Day 2 after uneventful phacoemulsification: pain, hypopyon and four asymptomatic co-patients
A 68-year-old man with well-controlled type 2 diabetes (HbA1c 7.1%) undergoes uncomplicated phacoemulsification with in-the-bag acrylic IOL implantation in the right eye. The posterior capsule is intact, the wound is sutureless, and on the first postoperative morning his acuity is 6/7.5 with a quiet anterior chamber and a comfortable eye.
At 40 hours postoperatively he telephones reporting deep aching pain and is seen the same afternoon. Acuity is counting fingers at 1 metre. There is marked lid oedema, 3+ conjunctival injection, diffuse microcystic corneal oedema, a 1.5 mm hypopyon with a fibrin pupillary membrane, and no red reflex. Intraocular pressure is 26 mmHg. B-scan ultrasonography shows clear vitreous with no membranes and no choroidal detachment. The same surgeon operated on four other patients that morning using instruments from the same phaco pack and the same 500 mL bottle of balanced salt solution; all four are reportedly asymptomatic.
1. What is your leading diagnosis, what is the main alternative, and how do the history and examination discriminate between them? What do you do in the next hour?
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Leading diagnosis: acute postoperative endophthalmitis (most often coagulase-negative staphylococci, though the timing here is early). Main alternative: toxic anterior segment syndrome (TASS).
Discriminating features:
- Timing – TASS typically presents 12–48 hours after surgery and peaks quickly; infectious endophthalmitis usually declares itself at 3–7 days, so 40 hours is compatible with either and the timing alone cannot decide.
- Pain – marked, deep, aching pain favours infection; TASS is often described as uncomfortable rather than painful.
- Tissue involved – TASS is a sterile anterior-segment inflammation: limbus-to-limbus corneal oedema, a fixed dilated pupil from preservative toxicity, and vitreous clear. Any vitritis strongly favours infection. Here the absent red reflex and hypopyon are not reassuring, and a clear B-scan does not exclude early infection.
- Course – TASS improves dramatically within 24–48 hours of intensive topical steroid; infection worsens.
Next hour: do not wait for cultures. Perform an anterior chamber paracentesis and a vitreous tap (0.1–0.2 mL via the pars plana 3.5–4 mm from the limbus) and inject intravitreal vancomycin 1 mg/0.1 mL plus ceftazidime 2.25 mg/0.1 mL. Send aqueous and vitreous for Gram stain, culture and sensitivity. Start intensive topical steroid (deferred 24–48 hours if there is concern about infection) and topical antibiotic cover, and admit or review daily. Per the Endophthalmitis Vitrectomy Study, eyes seeing hand movements or better are managed with tap and inject; light perception only prompts immediate vitrectomy.
2. The patient asks whether the other four patients from the same list should be contacted. How does a possible cluster change your differential, and what practical steps do you take?
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A cluster of simultaneous postoperative inflammation is a classic signal for TASS, pointing to a shared, non-infectious cause: retained instrument Cleaning residue (detergents, enzymatic cleaners), heat or chemical damage to instruments, altered osmolarity or pH of balanced salt solution, a contaminated or denatured ophthalmic viscosurgical device, or improper steam sterilisation.
However, a cluster does not license you to reclassify this symptomatic eye as sterile. Shared contamination (BSS, viscoelastic, a reprocessed instrument set) can also be bacterial, and this patient has pain, hypopyon and no red reflex - features that mandate tap and inject regardless. Treat the individual on clinical grounds.
Practical steps:
- Recall and examine every patient operated on that list the same day, including those who feel well; TASS may be mild and self-reported symptoms unreliable.
- Quarantine the implicated lots of BSS, viscoelastic and instrument trays; stop using them.
- Audit the sterilisation cycle and instrument reprocessing (residue testing, water quality, dryer filters), since TASS is most often a reprocessing failure.
- Report to the manufacturer and the national competent authority, and document the lot numbers.
- If TASS is confirmed in the asymptomatic patients, treat with intensive topical prednisolone acetate (hourly, tapering) and monitor for sequelae such as posterior synechiae and glaucoma. Prognosis is good if steroids start early.
3. Two days later the vitreous culture grows Staphylococcus epidermidis, acuity has improved to 6/60, and the hypopyon has shrunk. Would you repeat the intravitreal injection, and would you now consider vitrectomy?
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Judge the eye, not the culture bottle. Coagulase-negative staphylococci are both the commonest true pathogens and the commonest culture contaminants, so a positive result must be interpreted against the clinical trajectory. Here pain is settling, acuity is improving and the hypopyon is resolving - the features of a responding infection. That argues for continued observation with topical steroid and antibiotic, not for further intervention. Repeat the examination daily, with B-scan if the fundus remains obscured, and watch specifically for a secondary rise in pain, re-accumulation of hypopyon, worsening vitritis or a fall to light perception.
Repeat tap and inject is appropriate if the eye plateaus or deteriorates after an initial response, or if the organism proves resistant to the initial agents. Re-culture at that point because the organism or its sensitivities may differ.
Vitrectomy is indicated for: acuity of light perception only at presentation or on deterioration; worsening inflammation despite intravitreal antibiotics; dense vitritis with a non-clearing course; or a virulent organism (streptococci, gram-negatives) where the visual prognosis is poor and early surgery may be considered. The Endophthalmitis Vitrectomy Study showed no benefit of immediate vitrectomy for eyes with hand movements or better, so a responding eye at 6/60 should not go to theatre on the basis of the culture result alone.
Also counsel the patient that final acuity may take weeks to months to settle, and monitor for macular oedema, epiretinal membrane and secondary glaucoma.