‘All that glitters is not gold’: when hyperammonaemia is not from hepatic aetiology

Abstract

Hyperammonaemia is often caused by decompensated liver disease. However, non-hepatic causes can sometimes result in hyperammonaemia, severe enough to cause symptoms.We report a case of a 65-year-old man with a history of hypertension and bilateral peripelvic renal cyst who presented with acute confusion. Laboratory investigations revealed hyperammonaemia and normal liver function test. The abdominal ultrasound did not reveal any finding of liver disease or portal-systemic shunting but demonstrated bilateral peripelvic cysts with no hydronephrosis.Hyperammonaemia was attributed to urinary tract infection with a urea-splitting bacterium.Antibiotic therapy and lactulose were administered. His neurological status rapidly normalised over the next 48 hours, concomitantly with a decrease in ammonia level. Clinician awareness of non-hepatic causes of hyperammonaemic encephalopathy like urinary tract infection can contribute to early diagnosis and timely initiation of appropriate and potentially life-saving treatment including antimicrobial therapy, alleviating urinary obstruction, if present, and lactulose.

Prognosis of Patients with Sepsis and Non-Hepatic Hyperammonemia: A Cohort Study

“…Our results are consistent with previous studies, in which an increase in ammonia was associated with higher rates of infection by Enterobacteriaceae [ 3 , 13 , 22 ]. Therefore, serum ammonia should be measured when risk factors are present, such as intestinal infection or infection by E. coli .…”

“…An interesting finding in our study is that non-hepatic hyperammonemia may be associated with an increased risk of SAE [ 12 ]. SAE is mainly characterized by symptoms of delirium with changes in a patient’s consciousness, and it also can lead to coma [ 13 ]. Our study demonstrated that patients with hyperammonemia had lower GCS scores.…”

Noncirrhotic hyperammonemia: A factor behind dementia to alter mental status

“…It may also happen with normal hepatic function when mitochondrial pathways are interrupted by Reye's syndrome or medications, such as valproic acid, carbamazepine, salicylate, topiramate, or cytotoxic agents . Additionally, renal tubular acidosis, urinary tract dilatation or urinary tract infection, pregnancy, and hypoglycin may contribute to nonhepatic hyperammonemia.…”