High Pressure Neurological Syndrome

**Definition:** A syndrome related to increased atmospheric pressure and characterized by tremors, nausea, dizziness, decreased motor and mental performance, and SEIZURES. This condition may occur in those who dive deeply (c. 1000 ft) usually while breathing a mixture of oxygen and helium. The condition is associated with a neuroexcitatory effect of helium.

**Tree numbers:** - C10.228.566 - C24.410

**Synonyms:** - High Pressure Nervous Syndrome - High Pressure Neural Syndrome - HPNS