Persistent Lactate Elevation in a Patient with Asthma Exacerbation and a Congenital Portosystemic Shunt: A Case Report and Literature Review.

Background and Clinical Significance: When lactate production surpasses the body's clearance capacity, hyperlactatemia (lactate ≥ 2 mmol/L) or lactic acidosis (lactate ≥ 4 mmol/L) can develop. Lactic acidosis is classified into type A, which arises from regional or global tissue hypoperfusion, and type B, resulting from metabolic disturbances without tissue hypoxia. Type A lactic acidosis, often associated with conditions like sepsis or shock, is a critical marker of life-threatening conditions, whereas type B lactic acidosis is less frequently recognized in clinical practice. Case Presentation: A 95-year-old man presents with an asthma exacerbation and is treated with an albuterol inhaler. However, he is found to have persistently high lactate levels. Further investigation reveals a congenital intrahepatic portosystemic shunt on imaging. This, in conjunction with the ongoing use of beta-adrenergic receptor agonists, contributes to the development of type B lactic acidosis. Conclusions: The impact of lactic acidosis depends on its severity and clinical context. While beta agonists are a recognized cause of type B lactic acidosis, a potential role for structural liver abnormalities in reduced lactate clearance must be examined further.