Case of the Month I December 2018

Case of the Month

December 18, 2018

The Case

The patient was a 40 year old white woman with juvenile onset diabetes diagnosed 20 years ago, hypertension, hypothyroidism, and trigeminal neurology who presented with a two day history of a sudden onset of photopsias and a "spot blocking my vision" temporal to fixation in the left eye. Visual acuity was 20/20 OD and 20/30 OS. The examination was unremarkable except for a subtle finding in the left macula. The anterior and posterior chambers were quiet OU. What was the most likely diagnosis? What treatment, if any was needed?

The fundus photo shows subtle grayish discoloration nasal to the fovea in the left eye. The fluorescein angiogram was unremarkable. The OCT reveals swelling nasal to the fovea with subtle hyper-reflectivity at the level of the inner plexiform, inner nuclear, and outer plexiform layers. These findings are consistent with a rare condition called paracentral acute middle maculopathy (PAMM). Patients with PAMM, as with our patient, typically experience a sudden loss of central vision or a paracentral scotoma, and associated photopsias have been reported. Prior reports have hypothesized an ischemic etiology, implicating caffeine, vasoconstrictors, or systemic diseases associated with vascular occlusions. Our patient, with diabetes and hypertension, was at risk of microvascular occlusive disease. PAMM should be distinguished from acute macular neuroretinopathy, which likely has an inflammatory of infectious etiology and typically presents with central or paracentral disruptions of the ellipsoid zone on OCT. The scotoma in patients with PAMM is usually permanent. Our patient was observed closely and not treated, and she has not experienced a visual change four months after her initial presentation.

References

Tsui I, Sarraf D. Paracentral acute middle maculopathy and acute macular neuroretinopathy. Ophthalmic Surg Lasers Imaging Retina 2013;44:S33-S35.

Aziz HA, Kheir W, Young RC, Isom RF, Dubovy SR. Acute macular neuroretinopathy: A case report and review of the literature 2002-2012. Ophthalmic Surg Lasers Imaging Retina 2015;46:114-124.

Rahimy F, Kuehlewein L, Sadda SR, Sarraf D. Paracentral acute middle maculopathy: What we knew then and what we know now. Retina 2015;35:1921-1930.

Schwartz R, Hykin P, Sivaprasad S. Localization of paracentral acute middle maculopathy using optical coherence tomography angiography. Ophthalmic Surg Lasers Imaging Retina 2018;49:619-624.

Pecan PE, Smith AG, Ehlers JE. Optical coherence tomography angiography of acute macular neuroretinopathy/paracentral acute middle maculopathy. JAMA Ophthalmol 2015;133:1478-80 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4936525/

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Case Photos

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