Infective Endocarditis- Pathophysiology

What are the sites where the infection can occur? Cause these are areas of the nidus where the infection can occur! 

• Normal cardiac endothelium 
• Damaged valves
• Mitral valve and aortic valve are most likely to be involved
• Surgically constructed AV shunts 
• Prosthetic valves

Imagine, a breach in the endothelium caused by

• Turbulent flow (e.g. valvular stenosis or valvular regurgitation) or 
• Intravascular device-related injury (e.g. catheters)

After the breach, the platelets and WBC’s aggregate near injured endothelium like soldiers and give rise to the thrombus.

If dental procedures or any surgery takes place after thrombi formation, chances of transitent bacterium to colonize the thrombi is more.

Hence, immune system will be form fibrin meshwork on bacteria to seal it.

So, thrombus + bacteria + fibrin = is called vegetation 

When vegetation is dislodged, it may go anywhere in the body. 

• It can form embolus
• Since, it contains bacteria, it’s septicaemia in nature 
• It contains foreign particles too, hence immunogenic in nature