DEC 21, 2011
This article in the December issue of the Journal of Neuro-Ophthalmology describes a case of cortical blindness due to bilateral occipital lobe infarcts from near-drowning in a 23-year-old. MRI with fluid attenuated inversion recovery (FLAIR) showed widespread areas of abnormal hyperintensity. Diffusion-weighted images (DWI) confirmed the presence of restricted diffusion in the affected regions consistent with cytotoxic edema. The authors highlight that this is a different entity than posterior reversible encephalopathy syndrome and say the patient’s cold-water submersion may have provided some degree of neuroprotection, leading to focal infarcts rather than diffuse cerebral involvement.
They note that victims of near-drowning incidents, defined as cases in which an individual survives for at least some period after suffocation from submersion in a liquid, often suffer neurologic injury with long-term sequelae secondary to hypoxic-ischemic injury. Near-drowning leads to severe arterial hypoxemia and secondary ischemic infarcts of the brain and is a potential vascular source of injury leading to cortical blindness.
In the case included in this study, the patient was found unresponsive at the beach after a near-drowning incident while surfing. He was intubated and admitted to a trauma intensive care unit. CT of the chest showed bilateral airspace disease consistent with aspiration. MRI of the cervical spine showed a fracture of the C-5 vertebral body that did not require surgical intervention.
Shortly after the patient was extubated on the fourth day of his hospitalization, he complained of profound bilateral vision loss. Visual acuity was counting fingers in both eyes. There was no improvement in vision upon his discharge from the hospital six days later, and he refused further follow-up.
The patient had been found in water that ranged in temperature from 68.71° to 71.89°F. The authors point out that cold water is considered neuroprotective in near-drowning due to cold-induced decrease in cerebral metabolic rate for oxygen.