Infective Endocarditis

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This is a microbial infection of the endocardium, which may result in valvular damage, myocardial abscess, or mycotic aneurysm.

Causes Streptococcal species (especially Streptococcus viridans), Staphylococci, HACEK group, Enterococci.

Predisposing factors Preexisting valvular disease, congenital heart disease, dental and surgical procedures, intracardiac devices (prosthetic valves, pacemaker), intravascular catheters, intravenous drug abuse.

Can be acute and subacute.

Clinical features Symptoms

  • Fever
  • Night sweats
  • Arthralgia
  • Malaise
  • Weight loss
  • Dyspnea

Signs

  • Fever
  • Peripheral stigmata (splinter haemorrhages, Osler’s nodes, Janeway lesion, Roth’s spots)
  • Pallor and jaundice
  • Heart murmurs
  • Features of heart failure
  • Embolic phenomena
  • Splenomegaly
  • Hematuria

Diagnosis Duke’s criteria:

  1. Criteria for Infective Endocarditis
    1. Two major criteria or
    2. One major and three minor or
    3. Five minor criteria
  2. Major criteria
    1. Positive blood culture X >2 (typical microorganisms for infective endocarditis)
    2. Positive Echocardiographic study ( vegetation on the valves, wall abscess, new valve regurgitation)
  3. Minor criteria
    1. Predisposing heart condition or injected drug user
    2. Febrile syndrome
    3. Vascular phenomena (embolism, CNS haemorrhage, conjunctival haemorrhage, Janeway lesion)
    4. Immunologic phenomena (glomerulonephritis, Rheumatoid factor, Osler’s nodes, Roth’s spots, false-positive VDRL test)
    5. Microbiologic evidence (positive blood culture, but not typical microorganisms)
    6. Echocardiography: suggestive but not positive for infective endocarditis

Management Investigations

  • Blood culture
  • Echocardiography
  • FBC
  • Urinalysis and microscopy
  • U/E, LFTs

Treatment

  1.  Appropriate antibiotics: Penicillin G 10-20 MU /day IV in divided doses (4 times)or Ampicillin 8-12 g/day IV for 4 weeks and Gentamycin 1 mg/kg ( up to 80 mg) 3 times IV daily 2-4 week. If Staphylococcus aureus: Oxacillin or Vancomycin IV
  2. Bed rest
  3. Treat heart failure and arrhythmias
  4. Surgery - valvular replacement (indications: refractory heart failure, uncontrolled infection, fungal infections with large vegetation >10mm in size, recurrent systemic embolism, suppurative pericarditis, mycotic aneurysm or rupture of sinus of Valsalva)

Prophylaxis Conditions in which prophylaxis is recommended:

  1. Prosthetic cardiac valves
  2. Previous infective endocarditis
  3. Certain types of Congenital Heart Diseases (unrepaired cyanotic CHD, complete repair of CHD with prosthetic material or device for first 6 months; repaired CHD with the residual defects at the site of prosthetic valve or patch)
  4. Cardiac transplantation with valvulopathy No prophylaxis is recommended for most dental, GIT and GUT procedures, with acquired valve disease, hypertrophic cardiomyopathy, a pacemaker or coronary by-pass surgery.

Prevention Good oral hygiene, regular dental review

Antibiotics for prophylaxis, 1 hour before procedure:

Oral:

  • Amoxycillin 2 g (adult), 50 mg/kg (children) or
  • Cephalexin 2g (adult), 50 mg/kg (children) or Azithromycin 500 mg (adult), 15 mg/kg (children)

Parenteral

  • Amoxycillin 2 g IM/IV (adult), 50 mg/kg (children)
  • Cefazolin or Ceftriaxone 1 g IM/IV (adult), 50 mg/kg (children)
  • Clindamycin 600 mg IM/IV (adult), 20 mg/kg (children).