Intracranial complications of acute bacterial endocarditis

Unusual subacute endocarditis following herpes zoster infection. a case report

OBJECTIVE

This paper presents a rare case of subacute bacterial endocarditis (SBE) following a herpes zoster (HZ) episode, with no prior records found in the existing literature.

PATIENT INFORMATION

Specifically, we describe a case of a 76-year-old female whose diagnosis of SBE was hindered by the concurrent manifestation of HZ symptoms, which had emerged 3 weeks before the onset of SBE indicators.

FOLLOW-UP AND OUTCOMES

This delay in diagnosis resulted in profound complications, including a cerebrovascular accident and significant mitral valve destruction.

DISCUSSION

HZ episodes have not conventionally been linked in the medical literature to the occurrence of SBE. Nonetheless, it is noteworthy that HZ infections have been associated with the development of other consequential bacterial infections, such as pneumonia and necrotizing fasciitis.This case underscores the necessity for medical practitioners to recognize the possibility of HZ symptoms obscuring indications of critical underlying conditions and infections. The implications of this report highlight the significance of maintaining heightened vigilance for signs of other severe infections when managing patients presenting with HZ symptoms.

Blood vessel occlusion by Cryptococcus neoformans is a mechanism for haemorrhagic dissemination of infection

Meningitis caused by infectious pathogens is associated with vessel damage and infarct formation, however the physiological cause is often unknown. Cryptococcus neoformans is a human fungal pathogen and causative agent of cryptococcal meningitis, where vascular events are observed in up to 30% of patients, predominantly in severe infection. Therefore, we aimed to investigate how infection may lead to vessel damage and associated pathogen dissemination using a zebrafish model that permitted noninvasive in vivo imaging. We find that cryptococcal cells become trapped within the vasculature (dependent on their size) and proliferate there resulting in vasodilation. Localised cryptococcal growth, originating from a small number of cryptococcal cells in the vasculature was associated with sites of dissemination and simultaneously with loss of blood vessel integrity. Using a cell-cell junction tension reporter we identified dissemination from intact blood vessels and where vessel rupture occurred. Finally, we manipulated blood vessel tension via cell junctions and found increased tension resulted in increased dissemination. Our data suggest that global vascular vasodilation occurs following infection, resulting in increased vessel tension which subsequently increases dissemination events, representing a positive feedback loop. Thus, we identify a mechanism for blood vessel damage during cryptococcal infection that may represent a cause of vascular damage and cortical infarction during cryptococcal meningitis.

Meningitis is a life threatening form of infection in the brain that is difficult to treat. How infection spreads from the blood to cause meningitis is not well understood. Here we have shown how infection with the fungus Cryptococcus neoformans can be spread from the blood by blocking and bursting blood vessels. Using zebrafish larvae, we were able to follow the same infections over a period of days to understand how this infection behaves in blood vessels. We found that fungal cells become stuck within blood vessels depending on their size. These cells grow within blood vessels, resulting in the blood vessels becoming wider. We measured increased tension in blood vessels suggesting that, with the bloackage and widening of vessels, there was increased local blood pressure. We found that vessel blockage was associated with their rupture and spreading of fungus into the surround tissue. Finally, by increasing the tension in vessels we could increase the number of blood bursting events supporting our conclusion that blood vessel blockage leads to the spread of the infection outside of blood vessels.

Rothia dentocariosa causing intracranial mycotic aneurysm and ischaemic stroke

We describe a case of subacute bacterial endocarditis and mycotic brain aneurysm caused by Rothia dentocariosa due to untreated dental caries. R. dentocariosa is a rare cause of endocarditis that has a high incidence of aneurysmal and haemorrhagic complications. All patients with intracranial aneurysms who have signs of systemic infection should be considered to have mycotic aneurysms until proven otherwise. Dental habits should be included in regular medical assessment and dental care should be considered for patients presenting with infectious symptoms.