Endocarditis

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1- Introduction

2- Causes

3- Symptoms

4- Types of Endocarditis

5- Treatment

6- What Should You Avoid

Introduction

Endocarditis is an inflammation of the inner lining of the heart, known as the endocardium, most commonly involving the heart valves. The majority of cases are due to infection and are referred to as infective endocarditis (IE). It occurs when microorganisms—most often bacteria such as Staphylococcus aureus, Streptococcus viridans, or Enterococci—enter the bloodstream and attach to damaged areas of the endocardium or abnormal heart valves. This leads to the formation of vegetations, which are clusters of bacteria, fibrin, and immune cells. Endocarditis can present in an acute form, with rapid onset and severe symptoms, or as subacute, with a slower, more insidious course.

Causes

1. Infective Causes (most common)

A. Bacterial Causes:

Staphylococcus aureus
- Most common cause of acute infective endocarditis
- Often affects normal valves, especially in IV drug users
Viridans group Streptococci
- Common cause of subacute endocarditis
- Often follows dental procedures
- Affects abnormal or damaged valves
Enterococci
- Linked to genitourinary or gastrointestinal procedures
Staphylococcus epidermidis
- Associated with prosthetic valve endocarditis
Gram-negative bacteria
- Rare but may be involved in healthcare-associated infections
HACEK group organisms (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella)
- Rare, slow-growing bacteria that can cause culture-negative endocarditis

B. Fungal Causes:

Candida and Aspergillus
- Typically seen in immunocompromised patients or those with prolonged antibiotic use
- Often require surgical intervention

2. Non-Infective Causes (Rare)

Libman–Sacks endocarditis
- Seen in systemic lupus erythematosus (SLE)
Marantic (nonbacterial thrombotic) endocarditis
- Occurs in malignancy, especially with advanced cancers, and hypercoagulable states

3. Predisposing Conditions:

Pre-existing valvular heart disease
Congenital heart defects
Prosthetic heart valves
Rheumatic heart disease
Intravenous drug use
Recent dental, surgical, or invasive procedures
Immunosuppression or long-term catheter use

Symptoms

-General (Constitutional) Symptoms:

Fever (most common symptom; may be low-grade in subacute cases)
Chills and night sweats
Fatigue and malaise
Weight loss
Anorexia
Myalgia or arthralgia

-Cardiac Symptoms:

New or changing heart murmur (due to valve destruction)
Signs of heart failure (dyspnea, orthopnea, edema) in advanced cases

-Embolic and Vascular Phenomena:

Petechiae – small red/purple spots on skin or mucosa
Splinter hemorrhages – linear streaks under fingernails
Janeway lesions – painless red spots on palms/soles (vascular)
Osler nodes – painful nodules on fingers/toes (immunologic)
Roth spots – retinal hemorrhages with pale centers

-Neurological Symptoms (due to emboli):

Stroke or transient ischemic attacks (TIAs)
Confusion, seizures, or focal deficits

-Renal Symptoms:

Hematuria
Glomerulonephritis (immune complex-mediated)

-Musculoskeletal:

Arthralgia or back pain (vertebral osteomyelitis may occur with S. aureus)

-Fever and Chills: Often the first signs.

Heart Murmur: New or changed heart murmur.
Fatigue: Persistent tiredness.
Aching Joints and Muscles: Common symptom.
Night Sweats: Especially common in infective endocarditis.
Shortness of Breath: Due to heart dysfunction.
Swelling: In the feet, legs, or abdomen.
Petechiae: Small, red or purple spots on the skin.

Types of Endocarditis

A. Infective Endocarditis (IE)
The most common type, caused by microbial infection of the endocardium, especially heart valves.

Bacterial Endocarditis
- Staphylococcus aureus, Streptococcus viridans, Enterococci, HACEK organisms
- Most common and includes both acute and subacute forms
Fungal Endocarditis
- Candida or Aspergillus
- Typically seen in immunocompromised patients, intravenous drug users, or those with prosthetic valves

B. Non-Infective Endocarditis
Characterized by sterile vegetations (no microbial involvement)

Libman–Sacks Endocarditis
- Associated with systemic lupus erythematosus (SLE)
- Typically affects mitral and aortic valves
Marantic Endocarditis (Nonbacterial Thrombotic Endocarditis)
- Occurs in advanced malignancy and hypercoagulable states
- Sterile vegetations, often clinically silent but prone to embolization

2. Based on Clinical Course

Acute Endocarditis
- Rapid onset with severe systemic toxicity
- Often caused by virulent organisms like Staphylococcus aureus
- Affects normal or prosthetic valves
Subacute Endocarditis
- Slower progression with nonspecific symptoms like fatigue, low-grade fever
- Caused by less aggressive organisms like Streptococcus viridans
- Usually occurs in pre-damaged valves

3. Based on Anatomic Involvement

- Native Valve Endocarditis
  - Involves natural heart valves, often due to underlying structural abnormalities
- Prosthetic Valve Endocarditis
  - Involves mechanical or bioprosthetic valves
  - Early onset (<60 days post-surgery): often nosocomial, caused by Staphylococcus epidermidis
  - Late onset: similar to native valve IE
- Right-sided Endocarditis
  - Common in intravenous drug users
  - Primarily affects the tricuspid valve
  - Frequently caused by Staphylococcus aureus
- Left-sided Endocarditis
  - More common in non-IV drug users
  - Involves the mitral or aortic valve

Treatment

1. Empirical Antibiotic Therapy (Initial)

Before culture results are available, broad-spectrum intravenous antibiotics are started based on clinical suspicion. Blood cultures should be taken before starting antibiotics.

Native valve (subacute):
- Ampicillin + Gentamicin or
- Vancomycin + Ceftriaxone
Native valve (acute):
- Vancomycin + Gentamicin + Cefepime
Prosthetic valve:
- Vancomycin + Gentamicin + Rifampicin

Antibiotics are adjusted once the organism and sensitivities are known.

2. Targeted Antibiotic Therapy

Once blood culture results are available, antibiotic therapy is narrowed and tailored. Examples:

Streptococcus viridans:
- Penicillin G or Ceftriaxone, with or without Gentamicin
Staphylococcus aureus (MSSA):
- Nafcillin or Oxacillin
Staphylococcus aureus (MRSA):
- Vancomycin
Enterococci:
- Ampicillin + Gentamicin, or
- Vancomycin + Gentamicin

Duration: 4–6 weeks of intravenous antibiotics, depending on organism, valve type, and complications.

3. Surgical Management

Indicated in approximately 25–50% of cases. Consider surgery if there is:

Heart failure due to valvular dysfunction
Uncontrolled infection (abscess, persistent bacteremia despite antibiotics)
Large vegetations (>10 mm) with embolic risk
Prosthetic valve involvement
Recurrent embolic events

Surgical options include valve repair or replacement.

4. Supportive Care

Monitor for complications: emboli, renal failure, arrhythmias
Manage heart failure if present
Address underlying risk factors (e.g. IV drug use)

5. Prophylaxis (Prevention)

Recommended for high-risk individuals undergoing certain procedures (e.g., dental work), particularly those with:

Prosthetic heart valves
Previous endocarditis
Certain congenital heart diseases

Amoxicillin is commonly used as prophylaxis before procedures

What Should You Avoid

Delaying medical evaluation for suspicious symptoms
Starting antibiotics before blood cultures (unless emergency)
Self-medicating with antibiotics
Invasive procedures without prophylaxis (if high-risk)
Intravenous drug use
Poor dental hygiene
Smoking
Excessive alcohol consumption
Neglecting follow-up or stopping antibiotics early
Strenuous physical activity during active infection
Ignoring signs of embolism (e.g., stroke, limb pain)
Use of unsterile needles or medical devices