4.2 Uveitis Differential Diagnosis and Aetiologies

1. Classifying Uveitis
2. Anterior Uveitis
3. Intermediate Uveitis
4. Posterior Uveitis
5. Panuveitis
6. Scleritis

There are several different descriptors that can be used to sensibly categorise intraocular inflammatory diseases [i]. The primary classification should be anatomical. By then describing a patient’s findings in with these additional terms and combining this classification with the demographics of the patient and relevant investigation findings, the differential diagnosis can be narrowed rapidly.

• Anterior uveitis
• Intermediate uveitis
• Posterior uveitis
• Panuveitis

• Sudden
• Insidious

• Acute (<3 months)
• Chronic (>3 months)

• Acute (sudden onset, limited duration)
• Recurrent (repeated episodes with periods of inactivity off treatment)
• Chronic (repeated episodes requiring ongoing therapy)

• All causes of acute uveitis can become chronic if untreated
• Fuch’s uveitis syndrome
• Juvenile Idiopathic Arthritis (JIA)
• TINU

1. Idiopathic (80%)
   i. Pars-planitis- presence of a “snow bank” (30%)
2. Inflammatory
   i. Sarcoid
   ii. Multiple sclerosis (MS)
   iii. Inflammatory bowel disease (5% of IBD patients)
3. Malignancy
   i. Lymphoma (primary CNS) (older age and usually NO CMO)
4. Infective
   i. Tuberculosis
   ii. Toxocara
   iii. Syphilis

• Form a differential diagnosis based on clinical examination, history and review of symptoms
• If there are suspicious neurological symptoms, order neuroimaging to exclude MS or lymphoma. An MRI is also needed if considering treatment with biological agents.
• Perform a diagnostic vitreous biopsy if required
• The main complications of intermediate uveitis are CMO and disc oedema. Assess for this at every visit with the visual acuity and an OCT.

• After coming to a reasonable differential diagnosis and outlining your primary investigations, you will be expected to have a broad management plan and potentially tailor it to the individual patients’ circumstances.
• Treat the vision, not the inflammation. Cells in the vitreous do not cause the same complications as cells in the anterior chamber.
• Be sure to rule out syphilis and tuberculosis before treating with systemic steroids and comment on why you have selected your chosen treatment modality. i.e. for unilateral disease, start with topical or regional treatments prior to systemic options if the severity of the pathology allows.
• Medical
  • Topical
  • Periocular steroid (particularly for CMO)
  • Intraocular steroid (if non-infectious)
    • Triamcinolone 4mg / 0.1mL
    • Dexamethasone intravitreal implant
  • Systemic immunosuppression
    • Corticosteroids
    • Steroid-sparing agents
    • Biological agents

Children with intermediate uveitis present many challenges:

• Delayed presentation and poorer vision
• Difficult examination
• Risk of amblyopia
• Wider differential diagnosis
• Increased risk of complications including neovascularisation and haemorrhage
• Administration of periocular steroids or intravitreal treatment requires general anaesthetic
• Increased risk of steroid related IOP rise
• Growth stunting with systemic steroids
• Cataract formation
• Compliance

• Retinitis (obscures vessels)
• Neuroretinitis (swollen disc and macular star)
• Retinal vasculitis (arteritis, phlebitis)
• Choroiditis (does not obscure vessels)

The differential diagnosis of posterior uveitis is wide. A careful, broad history including a directed review of systems should be taken. Travel, pets, occupation, vaccinations, hobbies and sexual history are all relevant. Attempt to narrow down the diagnosis to an infection, inflammatory or an atypical cause, then proceed accordingly. Sight-threatening posterior uveitis requires immediate empirical treatment covering all reasonable elements of the differential. A vitreous biopsy is often required to confidently exclude infection in these cases.

Infections

Inflammatory conditions

• Sarcoid
• Behcets
• VKH
• Sympathetic ophthalmia
• Idiopathic chorioretinitis (“white dot syndromes”)
  i. APMPPE, Serpiginous, “Ampiginous”
  ii. MEWDS, PIC / MFC, AMN, AZOOR
  iii. Birdshot
  iv. IRVAN

Malignancy

• Lymphoma
• Metastasis