Dataset Information

Quantification of optic disc edema during exposure to high altitude shows no correlation to acute mountain sickness.

ABSTRACT:

Background

The study aimed to quantify changes of the optic nerve head (ONH) during exposure to high altitude and to assess a correlation with acute mountain sickness (AMS). This work is related to the Tuebingen High Altitude Ophthalmology (THAO) study.

Methodology/principal findings

A confocal scanning laser ophthalmoscope (cSLO, Heidelberg Retina Tomograph, HRT3®) was used to quantify changes at the ONH in 18 healthy participants before, during and after rapid ascent to high altitude (4559 m). Slitlamp biomicroscopy was used for clinical optic disc evaluation; AMS was assessed with Lake Louise (LL) and AMS-cerebral (AMS-c) scores; oxygen saturation (SpO?) and heart rate (HR) were monitored. These parameters were used to correlate with changes at the ONH. After the first night spent at high altitude, incidence of AMS was 55% and presence of clinical optic disc edema (ODE) 79%. Key stereometric parameters of the HRT3® used to describe ODE (mean retinal nerve fiber layer [RNFL] thickness, RNFL cross sectional area, optic disc rim volume and maximum contour elevation) changed significantly at high altitude compared to baseline (p<0.05) and were consistent with clinically described ODE. All changes were reversible in all participants after descent. There was no significant correlation between parameters of ODE and AMS, SpO? or HR.

Conclusions/significance

Exposure to high altitude leads to reversible ODE in the majority of healthy subjects. However, these changes did not correlate with AMS or basic physiologic parameters such as SpO? and HR. For the first time, a quantitative approach has been used to assess these changes during acute, non-acclimatized high altitude exposure. In conclusion, ODE presents a reaction of the body to high altitude exposure unrelated to AMS.

SUBMITTER: Willmann G

PROVIDER: S-EPMC3206056 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Quantification of optic disc edema during exposure to high altitude shows no correlation to acute mountain sickness.

Willmann Gabriel G Fischer M Dominik MD Schatz Andreas A Schommer Kai K Messias Andre A Zrenner Eberhart E Bartz-Schmidt Karl U KU Gekeler Florian F

PloS one 20111101 11

<h4>Background</h4>The study aimed to quantify changes of the optic nerve head (ONH) during exposure to high altitude and to assess a correlation with acute mountain sickness (AMS). This work is related to the Tuebingen High Altitude Ophthalmology (THAO) study.<h4>Methodology/principal findings</h4>A confocal scanning laser ophthalmoscope (cSLO, Heidelberg Retina Tomograph, HRT3®) was used to quantify changes at the ONH in 18 healthy participants before, during and after rapid ascent to high alt ...[more]

PMID: 22069483

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Project description:BackgroundCohen syndrome (Q87.8;ORPHA:193; OMIM#216550) is an autosomal recessive inherited genetic disorder caused by mutation in the VPS13B/COH1 gene. It is characterized by variable clinical symptoms such as deformity of the head, face, hands and feet, eye abnormalities, abdominal obesity, neutropenia and nonprogressive intellectual disability. The typical lesions in the eyeball in Cohen syndrome include high myopia, retinal dystrophy, strabismus, maculopathy and lens subluxation. The present study describes the coexistence of bilateral macular edema with pale optic disc in a patient with a homozygous deletion in the VPS13B/COH1 gene.Material and methodsA 6-year-old Caucasian girl with facial dysmorphism, microcephaly, prominent upper incisors, narrow hands with slender fingers, congenital heart defect and ophthalmic symptoms was subjected to genetic testing. The genetic evaluation revealed a homozygous deletion on the long arm of chromosome 8 encompassing 20-25 exons of the VPS13 gene, as confirmed by Cohen syndrome. She underwent a full ophthalmological examination with the assessment of slit lamp examination of anterior segment and fundoscopy, refraction error, biometry, central corneal thickness and additionally electroretinography, optical coherence tomography and fundus photography.ResultsIn the ophthalmologic examination, the girl had bilateral astigmatism accompanied by myopia and a marked reduction in central corneal thickness. Fundus examination showed pale optic nerve discs and "salt and pepper" retinopathy. Bilateral cystic macular edema was revealed in handheld optical coherence tomography. Electroretinography showed a reduced response amplitude of cones and rods.ConclusionIn a patient with high myopia, macular edema, pale optic disc and facial dysmorphism, Cohen syndrome should be considered in the differential diagnosis. The severity of individual clinical features in patients with Cohen syndrome varies. It can be assumed that the type of mutation affects the occurrence and severity of individual symptoms.

Project description:Abstract Objectives Some astronauts returning from missions to the International Space Station (ISS) have developed ophthalmic structural changes, including optic disc edema. Incidence of optic disc edema among astronauts has been linked to one-carbon pathway genetic variants and B-vitamin status. A recent 30-d 6-degree head-down tilt bed rest study in which all subjects were exposed to 0.5% CO2 documented the occurrence of optic disc edema in 5 of 11 subjects. The objective of this study was to determine the effect of one-carbon pathway genetics and B-vitamin status on the incidence of optic disc edema in the bed rest subjects. Methods The study was conducted at the : envihab facility at the German Aerospace Center in Cologne, Germany. Subjects (6 M/5F) were healthy volunteers, 33 ± 8 y (mean ± SD), having a mean BMI of 23.4 ± 2.2 kg/m2. After a 14-d ambulatory phase in a standard environment (i.e., not hypercapnic), a blood sample was collected to assess vitamin status and single nucleotide polymorphisms (SNPs) associated with one carbon metabolism. We focused on two SNPs (rs1801394, MTRR 66 and rs1979227, SHMT1 1420) based on our earlier findings in astronauts (Zwart et al., FASEB J, 30:141–8, 2016). The 30-d bed rest began after collection of this sample. Optical coherence tomography images were collected before, during (days 15 and 30), and after (6 and 13 days after reambulation) bed rest, and the change in total retinal thickness (TRT) at various distances from Bruch's membrane opening (BMO) was evaluated against the number of MTRR A66G G alleles and SHMT1 C1420T C alleles. Results The change in TRT at various distances from the BMO in bed rest subjects exposed to mild hypercapnia and headward fluid shifts was strongly associated with the number of MTRR 66 G and SHMT1 1420 C alleles. Conclusions This finding may increase understanding of mechanisms involved in optic disc edema in astronauts and patients on Earth, and hence lead to development of targeted countermeasures. Funding Sources This work was funded by the NASA Human Health Countermeasures Element of the NASA Human Research Program.

Dataset Information

Quantification of optic disc edema during exposure to high altitude shows no correlation to acute mountain sickness.

Background

Methodology/principal findings

Conclusions/significance

Publications

Quantification of optic disc edema during exposure to high altitude shows no correlation to acute mountain sickness.

Similar Datasets

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