ENDOCARDITIS - Disease Management

Endocarditis is a microbial infection of the endocardium and the heart valves, characterized by fever, heart murmurs, petechiae, anemia, embolic phenomena, and endocardial vegetations that may result in valvular incompetence or obstruction, myocardial abscesses, or mycotic aneurysm. The course may be acute or subacute and clinical findings vary greatly.

Classification

• Acute infective bacterial endocarditis (ABE)
• Subacute bacterial (SBE) endocarditis
• Prosthetic valvular endocarditis (PVE)
• Right-sided endocarditis

Causes

Native valve endocarditis: Streptococcus viridans, Enterococci, S. aureus, HACEK (Haemophilus, Actino-bacillus, Cardiobacterium, Eikenella, and Kingella).

Prosthetic valve endocarditis: Coagulase-negative staphylococci, Staphylococcus aureus, Enterococci, Gramnegative bacilli, fungi.

Endocarditis in IV drug users: S. aureus, streptococci, Gram-negative bacillus, enterococci, fungi, polymicrobial.

Culture negative (marantic endocarditis): A non-bacterial thrombotic endocarditis Acute bacterial endocarditis: S. aureus, Pneumo-coccus, group A streptococcus.

Other causes Infection may be acquired through Intravenous drug use, cardiac catheterization, and other invasive procedures, cuts, bruises and minor surgical procedures, dental procedures.

Risk Factors

• Underlying heart disease: Rheumatic valvular damage, Congenital heart disease, mitral valve prolapse, prosthetic valves, hypertrophic cardiomyopathy, and previous bacterial endocarditis are predisposing factors for endocarditis. With more virulent organisms, such as Staphylococcus aureus, previous valvular damage is present in only about 50% of the cases. 
• Events predisposing patients to bacteremia such as intravenous drug use, intravenous catheters, dental and genitourinary procedures.
• Age greater than 50 years

Signs and symptoms

Acute bacterial endocarditis

• Acute onset of fever, chills, arthralgias
• Sepsis
• Aseptic meningitis
• Ventricular failure and heart block
• Mycotic aneurysms
• Peripheral Janeway lesions

Subacute bacterial endocarditis

• Night sweats
• Fatigue
• Heart murmurs
• Hematuria
• Fever and chills
• Tachycardia
• Arthralgias
• Flank pain
• Abdominal pain
• Roth spots
• Splenomegaly
• Petechiae over the upper trunk
• Conjunctiva
• Osler nodes
• Acute arterial insufficiency

DIAGNOSIS

Differential Diagnosis

• Brain abscess
• Cerebral hemorrhage
• with fever
• Connective tissue
• diseases
• Glomerulonephritis
• Cerebral embolus
• Fever of unknown
• origin
• Intra-abdominal
• infections
• Meningitis
• Rheumatic fever
• Tuberculosis
• Salmonellosis
• Osteomyelitis
• Myocardial infarction
• Pericarditis
• Septic pulmonary infarcts

Investigations

• Blood cultures
• IgE
• Complete blood examination
• Echocardiograph
• Rheumatoid factor

TREATMENT

Goal

• Identification of causative organisms and decide on an optimal antibiotic regimen.
• Prevention of relapse.

Pharmacological Treatment

• Native Heart Valve (Acute infective endocarditis)
• Cloxacillin/Nafcillin
• Oxacillin plus Penicillin G or Ampicillin
• Penicillin allergy Vancomycin plus Gentamicin Prosthetic Heart Valve
• Vancomycin plus gentamicin plus rifampicin Penicillin-susceptible streptococci (Pen MICmcg/mL)
• Penicillin G plus gentamicin Penicillin-resistant Streptococci (Pen MICo.5mcg/mL)
• Penicillin G/ampicillin plus gentamicin. Methicillin-susceptible (H Staphylococcus aureus)
• Cloxacillin/nafcillin/oxacillin with or without rifampicin or gentamicin Methicillin-resistant (H Staphylococcus aureus)
• Vancomycin plus gentamicin and rifampin HACEK microorganisms (Haemophilus parainfluenza, H. aphrophilus, Actinobacillus actinomyces-temcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae)
• Ceftriaxone

Surgical Treatment

Cardiac valve surgery is indicated in early-onset PVE progressive CHF, multiple embolic events, fungal endocarditis, persistent bacteremia, an extension of infection into the conducting system, relapse of infection, and abscess on echo.

PATIENT EDUCATION

Emphasize patient regarding dental hygiene

Complications

• Congestive heart failure
•  Emboli
• Arrhythmias
• Stroke
• Glomerulonephritis
• Brain abscess
• Jaundice
• Severe heart valve damage
• Brain or nervous system changes

Prognosis

Untreated, infective endocarditis is always fatal. A poor prognosis is associated with heart failure, old age, aortic or multiple valve involvement, large vegetations, polymicrobial bacteremia, antimicrobial resistance, delay in initiating therapy, prosthetic valve infections, mycotic aneurysms, valve ring abscess, and major embolic events. After cardiac surgery, the mortality rate is higher in early-onset than in late-onset infective endocarditis and in fungal endocarditis.relapse after therapy usually occurs within 4 weeks.