Delayed Neurological Sequelae Successfully Treated with Adjuvant, Prolonged Hyperbaric Oxygen Therapy: Review and Case Report

Abstract

Carbon Monoxide (CO) intoxication is still a leading cause of mortality and morbidity in many countries. Due to the problematic detection in the environment and subtle symptoms, CO intoxication usually goes unrecognized, and both normobaric and hyperbaric oxygen (HBO) treatments are frequently administered with delay. Current knowledge is mainly focused on acute intoxication, while Delayed Neurological Sequelae (DNS) are neglected, especially their treatment. This work details the cases of two patients presenting a few weeks after CO intoxication with severe neurological impairment and a characteristic diffused demyelination at the brain magnetic resonance imaging, posing the diagnosis of DNS. After prolonged treatment with hyperbaric oxygen, combined with intravenous corticosteroids and rehabilitation, the clinical and radiological features of DNS disappeared, and the patients' neurological status returned to normal. Such rare cases should reinforce a thorough clinical follow-up for CO intoxication victims and promote high-quality studies.

Keywords: carbon monoxide; delayed neurologic sequelae; hyperbaric oxygen; hyperbaric oxygen therapy; intoxication; poisoning.

Figure 1

Brain Magnetic Resonance (MRI) two weeks after the carbon monoxide intoxication (A,B) showed no abnormalities; brain MRI after the development of neurological syndrome (C,D) showed bilateral and extended alteration of the supratentorial, periventricular, and centrum semiovale white matter, with hyper-intensity in Fluid-attenuated inversion recovery (FLAIR).

Figure 2

Brain Magnetic Resonance (MRI) 25 days after the carbon monoxide intoxication (A,B) showing diffused leukoencephalopathy; MRI after 8 hyperbaric oxygen (HBO) treatments with worsening findings (C,D); MRI after 36 days of HBO treatments showing persisting pathological findings (E,F); MRI performed 317 days after CO intoxication with general improvement (G,H). Sequences are fluid-attenuated inversion recovery (FLAIR).

Figure 2

Brain Magnetic Resonance (MRI) 25 days after the carbon monoxide intoxication (A,B) showing diffused leukoencephalopathy; MRI after 8 hyperbaric oxygen (HBO) treatments with worsening findings (C,D); MRI after 36 days of HBO treatments showing persisting pathological findings (E,F); MRI performed 317 days after CO intoxication with general improvement (G,H). Sequences are fluid-attenuated inversion recovery (FLAIR).