Pancreatitis in Maple Syrup Urine Disease – A Rare and Easily Overseen Complication

Introduction

Maple syrup urine disease (MSUD; OMIM #248600) is an autosomal recessive disorder caused by deficiency of branched chain alpha ketoacid dehydrogenase complex (BCKD; EC 1.2.4.4) which is responsible for the second common step in the breakdown of the branched chain amino acids (BCAA) valine, leucine and isoleucine.

Patients with classic MSUD present within the first days of life with poor sucking and lethargy progressing to coma and seizures due to leucine toxicity. This eventually leads to deterioration and death if treatment is not initiated. Delay of treatment can lead to irreversible brain damage, developmental delay and mental retardation. Long-term treatment consists of a diet restricted in natural, BCAA containing protein, and supplementation of non-BCAA amino acids as well as valine and isoleucine. Recurring acute metabolic crises during episodes of protein catabolism regularly complicate the disease course (Thimm E et al., Klin Padiatr 2010; 222: 264–265).

Pancreatitis has been described as a ­complication of organic acidemias including methylmalonic acidemia, isovaleric acidemia and propionic acidemia (Kahler SG et al., J Pediatr 1994; 124: 239–243; Marquard J et al., Eur J Pediatr 2011; 170: 241–245; Pena L et al., Am J Med Genet A 2011; 158 A: 1641–1646), however, it has rarely been reported in MSUD patients.

Here, we describe the case of a 5-year-old MSUD patient who developed acute pancreatitis in the course of metabolic derangement and discuss pitfalls of diagnosis and treatment. This case report serves as a reminder of an easily overseen condition in MSUD patients.