Paracentral acute middle maculopathy (PAMM) associated with ulcerative colitis and coexisting hyperhomocysteinemia: A case report.

Introduction: Paracentral acute middle maculopathy (PAMM) is a tomographic finding of a retinal occlusive vascular disorders with different aetiologies. Despite the well documented triple association among hyper-homocysteine, retinal vein occlusion and PAMM, up to date no reports exist on the development of PAMM in young patients affected by ulcerative colitis (UC).

Case Description: A multimodal imaging study, including fundus photographs, optical coherence tomography (OCT) B-scans, OCT angiography (OCT-A) and fluorescein and indocyanine green angiography, was performed in a 32-years-old male complaining of acute-onset paracentral scotoma in the right eye. Fundus images demonstrated the typical dark gray area of retinal capillary ischemia, corresponding on OCT B-scans to the hyper-reflective plaques in the INL, and consistent with PAMM lesions.The deep capillary plexus (DCP) was normal on OCT-A. Fluorescein angiography revealed a concurrent branch retinal vein preocclusion and showed capillary drop out parafoveally. Patient's anamnesis was negative except for a 15-years history of UC and use of acetylsalicylic acid (ASS). At the time of presentation, UC was quiescent, but new blood tests revealed concomitant high values of homocysteinemia requiring oral vitamin B12 and folate supplementation. Two months later PAMM lesions had disappeared on OCT B-scans and a retinal thinning at the level of the inner nuclear layer (INL) was visible. The DCP on OCT-A remained unchanged without any sign of capillary ischemia.

Conclusions: Although no definitive evidence directly links UC with PAMM, the latter should be suspected in young patients affected by IBD with coexisting hyper-homocysteinemia and unexplained visual symptoms.