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Delayed appearance of high altitude retinal hemorrhages.

Barthelmes D, Bosch MM, Merz TM, Petrig BL, Truffer F, Bloch KE, Holmes TA, Cattin P, Hefti U, Sellner M, Sutter FK, Maggiorini M, Landau K - PLoS ONE (2011)

Bottom Line: Significant negative (SpO₂ Beta: -0.4, p<0.001) and positive (hematocrit Beta: 0.2, p = 0.002, time at altitude Beta: 0.33, p = 0.003) correlations with hemorrhages were found.When closely examined, a very large amount of climbers exhibit retinal hemorrhages during exposure to high altitudes.The incidence of retinal hemorrhages may be greater than previously appreciated as a definite time lag was observed between highest altitude reached and development of retinal bleeding.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland.

ABSTRACT

Background: Retinal hemorrhages have been described as a component of high altitude retinopathy (HAR) in association with altitude illness. In this prospective high altitude study, we aimed to gain new insights into the pathophysiology of HAR and explored whether HAR could be a valid early indicator of altitude illness.

Methodology/principal findings: 28 mountaineers were randomly assigned to two ascent profiles during a research expedition to Mt. Muztagh Ata (7546 m/24,751 ft). Digital fundus photographs were taken prior to expedition at 490 m (1,607 ft), during expedition at 4497 m (14,750 ft = base camp), 5533 m (18,148 ft), 6265 m (20,549 ft), 6865 m (22,517 ft) and 4.5 months thereafter at 490 m. Number, size and time of occurrence of hemorrhages were recorded. Oxygen saturation (SpO₂) and hematocrit were also assessed. 79% of all climbers exhibited retinal hemorrhages during the expedition. Number and area of retinal bleeding increased moderately to medium altitudes (6265 m). Most retinal hemorrhages were detected after return to base camp from a high altitude. No post-expeditional ophthalmic sequelae were detected. Significant negative (SpO₂ Beta: -0.4, p<0.001) and positive (hematocrit Beta: 0.2, p = 0.002, time at altitude Beta: 0.33, p = 0.003) correlations with hemorrhages were found.

Conclusions/significance: When closely examined, a very large amount of climbers exhibit retinal hemorrhages during exposure to high altitudes. The incidence of retinal hemorrhages may be greater than previously appreciated as a definite time lag was observed between highest altitude reached and development of retinal bleeding. Retinal hemorrhages should not be considered warning signs of impending severe altitude illness due to their delayed appearance.

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Related in: MedlinePlus

Graphs describing hemorrhages in both groups of climbers at different altitudes.Panel A: total number of hemorrhages; panel B: total area of hemorrhages; panel C: percentage of mountaineers with hemorrhages in at least 1 eye.
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pone-0011532-g002: Graphs describing hemorrhages in both groups of climbers at different altitudes.Panel A: total number of hemorrhages; panel B: total area of hemorrhages; panel C: percentage of mountaineers with hemorrhages in at least 1 eye.

Mentions: Of 28 mountaineers, 22 (79%) exhibited retinal hemorrhages in at least one eye during the expedition. Details and an example can be found in Table 1, Fig. 2(Panels A–C) and Fig. 3. An increase in both number and area of hemorrhages in both groups occurred during ascent to C2. In Gr2, although further ascending, the number of hemorrhages stagnated whereas the area of bleeding increased. In both groups the majority of hemorrhages (number and area) were detected after descent to base camp. The total number of hemorrhages increased by 288% (Gr1) and 175% (Gr2) upon descent to BC2, whereas the total bleeding area increased by 480% (Gr1) and 130% (Gr2). The mean distance from the center of the optic disc to the center of the hemorrhage was 1.5±0.8 disc diameters in all climbers; no statistically significant differences were detected between groups and altitudes. No hemorrhages were sighted within the fovea.


Delayed appearance of high altitude retinal hemorrhages.

Barthelmes D, Bosch MM, Merz TM, Petrig BL, Truffer F, Bloch KE, Holmes TA, Cattin P, Hefti U, Sellner M, Sutter FK, Maggiorini M, Landau K - PLoS ONE (2011)

Graphs describing hemorrhages in both groups of climbers at different altitudes.Panel A: total number of hemorrhages; panel B: total area of hemorrhages; panel C: percentage of mountaineers with hemorrhages in at least 1 eye.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3040733&req=5

pone-0011532-g002: Graphs describing hemorrhages in both groups of climbers at different altitudes.Panel A: total number of hemorrhages; panel B: total area of hemorrhages; panel C: percentage of mountaineers with hemorrhages in at least 1 eye.
Mentions: Of 28 mountaineers, 22 (79%) exhibited retinal hemorrhages in at least one eye during the expedition. Details and an example can be found in Table 1, Fig. 2(Panels A–C) and Fig. 3. An increase in both number and area of hemorrhages in both groups occurred during ascent to C2. In Gr2, although further ascending, the number of hemorrhages stagnated whereas the area of bleeding increased. In both groups the majority of hemorrhages (number and area) were detected after descent to base camp. The total number of hemorrhages increased by 288% (Gr1) and 175% (Gr2) upon descent to BC2, whereas the total bleeding area increased by 480% (Gr1) and 130% (Gr2). The mean distance from the center of the optic disc to the center of the hemorrhage was 1.5±0.8 disc diameters in all climbers; no statistically significant differences were detected between groups and altitudes. No hemorrhages were sighted within the fovea.

Bottom Line: Significant negative (SpO₂ Beta: -0.4, p<0.001) and positive (hematocrit Beta: 0.2, p = 0.002, time at altitude Beta: 0.33, p = 0.003) correlations with hemorrhages were found.When closely examined, a very large amount of climbers exhibit retinal hemorrhages during exposure to high altitudes.The incidence of retinal hemorrhages may be greater than previously appreciated as a definite time lag was observed between highest altitude reached and development of retinal bleeding.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland.

ABSTRACT

Background: Retinal hemorrhages have been described as a component of high altitude retinopathy (HAR) in association with altitude illness. In this prospective high altitude study, we aimed to gain new insights into the pathophysiology of HAR and explored whether HAR could be a valid early indicator of altitude illness.

Methodology/principal findings: 28 mountaineers were randomly assigned to two ascent profiles during a research expedition to Mt. Muztagh Ata (7546 m/24,751 ft). Digital fundus photographs were taken prior to expedition at 490 m (1,607 ft), during expedition at 4497 m (14,750 ft = base camp), 5533 m (18,148 ft), 6265 m (20,549 ft), 6865 m (22,517 ft) and 4.5 months thereafter at 490 m. Number, size and time of occurrence of hemorrhages were recorded. Oxygen saturation (SpO₂) and hematocrit were also assessed. 79% of all climbers exhibited retinal hemorrhages during the expedition. Number and area of retinal bleeding increased moderately to medium altitudes (6265 m). Most retinal hemorrhages were detected after return to base camp from a high altitude. No post-expeditional ophthalmic sequelae were detected. Significant negative (SpO₂ Beta: -0.4, p<0.001) and positive (hematocrit Beta: 0.2, p = 0.002, time at altitude Beta: 0.33, p = 0.003) correlations with hemorrhages were found.

Conclusions/significance: When closely examined, a very large amount of climbers exhibit retinal hemorrhages during exposure to high altitudes. The incidence of retinal hemorrhages may be greater than previously appreciated as a definite time lag was observed between highest altitude reached and development of retinal bleeding. Retinal hemorrhages should not be considered warning signs of impending severe altitude illness due to their delayed appearance.

Show MeSH
Related in: MedlinePlus