We encountered a case of bacterial endophthalmitis caused by an intraocular cilium. This case was unique because of the absence of any history of penetrating ocular trauma and the history of treatment with an anti-TNF-α antibody for Crohn’s disease. Although the possibility of remotely unrecalled ocular trauma may have been involved in the cilium migration, there were no intraocular foreign bodies except the cilium detected during surgery. Moreover, the clinical course of scleritis - without intraocular inflammation antecedent to the onset of endophthalmitis - suggests that it may take time for the cilium migration, rather than a sudden trauma. During surgery, a focal scleral necrosis was found at the same site where the cilium was detected, suggesting that necrotized sclera gave the migrating cilium entrance to the globe. Such conditions are unlikely to be due to a sudden penetrating ocular trauma. We speculate that the accidentally migrated cilium under the conjunctiva caused chronic bacterial infection and then focal scleral necrosis and that subsequently, the cilium migrated into the vitreous cavity via the necrotised sclera, finally to cause exogenous endophthalmitis.
Cilium migration into the subconjunctival space usually does not cause chronic infection in immunocompetent people because microorganisms around the cilia are eliminated easily with innate immune responses. In this case, the history of treatment with infliximab, an anti-TNF-α antibody, may play a role in the migration of the intraocular cilium. TNF-α is a central key cytokine that mediates inflammatory response. Therefore, the anti-TNF-α drugs are highly effective treatment for chronic inflammatory diseases such as rheumatoid arthritis and Crohn’s disease. Meanwhile, TNF-α is also an important cytokine that plays a central role in the innate immune response towards microorganisms . The immune response eliminates them by inducing strong inflammation. However, under treatment with an anti-TNF-α drug, microorganisms survive easily, and the focal infection tends to persist with a mild inflammation . In this case, therefore, we speculate that a chronic infection in the subconjunctival space is prolonged due to the increased vulnerability to infection by the anti-TNF-α drug administration, which led to focal scleral necrosis subsequently.
This case indicates that intraocular cilia may be an aetiology of endophthalmitis even in patients without any history of trauma or surgery. Furthermore, anti-TNF-α drug therapy may play a role in the migration of the intraocular cilium and the development of endophthalmitis.