Foreign body reaction against intracameral Triamcinolone: Clinicopathological case report

Amy L. Wong, MRCSEd; Hunter K. L. Yuen FRCS;Christopher K.S. Leung, MD; Dennis S.C. Lam, MD.Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong

IntroductionTriamcinolone acetonide (TA) is a corticosteroid suspension with potent anti-inflammatory effect. Intravitreal TA has been advocated in the treatment of various conditions including refractory macular edemas1-2 choriodal neovascularizations secondary to AMD pathological myopia3 enhancing visualization of vitreous during vitrectomy4-5 and ERM peeling operations Common adverse effects of intravitreal injection of TA are transient elevated intraocular pressure cataract progression7 Endophthalmitis is a rare but devastating8-9 Non-infectious endophthalmitis or pseudoendophthalmitis as a result of toxic reaction10-12 Here, we report a patient who had persistent pseudohypopyon five weeks after intracameral TA injection following cataract surgery

Case report72/F; Good past medical health Underwent an uneventful phaco + IOL operation of the right eye in February 2007Immediately after the surgery, intracameral injection of 2 mg triamcinolone (40mg/ml, Kenacort A, Bristol-Myer, Squibb, Agani, Italy) was given for the control of postoperative inflammation.

Post op Day 1:On the next day, the TA was noted in the inferior part of the anterior chamber mimicking a shallow hypopyon (Fig. 1)BCVA: 0.4; IOP: normal; ACQ and no ocular painThe patient was managed conservatively with close observation

Case reportPost op 4 weeks:Pseudohypopyon persisted and anterior segment optical coherence tomography (Visante OCT, Carl Zeiss Meditec, Dublin, CA, USA) revealed that the pseudohypopyon covered 3 clock hours inferiorly and measured 0.78 mm in height (Fig. 2)A similar finding was noted one week later and there was no change in the extension and height of this pseudohypopyonThe anterior chamber washout was performed because of the persistent of pseudohypopyonIntraoperatively, the pseudohypopyon was found to be a soft mass like lesion instead of liquidThe patient had an uneventful recovery thereafterBCVA: 0.7; IOP: normal; ACQ

Histopathological analysisNumerous birefrigence particles consistent with TA crystals were identified when the pseudohypopyon was examined under polarized light (Fig. 3A)Microscopic examination disclosed numerous histiocytes with numerous clear dropout spaces of different sizesThese dropout spaces were presumably caused by removal of TA crystals during processing (Fig. 3B)The histiocytes were highlighted by CD163 immunstaining (Fig. 3C)The overall features were compatible with foreign body reaction against the injected TA

Fig. 1 Slit-lamp photo showing a shallow pseudohypopyon (arrow) located at 5 to 7 oclock region of right eye.

Fig. 2 ASOCT showing hyperreflective signal with vertical height of 0.78mm at inferior anterior chamber angle of right eye 4 weeks after intracameral triamcinolone injection.

Fig. 3 Histopathology of the pseudohypopyon. (A) Multiple birefrigence particles compatible with triamcinolone crystals (polarized light x 40). (B) The pseudohypopyon is composed of histiocytes with numerous clear dropout spaces of different sizes and brownish iris pigment ( H&E, x 400). (C) The histiocytes are confirmed by CD163 immunostaining (x 400).

DiscussionNon infectious endophthalmitis or pseudoendophthalmitis is a condition that mimics infectious endophthalmits and can post a diagnostic challenge10. It was postulated that pseudoendophthalmitis was probably an inflammatory reaction to some substances in the formulation of TA.

We have, for the first time, demonstrated by histopathology that intracameral triamcinolone usage can cause foreign reaction and pseudohypopyon formation in human eye. The presence of histiocytes surrounding the TA molecules in our specimen indicated that the intracamerally injected unfiltered Kenacort could have induced foreign body reaction.

Theorectically, triamcinolone will suppress inflammation and the exact reason for the development of foreign body reaction is unknown. We postulate that such inflammatory response could be a non infectious reaction to the drug or its vehicle.

DiscussionTo differentiate infectious from noninfectious endophthalmitis, clinicians should closely monitor the clinical symptoms and signs, like eye pain, visual acuity, intraocular pressure, progression of anterior chamber reaction and the level of hypopyonAnterior segment optical coherence tomography is also useful in monitoring the progression of hypopyon as demonstratedThis can objectively monitor the level, location and extension of the hypopyon in a non invasive, non contact manner with high resolution, cross sectional images of the anterior segment (18um).

ConclusionIntracameral injection of TA could trigger foreign body reaction in a healthy human eyeUsing a preservative free formulation or filtered suspension for injection could be considered as an alternative for intraocular injection in order to prevent the unwanted inflammatory response.

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