How does ocular syphilis present in an adult patient with a history of sexually transmitted infections or immunocompromised status, such as Human Immunodeficiency Virus (HIV)/Acquired Immunodeficiency Syndrome (AIDS)?

Clinical Presentation of Ocular Syphilis

Ocular syphilis most commonly presents as posterior uveitis or panuveitis, with visual acuity often severely impaired at presentation (worse than 6/60 in over half of cases), and can affect virtually any ocular structure at any stage of syphilis infection. 1, 2

Primary Clinical Manifestations

Anatomic Distribution

• Posterior uveitis is the most frequent presentation (approximately 54% of cases), followed by panuveitis (31%), anterior uveitis (15%), and optic neuritis 1, 2, 3
• Panuveitis occurs more commonly in HIV-infected patients with CD4 counts <200 cells/mm³ 4
• Diffuse necrotizing retinitis is significantly more common in HIV-positive patients compared to HIV-negative patients 3

Visual Acuity at Presentation

• Over 50% of patients present with visual acuity worse than 6/60 (20/200), indicating severe visual impairment at initial diagnosis 2
• Approximately 38% present with visual acuity between 6/15 to 6/60 2
• Only 8% present with visual acuity of 6/12 or better 2

Specific Ocular Symptoms and Signs

Patient-Reported Symptoms

• Blurred vision or decreased visual acuity 5
• Eye pain or ocular discomfort 5
• Photophobia (light sensitivity) 5
• Floaters or visual field defects (with posterior involvement) 6

Clinical Examination Findings

• Uveitis (anterior, posterior, or panuveitis) is the hallmark finding requiring slit-lamp examination for confirmation 1
• Iritis or iris involvement may occur as part of tertiary syphilis 1, 7
• Optic nerve involvement including optic neuritis 2, 8
• Macular edema (associated with worse visual prognosis) 8
• Vitritis and retinal vasculitis 6, 3

HIV-Specific Considerations

Presentation Differences

• Ocular syphilis leads to initial HIV diagnosis in 52% of HIV-infected cases, including patients with CD4 counts >200 cells/mm³ 4
• Approximately 31% of HIV-positive patients are newly diagnosed with HIV at the time of ocular syphilis presentation 3
• Posterior uveitis is significantly more common when CD4 count <200 cells/mm³ (p = 0.002) 4
• Ocular co-infections (especially tuberculosis) are more common in HIV-positive patients 3

Visual Outcomes

• HIV status, CD4 cell count, and HIV viral load do NOT predict visual acuity outcomes after treatment, contrary to what might be expected 8
• Both HIV-positive and HIV-negative patients show similar rates of visual improvement with appropriate treatment 8, 3

Diagnostic Pitfalls and Critical Warnings

Serologic Testing Limitations

• Three percent of confirmed ocular syphilis cases may have negative non-treponemal tests (RPR/VDRL), particularly in HIV-infected patients 4
• If clinical suspicion is high despite negative non-treponemal testing, treponemal-specific tests and repeat testing should be pursued 4

Neurosyphilis Association

• CSF abnormalities occur in 10-60% of patients with ocular syphilis, indicating frequent concurrent neurosyphilis 1
• Up to 50% have reactive CSF VDRL results 1
• However, CSF examination is NOT mandatory for isolated ocular findings with confirmed syphilis serology and ocular abnormalities on examination, as nearly 40% will have normal CSF 1

Prognostic Factors

Predictors of Poor Visual Outcome

• Visual acuity ≥1.00 logMAR (20/200 or worse) at presentation is the strongest predictor of poor final visual acuity 8
• Female sex is associated with worse visual outcomes 8
• Presence of macular edema predicts worse final visual acuity 8
• Longer duration of symptoms before treatment correlates with worse outcomes 1

Expected Treatment Response

• 84-97% of patients show visual improvement of at least one Snellen line after appropriate treatment 2, 4
• Complete resolution of ocular inflammation occurs in approximately 95% of treated patients 3
• Visual acuity of 6/12 (20/40) or better increases from 8% at presentation to 31% after treatment 2

Stage of Syphilis at Presentation

• Secondary syphilis is the most common stage when ocular involvement presents (approximately 73% of cases) 3
• Ocular syphilis can occur at any stage: primary, secondary, early latent, or tertiary infection 2, 6
• Acute inflammation typically occurs during primary, secondary, and early latent stages 2
• Chronic inflammation (including iris gumma) occurs during tertiary infection 7, 2

Demographics

• Males are predominantly affected (86% in some series), likely reflecting higher rates of syphilis infection in men who have sex with men 3
• Mean age of presentation is approximately 70 years in HIV-negative populations, though this varies widely 2
• HIV-infected patients tend to present at younger ages 4