Abdominal Pain and Hyperlactatemia in Thiamine Deficiency: A Case Report.

An eight-year-old boy with recurrent abdominal pain, refusal to eat, gagging, and weight loss for five months experienced a sudden clinical deterioration after a gastrointestinal endoscopy with biopsy. Initially misdiagnosed with pancreatitis, he underwent hospitalization, fasting, and parenteral nutrition (PN) for 15 days. Despite this, his symptoms persisted, and serum lactate levels progressively increased. Transferred to a university hospital, abdominal beriberi was suspected, and intravenous thiamine was promptly administered. Symptoms resolved within 24 h. A review of the PN prescribed revealed the absence of thiamine, confirming the diagnosis. Healthcare professionals often associate thiamine deficiency with alcoholic adults presenting Wernicke encephalopathy; however, abdominal beriberi should also be considered in children with acute abdomen, especially when elevated serum lactate indicates impaired cellular metabolism due to thiamine deficiency.