A Rare but Serious Risk
Banishing the nightmare of postoperative endophthalmitis. Dermot McGrath reports.
Postoperative endophthalmitis (POE) remains the most feared and devastating complication of intraocular procedures, but there are clear measures cataract surgeons can take to reduce the risk of its occurrence in the first place, according to Steve A Arshinoff MD, FRCSC, associate professor at the University of Toronto, Canada.
“Reports in the scientific literature identify the risk of endophthalmitis after cataract surgery as between one-in-2,000 and one-in-5,000 cases,” said Dr Arshinoff. Factors that increase the risk include diabetes, use of tamsulosin (Flomax), surgeon inexperience, duration of surgery, secondary lens procedures, contaminated devices such as irrigating solution, OVD, or other, vitreous loss, use of 2% xylocaine gel, and vitreous incarceration into the wound.
The good news is even bilateral simultaneous postoperative endophthalmitis (BSPOE) after immediately sequential bilateral cataract surgery (ISBCS) is extremely rare. “We estimate that the chance is less than one in 100 million. That means the chances of dying from general anaesthetic is 1,000 times higher, and the chances of winning the biggest lottery in Canada is seven times more likely,” Dr Arshinoff said at the 38th Virtual Congress of the ESCRS.
When dealing with suspect POE, Dr Arshinoff advised carefully reviewing the circumstances of the case to determine the odds that it really is endophthalmitis and not an inflammatory disorder. “We need to ask ourselves a battery of questions. Was this case bilateral surgery? If so, how is the other eye? Was it a phaco, femtosecond, or a manual small-incision cataract surgery? How long has it been since the surgery? Did we give antibiotics, and if so, which one and what was the amount and route of administration? Is the patient immunocompromised, does he or she have blepharitis, or wear contact lenses? Did anything go wrong in surgery? Was the capsule broken and was the incision sealed well? Were hooks or capsular tension rings used? Was it a black or white cataract? Were pseudoexfoliation, phacodonesis, or floppy iris or other small pupil problem present? What incision type was used?”
Answering these kinds of questions will change the risk profile and how you look at the patient to arrive at a diagnosis. “Perhaps it was a 95-year-old diabetic male who doesn’t take his eye drops reliably and is therefore a high-risk patient? Consider all these factors as you examine the eye,” said Dr Arshinoff.
The typical characteristics of POE to watch for include a mean time to onset of about two weeks postoperatively, presence of hypopyon, marked inflammation, variable pain, reduced vision, and cloudy vitreous said Dr Arshinoff.
Before settling on a firm diagnosis, it is important to rule out other possible causes, such as TASS. “Toxic anterior segment syndrome (TASS) begins quickly, usually the first day postoperatively, and presents with moderate pain, diffuse limbal to limbal corneal oedema, and minimal posterior segment inflammation. The retina and media should look fairly clear once the pupil is dilated and checked with an indirect ophthalmoscope,” he said.
Other more unusual possibilities include inflammation due to retained lens material, a flare-up of pre-existing uveitis in patients with sarcoidosis, ankylosing spondylitis or other inflammatory disorder, or endogenous endophthalmitis.
To treat POE, Dr Arshinoff advised handing over to a retina surgeon or one who frequently deals with such cases.
“The goal is to begin treatment as soon as possible. Perform culture and sensitivity tests, and administer intravitreal vancomycin and ceftazidime and repeat if the patient does not respond quickly. For fungal infections, treat with agents such as amphotericin B, miconazole, or voriconazole. For refractory cases with very severe inflammation throughout the eye, and light-perception visual acuity, the patient should undergo a complete pars plana vitrectomy,” he said.
For cases of delayed onset endophthalmitis, the time to onset and clinical presentation will help to identify the most likely responsible organism, said Dr Arshinoff.
To reduce the risk of POE, Dr Arshinoff advised using intracameral antibiotics such as cefuroxime or moxifloxacin, which have been proven to decrease the risk of POE in studies encompassing 8 to 10 million eyes, with an eightfold reduction of infection.
Dr Arshinoff said that he routinely uses intracameral moxifloxacin 600 micrograms in 0.4ml in his simultaneous bilateral cataract surgeries. He also prescribes a course of topical moxifloxacin, prednisolone acetate, and ketorolac six times a day for the first four days after surgery and then four times a day until the bottles are finished.
“If you give postoperative topical drops of moxifloxacin, you actually obtain a high enough level in the anterior chamber to kill the most common bacteria that usually cause endophthalmitis, although not high enough to kill the most resistant (CoNS and MRSA) strains. I also give a drop of pilocarpine at the end of surgery, which reduces the incidence and severity of postoperative pressure spikes and brings the pupil down, allowing the patients to have very good vision within an hour of surgery,” he said.