Thiamine is an essential water-soluble vitamin that must be obtained through diet. This vitamin is crucial for various biochemical reactions and is vital for aerobic metabolism. When individuals are deficient in thiamine, which can be due to hypermetabolism (such as in inflammation, ischemia, or malnutrition, among other reasons), anaerobic metabolism may be utilized to maintain energy needs. Such chemical processes produce lactic acid. Excess lactic acid can cause various clinical signs and symptoms, though lactate dehydrogenase (LDH) can typically break down this compound. The following case presents a very unusual instance where a 51-year-old Caucasian woman presented with the chief complaint of ongoing and severe abdominal pain. After an extensive work-up ruling out numerous diagnoses and an eight-day hospital stay, it was believed that she may be suffering from hyperlactatemia secondary to thiamine deficiency, as she improved significantly after administration of this vitamin. It was thought that this was likely due to her previous systemic lupus erythematosus (SLE) diagnosis, vasculitis, chronic inflammation, and a hypermetabolic state, in addition to concurrent LDH malfunction.