LAUSR

Introduction: Thiamine (vitamin B1) is an essential vitamin required for adenosine triphosphate production via aerobic metabolism. As a result of its short storage life, thiamine deficiency can occur with short-term nutritional deficiency and present with a metabolic crisis manifested by lactic acidosis, and either neurological manifestations or dilated cardiomyopathy. Description: An 11-year-old male with perforated appendicitis requiring multiple abdominal surgeries developed small bowel obstruction necessitating prolonged bowel rest. Multivitamin (MVI) was removed from total parental nutrition due to an allergic reaction. After 32 days on TPN he developed tachycardia. Initial echocardiogram showed good bi-ventricular function with moderate mitral regurgitation. His tachycardia progressively worsened and, seven days later, he developed hypotension requiring vasopressors and lactic acidosis (9 mmol/L). A repeat echocardiogram showed moderate mitral and aortic regurgitation and a dilated left ventricle with severely depressed function. His condition worsened requiring mechanical ventilation and multiple vasopressors. Despite this, his lactic acidosis did not normalize. Thiamine deficiency was suspected and later confirmed with a thiamine level of 64 nmol/L (normal 70-180 nmol/L). He was started on thiamine with normalization of his lactic acidosis over next 24 hours and a return to baseline of his ventricular function. He was subsequently extubated and discharged home with no cardiovascular or metabolic sequelae. Discussion: Our patient developed thiamine deficiency after a prolonged period on TPN without MVI supplementation. Although allergy to oral MVI is rarely seen, hypersensitivity reactions to parenteral preparation have been reported. In the Western countries, thiamine deficiency is rarely seen in children. Failure of early recognition may cause progression to cardiovascular impairment and lactic acidosis refractory to standard therapy. Fortunately, treatment can lead to rapid resolution of symptoms. Conclusion Thiamine deficiency is rare in Western countries but may develop in specific populations. A high index of suspicion is needed as timely treatment is life-saving.