Vision Threatening Raised Intracranial Pressure Associated with Recreational Nitrous Oxide Use

Nitrous oxide is used as an anaesthetic and analgesic agent in the medical setting and is known to cause raised intracranial pressure. The use of nitrous oxide recreationally for the drug’s euphoric and relaxant properties has been linked to multiple neurological and psychiatric sequelae including neuropathy, myelopathy, and psychosis. We describe a case of a young person who declared heavy nitrous oxide use resulting in vision-threatening papilloedema secondary to raised intracranial pressure. He underwent emergency lumbar drainage alongside high-dose acetazolamide and parenteral vitamin B12 injections. To our knowledge, there have yet to be other reports of cases where heavy nitrous oxide use has caused secondary pseudotumor cerebri syndrome

Is Visual Snow a Thalamo-Cortical Dysrhythmia of the Visual Processing System - A Magnetoencephalogram Study (Video)

Visual snow (VS) has been described as a unique clinical entity, which may occur with increased neuronal excitability. (1) Sensory information processing relies on the interactions between thethalamus and cortex. When hyperexcitability affects cortical networks, it can lead to thalamocortical dysrhythmias, resulting in tinnitus. (2) We hypothesize that VS is the visual manifestation ofthalamocortical dysrhythmia. Visual cortex gamma oscillations reflect cognitive processing and alpha oscillations are associatedwith thalamically generated pulses of cortical inhibition, altering information processing. (3) Thisoscillatory network activity is a characteristic property of the thalamocortical system.Therefore, we used Magnetocephalography (MEG) to record the visual cortex oscillatory dynamics,as a measure of possible thalamocortical dysrhythmia in VS patients and controls.ICvisualsno

Is Visual Snow a Thalamo-Cortical Dysrhythmia of the Visual Processing System - A Magnetoencephalogram Study (PDF)

ICvisualsno

Is Visual Snow a Thalamo-Cortical Dysrhythmia of the Visual Processing System - A Magnetoencephalogram Study (Slides)

Visual snow (VS) has been described as a unique clinical entity, which may occur with increased neuronal excitability. (1) Sensory information processing relies on the interactions between thethalamus and cortex. When hyperexcitability affects cortical networks, it can lead to thalamocortical dysrhythmias, resulting in tinnitus. (2) We hypothesize that VS is the visual manifestation ofthalamocortical dysrhythmia. Visual cortex gamma oscillations reflect cognitive processing and alpha oscillations are associatedwith thalamically generated pulses of cortical inhibition, altering information processing. (3) Thisoscillatory network activity is a characteristic property of the thalamocortical system.Therefore, we used Magnetocephalography (MEG) to record the visual cortex oscillatory dynamics,as a measure of possible thalamocortical dysrhythmia in VS patients and controls.ICvisualsno