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OP5.1-2 | Sclera — PBL Case

CLINICAL SETTING

Mrs Meena Sharma, a 44-year-old schoolteacher, presents to the ophthalmology outpatient department with a 10-day history of painful redness in her right eye. She describes the pain as deep, boring, and constant, radiating to her right temple and occasionally to her jaw. The pain woke her from sleep on two nights. She has had two prior episodes of mild eye redness over the past three years, both of which resolved spontaneously within two weeks without significant pain. She reports no prior diagnosis of eye disease. On direct questioning, she mentions that she was diagnosed with rheumatoid arthritis four years ago and is currently managed with methotrexate and hydroxychloroquine, though she admits she stopped her medications six months ago because she felt well. Her GP noted elevated ESR at her last review. On examination: visual acuity is 6/6 bilaterally. The right eye shows diffuse scleral injection with a deep violaceous hue extending 360 degrees. Mild conjunctival chemosis is present. The phenylephrine 2.5% test is performed: after 90 seconds, the redness does not blanch. Anterior chamber is deep and quiet. Fundus examination is unremarkable. The left eye is normal.

Trigger 1: Initial Presentation and Clinical Diagnosis

Mrs Sharma presents with a 10-day history of deep, boring right eye pain radiating to the temple, waking her from sleep. She has had two prior mild self-resolving red eye episodes. She has rheumatoid arthritis and stopped her DMARDs six months ago. Examination shows diffuse violaceous scleral injection; phenylephrine 2.5% does not blanch the redness. Visual acuity is 6/6.

DISCUSSION POINTS

  • What features of Mrs Sharma's history and examination distinguish this presentation from episcleritis? List at least four clinical differences.
  • Apply the Watson-Hayreh classification: which subtype of scleritis does this most likely represent, and why?
  • Why does phenylephrine 2.5% fail to blanch the redness in scleritis? Explain the anatomical basis.
  • What is the significance of the two prior self-resolving red eye episodes in her history? How might you retrospectively classify them?
Click to reveal Trigger 2: Systemic Work-Up and the Haematuria Trap (discuss previous trigger first!)

Trigger 2: Systemic Work-Up and the Haematuria Trap

You decide to initiate a systemic work-up. Initial results: RF positive (titre 1:320), ESR 78 mm/hr, CRP 42 mg/L. You send ANCA, ANA, and urine microscopy. Two days later the results return: p-ANCA weakly positive, ANA negative, urine microscopy shows 15-20 RBC/HPF with one red cell cast. Chest X-ray is clear. She has no current respiratory or joint symptoms beyond morning stiffness.

DISCUSSION POINTS

  • Which systemic diagnoses were on your differential before the results, and how do these results change your ranking?
  • The urine shows red cell casts in a p-ANCA positive patient with scleritis. What is the clinical significance of this finding and what is the haematuria trap?
  • What is the immediate management priority: ocular treatment, systemic referral, or both simultaneously? Justify your answer.
  • If the ANCA had been c-ANCA positive instead of p-ANCA, which specific diagnosis would be most likely and what additional investigations would you request?
Click to reveal Trigger 3: Management, Referral, and Long-Term Partnership (discuss previous trigger first!)

Trigger 3: Management, Referral, and Long-Term Partnership

You refer Mrs Sharma urgently to rheumatology. The rheumatologist diagnoses ANCA-associated vasculitis with microscopic polyangiitis and initiates systemic immunosuppression (high-dose prednisolone and azathioprine). You begin oral NSAIDs and arrange close ophthalmology follow-up. At the two-week review, the scleral injection has reduced and her pain is significantly improved. The rheumatologist asks you to advise on the role of ongoing ophthalmology monitoring.

DISCUSSION POINTS

  • Outline the short-term ophthalmological management of active anterior scleritis while awaiting systemic immunosuppression to take effect.
  • What ocular complications would you monitor for over the coming months, and at what frequency should she attend ophthalmology follow-up?
  • Describe the ophthalmologist-rheumatologist partnership model for managing scleritis associated with systemic disease. What information should each specialist communicate to the other?
  • Compare the referral thresholds for episcleritis versus scleritis. Under what circumstances would you refer a patient with episcleritis to rheumatology?

Learning Issues

Research these questions and bring your findings to the discussion.

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