Fatal hyperammonemic encephalopathy after gastric bypass surgery

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.

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].

Non-cirrhotic hyperammonaemia: are we missing the diagnosis?

Hepatic encephalopathy secondary to hyperammonaemia is a known complication of chronic liver disease. In contrast, non-cirrhotic hyperammonaemia is a lesser-known entity that should be considered in a patient with acute encephalopathy as part of the diagnostic workup as prompt identification can help to avoid complications such as seizures and cerebral oedema. We present a case of a middle-aged woman who presented electively for a total pancreatectomy-duodenectomy with splenectomy, hepatico-jejunostomy, gastro-jejunostomy and developed encephalopathy on postoperative day 10 due to non-cirrhotic hyperammonaemia.

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.

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.

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.

Noncirrhotic hyperammonemia causing relapsing altered mental status

Hyperammonemia is a recognized cause of encephalopathy. However, it is commonly seen in patients with liver disease. The clinical entity of noncirrhotic hyperammonemia is now being increasingly recognized. We report a man who presented to our hospital with relapsing altered mental status later diagnosed as noncirrhotic hyperammonemia.

Hyperammonemia-induced encephalopathy: A rare devastating complication of bariatric surgery

The clinical manifestations of hyperammonemia are usually easily identifiable to the clinician when associated with liver disease and lead to prompt diagnosis and treatment. However, hyperammonemia-induced encephalopathy is rare in adults in the absence of overt liver disease, thus diagnosis is often delayed or missed leading to potentially life threatening complications. Without proper treatment, such patients can decompensate rapidly with poor outcomes including seizures, coma, and death. Early assessment of plasma ammonia levels in patients with normal hepatic function and characteristic symptoms of encephalopathy can lead to early intervention while investigating the underlying etiology. We describe a patient who presented with a 2-year progression of waxing and waning acute mental status changes after a Roux-en-Y gastric bypass surgery. He was found to have elevated ammonia level as well as orotic aciduria; results consistent with a urea cycle disorder. After consulting neurology as well as toxicology, he ultimately improved after dietary protein restriction, sodium benzoate and lactulose therapy. While rare, clinicians should have a high index of suspicion for late onset urea cycle disorders in symptomatic patients presenting with encephalopathy secondary to hyperammonemia.

Spontaneous portosystemic shunts in noncirrhotic patients presenting with encephalopathy

Portosystemic shunts (PSS) are common in patients with chronic liver disease and portal hypertension, however, their occurrence in noncirrhotic individuals is likely under appreciated. Patients may present with symptoms of hepatic encephalopathy and/or gastrointestinal bleeding and undergo extensive work up for liver disease to no avail. Often, these patients suffer for years with accruing medical expenses and numerous hospitalizations related to repeated episodes of encephalopathy. The underlying cause may go undiagnosed or misdiagnosed as occult hepatic dysfunction or even a neuropsychological disorder. In many cases, abdominal CT imaging demonstrates the abnormal portosystemic connection well before it is recognized as the cause of symptoms. In this brief report, we discuss three cases presenting with symptoms of encephalopathy and report successful management with endovascular occlusion of the portosystemic shunts.

Hyperammonemic syndrome after Roux-en-Y gastric bypass

OBJECTIVE

Hyperammonemic encephalopathy is an uncommon but severe complication of the Roux-en-Y gastric bypass surgery for obesity. Mechanisms underlying this complication are incompletely understood, resulting in delayed recognition and management. This study evaluated common laboratory findings and possible etiology of hyperammonemic encephalopathy after successful Roux-en-Y gastric bypass surgery.

METHODS

A retrospective review of 20 patients identified through our own clinical practice was conducted, with the addition of similar cases from other institutions identified through the review of literature.

RESULTS

Patients presenting with hyperammonemic encephalopathy after Roux-en-Y gastric bypass surgery presented with overlapping clinical and laboratory findings. Common features included: (1) weight loss following successful Roux-en-Y gastric bypass for obesity; (2) hyperammonemic encephalopathy accompanied by elevated plasma glutamine levels; (3) absence of cirrhosis; (4) hypoalbuminemia; and (5) low plasma zinc levels. The mortality rate was 50%. Ninety-five percent of patients were women. Three patients were diagnosed with proximal urea cycle disorders. One patient experienced improvement in the hyperammonemia after surgical correction of spontaneous splenorenal shunt.

CONCLUSIONS

Hyperammonemic encephalopathy after Roux-en-Y gastric bypass surgery is a newly recognized, potentially fatal syndrome with diverse pathophysiologic mechanisms encompassing genetic and nongenetic causes.

Surgery for gastric cancer in a patient with non-cirrhotic hyperammonemia: a case report

We report a case of gastric cancer in a patient with non-cirrhotic hyperammonemia secondary to a spontaneous portacaval shunt. The patient, a 69-year-old male, had more than 40 years of abdominal discomfort. On gastroscopy, 2.0 × 1.5-cm irregular uplift ulcers were seen on the lesser curvature of the stomach, and tissue biopsy revealed poorly differentiated adenocarcinoma. His hyperammonemia was found on celiac angiography to be due to the formation of a spontaneous portacaval shunt. Imaging revealed no evidence of cirrhosis or portal hypertension. The patient ultimately underwent a distal gastrectomy and gastroduodenal anastomosis; the spontaneous portacaval shunt was left untreated. Postoperatively, there were no short-term complications such as anastomotic leakage, stricture, or bleeding, and the patient’s blood ammonia level decreased to within the normal range. Radical gastrectomy without splenectomy or closure of the abnormal shunt was feasible for the treatment of gastric cancer in a patient with non-cirrhotic hyperammonemia.

Formerly obese, now thin and confused: the utility of mnemonics in the approach to altered mental status

Altered mental status represents a common cause for admission to general medicine services. Often a significant workup ensues to define an underlying etiology. When a history of bariatric surgery with small bowel resection precedes the presentation, the differential diagnosis expands. We review a patient, having prior bariatric surgery and small bowel resection, who presents with altered mental status. After an extensive workup, she was diagnosed with a rare clinical problem, D-lactic acidosis. In presenting this case, we examine the use of mnemonics in medicine and how this can assist in solving clinical problems.

Endocrine system and obesity

Obesity is associated with significant alterations in endocrine function. An association with type 2 diabetes mellitus and dyslipidemia has been well documented. This article highlights the complexities of treating endocrine system disorders in obese patients.

Cardiac repolarization during hypoglycaemia in type 1 diabetes: impact of basal renin-angiotensin system activity

AIMS

Hypoglycaemia-induced cardiac arrhythmias may be involved in the pathogenesis of the 'dead-in-bed syndrome' in patients with type 1 diabetes. Evidence suggests that the renin-angiotensin system (RAS) influences the occurrence of arrhythmias. The aim of this study was to explore if basal RAS activity affects cardiac repolarization during hypoglycaemia, thereby potentially carrying prognostic information on risk of the 'dead-in-bed syndrome'.

METHODS AND RESULTS

Nine subjects with high RAS activity and nine subjects with low RAS activity were subjected to single-blinded placebo-controlled hypoglycaemia (nadir plasma glucose 2.4 mmol/L). QTc/QTcF and QT dynamics were registered by Holter monitoring. QTc prolonged during [8 (+/-2.3) ms, P < 0.01] and after [11 (+/-3) ms, P < 0.001] hypoglycaemia. Dynamic QT parameters reacted ambiguously. Low RAS activity was associated with a slightly more pronounced QT prolongation [6 (+/-3) ms, P = 0.04]. Adrenaline tended to increase more in the low-RAS group (P = 0.08) and was correlated to QTc (r = 0.67, P < 0.01) and QTcF (r = 0.58, P < 0.05) during hypoglycaemia.

CONCLUSION

Low basal RAS activity may be associated with a slightly more pronounced QT prolongation during hypoglycaemia, when compared with high RAS activity. The impact, however, is modest and the clinical consequence is unclear.