INTRACRANIAL-PRESSURE AT HIGH-ALTITUDE AND ACUTE MOUNTAIN-SICKNESS

1. Raised intracranial pressure has been noted in severe forms of acut e mountain sickness and high-altitude cerebral oedema, but the role of intracranial pressure in the pathogenesis of mild to moderate acute m ountain sickness is unknown. 2. Serial measurements of intracranial pr essure were made indirectly by assessing changes in tympanic membrane displacement in 24 healthy subjects on rapid ascent to 5200 m. 3. Acut e hypoxia at 3440m was associated with a rise in intracranial pressure , but no difference was found in pressure changes at 4120 or 5200 m in subjects with or without symptoms of acute mountain sickness. 4. Rais ed intracranial pressure, though temporarily associated with acute hyp oxia, is not a feature of acute mountain sickness with mild or moderat e symptoms.