Frosted branch angiitis associated with streptococcal infection: optical coherence tomography as a follow‐up tool

Abstract

7-year-old boy presented withdecreased vision and conjuncti-vitis in both eyes. He had a flu-likeepisode with fever about 2 weeks ear-lier, and the skin of both palms hadpeeled off. His visual acuity (VA) was0.15 OD and 0.1 OS. Slit-lamp exami-nation showed conjunctival and ciliaryinjection, cells in the anterior cham-ber, flare and fine keratic precipitatesbilaterally. Ophthalmoscopy revealeddiffuse, white perivascular sheathingof the arteries and veins, tortuous anddilatated veins, scattered retinal haem-orrhages and papilloedema in botheyes (Fig. 1A). Fluorescein angiogra-phy demonstrated extensive dye leak-age from almost all vessels (Fig. 1B)and both optic discs were hyperfluo-rescent in the late phase. Indocyaninegreen angiography (ICGA) showed amottled background pattern, stainingof the vessels especially in the poster-ior pole, and hypofluorescence of thediscs with blurred margins (Fig. 1C).Optical coherence tomography (OCTModel 2000; Carl Zeiss Meditec, Inc.,Dublin, CA, USA) showed a clear ser-ous detachment and oedema in themacula (Fig. 1D, E). Goldmann peri-metry showed an enlarged blind spot.The amplitudes of the a- and b-wavesand the oscillatory potentials of theelectroretinograms (ERGs) elicited bya bright flash were significantlyreduced (Fig. 1F).Systemic examinations disclosed noabnormal findings except for high titresof anti-streptolysin O (ASO, 1830·)and anti-streptokinase (ASK, 5120·).From these findings, the subject wasdiagnosed with frosted branch angiitis(FBA). He was treated with topical0.1% betamethasone and 1.0% atro-pine along with i.v. prednisolone(580 mg⁄day) for 3 days and subse-quently oral prednisolone for 15 days(total 165 mg). Three days later, theaqueous inflammation and the peri-vascular sheathing were markedlyreduced. Thereafter, OCT and oph-thalmoscopy of the macular areashowed a resolution of the oedemafollowed by the appearance of a star-shaped figure (Fig. 1G, H). The sub-ject’s ERGs were markedly improvedbut were still not normal (Fig. 1I).The serous detachment (Fig. 1J, K)and finally exudates disappeared.Despite the rapid improvement inthe appearance of the retina, thepatient’s VA improved much moreslowly and attained 1.0 only after3 months. Fundus angiography at thattime demonstrated the complete reso-lution of all abnormal findings.The increase in the number of casesdiagnosed as FBA raises questionsabout whether this disorder representsa distinct clinical syndrome or merelya clinical sign of eyes with inflamma-tory conditions. From their descrip-tions in the literature, cases diagnosedas FBA are characterized by bilat-eral, perivascular retinal blood vesselsheathing, retinal haemorrhages andoedema of different degrees, panuveitisand papilloedema (Walker et al. 2004).Our case had diffuse angiitis involvingthe vessels of the macular and periph-eral retina and the choroid. Anterioruveitis and papilloedema were alsopresent. The abnormal ICGA findingssuggested that the choroid was alsoaltered, which probably accounts forthe decreased a-waves on ERG. Thereduced b-waves indicated alterationsto the inner retina. Whether thesefindings are also found in other chori-oretinal inflammatory diseases is yet tobe determined. The prevalence of FBAis reported to be higher in Asians thanin White populations (Walker et al.2004).Despite the marked panophthalmicinflammation, the eye responded wellto steroids. Our subject’s VA recov-ered to normal levels, but some FBAsubjects suffer a permanent loss ofvision caused by macular scarring(Kleiner et al. 1988; Walker et al.2004).