18 - posner-schlossman syndrome

Glaucomatocyclitic crisis is a condition with self-limited recurrent episodes of markedly elevated intraocular pressure (IOP) with mild idiopathic anterior chamber inflammation. It is most often classified as secondary inflammatory glaucoma. In 1948, Posner and Schlossman first recognized glaucomatocyclitic crisis and described the features of this syndrome. For this reason, the entity is often termed Posner-Schlossman syndrome (PSS). They identified the following features:

• Recurrent episodes of mild cyclitis
• Uniocular involvement
• Duration of attack varying from a few hours to several weeks
• Signs of a slight decrease in vision, elevated IOP with open angles, corneal edema with a few keratic precipitates, heterochromia with anisocoria, and a large pupil in the affected eye
• Normal visual fields
• Normal optic disc
• Normal IOP, outflow facility, and all provocative tests between episodes

Since this original description, other cases attributed to glaucomatocyclitic crisis have been found to deviate from these criteria. For instance, some patients with glaucomatocyclitic crisis have abnormal aqueous humor dynamics and may have an underlying primary open-angle glaucoma (POAG). Additional features that are now recognized are as follows:

• Almost exclusively, this condition affects individuals aged 20-50 years.
• Both eyes may be involved at different times but very rarely contemporaneously.
• The rise of IOP is out of proportion to the severity of the uveitis, and this rise in IOP precedes the identifiable inflammatory reaction, often by several days.

Episodic changes in the trabecular meshwork lead to impairment of outflow facility and result in an elevation of IOP. These changes are accompanied by mild intraocular inflammation. In the acute phase of PSS, optic nerve head parameters and retinal flow rates were altered; however, all returned to normal without any permanent damage after resolution of the elevated IOP. Electroretinogram studies in the acute phase demonstrate a selective reduction in the S-cone b-wave.

Causes :

• The etiology of glaucomatocyclitic crisis has remained elusive. Several factors have been postulated as contributors to the development of glaucomatocyclitic crisis, to include the following:

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• Abnormal vascular process
• Autonomic defect
• Allergic condition
• Variation of developmental glaucoma
• Cytomegalovirus (CMV)
• Herpes simplex virus
• Description of a final common pathway usually includes a reference to changes in the trabecular meshwork leading to a reduction of outflow facility. However, some authors describe an increase in aqueous production.
• Transfer coefficients of fluorescein in aqueous in the anterior chamber, by flow and by diffusion, are elevated during attacks of glaucomatocyclitic crisis. Between attacks, both coefficients return to normal.
• Elevations in IOP are postulated to be secondary to inflammation of the trabecular meshwork, which may be mediated by prostaglandins.
• Prostaglandins, especially prostaglandin E, have been found in higher concentration in the aqueous humor of patients during acute attacks. These levels return to normal between episodes.

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• In a study using rabbit eyes, prostaglandin E was shown to contribute to a breakdown of the blood-aqueous barrier. This increase in the transfer coefficient of fluorescein is consistent with a similar response in animal eyes to prostaglandin E.
• The vascular effects of prostaglandins may contribute to the tortuosity seen in iris vessels and the leakage demonstrated with fluorescein angiography of the iris.
• To confuse matters, in another animal study, elevated prostaglandins increased outflow facility, which would contribute to a lower IOP and, thus, not be consistent with the reduced outflow facility seen in patients with glaucomatocyclitic crisis during an acute episode.
• Another theory purports an increased aqueous production resulting from elevated levels of aqueous prostaglandins.
• In summary, the exact mechanism by which prostaglandins regulate IOP has not been described, but a direct correlation between elevated levels of prostaglandins in the aqueous humor and the level of IOP has been found during acute attacks of glaucomatocyclitic crisis.
• Evidence exists that glaucomatocyclitic crisis may be associated with POAG. Patients with a 10-year or longer history of PSS are 3 times more likely to develop visual field changes and optic disc changes. These patients may have a higher than normal incidence of corticosteroid responsiveness, leading to an elevated IOP. This must be kept in mind during the treatment of this disorder with corticosteroids.
• Associations with immunogenetic factors also exist; in one study, the presence of human leukocyte antigen Bw54 (HLA-Bw54) was found in 41% of patients.
• Associations with certain allergic conditions and gastrointestinal diseases, most notably peptic ulcer disease, have been described.

Physical examination of the eye :

• On examination, the eye is quiet with either no injection or a mild ciliary flush.
• The pupil often is dilated slightly or sluggishly reactive; the anterior chamber is deep and has an open angle.
• This condition should be differentiated from closed-angle glaucoma with the help of gonioscopy.
• IOP usually is elevated in the range of 40-60 mm Hg.
• IOP is related to the duration of uveitis but not to the degree of uveitis.
• Eyes with active inflammatory disease often have wide swings in IOP, leading to glaucomatous damage.
• The elevated IOP can last for several hours to a few weeks; therefore, it can be missed on initial examination.
• If the elevated IOP is of significant duration and elevation, corneal epithelial edema develops.
• Signs of anterior inflammation are characteristically minimal with faint flare, rare cells, and only a few keratic precipitates that are stellate, flat, nonpigmented, and concentrated over the inferior half of the endothelium.
• Fine keratic precipitates appear after 2-3 days of elevated IOP and resolve rapidly.
• The inflammation never leads to the development of posterior synechiae or peripheral anterior synechiae.
• Fresh precipitates may appear with each episode of increased IOP.
• Heterochromia, described originally, is no longer considered a characteristic of this syndrome.
• Typical of inflammatory conditions, early segmental iris ischemia and associated late iris-vessel congestion have been observed. These vessels leak on iris fluorescein angiography.

Treatment :

Complete medical care for patients presenting with glaucomatocyclitic crisis includes a reasonably thorough history of present illness, a review of drug allergies and sensitivities, a targeted past medical history and review of systems, a complete eye examination, a careful explanation of the disorder in accordance with the patient's level of understanding, and a commitment to long-term follow-up care of the patient.

• Medical therapy should be individualized to meet the patient's needs. Currently, the favored initial treatment is a combined regimen of a topical nonsteroidal anti-inflammatory drug (NSAID) and an antiglaucoma drug.
• Treatment recommendations include the following:

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• Topical steroids - Prednisolone acetate 1% 1 gtt qid, followed by taper
• Topical antiglaucoma drops - Timolol 0.25-0.5% 1 gtt bid or equivalent, or dorzolamide 2% 1 gtt bid/tid or equivalent (Beta-blockers should be avoided in patients with asthma.)
• Systemic carbonic anhydrase inhibitors - Acetazolamide 250 mg PO qid
• Topical NSAIDs - Diclofenac 0.1% 1 gtt tid/qid or equivalent
• Oral NSAIDs - Indomethacin 75-150 mg/d PO
• Miotics and mydriatic agents seldom are used because they may have further deleterious effects on the blood-aqueous barrier, and long-acting periocular steroids are frowned upon because of lingering IOP effects.
• NSAIDs reduce the inflammatory component by inhibiting the production of prostaglandins, and antiglaucoma medications reduce the influx of new aqueous; both these effects rapidly control the IOP. This combination also avoids potential IOP elevations caused by steroids in steroid-responsive patients.
• Well-informed and educated patients often can sense an impending attack based on ocular symptomatology, and they can institute appropriate self-therapy using an aqueous suppressant and a topical NSAID to blunt IOP elevations associated with treatment delays.
• Carefully observe patients periodically for recurrences of attacks and for development of POAG.
• In the absence of underlying chronic glaucoma, antiglaucoma agents do not prevent recurrences of glaucomatocyclitic crisis; therefore, they are not necessary between episodes.

An occasional patient may require a filtering procedure, which is not effective in preventing recurrences of the episodes of iritis but may be useful in the management of high IOP seen with these episodes. For example, a patient with excessively high pressures threatening vascular perfusion would be a candidate for a filtering procedure. No benefit is gained from laser trabeculoplasty.