HYPERAMMONEMIA POSTLUNG TRANSPLANTATION: AN UNCOMMON BUT LIFE-THREATENING COMPLICATION

ABSTRACT

SESSION TITLE Lung Transplantation Cases SESSION TYPE Rapid Fire Case Reports PRESENTED ON 10/18/2022 1015 am - 1110 am INTRODUCTION: Hyperammonemia is an uncommon yet serious complication that has been described in patients after solid organ transplantation, most commonly after lung transplantation. It has an incidence of about 2-4 % and a high fatality rate. Given the myriad of etiologies that can lead to encephalopathy post lung transplantation, hyperammonemia can easily be missed unless we have a high index of suspicion. Unlike in hepatic cirrhosis, non cirrhotic hyperammonemia can result in rapidly rising high levels of ammonia which can result in cerebral edema, seizures and long term neurological deficits. Hence, quick diagnosis and a multi faceted treatment approach is required for a favorable outcome CASE PRESENTATION 37 year old man with COVID pneumonia and respiratory failure on ECMO support underwent bilateral orthotopic lung transplant. He had no significant past medical history. ECMO was decannulated on post op day 4 and by day 6 he was progressing well and working with physical therapy. On post op day 11 he had an abrupt decline in mental status and had an episode of seizure. Initial ammonia level was 181 uMol/L (Normal < 45 uMol/L) with a peak level of 248 uMol/L. Bronchial wash was positive for Ureaplasma species by PCR. CT head did not reveal any signs of cerebral edema. Management included daily hemodialysis, Sodium phenyl butyrate, Levocarnitine, Rifaximin, Lactulose and Doxycycline. Mental status started improving and ammonia levels normalized in the next 4 days. He was subsequently discharged home from the hospital without any neurological deficits. DISCUSSION: The etiology of post lung transplant hyperammonemia is not very clear. The etiology with the most evidence is an infection with urease producing bacteria as in our patient. Based on this, obtaining a PCR screening for these organisms in the Donor/recipient has been proposed. Obtaining a screening ammonia level at around day 7 post transplant has also been suggested. Given the high mortality and morbidity associated with this condition an aggressive multimodal treatment approach is required that includes renal replacement therapy, Nitrogen scavengers, bowel decontamination and empiric antibiotics. Hemodialysis has been shown to be more effective than continuous veno-venous hemodialysis for ammonia clearance. Antibiotics such as Azithromycin and Doxycycline that would be effective against urease producing organisms should be administered. In patients with signs of raised intracranial pressure, prompt neuroimaging and also measures to reduce cerebral edema must be instituted. CONCLUSIONS: Clinical signs of hyperammonemia should be promptly recognized in post lung transplant patients and managed aggressively given high mortality rates without treatment. A multi-pronged treatment approach with Intermittent high flux hemodialysis, bowel decontamination and agents targeting the urea cycle should be used to rapidly decrease the ammonia levels. Reference #1 Krutsinger D, Pezzulo A, Blevins AE, Reed RM, Voigt MD, Eberlein M. Idiopathic hyperammonemia after solid organ transplantation Primarily a lung problem? A single-center experience and systematic review. Clin Transplant. 2017 May;31(5). doi 10.1111/ctr.12957. Epub 2017 Apr 7. PMID 28295601. Reference #2 Leger RF, Silverman MS, Hauck ES, Guvakova KD. Hyperammonemia Post Lung Transplantation A Review. Clin Med Insights Circ Respir Pulm Med. 2020 Oct 26;141179548420966234. doi 10.1177/1179548420966234. PMID 33192115;PMCID PMC7594252. Reference #3 Anwar S, Gupta D, Ashraf MA, Khalid SA, Rizvi SM, Miller BW, Brennan DC. Symptomatic hyperammonemia after lung transplantation lessons learnt. Hemodial Int. 2014 Jan;18(1)185-91. doi 10.1111/hdi.12088. Epub 2013 Sep 2. PMID 23998793. DISCLOSURES Research Grant relationship with Alung Please note $1001 - $5000 by Bindu Akkanti, value=Grant/Research Support No relevant relationships by Soma Jyothula no disclosure on file for Manish Patel;No relevant relationships by Sandeep Patri