Abstract: PO0844
Hyperammonemia in an ESRD Patient
Session Information
- Dialysis Care: Epidemiology and the Patient Experience
November 04, 2021 | Location: On-Demand, Virtual Only
Abstract Time: 10:00 AM - 12:00 PM
Category: Dialysis
- 701 Dialysis: Hemodialysis and Frequent Dialysis
Authors
- Rajan, Roy, Dartmouth-Hitchcock Health GraniteOne, Lebanon, New Hampshire, United States
- Manzella, Kimberly J., Dartmouth-Hitchcock Health GraniteOne, Lebanon, New Hampshire, United States
- Hopley, Charles W., Dartmouth-Hitchcock Health GraniteOne, Lebanon, New Hampshire, United States
Introduction
Carnitine is an important co-factor in long-chain fatty acid metabolism, and is involved in transport of long chain fatty acids into the mitochondria. Carnitine deficiency can present with hyperammonemia. We present a patient with ESRD with hyperammonemia and encephalopathy.
Case Description
This is a 48-year-old man with End Stage Renal disease due to neprocalcinosis secondary to treatment complications due to X- Linked Hypohposphatemic rickets, presented to emergency room with nausea vomiting and severe confusion. He had no known liver disease or seizure disorder and was not on valproate or any other psychotropic medications. His liver enzymes were normal AST, ALT, albumin levels but he had persistently elevated alkaline phosphatase of 313 unit / L (40-130). PCO2 levels were normal. L. His ammonia level of 578 micro mol/L. There was no intracranial abnormalities on imaging.
Free carnitine (FC) levels came back as 26 nmol/ml ( 25-54), Acyl Carnitine ( AC) 13 nmol/ml ( 5-30) AC/FC ratio of 0.5. Even though he had low normal FC levels, his AC/FC ratio was elevated and it has been proposed that car/acyl car ratio greater than 0.4 represents carnitine deficiency.
Patient initiated on IV L carnitine 20 mg/Kg three times weekly without repeat episode of hyperammonia. It was also noted that patient no longer experienced intradialytic hypotension.
Discussion
Carnitine deficiency causes accumulation of non-oxidized fatty acyl-coenzyme A in the mitochondria, which inhibits degradation of ammonia. This typically responds to supplementation. An inverse correlation between plasma carnitine levels and ammonia has been observed in patients treated with valproic acid, and L Carnitine has been used as treatment reduce the ammonia levels in valproate induced hyperammonemia.
Carnitine deficiency can present with hyperammonia, and clinicians should have high index of suspicion for this entity in malnourished dialysis patients without significant liver disease. Treatment is directed at replacement with intravenous Carnitine.Oral preparation containing mixture of D and L- carnitine is available but D- Carnitine is toxic. L- carnitine has limited oral absorption and has a limited bioavailability of 15% . The unabsorbed carnitine is degraded by intestinal bacteria to metabolites that are potentially toxic and have been shown to cause cognitive impairment. These limits use of oral supplementation of Carnitine.