Abstract
Purpose :
While choroidal effusions are known to be associated with SLE, the cause is unknown. Some have postulated a transudative process, either related to hypoalbunemia/hypoproteinema or from abnormal anatomy. Others have suggested an exudative etiology from an inflammatory process. In the work here, we investigated the etiology of an SLE-related choroidal effusion by analyzing the fluid after surgical drainage using Light's criteria. Understanding the cause of fluid accumulation will help guide development of therapies.
Methods :
In a patient with bilateral choroidal effusions secondary to acute SLE (Fig 1), a partial-thickness scleral flap was made under the effusion site. A small full-thickness scleral hole was then created and the choroidal fluid was allowed to percolate onto the everted flap. As the fluid slowly effluxed, the fluid was aspirated from the flap surface and sent to the lab for analysis using Light's criteria.
Results :
The choroidal fluid from the patient's right eye contained 3.4 g/dL protein and 187 U/L LDH. The fluid from the left eye was similar in composition. Using Light's criteria, the fluid is exudative if at least one of the following criteria is met: the fluid-to-serum protein ratio is greater that 0.5, the fluid-to-serum LDH ratio is greater than 0.6, or the fluid LDH level is at least 2/3 the serum LDH upper-limit-of-normal. Applying Light’s criteria, the choroidal fluid from both eyes was exudative (Fig 2).
Conclusions :
Light's criteria was originally developed to help internists distinguish transudative from exudative pleural effusions. Using fluid protein and LDH levels, and normalizing to serum levels, one can predict the cause of fluid accumulation. Here, this technique was applied to SLE choroidal effusions which revealed a frankly exudative process. This suggests the effusions in SLE are most likely related to localized inflammation. It is therefore likely that the choroid is a primary target of immune complex deposition and not just responding to the low oncotic pressure. This suggests that treatment of the eye with an anti-inflammatory medication may be an effective therapy for SLE-induced choroidal effusions. This technique could be applied to a wide range of diseases with chroidal fluid retention, help elucidate disease mechanisms, and guide development of new therapies.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.