A case of pigmented paravenous retinochoroidal atrophy

She was promptly seen in the neuro-ophthalmology clinic. The Humphrey Visual Field (HVF) test demonstrated a bitemporal field defect (Fig 1). However, the dilated fundus examination noted the presence of perivascular pigmented changes along the superior and inferior retinal vascular arcades, characteristic of PPRCA (Fig 2). HVF analysis showed changes consistent with a bitemporal defect (Fig 1). An MRI of the brain did not reveal any pituitary tumour.

Discussion

Pigmented paravenous retinochoroidal atrophy is a rare condition characterised by slowly progressive atrophy of the retinal pigmented epithelium (RPE) and the choriocapillaris. These changes are bilateral, often asymmetric and characterised by bone corpuscle pigment accumulation limited to the retinal vascular arcades and the peripapillary region¹.

Although the exact mechanism remains unknown, many dysgenetic, degenerative, hereditary and inflammatory conditions have been associated with the disease. PPRCA was initially described in 1937 by Dr Hewitson-Brown as retino-choroiditis radiata in a patient with tuberculosis². Further inflammatory associations include sarcoidosis, Behçet disease, measles, rubeola, syphilis and tuberculosis³.

As the majority of the patients are asymptomatic – uncommonly, patients may present with blurry vision in cases where the atrophy extends to include the foveal region⁴ – so initial diagnosis is based on incidental retinal findings during routine eye examinations.

The definitive diagnosis is usually based on clinical examination and is aided by multimodal imaging. Advances in multimodal imaging techniques, such as optical coherence tomography, ultra-widefield imaging and fundus autofluorescence, have significantly improved diagnostic capabilities⁵. Visual fields exhibit variable functional defects depending on the anatomical location of the pigmentary changes.

PPRCA should be differentiated from retinitis pigmentosa, which is typically a bilateral, symmetric inherited retinal disorder, which typically presents with progressive peripheral vision loss and night blindness.

Currently, there are no effective treatment options for atrophy of the retina, retinal pigmented epithelium and choriocapillaris, all layers that are affected in PPRCA⁶.

Key takeaways

• Retinal assessment through a dilated pupil is essential to pick up unusual retinal pathology.
• Our natural instinct links bitemporal field defects with chiasmal lesions; in some cases, such as PPRCA, localised retinal insult is the cause.
• Prompt referral is warranted to investigate any systemic inflammatory associations.

References

1. Antropoli A, Arrigo A, Pili L, Bianco L, Berni A, Saladino A, Bandello F, Battaglia Parodi M. Pigmented paravenous chorioretinal atrophy: Updated scenario. European Journal of Ophthalmology. 2024 Jul;34(4):941-51.
2. Brown TH. RETINO-CHOROIDITIS RADIATA. Br J Ophthalmol. 1937 Dec;21(12):645-8.
3. Ghosh B et al. SD-OCT in pigmented paravenous retinochoroidal atrophy. Ophthalmic Surg Lasers Imaging. 2012 May 10; 43(3):e41-3. PMID: 22589361.
4. R. Romero, A. Castano, M. Moriche, B. Poyales, M. Granados. Pigmented paravenous retinochoroidal atrophy with macular involvement. Arch Soc Esp Oftalmol, 88 (2) (2013), pp. 77-79
5. Lee EK, Lee SY, Oh BL, et al. Pigmented paravenous chorioretinal atrophy: clinical Spectrum and multimodal imaging characteristics. Am J Ophthalmol 2021; 224: 120–132
6. Huang HB, Zhang YX. Pigmented paravenous retinochoroidal atrophy (Review). Exp Ther Med. 2014 Jun;7(6):1439-1445.