Cerebral microbleeds in the poisoned patient: An observational magnetic resonance imaging study

Critical illness-associated cerebral microbleeds of poorly understood pathophysiology have been observed on magnetic resonance imaging (MRI) in severely hypoxaemic patients similarly to high-altitude cerebral oedema patients. The prevalence and circumstances of occurrence of such cerebral microbleeds in the severely poisoned patients are unknown. We retrospectively reviewed all cerebral MRIs performed in the poisoned patients with atypical neurological presentation or outcome admitted to our intensive care unit in 2014-2021. Three out of 64 patients (4.7%) investigated with cerebral MRI among the 2986 severely poisoned patients presented cerebral microbleeds. Microbleeds were localized in the white cerebral matter mainly in the corpus callosum. Ingested toxicants included dichlorvos, methadone and tramadol. Patients were found comatose with possibly prolonged severe hypoxaemia requiring prompt tracheal intubation and mechanical ventilation. They presented delayed arousal and dysexecutive syndrome leading to sequelae. Microbleeds on MRI can occur in the critically ill poisoned patients and seems to be a multifactorial phenomenon. A direct relationship with the toxicant seems improbable. Physicians should be aware of such a non-specific complication accounting for sequelae.