Hyperammonemic encephalopathy associated with acute liver dysfunction in patients with sepsis: evaluation of neuroimaging features

Objective. To investigate characteristic magnetic resonance imaging (MRI) findings of the brain in patients with hyperammonemic encephalopathy (HE) and to identify the main neuroimaging features of this pathology.

Methods. A prospective study analyzed brain MRI data from 15 patients with sepsis and clinically confirmed HE. Assessment of cerebral changes was performed using a standard MRI protocol. The following parameters were evaluated during the analysis: localization and signal intensity characteristics of the lesions on MRI, presence or absence of diffusion restriction, presence magnetic susceptibility artifacts, as well as reversibility of structural changes.

Results. Neuroimaging revealed pathological changes in all 15 patients. In 13 patients (86.7%) had symmetrical lesions of the insular cortex and cingulate gyrus; 1 patient (6.7%) had symmetrical lesions of the basal ganglia; and in 1 patient (6.7%) had cortico-subcortical lesions in the cerebral hemispheres. All detected lesions were characterized by hyperintense signal on T2-weighted and T2-FLAIR images. On diffusion-weighted imaging (DWI), cytotoxic edema was observed in all patients. Follow-up MRI was performed in all patients after treatment adjustment and renal replacement therapy, demonstrating marked regression of all noted changes, concurrent with normalization of serum ammonia, lactate, transaminases, sepsis markers.

Conclusion. The present study characterized the MRI semiotics HE in patients with sepsis and identified its key neuroimaging patterns. The bilateral insular‑cingulate pattern should be considered a potentially valuable neuroimaging marker enabling early verification of HE.

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