Lactic acidosis is a common feature of patients presenting with sepsis, volume depletion due to ketoacidosis, tissue ischemia, shock and liver disease. These cases typically presume tissue hypoxia and anaerobic metabolism leading to lactic acidosis. Thiamine deficiency is an underappreciated cause of type B lactic acidosis, which is not caused by anaerobic metabolism. We present a case series of 11 patients admitted to the medicine service who were not in shock, and who had a lactic acidosis (average of 4.5 mmol/L) that improved after thiamine administration (resolving to <2 mmol/L in 10 of 11 patients). We then review thiamine and lactate physiology, and provide clinicians with evidence based recommendations to consider when treating patients with persistent lactic acidosis who are vitally stable.

With the increased longevity in modern western society, multiple chronic illnesses that have been historically seen primarily in younger individuals have persisted into middle age and more recently elderly (>65) individuals. This is particularly relevant to mast cell- and eosinophil-mediated diseases such as allergic sensitization (rhinitis, eczema, gastrointestinal diseases) and asthma. The reasons for this persistence into patients' later years of life are not fully understood but likely involve changes in external environmental influences (e.g. pollution, climate change, altered food sources and dietary habits) and internal environmental influences (e.g. sleep disturbances, decreased physical condition, increased depression, anxiety and stress perception). Optimal approaches to diagnosis demand obtaining an accurate medical history and physical examination in order to link variable clinical presentations to specific allergic (IgE)-mediated diseases. Therapies typically used for younger patients can also be used in elderly patients but with caution regarding potential direct adverse effects due to concomitant medical comorbidities and associated drug-drug interactions.