Infections causing stroke
There are several scenarios where infection may be responsible for stroke. Infection itself appears to be an important trigger that precedes up to a third of ischaemic strokes. There are several suggested potential mechanisms. Infection may decrease atherosclerotic plaque stability resulting in plaque rupture and in situ thrombosis and /or embolism with artery to artery stroke. Infection may also affect the balance between endogenous pro and anticoagulants resulting in a prothrombotic state. Infection may precipitate AF. There may be affects with elevated stress hormones. These are quite distinct
Patients with infective endocarditis will throw off septic emboli which can seed the brain. These may cause infarcts or bleeds. Any patient with known valvular heart disease and a stroke must be assessed as to whether they have endocarditis. Many will have AF. The inexperienced stroke physicians may miss the point that cerebral haemorrhage can equally suggest embolic infection. Anticoagulation must be avoided as there is a high risk of secondary haemorrhage. Suspicion of endocarditis needs multiple cultures, CRP, WCC, urinalysis and echocardiogram and appropriate antibiotic therapy once cultures have gone off. Involve cardiology early on and patient may need to go to a tertiary centre if valve surgery contemplated.