Characteristics of Headache at Altitude among Trekkers; A comparison between Acute Mountain Sickness and Non-Acute Mountain Sickness Headache

PURPOSE Headache at altitudes has had an incidence of 25-62% through many related studies. Many reasons are identified concerning headache at altitudes such as acute mountain sickness (AMS), sinus headache, migraine, tension type headache, and frontal tension headache. This study tried to compare different types of headache among trekkers on Mount Damavand, a 5671m mountain, Iran, to find their incidence and related symptoms and signs. METHODS Through a cross-sectional study, we evaluated headache incidence and its correlation to AMS among people who climbed Mount Damavand. Lake Louise Score, a self-report questionnaire, was applied to make AMS diagnosis through three separate stages of trekking programs. Chi-square test was employed as the main mean of analysis. RESULTS Totally, 459 between 13-71 year olds participated in the study among which females were 148 (32.1%) and males 311 (67.8%). Headache was found in 398 (86.7%) among whom 279 (70%) were proved as AMS. Investigating the types of headache in the cases of AMS showed 64.5% to be of steady, 31% throbbing and 4.5% stabbing characters which had significant differences with a P value = 0.003. The majority of headaches were stated as frontal (38.9%) and the least prevalence belonged to the parietal area (4.4%), while global headache was reported in 27%. CONCLUSIONS This study specifies the exact location of headaches at altitude in cases of AMS and non-AMS headaches. Many cases of high altitude non-AMS headache are resulted by tension and light reflection at altitude.