Keywords

Overview

  • Definition

    • A subset of intermediate uveitis that is not associated with a systemic disease or infection and characterized by the presence of snowballs in the vitreous and snowbanks along the inferior pars plana and retinal periphery

    • After idiopathic and JIA, it is the third most common etiology of pediatric uveitis

  • Symptoms

    • Floaters

    • Blurry vision

  • Laterality

    • >75% bilateral, but can be asymmetric

  • Course

    • Gradual onset

    • Chronic with low incidence of remission

  • Age of onset

    • Most commonly childhood to adolescence, but also older adults in their 40s

  • Gender/race

    • Equal gender distribution in pediatric population; slight female preponderance in older cases

    • Caucasians

  • Systemic association

    • By definition, pars planitis is not associated with any systemic disease

Exam: Ocular

Anterior Segment

  • Mild to moderate AC inflammation

  • Band keratopathy

  • Keratic precipitates

  • Posterior synechiae

  • Peripheral corneal endotheliopathy

  • Cataracts

Posterior Segment

  • Vitreous haze and cells

  • Snowballs/snowbanks (65–98%): must indent sclera inferiorly

  • Retinal vasculitis (17–90%)

  • Optic nerve leakage (70%)

  • CME and ERM common

  • Retinal and optic disc neovascularization

  • Vasoproliferative tumor

  • Retinoschisis (children only)

  • Rhegmatogenous/tractional/exudative RD

  • Glaucoma requiring surgery is rare

Exam: Systemic

  • No systemic findings in true pars planitis, but must keep in mind of DDx (below) and ask pertinent questions

Imaging

  • OCT

    • CME

    • ERM

  • FA

    • Retinal vasculitis (may be only visible on wide-field FA)

    • Optic nerve leakage

    • Macular leakage

Laboratory and Radiographic Testing

Pars planitis is a diagnosis of exclusion, so systemic diseases must be ruled out:

  • Multiple sclerosis: MRI brain/spine, HLA-DR15, and DR2

  • Sarcoidosis: ACE, lysozyme, CT chest, Gallium scan

  • Syphilis: RPR, FTA-ABS

  • Lyme and Bartonella serologies

  • Tuberculosis: chest radiograph, PPD, QuantiFERON

  • Intraocular lymphoma: MRI brain, diagnostic vitrectomy

Differential Diagnosis

  • Multiple sclerosis

  • Sarcoidosis

  • Syphilis

  • Lyme disease

  • Cat scratch disease

  • Tuberculosis

  • Whipple’s disease

  • Intraocular lymphoma (elderly patients)

  • Other conditions that can mimic intermediate uveitis

    • Anterior uveitis with spill-over cells: FHI, HLA-B27

    • Mild vitritis with subtle chorioretinitis: Behcet’s, VKH, Eales disease

    • Severe vitritis with visually obscured chorioretinitis: toxoplasmosis, toxocariasis, ARN, endophthalmitis

Treatment

  • Treatment is indicated when there is reduced vision, significant vitreous opacities, macular edema, or retinal vasculitis

  • Periocular corticosteroid injection (triamcinolone 40 mg/1 ml) with topical steroids if AC inflammation is also present; supplement with oral corticosteroids if necessary

  • After three recurrences in the affected eye(s), or in presence of steroid-induced OHTN/glaucoma, or if inflammation is refractory to corticosteroids, treatment should be escalated. Four options:

    1. 1.

      Peripheral retinal cryopexy or indirect laser photocoagulation to the snowbanks of the inferior pars plana

      • Induces regression of vitreous base neovascularization and consequently stabilizes inflammation

    2. 2.

      Steroid-sparing IMT

      • When disease is bilateral, and/or there is significant retinal vasculitis

      • Anti-metabolites and cyclosporine are first line

      • Biologics including adalimumab, infliximab, and tocilizumab are all effective

        • Keep in mind of association of pars planitis and intermediate uveitis with MS, as TNF-alpha inhibitors – and perhaps tocilizumab as well – can trigger or unmask demyelination

        • Must conduct careful neuro-ROS and inquire about family history of MS and other demyelinating disorders

        • When in doubt, consider neurology consult and MRI

      • Preferred over PPV/cryo/laser (see below) if disease is bilateral or if there is significant retinal vasculitis

    3. 3.

      Pars plana vitrectomy with cryopexy/endolaser

      • When disease is unilateral or asymmetric bilateral, or when there are visually significant vitreous opacities or concurrent VR complications (VH, ERM, TRD)

      • In our experience, this approach alone rarely results in disease quiescence in the presence of retinal vasculitis, but may reduce IMT burden

      • Stronger anti-inflammatory effects than cryopexy/laser photocoagulation along, by way of removing the vitreous which serves as a cytokine scaffold

      • Cryopexy is favored over endolaser in phakic patients to avoid peripheral instrument-crystalline lens touch

    4. 4.

      Fluocinolone acetonide 0.59 mg implant (Retisert)

      • If all else fail, but cataract is a guarantee and glaucoma requiring surgery is likely

Referral/Co-management

  • Rheumatology