Abstract
Purpose: To report a patient with a history of exposure keratopathy who presented with bilateral bacterial keratitis associated with streptococcal pharyngitis and use of bilevel positive airway pressure (BiPAP).
Design: Case report.
Methods: Pulsed-field gel electrophoresis of patient isolates from ocular and pharyngeal cultures.
Results: Ocular and oropharyngeal cultures from a 24-month-old child with a history of cerebral palsy on BiPAP at night revealed the same strain of Streptococcus pyogenes.
Conclusions: Use of mechanical ventilation, such as BiPAP, may precipitate inoculation of eye with respiratory or oropharyngeal pathogens. To the authors’ knowledge this is the first report demonstrating the association between concurrent streptococcal pharygitis, keratitis, and use of BiPAP.
CASE REPORT
A 24-month-old child with a history of cerebral palsy and significant obstructive sleep apnea, on bilevel positive airway pressure (BiPAP) at night, presented with a 2-day history of red eyes and sore throat. His past ocular history was significant for cortical visual impairment, optic nerve hypoplasia, poor lid closure, and exposure keratopathy. On examination, the child was noted to have moderate bilateral conjunctival infection with purulent discharge, bilateral epithelial defects with central ulceration, and crescent-shaped white corneal infiltrates. A tentative diagnosis of bacterial keratitis secondary to exposure keratopathy was made, cultures were obtained, and the child was started on fortified vancomycin (25 mg/mL) and tobramycin (14 mg/mL) ophthalmic solution every hour, and bacitracin ointment 4 times per day. Cultures produced beta hemolytic streptococci, group A (S. pyogenes). Repeat corneal cultures at 1 month from initial diagnosis showed no growth. Four-month follow-up evaluation revealed mild corneal scarring and resolution of the corneal ulcerations.
A differential diagnosis of irritation from assisted ventilation (BiPAP), pharyngoconjunctival fever, viral/bacterial pharyngitis, tonsillitis, atypical pneumonia, allergy, trauma/foreign body, and gastro-esophageal reflux was considered for the sore throat in this patient. Nasopharyngeal and oropharyngeal cultures were obtained. Pulsed-field gel electrophoresis identified the child’s ocular and oropharyngeal cultures as the same strain of S. pyogenes (), a relatively rare ocular pathogen associated with a broad spectrum of diseases and complications, including post-streptococcal uveitis, optic atrophy, and necrotizing anterior scleritis and keratitis.Citation1,Citation2 He was treated both for streptococcal pharyngitis and keratitis.
FIGURE 1 Pulsed-field gel electrophoresis of patient isolates from ocular (A) and pharyngeal (B) cultures of group A β-hemolytic streptococci.
Factors that increased this child’s risk of developing infectious keratitis include his history of exposure keratopathy and his concurrent upper respiratory tract infection. Additionally, this child was on assisted ventilation with BiPAP for obstructive sleep apnea. It can be hypothesized that BiPAP leads to inoculation of the eyes with respiratory pathogens. In such patients, multiple risk factors, including mechanical ventilation and exposure keratopathy, have been identified which increase the potential for the development of bacterial keratitis.Citation3,Citation4
DISCUSSION
To our knowledge, this is the first case reported in the literature of concurrent pharyngitis and keratitis connected to the use of BiPAP. With this child’s history of incomplete eyelid closure while sleeping and exposure keratopathy, his ongoing use of BiPAP at night with its potential for recurrent inoculation of oropharyngeal flora into the eye led to an increased risk for developing keratitis. An association between the development of keratitis and mechanical ventilation in the intensive care setting has been established.Citation3,Citation4 Colonization of the respiratory tract with a pathogenic organism often precedes the development of keratitis, a complication that is preventable by use of lubrication, closed moisture chambers, and other means.Citation5 The most common pathogen in the hospital setting is Pseudomonas aeruginosa.Citation3,Citation4 In this case, however, both ocular and pharyngeal cultures revealed an identical pathogenic strain of S. pyogenes.
Although the association with mechanical ventilation and the development of bacterial keratitis has been made, there has been no prior report of the development of bacterial keratitis in the setting of acute pharyngitis and the use of noninvasive ventilation. We report this case to make other physicians aware of the potential risk of ocular inoculation of respiratory and pharyngeal pathogens with any method of assisted ventilation. The threat to good visual outcome from bacterial keratitis is significant, and both prevention and early recognition and treatment are paramount.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
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