Abstract
Pars planitis is 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.
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Keywords
Overview
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Definition
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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
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After idiopathic and JIA, it is the third most common etiology of pediatric uveitis
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Symptoms
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Floaters
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Blurry vision
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Laterality
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>75% bilateral, but can be asymmetric
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Course
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Gradual onset
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Chronic with low incidence of remission
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Age of onset
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Most commonly childhood to adolescence, but also older adults in their 40s
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Gender/race
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Equal gender distribution in pediatric population; slight female preponderance in older cases
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Caucasians
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Systemic association
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By definition, pars planitis is not associated with any systemic disease
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Exam: Ocular
Anterior Segment
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Mild to moderate AC inflammation
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Band keratopathy
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Keratic precipitates
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Posterior synechiae
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Peripheral corneal endotheliopathy
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Cataracts
Posterior Segment
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Vitreous haze and cells
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Snowballs/snowbanks (65–98%): must indent sclera inferiorly
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Retinal vasculitis (17–90%)
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Optic nerve leakage (70%)
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CME and ERM common
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Retinal and optic disc neovascularization
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Vasoproliferative tumor
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Retinoschisis (children only)
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Rhegmatogenous/tractional/exudative RD
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Glaucoma requiring surgery is rare
Exam: Systemic
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No systemic findings in true pars planitis, but must keep in mind of DDx (below) and ask pertinent questions
Imaging
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OCT
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CME
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ERM
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FA
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Retinal vasculitis (may be only visible on wide-field FA)
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Optic nerve leakage
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Macular leakage
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Laboratory and Radiographic Testing
Pars planitis is a diagnosis of exclusion, so systemic diseases must be ruled out:
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Multiple sclerosis: MRI brain/spine, HLA-DR15, and DR2
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Sarcoidosis: ACE, lysozyme, CT chest, Gallium scan
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Syphilis: RPR, FTA-ABS
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Lyme and Bartonella serologies
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Tuberculosis: chest radiograph, PPD, QuantiFERON
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Intraocular lymphoma: MRI brain, diagnostic vitrectomy
Differential Diagnosis
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Multiple sclerosis
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Sarcoidosis
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Syphilis
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Lyme disease
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Cat scratch disease
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Tuberculosis
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Whipple’s disease
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Intraocular lymphoma (elderly patients)
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Other conditions that can mimic intermediate uveitis
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Anterior uveitis with spill-over cells: FHI, HLA-B27
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Mild vitritis with subtle chorioretinitis: Behcet’s, VKH, Eales disease
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Severe vitritis with visually obscured chorioretinitis: toxoplasmosis, toxocariasis, ARN, endophthalmitis
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Treatment
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Treatment is indicated when there is reduced vision, significant vitreous opacities, macular edema, or retinal vasculitis
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Periocular corticosteroid injection (triamcinolone 40 mg/1 ml) with topical steroids if AC inflammation is also present; supplement with oral corticosteroids if necessary
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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:
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Peripheral retinal cryopexy or indirect laser photocoagulation to the snowbanks of the inferior pars plana
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Induces regression of vitreous base neovascularization and consequently stabilizes inflammation
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Steroid-sparing IMT
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When disease is bilateral, and/or there is significant retinal vasculitis
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Anti-metabolites and cyclosporine are first line
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Biologics including adalimumab, infliximab, and tocilizumab are all effective
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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
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Must conduct careful neuro-ROS and inquire about family history of MS and other demyelinating disorders
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When in doubt, consider neurology consult and MRI
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Preferred over PPV/cryo/laser (see below) if disease is bilateral or if there is significant retinal vasculitis
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Pars plana vitrectomy with cryopexy/endolaser
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When disease is unilateral or asymmetric bilateral, or when there are visually significant vitreous opacities or concurrent VR complications (VH, ERM, TRD)
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In our experience, this approach alone rarely results in disease quiescence in the presence of retinal vasculitis, but may reduce IMT burden
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Stronger anti-inflammatory effects than cryopexy/laser photocoagulation along, by way of removing the vitreous which serves as a cytokine scaffold
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Cryopexy is favored over endolaser in phakic patients to avoid peripheral instrument-crystalline lens touch
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4.
Fluocinolone acetonide 0.59 mg implant (Retisert)
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If all else fail, but cataract is a guarantee and glaucoma requiring surgery is likely
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1.
Referral/Co-management
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Rheumatology
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Hunchangsith, B. (2021). Pars Planitis. In: Foster, C.S., Anesi, S.D., Chang, P.Y. (eds) Uveitis. Springer, Cham. https://doi.org/10.1007/978-3-030-52974-1_11
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DOI: https://doi.org/10.1007/978-3-030-52974-1_11
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