Diagnostic approach to inborn errors of metabolism in an emergency unit

Objectives: Our aim was to review the patients with a final diagnosis of inborn error of metabolism (IEM) who had previously required clinical attention at the emergency unit of our hospital over the last 9 years. Methods: From the 184 patients with IEM, we selected 53 patients who required clinical attention at the EU as a prior step that led to a definitive diagnosis. We analyzed the frequency of the various IEM, their clinical presentations, and basic biochemical abnormalities in decompensation. Results: We detected a predominance of neurologic signs (in 85% of our patients), followed by digestive symptoms (58.5%). Both were associated in 51% of patients. Vomiting and other digestive signs were observed in the same proportion as described in other series, but dehydration was only seen in three of our patients, probably because of early attention and fluid correction. Conclusions: 1) the diagnosis of an IEM has often been made after the first consultation at the EU, leading to hospitalization; 2) we should suspect an IEM in patients with neurologic abnormalities (eg, developmental delay, hypotonus or feeding difficulties), especially in those patients with multisystem involvement who appear with acute symptoms; 3) it is of the greatest importance that the appropriate sample collection be made before starting any treatment, because abnormal biochemical data can yield a first approach and allow the definitive diagnosis; and 4) the diagnosis of a patient with an IEM is not based on a single clinical or biochemical data but rather on all abnormal features taken together.