Case #63 – Let it Snow: A Case of Retinal Whitening

Back to the Patient  2-week follow upBCVA: 20/800 OS (previously 20/25)IOP 14/13Carotid Doppler: no stenosisMRI/MRA: unremarkableLabs: within normal limitsEKG/ECG: unremarkable

Treatment/Management   There is no effective treatment to reverse the ischemia Case reports of reversal of PAMM after initiating anti-platelet therapy1 Risk factors should be questioned Due to PAMM lesions being an ischemic event and reports of impending RAO, patients should have a stroke work up performed urgently including: MRI MRA/CTA Carotid Doppler ECG/EKG

Risk Factors Continued Reports have seen PAMM lesions may proceed RAOsIn one report, a 63-year-old male with history of third-degree atrioventricular heart block developed vision changes. PAMM lesions were seen on OCT with no other findings. Labs ruled out GCA and 5 days later developed a CRAO.      Louie E, Tang A, and King B. Paracentral

Risk Factors Continued  There have been case reports of PAMM lesions seen in other conditions seen below.Inflammatory DisordersRetinal vasculitis, birdshot chorioretionopathy, GCAMedications:SympathomimeticsEpinephrine, caffeineContraceptivesMigrainesGlaucoma: particularly acute angle closurePost surgery: CEIOL, PPVViral or post vaccineIt’s hypothesized that in these cases there is an acute ischemic event leading to the development of PAMM lesions.

Risk Factors Associated with retinal vascular disease (Diabetic Retinopathy, Hypertensive Retinopathy, Sickle Cell Retinopathy).In a recent retrospective study in patients with confirmed PAMM lesions, 25.4% were seen with RVOs, 21.4% seen with RAOs, 2.6% in combined RAO and RVO, and 50.6% seen with no other RVD Limoli C

EpidemiologyMean age: 49-53 years oldNo racial or gender predilection50-70% of eyes have VA >/= 20/50  

Acute vs. Chronic PAMM Acute: ICP/DCP capillary dropout or refillingHyper-reflectivity at the OPLRetinal whitening Chronic: Middle retinal layer atrophyOccasionally, spontaneous improvement OCT 6 months after a PAMM lesion was visualized showing atrophy of the middle retinal layers with an intact overlying RNFL and intact

Multimodal Imaging of PAMM   OCTA en face imaging reveals hypo-reflective lesions in the areas of PAMM (E). Intermediate/deep retinal capillary dropout may also be seen (G1-3). Occasionally, there will be spontaneous refilling with no dropout visualized.  OCTA: intermediate/deep retinal capillary dropout. Occasionally, there will be spontaneous refilling with no dropout visualized.

Multimodal Imaging of PAMM  OCT: hyper-reflectivity of the middle macular layers at the OPL

Multimodal Imaging of PAMM   Fundus PhotographyWhitish-gray lesions of the retina