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Fuchs’ Uveitis Syndrome

Home /Intraocular Inflammation and Uveitis / Noninfections (Autoimmune) Uveitis

Title: Fuchs’ Uveitis Syndrome
Author(s): Caroline Brereton, BS, Albert Vitale, MD
Photographer: James Gilman, CRA, FOPS
Date: 09/02/2022
Keywords/Main Subjects: Fuchs’ Uveitis Syndrome, chronic anterior uveitis, iris crystals

Diagnosis: Fuchs’ Uveitis Syndrome

Image Description: A 42-year-old man with no significant past medical or ocular history was referred to the uveitis clinic after he was noted to have keratic precipitates OS for several years without other documented abnormalities.  On slit lamp examination, a featureless iris with diminished crypts OS compared to OD was noted, as well as heterochromia with a greener iris OS.  Iris crystals were also noted on exam.  The patient’s OCT was within normal limits.  Due to the presence of iris crystals, an SPEP and serum Immunoglobulin subclasses were ordered.

 

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Description of Case:

Fuchs’ Uveitis Syndrome (FUS) is a form of chronic anterior uveitis that typically presents unilaterally.  Patients will often complain of visual abnormalities related to secondary complications, such as glaucoma and cataracts. ¹ The etiology of the disease is not entirely known, however, a study completed in 2004 suggested that it may be related to rubella infection.2 Rubella antibodies have been discovered in aqueous humor samples of patients with FUS, suggesting that it may be the cause of this chronic inflammation.  Patients generally present asymptomatically, however, some may complain of decreased vision with low-grade cells in the anterior chamber and vitreous.  Posterior synechiae are distinctly uncommon while cataracts and glaucoma occur frequently.  Cataract formation has a prevalence of 23 to 90.7% in patients with FUS.  Secondary glaucoma is seen in 15 to 59% of cases and treatment requires trabeculectomy since medical therapy is typically unsuccessful. ¹ Macular edema is uncommonly seen while chorioretinal scars resembling those of toxoplasmosis, retinal periphlebitis, and vitreous floaters have been reported.3

Heterochromia, or multi coloration of the iris, is a common finding in FUS and is due to anterior stroma atrophy.  Patients with darker iris pigmentation may not present with this manifestation as heterochromia is dependent on the patient’s iris color and the amount of epithelial pigment.  This manifestation can be appreciated while completing a slit lamp examination.  The iris sphincter may also undergo atrophy and patients can present with an irregularly shaped pupil.  Another classic finding is the presence of white stellate keratic precipitates throughout the corneal endothelium. ¹ FUS has been reported to be associated with iris crystals, however, this exam finding is rare.  Iris crystals are thought to be seen in the presence of immunoglobulin production in the anterior chamber, and when detected on exam, lymphoproliferative diseases should be ruled out.4,5 Other uncommon findings include angle neovascularization.  These “bridging vessels” in the chamber angle may lead to a hyphema during cataract surgery or after an anterior chamber paracentesis (Amsler Sign).6 Iris nodules are also found in FUS.  Nodules found at the pupillary border are known as Koeppe nodules and those found on the surface of the iris are referred to as Busaca nodules. 7

FUS is a clinical diagnosis, dependent on the eye examination.  To detect the presence of rubella-specific antibodies, an anterior chamber paracentesis may be completed, however, this is not a specific finding. ¹ FUS has also been associated with diffuse and full-thickness choroidal thinning on enhanced depth imaging optical coherence tomography (EDI-OCT).  This finding may be attributed to the inflammation seen in this disease process.8 In-vivo confocal microscopy (IVCM) has also been used to analyze keratic precipitates in patients with a known diagnosis.  A study in 2009 utilized IVCM for patients with FUS and determined that the patients’ keratic precipitates and corneal endothelium images appeared similarly to patients with infectious uveitis.1,9 This provided further evidence that it may have an infectious etiology such as rubella, however, IVCM is not routinely utilized for the diagnosis of this disease.

The differential diagnosis of FUS includes other common causes of anterior uveitis.  Herpetic iridocyclitis presents with dendritic ulcers and sectoral iris atrophy, rather than diffuse atrophy seen in FUS.  VZV presents with pseudodendritic ulcers and a vesicular rash along the ophthalmic division of the fifth cranial nerve.  The iris atrophy is also sectoral, like HSV.  CMV remains latent in the iris and ciliary body and may also be a possible cause of hypertensive anterior uveitis in individuals.6   Posner-Schlossman syndrome (glaucomatocyclitic crisis), which is characterized by recurrent attacks of unilateral anterior uveitis and some keratic precipitates, must also be considered.  The inflammation associated with Posner-Schlossman Syndrome resolves with a short course of steroids, which can help differentiate this disease from FUS. 10 Diffuse iris melanoma may also present with heterochromia and unilateral glaucoma. 11 Iris cysts or nodules found in FUS may appear similarly to other iris tumors, such as iris pigment adenoma and adenocarcinoma.  A thorough slit-lamp examination and high-frequency ultrasound biomicroscopy may be necessary to rule out these diagnoses. 12 Neovascular glaucoma, toxoplasmosis, and sarcoidosis should also be ruled out.

Treatment is frequently directed toward management of the secondary manifestations of the disease, such as cataract formation and glaucoma.  Topical corticosteroids may be used to lower intraocular pressure during episodes of active inflammation, however, long term treatment with topical corticosteroids and cycloplegia is of little value as low-grade anterior chamber cells are frequently present and do not resolve with topical therapy.  Topical corticosteroids may exacerbate ocular hypertension and cataract formation. Systemic corticosteroids are of no benefit for patients. The outcomes following cataract surgery and IOL placement are extremely good, with an 85% success rate.  Ocular hypertension and glaucoma are typically the most difficult to manage.  Prognosis is good for patients if these are well-managed and treated. ¹

Summary of the Case: Fuchs’ Uveitis Syndrome is a form of chronic anterior uveitis that typically presents asymptomatically and unilaterally in patients.  It is theorized to be related to chronic inflammation secondary to a rubella infection.  The presence of iris crystals is rare but suggests that immunoglobulins are produced, further corroborating the theory that this disease has an infectious etiology.

References:

  1. Moshirfar M, Villarreal A, Ronquillo Y. Fuchs Uveitis Syndrome. In: StatPearls. Treasure Island (FL): StatPearls Publishing; July 13, 2022.
  2. Quentin CD, Reiber H. Fuchs heterochromic cyclitis: rubella virus antibodies and genome in aqueous humor. Am J Ophthalmol. 2004;138(1):46-54. doi:10.1016/j.ajo.2004.02.055
  1. de Groot-Mijnes JD, de Visser L, Rothova A, Schuller M, van Loon AM, Weersink AJ. Rubella virus is associated with fuchs heterochromic iridocyclitis. Am J Ophthalmol. 2006;141(1):212-214. doi:10.1016/j.ajo.2005.07.078
  2. Callear AB, Reynolds A, Harry J, Murray PI. Iris crystals in chronic uveitis. British Journal of Ophthalmology. 1999;83(6):703-706. doi:10.1136/bjo.83.6.703
  3. Goldstein DA. Iris crystals in Fuch Heterochromic iridocyclitis. Archives of Ophthalmology. 1998;116(12):1692. doi:10.1001/archopht.116.12.1692
  4. Babu K, Konana VK, Ganesh SK, et al. Viral anterior uveitis. Indian J Ophthalmol. 2020;68(9):1764-1773. doi:10.4103/ijo.IJO_928_20
  5. Shaikh N, Kumar V, Venkatesh P. Iris nodules in Fuchs heterochromic iridocyclitis. Indian J Ophthalmol. 2019;67(8):1339. doi:10.4103/ijo.IJO_2105_18
  6. Cerquaglia A, Iaccheri B, Fiore T, et al. Full-thickness choroidal thinning as a feature of Fuchs Uveitis Syndrome: quantitative evaluation of the choroid by Enhanced Depth Imaging Optical Coherence Tomography in a cohort of consecutive patients. Graefes Arch Clin Exp Ophthalmol. 2016;254(10):2025-2031. doi:10.1007/s00417-016-3475-y
  7. Labbé A, Dupas B, Offret H, Baudouin C, Labetoulle M. Evaluation of keratic precipitates and corneal endothelium in Fuchs’ heterochromic cyclitis by in vivo confocal microscopy. Br J Ophthalmol. 2009;93(5):673-677. doi:10.1136/bjo.2008.146100
  8. Fuchs Heterochromic iridocyclitis. EyeWiki. https://eyewiki.aao.org/Fuchs_Heterochromic_Iridocyclitis#Differential_diagnosis. Published December 6, 2021. Accessed September 11, 2022.
  9. Skalicky SE, Giblin M, Conway RM. Diffuse iris melanoma: Report of a case with review of the literature. Clin Ophthalmol. 2007;1(3):339-342.
  10. Rao RC, Harbour JW. An Iris Tumor. JAMA Ophthalmol. 2016;134(9):1063-1064. doi:10.1001/jamaophthalmol.2016.0924

Identifier: Moran_CORE_126091
Faculty Approval by: Griffin Jardine, MD
Copyright: Caroline Brereton ©2022. For further information regarding the rights to this collection, please visit: http://morancore.utah.edu/terms-of-use/