Bacterial Infectious Scleritis: A Case Report

Introduction

Infectious scleritis (IS) is a rare and severe ocular disorder responsible for approximately 5–10% of all scleritis cases,¹ with Pseudomonas aeruginosa (P. aeruginosa) the most prevalent microorganism associated with its onset.² Among the types of IS, the most common is bacterial scleritis. In these cases, bacteria usually invade the sclera during ocular surgery or trauma. Through this route, IS can arise after cataract surgery. Although postoperative bacterial scleritis is not very rare, due to the difficulty of ensuring its timely diagnosis and cure, multiple surgeries are often required over the long term to treat the infection, and eye enucleation may even be necessary to prevent orbital cellulitis. In our clinical practice, a case of P. aeruginosa scleritis was diagnosed after non-traumatic cataract surgery and cured after a single surgery. Good vision was ultimately preserved, as we report herein.

Case Report

A 69-year-old man with a history of diabetes, hypertension, and vitrectomy presented with severely poor vision (3.0 logMAR, hand motion), lens opacity, and nuclear hardness grade 5 (LOCTS II grading standard) in his left eye (Figure 1). The patient had been diagnosed with type 2 diabetes about 30 years prior, and with insulin and drug treatment, his blood glucose control was satisfactory. The patient’s HBA1c level before surgery was 6.7%. He also had a 15-year history of hypertension, though his blood pressure was regulated with oral medication. Approximately 3 years ago, the patient underwent vitrectomy for vitreous hemorrhage due to diabetic retinopathy at another hospital. The vitreous cavity was filled with gas after the surgery, and his vision improved about half a month after the procedure.

Figure 1 Photograph of lens opacity. The lens is severely cloudy, with nuclear hardness grade 5.

In July 2023, the patient underwent cataract extraction combined with intraocular lens implantation, performed via nasal clear corneal incision (2.5 mm) and 2-point temporal clear corneal incision (1 mm), under the standard disinfection strategy at Qingdao Eye Hospital of Shandong First Medical University. The patient had no eye pain, and his uncorrected vision acuity was 0.82 logMAR on the first postoperative day. The operated eye was administered both topical prednisolone 1% eye drops and gatifloxacin 0.3% eye drops four times per day, as well as tobramycin and dexamethasone eye cream once at night.

At the 1-week postoperative assessment, the patient complained of pain in the operated eye. Upon examination, we found that the uncorrected vision acuity of the eye had decreased to 3.0 logMAR. The operated eye had obvious conjunctival chemosis, ciliary congestion, and a moderate intraocular reaction in the anterior chamber with grade 2+ cells and no hypopyon. There was mild infiltration by inflammatory cells in the vitreous identified with B-scan ultrasound. The optic nerve and large retinal vessels could be seen, but other details of the retina were not visible under wide-angle fundus photography, indicating acute postoperative endophthalmitis (Figure 2).

Figure 2 Indications of suspected endophthalmitis, 1 week postoperative. (A and B) The operated eye had obvious conjunctival chemosis, ciliary congestion, and a moderate intraocular reaction in the anterior chamber with grade 2+ cells and no hypopyon. (C) Mild infiltration by inflammatory cells in the vitreous identified with B-scan ultrasound. (D) The optic nerve and large retinal vessels could be seen, but other details of the retina were not visible under wide-angle fundus photography.

The eye was treated with systemic (cefuroxime, intravenous drip) and topical antibiotics (gatifloxacin 0.3%, tobramycin, and dexamethasone eye drops administered once every 2 hours). According to Chinese expert consensus on the diagnosis and management of infectious endophthalmitis after ophthalmic surgery,³ the anterior chamber was irrigated with ceftazidime 2% and vancomycin 1%, and the vitreous cavity was injected with vancomycin 1 mg/0.1 mL combined with ceftazidime 2 mg/0.1 mL. Fungal and bacterial cultures of the anterior aqueous humor were negative. However, a bacterial culture of the conjunctival sac was positive for P. aeruginosa, and so we administered the sensitive antibacterial agents ciprofloxacin (intravenous drip) and gatifloxacin (topical ocular administration). After 1 week of these treatments, the signs of disease had lessened, and the uncorrected vision acuity of the left eye had improved to 2.0 logMAR (counting fingers), but eye pain was not significantly reduced. The patient was discharged and continued treatment with a topical antibiotic.

The patient was then reviewed 25 days after cataract surgery and 10 days after his discharge, as he still had severe eye pain. We observed a yellow–white abscess under the conjunctiva in the superonasal quadrant of the left eye (Figure 3A). The intraocular condition was not significantly worse than it had been previously. In the operating room, the conjunctiva was found to be intact and had no signs of infection. On opening the conjunctiva, the scleral tissue demonstrated erosion and necrosis, presenting a viscous mucus of about half the full scleral thickness (10 × 4 mm), extending from 10 to 2 o’clock in position (Figure 3B). We cleaned the necrotic tissue completely and rinsed the wound with ciprofloxacin. The opened conjunctiva was not sutured. A bacteria culture of the necrotic scleral tissue determined the presence of P. aeruginosa, and we administered the sensitive antibacterial agents ciprofloxacin and gatifloxacin. The wound was not sutured, but it was cleaned daily. Under topical anesthetic, the pus and exudates on the surface of the wound were removed, and the wound was washed thoroughly using a 20-mL ciprofloxacin injection (0.2 g:100 mL). Over the next 2 weeks, the lesion gradually improved, and the conjunctival and scleral wounds healed. The patient’s condition was observed to be stable over the next 3 months, and the uncorrected vision acuity of the left eye improved to 0.22 logMAR (Figure 3C and D). Pathological examination of the scleral tissue revealed chronic inflammation of the fibrous connective tissue (Figure 4).

Figure 3 The therapeutic process of infected scleritis. (A) A yellow–white abscess under the conjunctiva in the superonasal quadrant of the left eye. (B) The scleral tissue demonstrated erosion and necrosis, presenting a viscous mucus of about half the full scleral thickness (10 × 4 mm), extending from 10 to 2 o’clock in position. (C) The wound edges of the conjunctiva had healed 10 days after scleral surgery. (D) The conjunctival wounds had completely healed 16 days after scleral surgery.

Figure 4 The pathological examination of the scleral tissue. Fibrous connective tissue hyperplasia presents in a cystic form, with chronic inflammatory cell infiltration. The scale bars indicate 50 μm.

Discussion

Necrotizing scleritis is the most severe form of IS, posing a serious threat to vision.⁴ Necrotizing scleritis typically has an onset of several days to weeks and is characterized by severe ocular pain centered around the eye globe and radiating to the ear, scalp, forehead, and jaw.⁵ Pterygium surgery is the most common factor inciting the development of IS, though other causes include cataract surgery and trauma.⁶ This reported case occurred after non-traumatic cataract surgery. The IS lesion area was not damaged during cataract surgery, but scleral wounds at the trocar puncture site for vitrectomy is routine in this area, so there is a possible relationship between the IS lesion and the patient’s previous vitrectomy. The etiology of IS is predominantly bacterial, with P. aeruginosa the most common organism responsible for the infection’s onset.⁷ Ocular infection with P. aeruginosa often occurs in a compromised host,⁸ consistent with our patient’s history of diabetes, hypertension, and vitrectomy. Treatment options for IS include topical and systemic antibiotic therapy, as well as surgical debridement.⁹

Infectious necrotizing scleritis must be actively treated after diagnosis, with early infection control offering the key to avoiding ocular damage and other serious complications. Since drug penetration in the sclera is very limited, 80% of patients with IS cannot simply be administered drugs to control the disease; instead, they require local debridement and multiple surgeries.⁵ Scleral transplantation and amniotic membrane transplantation are required in many patients due to severe scleral and conjunctival necrosis. Despite these surgical efforts, many cases of necrotizing scleritis cannot be controlled, necessitating enucleation of the eye to prevent orbital cellulitis. Instead, in the reported case, the patient’s IS was effectively cleaned and rinsed with antibiotics during just one operation and every day thereafter during the patient’s recovery. The conjunctiva and sclera wounds healed quickly, and the patient’s vision improved.

In conclusion, severe eye pain inconsistent with intraocular infection after ocular surgery should raise suspicion of IS. Thorough debridement and antibiotic irrigation are the key measures to treat this disease.