Infective Endocarditis: Etiology, Pathophysiology, Pathology, Diagnosis, and Complications

Introduction

Infective endocarditis (IE) is a life-threatening infection of the heart's inner lining, typically affecting the heart valves. It is caused by microbial invasion, leading to inflammation and destruction of cardiac tissues.

Etiology

IE is primarily caused by bacterial pathogens, including:

• Staphylococcus aureus – Most common in acute cases
• Streptococcus viridans – Associated with dental procedures
• Enterococci – Common in genitourinary infections
• HACEK organisms – Rare but significant

Pathophysiology

The disease progresses through several stages:

1. Microbial adherence to damaged endocardium
2. Formation of vegetations composed of fibrin, platelets, and bacteria
3. Embolization leading to systemic complications

Pathology

Histopathological findings include:

• Vegetations on heart valves
• Inflammatory infiltrates
• Microabscesses and necrosis

Diagnosis

Clinical Presentation

Patients may present with:

• Fever and chills
• Heart murmurs
• Janeway lesions, Osler nodes, and Roth spots

Imaging Techniques

Key imaging modalities include:

• Echocardiography – Transthoracic (TTE) and transesophageal (TEE) for detecting vegetations
• CT/MRI – Identifying embolic complications

Laboratory Findings

• Positive blood cultures
• Elevated inflammatory markers (CRP, ESR)
• Normocytic anemia and leukocytosis

Complications

IE can lead to severe complications, including:

• Heart failure due to valvular destruction
• Septic embolism causing stroke or organ infarction
• Mycotic aneurysms

Conclusion

Early diagnosis and prompt treatment are crucial in managing infective endocarditis. A multidisciplinary approach involving cardiologists, infectious disease specialists, and surgeons is essential for optimal patient outcomes.