Introduction: Although several risk factors for stroke have been identified, studies have shown that a large number of strokes still remain unexplained. A recent study has identified Streptococcus mutans expressing collagen-binding protein (CBP) as a potential risk factor in hemorrhagic stroke. In the past, S. mutans has been implicated in several cases of infective endocarditis post-dental procedures, however cases of S. mutans-induced intracerebral hemorrhage have seldom been reported. Most reports have described the mechanism of the induction of platelet activation and aggregation by various bacteria, but new reports show that bacteria with specific CBPs, like those of S. mutans, may inhibit platelet aggregation and cause bleeding.
Methods: Our report presents the case of a 62-year-old male with S. mutans septicemia who suffered and was treated for two separate episodes of intracerebral hemorrhages (ICHs) in different locations within two months of one another. The first case was a left frontal hemorrhage which involved the left MCA territory, while the second case was a hemorrhage that was localized to the right cerebellar hemisphere (Fig. 1).
Results: A diagnostic cerebral angiogram was conducted and ruled out any vasculopathies as potential causes for stroke. Both hemorrhagic lesions were biopsied and examined microscopically. Pathology reports were negative for amyloid angiopathy and vasculitis. Blood cultures obtained from the patient prior to the first ICH were positive for gram positive coccobacilli most consistent with S. mutans.
Conclusions: S. mutans with CBPs can interrupt the interaction between exposed collagen fibers in damaged vessels and platelets, effectively disrupting the initiation of platelet aggregation. Furthermore, S. mutans can activate matrix metalloproteinases which leads to further disruption of blood vessel barriers and augments bleeding.
Patient Care: Clarifying the level of risk involved with S. mutans septicemia and its potential association with intracerebral hemorrhage in intermediate and high risk patients can lead to better strategies for counselling and monitoring patients post-infection
Learning Objectives: 1. To identify risk factors implicated in hemorrhagic stroke
2. To acknowledge that specific collagen binding proteins, such as the Cnm type produced by S. mutans, may inhibit platelet aggregation and cause bleeding
3. To clarify the level of risk involved with S. mutans septicemia and its potential association with intracerebral hemorrhage in intermediate and high risk patients can lead to better strategies for counselling and monitoring patients post-infection