Neuroradiological and Spectroscopic Findings in Propionic Acidemia: A Pediatric Case Communication

Dear Editor, Propionic acidemia is a rare inborn error of metabolism caused by a deficiency of propionyl-CoA carboxylase, clinically characterized by recurrent episodes of metabolic encephalopathy. Central nervous system involvement represents one of the main causes of morbidity and mortality, and neuroimaging plays a relevant role in early differential diagnosis.[1] Here, we present the case of a pediatric patient admitted in the context of acute metabolic decompensation with progressive neurological deterioration. Brain magnetic resonance imaging demonstrated bilateral and symmetrical lesions involving the basal ganglia, predominantly the putamina, showing hyperintensity on T2-weighted and fluid-attenuated inversion recovery sequences associated with diffusion restriction. This imaging pattern has been described as characteristic during metabolic crises in propionic acidemia and other organic acidemias [Figure 1].[1,2]Figure 1: Increased volume and signal intensity changes of the caudate nuclei (white arrows) and lenticular nuclei, with bilateral cystic necrotic changes of the putamina, predominantly hypointense on axial T1-weighted images (a) and hyperintense on coronal T2-weighted images (b; white arrows), with diffusion restriction and corresponding signal drop on axial apparent diffusion coefficient maps (c and d; white arrows). A focal hyperintense lesion with similar characteristics is also observed in the vermis (e; white arrow). Images courtesy of the Dr. Roberto Gilbert E. Children’s HospitalSingle-voxel proton magnetic resonance spectroscopy, with the volume of interest centered on the basal ganglia, revealed a prominent lactate peak along with reduced N-acetylaspartate, findings consistent with impaired energy metabolism and neuronal dysfunction. This spectroscopic profile is particularly useful in supporting the metabolic origin of brain injury and contributes to differentiating this condition from other pediatric disorders affecting the basal ganglia, such as hypoxic–ischemic encephalopathy or primary mitochondrial encephalopathies [Figure 2].[3,4]Figure 2: Magnetic resonance spectroscopy performed in the right (a) and left (b) putaminal nuclei demonstrates an inverted lactate doublet, associated with predominance of the choline peak over N-acetylaspartate, decreased myo-inositol, and an elevated peak in the glutamate/glutamine region. Image courtesy of the Dr. Roberto Gilbert E. Children’s HospitalThe selective vulnerability of the basal ganglia in propionic acidemia has been attributed to their high energy demand and to inhibition of the Krebs cycle secondary to the accumulation of toxic organic acids.[1,3] In this setting, the combination of conventional magnetic resonance imaging and magnetic resonance spectroscopy constitutes a valuable diagnostic tool, particularly during acute phases, when definitive biochemical confirmation may not be immediately available. In conclusion, this case illustrates a neuroradiological and spectroscopic pattern suggestive of propionic acidemia and highlights the role of advanced neuroimaging as a diagnostic adjunct in pediatric metabolic encephalopathies. Early recognition of these imaging findings may contribute to timely clinical management and help avoid misdiagnosis in neurological emergency settings. Author contributions AJVH, SSCS, MICF, and MVM made substantial contributions to the conceptualization, methodology, investigation, acquisition, and analysis of imaging data, drafting of the original manuscript, critical revision of the intellectual content, final editing, and supervision of the study. Data availability statement The data supporting the findings of this study are available from the corresponding author upon reasonable request. Ethical approval This study was conducted in accordance with International Ethical Principles and ensured full patient anonymity. Fully anonymized secondary data sources were used for image acquisition; therefore, informed consent and approval by an Institutional Review Board were not required. Financial support and sponsorship This work was entirely funded by the authors. Conflicts of interest There are no conflicts of interest.