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.

Signs and Symptoms

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

Investigations

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

Duke’s criteria:

Two major criteria or One major and three minor or Five minor criteria

  • Major criteria
    • Positive blood culture X >2 (typical microorganisms for infective endocarditis)
    • Positive Echocardiographic study ( vegetation on the valves, wall abscess, new valve regurgitation)
  • Minor criteria
    • Predisposing heart condition or injected drug user
    • Febrile syndrome
    • Vascular phenomena (embolism, CNS haemorrhage, conjunctival haemorrhage, Janeway lesion)
    • Immunologic phenomena (glomerulonephritis, Rheumatoid factor, Osler’s nodes, Roth’s spots, false-positive VDRL test)
    • Microbiologic evidence (positive blood culture, but not typical microorganisms)
    • Echocardiography: suggestive but not positive for infective endocarditis

Treatment

Supportive

  • Bed rest
  • Good oral hygiene, regular dental review

Pharmacological

  • 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
  • Treat heart failure and arrhythmias

Surgical 

  • 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:

  • Prosthetic cardiac valves
  • Previous infective endocarditis
  • 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)
  • 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.

PreventionAntibiotics 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).