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Kidney Week

Abstract: FR-PO541

Low Alanine Aminotransferase in Hemodialysis Patients: A Marker for Pyridoxine Deficiency

Session Information

Category: Trainee Case Report

  • 1300 Health Maintenance, Nutrition, and Metabolism

Authors

  • Giehl, Nolan M., University of California Davis Medical Center, Sacramento, California, United States
  • Howard, John, University of California Davis Medical Center, Sacramento, California, United States
  • Young, Brian Y., University of California Davis Medical Center, Sacramento, California, United States
Introduction

Hemodialysis (HD) patients often have lower serum alanine aminotransferase (ALT) levels than those with normal kidney function. There are multiple proposed mechanisms with controversy surrounding the contribution of pyridoxine (vitamin B6) deficiency, a cofactor for liver aminotransferase synthesis. We present a remarkable case of pyridoxine deficiency diagnosed in a HD patient by an undetectable ALT.

Case Description

A 71-year-old woman on HD for 6 years was admitted for an infected hand wound. She also had a duodenal switch surgery for obesity 17 years prior. Home medications included a dialysis multivitamin and pyridoxine 100 mg daily, though she hinted at variable adherence to both due to insurance issues. Admit labs incidentally showed an undetectable ALT level, confirmed on repeated testing. Bilirubin and AST were normal. She had a normal ALT 4 months prior and past imaging showed no cirrhosis. Subsequent pyridoxine testing, measured in its active form of pyridoxal 5’-phosphate, was low at 7.3 nmol/L [Normal 20-125 nmol/L]. Other water-soluble vitamin levels including thiamine and cobalamin were normal. She was given 10 mg pyridoxine IV daily for one week with maintenance 100 mg oral daily. Follow up 4 weeks later revealed improved pyridoxine levels to 29.3 nmol/L and a now detectable ALT level of 9 U/L. She remains on a dialysis multivitamin and oral pyridoxine 100 mg daily.

Discussion

Aminotransferases are often drawn with routine labs in the dialysis population, with elevations signaling concern for pathology such as infectious hepatitis. However, undetectable or borderline levels may not alarm practitioners, particularly as aminotransferases are known to be lower in HD patients. This poses a risk of missing a diagnosis of pyridoxine deficiency, which may ultimately cause progressive anemia, neuropathy, and confusion. Vitamin B supplementation in HD is accepted as routine due to a restrictive diet and dialytic removal, though insurance coverage may be sporadic. Our patient had an additive risk factor of malabsorption due to her bariatric surgery. This case highlights a noteworthy presentation that should prompt providers to investigate water-soluble vitamin levels and adherence to supplementary vitamins. Our patient showed that dramatically low ALT levels may be an early and only sign of pyridoxine deficiency in HD patients.