, giving an incidence of 14% in this subset of patients. Neither mortality nor cerebral edema was associated with peak ammonia level.

CONCLUSIONS

Critically ill patients with severe hyperammonemia have a high mortality rate and are at risk of developing cerebral edema.

Noncirrhotic hyperammonemia after deceased donor kidney transplantation: A case report

A 72-year-old woman with end-stage kidney disease due to recurrent urinary tract infections and obstructive uropathy of a solitary kidney presented to our hospital for renal transplantation. She underwent successful transplantation of a deceased donor allograft, but developed acute mental status deterioration on the fifth postoperative day. Her serum ammonia was found to be markedly elevated to 447 μmol/L in the setting of normal hepatic function. She was treated with emergent dialysis and empiric antibiotics targeting urea-splitting organisms, and ultimately made a full neurologic recovery with stable renal allograft function. Noncirrhotic hyperammonemia (NCH) is an exceedingly rare clinical entity but seems to have a predilection for patients who have undergone solid organ transplantation. This report emphasizes the importance of rapid diagnosis and initiation of treatment for NCH, which is associated with a high rate of mortality and irreversible neurological morbidity. We outline the successful workup and management approach for this patient.

Nonfatal Hyperammonemic Encephalopathy as a Late Complication of Roux-en-Y Gastric Bypass

Roux-en-Y gastric bypass (RYGB) is the most common weight loss procedure performed in the US. Gastric bypass–related hyperammonemia (GaBHA) is a potentially fatal entity, characterized by encephalopathy associated with hyperammonemia and various nutritional deficiencies, which can present at variable time intervals after RYGB. Twenty-five cases of hyperammonemic encephalopathy after bariatric surgery have been previously reported in the literature. We describe the case of a 48-year-old Hispanic woman with no prior history of liver disease, presenting with nonfatal hyperammonemic encephalopathy as a late postoperative complication 20 years after undergoing a RYGB. Hyperammonemic encephalopathy in the absence of known hepatic dysfunction presents a diagnostic dilemma. An early diagnosis and intervention are crucial to decrease morbidity and mortality.

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.

Bariatric Surgery Causing Hyperammonemia

Bariatric surgery is recognized as a highly effective therapy for obesity but it does carry a risk of short term and long term complications since it results in a permanent alteration of the patient's anatomy. We present a case of 45-year-old female presented with a macular rash on extremities and facial rash from a rehabilitation center after having been discharged a month earlier from a revision surgery on her gastric bypass for anastomotic bleeding. She progressively became lethargic with Magnetic Resonance Imaging (MRI) of the brain showed symmetrically restricted diffusion concerning for hypoxic injury. Her ammonia levels were at 142 micromoles per liter (mmol/L) at the initial check which worsened to 432 mmol/L over a few days, despite treatment. Laboratory investigation later revealed her to be deficient in zinc along with many essential and nonessential amino acids. Supplemental nutrition was initiated, specifically fortifying her parenteral feeds with the essential amino acid combinations that were found deficient on testing. This lead to a slow but progressive improvement in encephalopathy. This case highlights the importance of understanding the short and long term complications of bariatric surgery. Although neurological complications are rare with peripheral neuropathy being the most common one, hyperammonemic encephalopathy is a very severe complication, with incompletely understood mechanisms and predispositions, frequently resulting in failure of recognition and subsequent delays in intervention.

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.

Hyperammonemia and lactic acidosis in adults: Differential diagnoses with a focus on inborn errors of metabolism

The adult endocrinologist may be asked to consult on a patient for unexplained biochemical disturbances that could be caused by an underlying inborn error of metabolism. A genetic disorder is generally less likely to be the cause as these disorders are individually rare, however inborn errors of metabolism are collectively not infrequent and important to consider as they may be treatable and tragic outcomes avoided. Hyperammonemia or lactic acidosis are most often secondary markers of an acquired primary disease process, but they may be a clue to the presence of a genetic disorder. Herein is presented an approach to the differential diagnosis of elevated ammonia and lactate, and a brief discussion of management for when an inborn error is diagnosed.

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.

Brain MRS glutamine as a biomarker to guide therapy of hyperammonemic coma

Acute idiopathic hyperammonemia in an adult patient is a life-threatening condition often resulting in a rapid progression to irreversible cerebral edema and death. While ammonia-scavenging therapies lower blood ammonia levels, in comparison, clearance of waste nitrogen from the brain may be delayed. Therefore, we used magnetic resonance spectroscopy (MRS) to monitor cerebral glutamine levels, the major reservoir of ammonia, in a gastric bypass patient with hyperammonemic coma undergoing therapy with N-carbamoyl glutamate and the ammonia-scavenging agents, sodium phenylacetate and sodium benzoate. Improvement in mental status mirrored brain glutamine levels, as coma persisted for 48h after plasma ammonia normalized. We hypothesize that the slower clearance for brain glutamine levels accounts for the delay in improvement following initiation of treatment in cases of chronic hyperammonemia. We propose MRS to monitor brain glutamine as a noninvasive approach to be utilized for diagnostic and therapeutic monitoring purposes in adult patients presenting with idiopathic hyperammonemia.

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

Bariatric surgery is well established in reducing weight and improving the obesity-associated morbidity and mortality. Hyperammonemic encephalopathy following bariatric surgery is rare but highly fatal if not diagnosed in time and managed aggressively. Both macro- and micronutrients deficiencies play a role. A 42-year-old Hispanic female with a history of Roux-en-Y Gastric Bypass Procedure was brought to ED for progressive altered mental status. Physical exam was remarkable for drowsiness with Glasgow Coma Scale 11, ascites, and bilateral pedal edema. Labs showed elevated ammonia, low hemoglobin, low serum prealbumin, albumin, HDL, and positive toxicology. She remained obtunded despite the treatment with Narcan and flumazenil and the serum ammonia level fluctuated despite standard treatment with lactulose and rifaximin. Laboratory investigations helped to elucidate the etiology of the hyperammonemia most likely secondary to unmasking the functional deficiency of the urea cycle enzymes. Hyperammonemia in the context of normal liver function tests becomes diagnostically challenging for physicians. Severe hyperammonemia is highly fatal. Early diagnosis and aggressive treatment can alter the prognosis favorably.