Abstracts

Twenty million people vacation in the American Rockies and Sierras annually. The physiologic consequences of transient environmental hypoxia have been responsible for everything from poor sleep to pulmonary edema. And on occasion, a first-time seizure or worsening of well controlled epilepsy erupts in this setting. Epidemiologic data for high altitude seizures at the moderate altitudes ([gt] 8000 ft) of our American resort towns does not exist., A retrospective chart review examining the risk factors in subjects with new or worsening seizures upon arrival to the moderate altitudes of Colorado resort towns was performed. Electronic records from Summit County Emergency Department (a cachement area including Breckenridge, Arapahoe Basin, and Keystone ski resorts) were reviewed from January 2001 to October 2005 for the ICD9 diagnosis codes for seizures and epilepsy., A total of 64 individual subjects suffered one or more seizures, 28 (43%) of which occurred in subjects visiting from elevations less than 8000 ft. Sixteen of the 28 (57%) subjects from lower elevations had an average POx reading of 82.6%. Twelve of the 36 (33%) subjects from Summit County averaged POx of 87.3%. Alcohol abuse was noted in 3/28 low elevation subjects and 6/36 Summit County subjects. Headaches, sleep disturbances, and tachycardia at presentation were more frequent in low elevation subjects. CT abnormalities were seen more frequently in Summit County subjects and more commonly associated with EtOH abuse. Newly found CT lesions in low elevation subjects without a history of prior seizure was not seen. CXR abnormalities were seen in 2/28 low elevation subjects and 1/36 Summit County subjects. Electrolyte disturbances, infections, and pharmaco-nonadherence did not appear to show any differences between the two groups., Subjects who experienced new or worsening seizures, from elevations less than 8000 ft, were more likely to show signs of hypoxia-related physiologic changes. Compared with subjects from elevations of 8000 ft or greater, these subjects demonstrated lower average oxygen saturations, increased tachycardia, and more sleep disturbances and headaches. Transient exposure to hypobaric hypoxia is suspected of altering cerebral physiology in such a way as to increase the risk of developing a seizure. Mechanisms are yet unknown, and further research, including a prospective collection of epidemiologic data is required.,