Cotton-wool spots in primary HIV infection

Neuro-Ophthalmology of Space Flight

BACKGROUND

To describe the history, clinical findings, and possible pathogenic etiologies of the constellation of neuro-ophthalmic findings discovered in astronauts after long-duration space flight and to discuss the terrestrial implications of such findings.

EVIDENCE ACQUISITION

Retrospective review of published observational, longitudinal examination of neuro-ophthalmic findings in astronauts after long-duration space flight; analysis of postflight questionnaires regarding in-flight vision changes in approximately 300 additional astronauts; and hypothesis generating for developing possible future countermeasures and potential implications for neuro-ophthalmic disorders on Earth. Astronauts with neuro-ophthalmic findings, which were not present at the start of a space flight mission and only seen on return from long-duration space missions to the International Space Station, will be discussed.

RESULTS

After 6 months of space flight, 7 astronauts had ophthalmic findings consisting of optic disc edema in 5, globe flattening in 5, choroidal folds in 5, cotton-wool spots in 3, nerve fiber layer thickening detected by optical coherence tomography in 6, and decreased near vision in 6. Five of 7 astronauts with near vision complaints had a hyperopic shift ≥+0.50 diopters (D) between pre-/post-mission spherical equivalent refraction in 1 or both eyes (range, +0.50 to +1.75 D). These 5 astronauts showed globe flattening on magnetic resonance imaging. A total of 6 lumbar punctures have been performed to date (4 in the originally described cohort) and documented opening pressures of 18, 22, 21, 21.5, 28, and 28.5 cm H2O. These were performed at 8, 66, 19, 7, 12, and 57 days after mission, respectively. The 300 postflight questionnaires documented that approximately 29% and 60% of astronauts on short-duration and long-duration missions, respectively, experienced a degradation in distant and near visual acuity. Some of these vision changes remain unresolved for years after flight. Several possible pathogenic mechanisms, as well as potential countermeasures and discussion of possible terrestrial implications, are described.

CONCLUSIONS

We previously hypothesized that the optic nerve and ocular changes that we described in astronauts may be the result of orbital and cranial cephalad fluid shifts brought about by prolonged microgravity exposure. The findings we reported previously and continue to see in astronauts may represent parts of a spectrum of ocular and cerebral responses to extended microgravity exposure. Future investigations hopefully will lead to countermeasures that can be used to eliminate or lessen the magnitude of these potentially harmful findings before long-duration space flight including the possibility of a manned mission to Mars.

Optic disc edema, globe flattening, choroidal folds, and hyperopic shifts observed in astronauts after long-duration space flight

PURPOSE

To describe the history, clinical findings, and possible etiologies of ophthalmic findings discovered in 7 astronauts after long-duration space flight, and document vision changes in approximately 300 additional astronauts.

DESIGN

Retrospective, observational examination of ophthalmic findings in 7 astronauts and analysis of postflight questionnaires regarding in-flight vision changes in approximately 300 additional astronauts.

PARTICIPANTS

Seven astronauts with ophthalmic anomalies upon return from long-duration space missions to the International Space Station and 300 additional astronauts who completed postflight questionnaires regarding in-flight vision changes.

METHODS

Before and after long-duration space flight, all 7 subjects underwent complete eye examinations, including cycloplegic and/or manifest refraction and fundus photography. Six underwent postmission optical coherence tomography (OCT) and magnetic resonance imaging (MRI); 4 had lumbar punctures (LP). Approximately 300 astronauts were queried regarding visual changes during space missions.

MAIN OUTCOME MEASURES

Refractive change, fundus photograph examination, retina OCT, orbital MRI, LP opening pressures, and examination of visual acuity data.

RESULTS

After 6 months of space flight, 7 astronauts had ophthalmic findings, consisting of disc edema in 5, globe flattening in 5, choroidal folds in 5, cotton wool spots (CWS) in 3, nerve fiber layer thickening by OCT in 6, and decreased near vision in 6 astronauts. Five of 7 with near vision complaints had a hyperopic shift ≥+0.50 diopters (D) between pre/postmission spherical equivalent refraction in 1 or both eyes (range, +0.50 to +1.75 D). These 5 showed globe flattening on MRI. Lumbar punctures performed in the 4 with disc edema documented opening pressures of 22, 21, 28, and 28.5 cm H(2)O performed 60, 19, 12, and 57 days postmission, respectively. The 300 postflight questionnaires documented that approximately 29% and 60% of astronauts on short and long-duration missions, respectively, experienced a degradation in distant and near visual acuity. Some of these vision changes remain unresolved years after flight.

CONCLUSIONS

We hypothesize that the optic nerve and ocular changes we describe may result from cephalad fluid shifts brought about by prolonged microgravity exposure. The findings we report may represent parts of a spectrum of ocular and cerebral responses to extended microgravity exposure.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Validation of the Sign and Symptom Check-List for Persons with HIV Disease (SSC-HIV)

Symptom management for persons living with HIV disease is recognized as an extremely important component of care management. This article reports the validation of a new sign and symptom assessment tool designed to assess the intensity of HIV-related symptoms using two samples (study 1: n=247; study 2: n=686) of people living with HIV disease. Study 1 data were collected between 1994 and 1996 before the initiation of highly active antiretroviral therapy (HAART). Study 2 data were collected between 1997 and 1998 after the wide adoption of HAART therapy. The initial version of the Sign and Symptom Check-List for Persons with HIV Disease (SSC-HIV) included 41 signs and symptoms. This scale was submitted to a principal components factor analysis with a varimax rotation. The final solution reports six factors explaining 68.9% of the variance. The six symptom clusters (factors), the number of items in the factor, and the Cronbach alpha reliability estimates were: malaise/weakness/fatigue (six items, alpha=0.90); confusion/distress (four items, alpha=0.90); fever/chills (four items, alpha=0.85); gastrointestinal discomfort (four items, alpha=0. 81); shortness of breath (three items, alpha=0.79); and nausea/vomiting (three items, alpha=0.77). These six factors have strong reliability estimates and a stable factor structure that supports the construct validity of the 26-item instrument. Additional evidence supports the concurrent validity of the scale as well as its sensitivity to change over time. The final version of the SSC-HIV is a 26-item scale available for use by clinicians and researchers to measure the patient's self-report of HIV-related signs and symptoms.