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Pseudomonal scleritis complicating scleral buckling surgery is described in a patient unable to tolerate systemic side effects from aminoglycoside antibiotics. Particular reference is made to a novel antibiotic regimen comprising systemic ceftazidine and ciprofloxacin.
Pseudomonal scleritis is notoriously difficult to treat even with the use of conventional high-dose aminoglycoside antibiotics. This case demonstrates a successful alternative treatment strategy in a patient who was unable to tolerate aminoglycoside antibiotics.
A 59-year-old Caucasian man presented with a 10-day history of a progressive supero-nasal field defect in his right eye. He had been highly myopic prior to bilateral cataract surgery performed 4 years previously. Examination revealed an infero-temporal rhegmatogenous retinal detachment due to two small U-shaped retinal breaks. His past medical history included dilated and ischaemic cardiomyopathy and renal impairment. A non-drainage scleral buckling procedure was performed comprising cryotherapy and placement of a 4 mm radial scleral explant (Labtician Ophthalmics Inc, Canada) using 5.0 polyester sutures. The conjunctiva was closed with 8.0 vicryl sutures and subconjunctival cefuroxime (125 mg) was given. The retina was successfully re-attached on the first postoperative day. Three days later, he presented to his general practitioner with a painful right eye associated with diplopia and a mucopurulent discharge. Treatment was started with amoxicillin (500 mg three times daily orally) and chloramphenicol 1% eye ointment. A rapid deterioration in his symptoms occurred a few days later prompting re-presentation to our institution.
Visual acuity was 6/9 OD and 6/6 OS. The right eye was very painful and injected with copious mucopurulent discharge and point tenderness over the scleral explant (figure 1). Immediate management involved removal of the scleral explant and polyester suture with samples being sent for microbiology. Empirical antibiotic treatment was initiated comprising systemic ceftazidime (1 g three times daily intravenously) and ciprofloxacin (750 mg twice daily orally) with topical chloramphenicol 0.5% hourly.
Microbiology results available 2 days later demonstrated isolation of Pseudomonas aueroginosa sensitive to gentamicin and ciprofloxacin with resistance to chloramphenicol. Antibiotic treatment was changed to systemic ceftriaxone (2 g once daily intravenously) and ciprofloxacin (750 mg twice daily orally) with topical ciprofloxacin 0.3% hourly. This treatment regime resulted in steady clinical improvement. He was discharged after 5 days in hospital on a treatment regime comprising systemic cefaclor (500 mg three times daily orally) and ciprofloxacin (750 mg twice daily orally) with topical ciprofloxacin 0.3% four times daily and dexamethasone 0.1% four times daily. His retina remained fully re-attached and both tears over the previous buckle site were closed.
During the following weeks, there was only modest further clinical improvement with a persistent non-healing necrotic ulcer. Therefore, he was re-admitted for a prolonged intensive course of antipseudomonal agents in order to eradicate the infection. The antibiotic treatment comprised systemic ceftazidime (2 g three times daily intravenously) and ciprofloxacin (750 mg twice daily orally) with topical ceftazidime 5% four times daily and ciprofloxacin 0.3% four times daily. This antibiotic treatment was continued for 3 weeks resulting in steady healing of the necrotic ulcer.
Microbiology investigations as above. No other antibiotic sensitivities were available.
He continued oral ciprofloxacin 750 mg twice daily and oral cephalexin 500 mg three times daily following discharge for a further 6 weeks.
This antibiotic regime resulted in complete healing of the pseudomonal scleritis. Scleral necrosis led to anterior staphyloma formation (figure 1B), which induced −4.0 dioptres of irregular astigmatism. Final visual acuity was 6/9 OD and 6/6 OS.
Pseudomonal scleritis has been strongly associated with scleral buckling procedures1 and pterygium removal,2 potentially occuring many years after surgery. Fulminant pseudomonal scleritis infections resistant to conventional antibiotic treatment have been found in immunocompromised3 and immunocompetent2,4,5 patients owing to pseudomonal biofilm secretion and poor scleral penetration of systemic or topical antibiotic. Severe complications, such as abscess formation with exudative retinal detachment and endophthalmitis, have been reported2 especially with delay in buckle removal. Successful treatment regimes have included surgical debridement with topical fortified aminoglycosides, more fulminant infections requiring intravenous ceftazidime and aminoglycosides.1
High-dose prolonged aminoglycosides were contraindicated in our patient with renal failure and the risk of ototoxicity. A novel regime using ceftazidine (active against cell wall synthesis) and ciprofloxacin (interfering with bacterial DNA synthesis) was used for their synergistic action against the pseudomonal organism. A prolonged 3-week course in hospital was followed by an intensive 6-week course of systemic antimicrobial treatment to eradicate the infection successfully. Relative resistance to antibiotics from poor scleral tissue and pseudomonal biofilm penetration may also have accounted for the lack of pseudomonal eradication from the initial antibiotic treatment.
In patients with pseudomonal scleritis who have contraindications to aminoglycoside antibiotics, prolonged combination systemic treatment with ceftriaxone and ciprofloxacin is effective treatment in bacterial isolates susceptible to these antibiotics. As Knauff et al6 showed a statistically significant increase in ciprofloxacin-resistant systemic isolates from 1988–93, caution is advised against this combination as primary treatment.
We would like to thank the Photography Department at Addenbrookes Hospital for their outstanding images.
Competing interests: None.
Patient consent: Patient/guardian consent was obtained for publication.