ASN's Mission

ASN leads the fight to prevent, treat, and cure kidney diseases throughout the world by educating health professionals and scientists, advancing research and innovation, communicating new knowledge, and advocating for the highest quality care for patients.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005


The Latest on Twitter

Kidney Week

Abstract: FR-PO579

Treatment of Refractory Hyperammonemic Coma with CRRT in a Patient with Ureterosigmoidostomy

Session Information

Category: Trainee Case Report

  • 902 Fluid and Electrolytes: Clinical


  • Alperstein, Adam S., University of Kentucky, Lexington, Kentucky, United States
  • McKeown, John Wade, University of Kentucky, Lexington, Kentucky, United States
  • Ahmed, Sadiq, University of Kentucky, Lexington, Kentucky, United States

Hyperammonemia is most common in liver disease but other rare causes exist.Serum ammonia (NH3) concentrations >150umol/L is linked to poor neurological outcomes and even death. In severe cases, extracorporeal removal of NH3 can be lifesaving.

Case Description

A 64-year-old female was admitted to the ICU with coma & NH3 level of 534umol/L with normal liver & renal function.She had ureteosigmoidestomy as a child for bladder extrophy.The high NH3 was attributed to increased colonic absorption from urine & increased NH3 production from bacterial splitting of urea in the colon.She did not respond to Lactulose & Rifaximin.Urology was consulted for percutaneous nephrostomy, however, her clinical status declined, so an urgent decision was made to remove NH3 by CVVHDF. NH3 level & coma improved in 8 hours. Next day, nephrostomy tubes were placed, the NH3 levels remained low, and her mental status improved.


Patients with ureterosigmoidostomy can present after many years with hyperammonemia.The treatment is a new urinary diversion to avoid contact with the colon. Nephrostomy is a temporary solution followed by a permanent procedure, such as an ileal conduit. NH3 level >150 is related to cerebral edema, increased intracranial pressure (ICP) and brain herniation.Therefore, in severe cases, urgent extracorporeal removal should be considered. While the use of renal replacement therapy to remove NH3 has been reported, there is no definite guideline.Some reports favor HD over CRRT due to higher clearance.However, when the NH3 is continuously produced at a high rate, CRRT may be more beneficial since it offers fewer interruptions, less rebound, & less rapid fluid shifts which can worsen ICP.
This case highlights that CRRT can be an effective bridging strategy in patients with severe hyperammonemic encephalopathy.