Acute Metabolic Decompensation of Isovaleric Acidemia Presenting as Persistent Metabolic Acidosis in a Middle-Aged Man: A Case Report.

Isovaleric acidemia is a rare autosomal recessive inborn error of metabolism that affects the breakdown of the essential amino acid leucine. Acute metabolic decompensation is often triggered by stressors such as surgery, concurrent illness, excessive protein intake, or dehydration. This can lead to a catabolic state with increased endogenous protein turnover, posing a risk of potentially life-threatening crises due to the accumulation of toxic metabolites from incomplete leucine breakdown. Such episodes are rarely observed beyond childhood and adolescence, and the disease's rarity typically prevents single centers from gaining extensive experience with its full spectrum. This lack of familiarity can be challenging for adult physicians, who may not be well versed in the appropriate management strategies. This case report describes an acute metabolic crisis in a middle-aged man in his late 30s, triggered by an influenza virus infection and presenting as persistent and unresolved metabolic acidosis. We aim to emphasize the importance of early and prompt recognition of metabolic crises in metabolically stable adults with inborn errors of metabolism, particularly for intensivists and acute care physicians.