A Monocular Patient Presenting with a Red, Painful Eye
A 55-year-old woman presents with a 2-day history of a red, painful right eye with photophobia and blurred vision. She is functionally monocular: her left eye has been blind since childhood from trauma with a phthisical globe. On exam, the right eye has acuity 20/60 (baseline 20/25), IOP 34 mmHg, diffuse conjunctival injection, a hazy cornea with fine keratic precipitates, a 2+ anterior chamber cell and flare, and a mitotic pupil with posterior synechiae beginning to form. She wears soft contact lenses but removed them when symptoms began. She is systemically well with no rash or joint symptoms.
1. What is your differential and working diagnosis, and what makes this presentation urgent in a monocular patient?
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Working diagnosis: acute anterior uveitis (iritis) of the right eye, supported by pain, photophobia, blurred vision, fine KPs, 2+ cell/flare, miosis, and posterior synechiae. Elevated IOP (34) suggests either trabecular obstruction by inflammatory cells or steroid response if previously treated.
Differential to exclude:
- Infectious keratitis (contact lens wearer) - must check for epithelial defect and infiltrate; a contact-lens-related ulcer would change management dramatically.
- Endophthalmitis - usually post-surgical/post-traumatic; not supported here but must be considered if hypopyon or vitritis.
- Acute angle closure - IOP is elevated but the anterior chamber is inflamed with KPs, not shallow with a fixed mid-dilated pupil.
Why urgent: she has one seeing eye. Any treatable process threatening that eye demands same-day treatment and close follow-up. Posterior synechiae can become permanent, and uncontrolled inflammation or pressure risks irreversible damage. First-line management includes topical steroid, cycloplegic to break synechiae and relieve spasm, IOP control, and same-day ophthalmology co-management. She must be told to return immediately if vision drops.
2. What systemic workup would you consider, and how does the monocular status change your threshold for referral?
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Systemic workup: acute anterior uveitis is often idiopathic, but first-episode workup should consider HLA-B27-associated disease, sarcoidosis, and (in the right demographic) herpesviruses. Targeted history and exam drive testing rather than a blanket panel:
- Ask about back pain, psoriasis, inflammatory bowel disease, and oral/genital ulcers.
- Check for rash and joint symptoms; she denies them.
- If recurrent or bilateral, broaden to sarcoidosis and HLA-B27 testing.
Monocular status changes the threshold: with no reserve eye, I would:
- Refer the same day to ophthalmology rather than manage entirely in primary care.
- Arrange review within 24-48 hours to confirm synechiae are breaking and IOP is controlled.
- Give explicit red-flag instructions (worsening pain, vision drop, new floaters).
- Document the fellow eye's status and counsel on protection (polycarbonate safety eyewear) to prevent injury to the remaining eye.
The key judgment is that standard uveitis care applies, but the acceptable margin for error is far smaller.