Invasive Neisseria gonorrhoeae producing pre-septal cellulitis and keratoconjunctivitis: diagnosis and management

To the Editor:

A 53-year-old woman experienced rapid onset of left eyelid pain, swelling and purulent discharge (Box 1). She presented to our eye hospital 3 days later and, on assessment, the lids were exquisitely tender, inflamed and difficult to open. There was chemosis, microcystic corneal oedema with Descemet membrane folds and moderate inflammation in the anterior chamber. Visual acuity was 6/24 in the left eye and 6/9 in the right eye. Ocular motility appeared normal.

The severe inflammation and visual impairment raised concerns for post-septal orbital cellulitis. A computed tomography scan showed severe pre-septal stranding only (Box 2). A diagnosis of left pre-septal cellulitis and keratoconjunctivitis was made. She was given intravenous ceftriaxone 2 g daily, intravenous flucloxacillin 2 g four times a day, topical chloramphenicol 0.5% four times a day and regular eye washings.

Microscopy found gram-negative diplococci, and polymerase chain reaction testing was positive for Neisseria gonorrhoeae. The patient denied history of sexually transmissible infection. A urine and serum sexually transmissible infection screen for N. gonorrhoeae, Chlamydia trachomatis and blood-borne viruses was negative. Treatment was rationalised to intravenous ceftriaxone 1 g daily, with a single 1 g dose of oral azithromycin. The patient had dramatic improvement over 4 days, and visual acuity improved to 6/7.5 at discharge (Box 3). One week later, the infection had predominately resolved.

N. gonorrhoeae typically produces a hyperacute unilateral conjunctivitis. While the source of infection in this patient is unclear, in most cases infection is acquired via sexual transmission and reaches the conjunctiva through hand–eye auto-inoculation.1,2 The bacteria can invade the corneal epithelium, producing keratitis and corneal melting necessitating therapeutic keratoplasty.1,2 Gonococcal periorbital infection is rare, with only three cases of pre-septal cellulitis and two cases of post-septal cellulitis reported.3 All patients were successfully treated with parenteral antibiotics.

N. gonorrhoeae has increasing antimicrobial resistance, creating a therapeutic challenge. The Australian Gonococcal Surveillance Programme has shown an emerging resistance to ceftriaxone — the antibiotic of choice — from 0.6% in 2006 to 5.4% in 2014.4 Azithromycin resistance occurs in 2.4% of strains.4 The Australian Therapeutic Guidelines recommend treatment of N. gonorrhoeae with parenteral ceftriaxone and oral azithromycin, for bactericidal synergy and cotreatment for C. trachomatis.

When presented with pre-septal cellulitis and purulent keratoconjunctivitis, the clinician should be vigilant for a sight-threatening N. gonorrhoeae infection.

Box 1 – Lid inflammation and purulent discharge at onset, 3 days before presentation

Box 2 – Contrast-enhanced computed tomography scan showing significant pre-septal subcutaneous stranding (blue arrow) and severe conjunctival chemosis (yellow arrow)

Box 3 – Marked improvement in periorbital inflammation after 3 days of antibiotic therapy, with residual conjunctival injection