Abstract: FR-PO1012
Fluctuating Hyperammonemia and Mental Status Changes in Adult-Onset Lysinuric Protein Intolerance: Does the Patient Need Hemodialysis?
Session Information
- Hemodialysis: Clinical Challenges, Patient-Centered Outcomes, and Quality of Life
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Dialysis
- 801 Dialysis: Hemodialysis and Frequent Dialysis
Authors
- Aulakh, Gagan, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States
- Aamir, Nawal, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States
- Singh, Arshdeep, Government Medical College Amritsar, Amritsar, PB, India
Introduction
Lysinuric protein intolerance (LPI) is an autosomal recessive disorder due to SLC7A7 mutations causing defective transport of lysine, arginine, and ornithine. This leads to intestinal malabsorption and renal wasting of dibasic amino acids, resulting in low plasma levels and secondary urea cycle dysfunction. Clinical features include protein intolerance, GI symptoms, poor growth, hepatosplenomegaly, hypotonia, and recurrent hyperammonemic encephalopathy triggered by protein intake or stress. Long-term complications include renal and lung disease, osteoporosis, cytopenias, dyslipidemia, pancreatitis, and HLH-like inflammatory syndromes.
Case Description
A 31-year-old man with a history of GERD and IBS presented with altered mental status and severe hyperammonemia. Extensive infectious, neurologic, hepatic, and metabolic evaluation for encephalopathy was unrevealing. His course was notable for waxing and waning mental status that appeared to correlate with fluctuating ammonia levels ranging from 89–435 µmol/L (reference <79), raising concern for an underlying metabolic disorder. Nephrology was consulted for consideration of hemodialysis; however, the marked variability in ammonia levels and corresponding neurologic symptoms created uncertainty regarding optimal timing for dialysis initiation.
Plasma amino acid analysis demonstrated low arginine, lysine, and ornithine with markedly elevated glutamine (>1000 µmol/L), along with elevated glycine, alanine, proline, serine, and asparagine. Urine amino acid analysis revealed markedly elevated lysine and increased arginine excretion. Additional findings included splenomegaly, leukopenia, elevated ferritin, and elevated LDH. Together, these findings were highly suggestive of LPI, a rare inherited defect of dibasic amino acid transport causing secondary urea cycle dysfunction and hyperammonemia.
Rapid whole genome sequencing confirmed a homozygous likely pathogenic frameshift variant in SLC7A7, previously reported only once in association with an immunodeficiency phenotype. The patient improved with protein restriction, dextrose-containing intravenous fluids, and amino acid supplementation, with stabilization of ammonia levels and mental status.
Discussion
We must remain vigilant for rare urea cycle disorders causing fluctuating hyperammonemia, which may be managed medically without hemodialysis in selected cases.