Department of Hepatology and Gastroenterology, Aarhus University Hospital, Palle Juul-Jensens Boulevard, Aarhus, Denmark.
Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
Metab Brain Dis. 2024 Nov 28;40(1):46. doi: 10.1007/s11011-024-01434-4.
Hyperammonaemic encephalopathy in the absence of liver failure is a major diagnostic challenge. A rare cause is as a complication to previous gastric bypass surgery, a condition reported to be associated with high mortality. In this case report, we present the exhaustive diagnostic work-up and clinical reversal of deep and recurrent hyperammonaemic encephalopathy in a patient with previous gastric bypass surgery. As a key finding, the patient exhibited an extreme reduction of the in vivo capacity for urea synthesis, which was reverted by long-standing correction of severe protein and micronutrient malnourishment (Functional Hepatic Nitrogen Clearance; 2.9 to 25.5 L/h). In addition, we observed reduced levels of fasting plasma amino acids (α-amino nitrogen; 2.7 to 3.6 mmol/L) and glucagon (0.3 to 2.6 pmol/L) before clinical improvement, which may contribute to the non-functioning urea synthesis. These observations elucidate the underlying pathophysiology of hyperammonaemia as a complication of gastric bypass and highlight a potential mechanism - non-functioning urea cycle as a result of protein malnourishment and hepatic glucagon resistance.
在没有肝功能衰竭的情况下发生高氨血症性脑病是一个重大的诊断挑战。一种罕见的病因是胃旁路手术后的并发症，这种情况据报道与高死亡率相关。在本病例报告中，我们介绍了一例既往行胃旁路手术患者深度和反复性高氨血症性脑病的详尽诊断过程和临床逆转。一个关键发现是，患者表现出尿素合成的体内能力极度降低，通过长期纠正严重的蛋白质和微量营养素营养不良（功能性肝氮清除率；2.9 至 25.5 L/h）得到逆转。此外，我们观察到在临床改善之前空腹血浆氨基酸（α-氨基氮；2.7 至 3.6 mmol/L）和胰高血糖素（0.3 至 2.6 pmol/L）水平降低，这可能导致尿素合成功能障碍。这些观察结果阐明了胃旁路术后高氨血症性脑病的潜在病理生理学，并强调了一种潜在的机制 - 由于蛋白质营养不良和肝胰高血糖素抵抗导致尿素循环功能障碍。
