Neurologic Complications of Infective Endocarditis

Symptomatic neurologic complications of IE are frequent, and asymptomatic cerebral embolism diagnosed by magnetic resonance imaging (MRI) occurs in many more patients. Neurologic complications increase mortality and complicate surgical decision-making. The most common neurologic complication is stroke due to septic embolism. Other complications include micro- and macro-abscesses, infectious aneurysms, and more general toxic-metabolic encephalopathies, cerebrospinal fluid (CSF) pleocytosis, and seizures. Neurologic complications influence diagnosis, management, and prognosis. MRI should be obtained in all patients with suspected IE and may identify cerebral abnormalities in many IE patients who do not have neurologic symptoms. MRI sequences should include diffusion weighted imaging (DWI) and gradient echo (GRE) to detect ischemic and hemorrhagic infarction. The detection of clinically silent ischemic or hemorrhagic brain lesions may affect performance or timing of surgery, choice of valve prosthesis, and antimicrobial or anticoagulant therapeutic planning. Neurologists should recommend urgent cerebral angiography in the setting of intracranial hemorrhage so that endovascular treatment of mycotic (infectious) aneurysms can be planned. Patients with large vegetations by echocardiography should be considered for surgery before embolism occurs. They should be referred to centers with extensive surgical experience in debridement of infected tissue and infectious disease expertise in antibiotic choice. Additional indications for surgery to replace the affected valve include heart failure, difficult-to-treat pathogens (such as fungi), elevated left ventricular or atrial pressure due to valvular regurgitation, and perivalvular abscess. Patients with cerebral embolism due to IE should not be anticoagulated. Anticoagulation should be stopped as soon as a diagnosis of IE is suspected, particularly if S. aureus infection is likely. Early surgery is recommended for those with transient ischemic attacks and small infarctions. Neurologists can assist the surgical team by providing neurological preoperative clearance for surgical intervention. Contraindications to early valve replacement include coma, large cerebral infarctions and intracranial hemorrhage.