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OP6.1-4 | Iris, Uvea and Anterior Chamber — PBL Case

CLINICAL SETTING

Rahul, a 28-year-old male postgraduate student, presents to the ophthalmology outpatient clinic with a 3-day history of painful redness, intense photophobia, and blurred vision in his right eye. He reports that this is his third episode of a similar presentation in the past two years, each time affecting one eye and resolving after he was given 'some eye drops.' He never followed up after his previous two episodes. On direct questioning, he mentions intermittent low back pain over the past 4 years that is worse when he wakes up and improves as the day progresses. He has no significant past medical history and is on no medications. On examination, his best corrected visual acuity is 6/18 right eye and 6/6 left eye. The right eye shows ciliary flush (perilimbal injection), a miotic pupil, and marked photophobia. Slit-lamp examination reveals fine stellate KPs on the lower corneal endothelium, 3+ cells and 2+ flare in the anterior chamber, and the beginning of a posterior synechia at the 6 o'clock position. IOP is 8 mmHg right eye, 14 mmHg left eye. The anterior chamber is deep and there is no hypopyon. The left eye is entirely normal.

Trigger 1: Recognition and Classification

The ophthalmology resident examines Rahul and records the above findings. The attending specialist asks the resident to classify this case using the SUN Working Group criteria and to explain the pathophysiological basis of each slit-lamp finding before any investigation is ordered.

DISCUSSION POINTS

  • Apply the SUN Working Group anatomical classification to this case. What type of uveitis does Rahul have, and what structures are inflamed?
  • Explain the mechanism behind each finding: ciliary flush, KPs on the corneal endothelium, aqueous cells and flare, miotic pupil, and low IOP. What does the mnemonic CAMP represent?
  • Is this granulomatous or non-granulomatous iridocyclitis? What three slit-lamp features would suggest a granulomatous process instead?
  • The attending asks: what makes iridocyclitis sight-threatening even in an apparently 'mild' episode? Explain the cascade from posterior synechiae to acute angle-closure glaucoma.
Click to reveal Trigger 2: Systemic Workup and Complication Risk (discuss previous trigger first!)

Trigger 2: Systemic Workup and Complication Risk

The resident is now told that this is Rahul's third episode of acute anterior uveitis. An HLA-B27 test is ordered and comes back positive. A sacroiliac joint X-ray shows early sacroiliitis. The rheumatologist confirms a diagnosis of ankylosing spondylitis. Rahul is started on topical prednisolone acetate 1% hourly and cyclopentolate 1% three times a day. Three weeks into treatment, at his review visit, his IOP has risen to 30 mmHg and a posterior subcapsular haze is noted on the lens.

DISCUSSION POINTS

  • Why is HLA-B27 testing appropriate in this clinical context? Which four systemic conditions associated with HLA-B27 also cause anterior uveitis?
  • The posterior synechia at 6 o'clock was noted at presentation. If left untreated, trace the complication sequence from this finding to potential blindness — name each stage.
  • The IOP has risen to 30 mmHg on topical steroids. Is this caused by the inflammation or the treatment, and how do you distinguish? What is the management?
  • A posterior subcapsular haze is now present. What are the two mechanisms responsible for cataract formation in a patient with uveitis on steroids? At what point is surgical intervention considered?
  • The attendant also asks Rahul about his family history of back pain. Why is family history relevant in uveitis workup?
Click to reveal Trigger 3: Counselling and Long-Term Management (discuss previous trigger first!)

Trigger 3: Counselling and Long-Term Management

Rahul's inflammation is controlled after 6 weeks. He is being tapered off topical steroids. He has many questions: he wants to know if this will come back, whether he can stop his drops when the eye looks normal, and whether his children might be affected. He is anxious about his vision long-term. The attending asks you to counsel Rahul in a structured, patient-centred manner.

DISCUSSION POINTS

  • Structure a counselling session for Rahul covering: (a) the nature of his condition and why it is likely to recur, (b) the purpose of each medication he has been given, (c) two serious complications of abrupt steroid cessation and why he must taper as directed.
  • What two warning signs must Rahul understand require immediate return to the clinic — without waiting for a scheduled appointment?
  • Rahul asks whether his son (aged 6) might be at risk. How do you explain the role of HLA-B27 in disease predisposition without causing unnecessary alarm?
  • If Rahul were ANA-positive and had been a young girl with oligoarticular arthritis instead, how would the counselling and monitoring plan differ — particularly regarding ocular screening frequency and the silent nature of that uveitis type?
  • What long-term monitoring parameters must be tracked at every visit for any patient with chronic uveitis on topical steroids? Enumerate them systematically.

Learning Issues

Research these questions and bring your findings to the discussion.

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