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Intermediate Uveitis

URGENT — Uveitis

Symptoms

painless floaters and blurred vision

minimal photophobia or redness (characteristically a "quiet" eye)

usually bilateral but often asymmetric

typically affects patients aged 15–40 years

Clinical Findings

Signature signs

  • snowballs: discrete, spherical, white-yellow vitreous cellular aggregates
  • snowbanking: confluent white fibroglial exudates over the inferior pars plana
  • vitritis: significant vitreous haze and cells out of proportion to anterior segment reaction

Clinical complications

  • cystoid macular edema (cme): most common cause of vision loss
  • peripheral retinal periphlebitis and vascular sheathing
  • peripheral neovascularization (may lead to vitreous hemorrhage)
  • secondary signs: posterior subcapsular cataract, band keratopathy, and glaucoma

Etiology

Idiopathic

  • pars planitis: subtype accounting for >70% of cases (idiopathic snowbanking/snowballs)

Systemic associations

  • multiple sclerosis (ms): associated with 10–20% of cases; uveitis may precede demyelination
  • sarcoidosis: often presents with prominent vitritis and snowballs
  • infectious: lyme disease, syphilis, and tuberculosis

Masquerades

  • primary intraocular lymphoma (suspect in patients >50 years)
  • toxocariasis or retinoblastoma (suspect in children)

Red Flags

unexplained vitritis in a young woman (requires ms screening/mri)

new-onset intermediate uveitis in patients >50 years (rule out lymphoma)

use of anti-tnf-α agents if ms is suspected (can worsen demyelination)

vitreous hemorrhage in a young patient (check for neovascular snowbanks)

Investigations

Ocular diagnostics

  • indirect ophthalmoscopy with scleral depression: mandatory to view inferior pars plana
  • oct and fa: to identify cme, retinal vasculitis, or neovascularization
  • diagnostic vitrectomy: indicated in older patients to rule out lymphoma

Systemic workup

  • labs: rpr/fta-abs (syphilis), ace (sarcoid), quantiferon-tb gold, and lyme titers
  • imaging: chest x-ray or ct (sarcoid/tb)
  • mri brain with gadolinium: if neurological symptoms or high ms suspicion

Treatment

Local therapy (unilateral/CME)

  • periocular (sub-tenon) or intravitreal triamcinolone injections
  • long-acting steroid implants (ozurdex/yutiq) for chronic non-infectious cases

Systemic therapy (bilateral/severe)

  • oral prednisone (1 mg/kg/day) with a slow taper
  • steroid-sparing agents: methotrexate, mycophenolate mofetil, or azathioprine
  • biologic therapy: adalimumab (only if ms is excluded)

Surgical/procedural

  • pars plana vitrectomy: for non-resolving haze, erm, or traction
  • laser or cryotherapy: for peripheral neovascularization

Clinical Pearl

Snowbanking at the pars plana with vitreous snowballs is pars planitis — screen for MS in adults and for sarcoidosis and Lyme in the young; most need chronic steroid-spancy immunosuppression.

Differential Diagnosis

  • multiple sclerosis-associated pars planitis
  • sarcoidosis
  • lyme disease
  • syphilis
  • primary intraocular lymphoma
  • idiopathic pars planitis

Related Uveitis Conditions