Thiamine deficiency: the importance of recognition and prompt management.

In a recent Nutrition article, Bravata et al. [1] studied thiamine transporter genes in a patient with “sporadic beriberi.” This case illustrated how thiamine deficiency can present in clinical practice and why clinicians should be alert to its diagnosis and management. Thiamine deficiency is no longer a clinical curiosity or limited to populations with suboptimal access to food [2]. Deficiency states occur often but may not always be recognized by the treating clinician as a result of a lack of familiarity with the condition, absence of “classic” signs and symptoms, and a lack of readily available confirmatory laboratory tests [3,4]. Clinical manifestations are myriad and may be confusing. It is puzzling as to why different patients present with various signs and symptoms. The study by Bravata et al. [1] dealing with the genetics of thiamine metabolism may provide us with answers. Although thiamine deficiency often is associated with alcohol intake, consumption of a seemingly normal alcohol-free diet does not preclude its diagnosis. Thiamine deficiency is also common in obese patients and after bariatric surgery, patients with macronutrient excess but with micronutrient deficiency. Various medications (e.g., proton-pump inhibitors and metformin) are known to cause this deficiency. Thiamine deficiency may occur in critically ill patients, especially those on parenteral and enteral nutrition support. Refeeding syndrome is another situation in which thiamine deficiency can rapidly occur. Cardiac failure with resultant dependent edema occurs in so-called “wet” beriberi, and neurologic manifestations are the hallmarks of “dry” beriberi. A diagnosis of delirium in the intensive care unit is rarely made without first considering Wernicke-Korsakoff syndrome. Other less known manifestations are “gastrointestinal beriberi,” presenting as severe abdominal pain; mimicking mesenteric vascular occlusion, and intestinal ischemia, with unexplained lactic acidosis. It is highly likely that different patients, or perhaps different subgroups or disease states, present with one or more of the varying manifestations of thiamine deficiency, depending on the gene or genes that are affected [5–17]. Some of the numerous causes of thiamine deficiency are depicted in Table 1. The rapid resolution of edema in the case report [1] is surprising indicating an immediate effect of thiamine on cardiac function. Although this may be considered unusual for a vitamin in contrast to a medication, lactic acidosis and mental changes also can be rapidly reversed with parenterally administered thiamine. The daily oral requirement for thiamine is only about