Questions on infective endocarditis

  • Define infective endocarditis. H177
  • What are the types of infective endocarditis? H178
  • What are the common organisms involved in infective endocarditis? H179
  • What are the peripheral stigmata of infective endocarditis? H180
  • Tell the emperical therapy of infective endocarditis? H181

Rimikri

SOLVES


Definition and Classification
Define infective endocarditis.

This is due to microbial infection of a heart valve (native or prosthetic), the lining of a cardiac chamber or blood vessel, or a congenital anomaly (e.g. septal defect).

* Pre-exam preparation for medicine, HN Sarker
What are the types of infective endocarditis?

The types of endocarditis are:

  1. Acute infective endocarditis
  2. Subacute infective endocarditis
  3. Postoperative infective endocarditis.
* Pre-exam preparation for medicine, HN Sarker
Epidemiology
Etiology and Pathophysiology
What are the common organisms involved in infective endocarditis?
  1. Streptococcus— Viridens group and enterococci.
  2. Staphylococcus—Staphylococcus aureus and coagulase negative
  3. Gram-negative bacilli—Haemophilus anaerobes
  4. Others—Rickettsiae and fungi.
* Pre-exam preparation for medicine, HN Sarker
Clinical Manifestations
Examination
What are the peripheral stigmata of infective endocarditis?

The peripheral stigmata of infective endocarditis are:

  • Clubbing
  • Splinter hemorrhage
  • Osler’s nodes
  • Janeway lesions
  • Purpura
  • Roth’s spots.
* Pre-exam preparation for medicine, HN Sarker

Figure: Clinical features which may be present in endocarditis
* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 627
Investigations
What investigations do you suggest in endocarditis?

Investigations

  1. Blood culture
    • It is the crucial investigation because it may identify the infection and guide antibiotic therapy.
  2. Echocardiography
    • For detecting and following the progress of vegetations, for assessing valve damage and for detecting abscess formation.
  3. ESR: Elevation
  4. CRP: Measurement of serum CRP is more reliable than the ESR in monitoring progress.
  5. Hb% and PBF: Normocytic normochromic anaemia
  6. CBC: Leucocytosis
  7. Urinalysis:
    • Proteinuria may occur and microscopic haematuria is usually present.
  8. ECG
    • Development of AV block (due to aortic root abscess formation) and occasionally infarction due to emboli.
  9. Chest X-ray
    • Evidence of cardiac failure and cardiomegaly.
* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 627, 628
Diagnosis
Describe the diagnosis of infective endocarditis (modified Duke criteria).

Diagnosis of infective endocarditis (modified Duke criteria)

Major criteria

  • Positive blood culture
    • Typical organism from two cultures
    • Persistent positive blood cultures taken > 12 hrs apart
    • Three or more positive cultures taken over > 1 hr
  • Endocardial involvement
    • Positive echocardiographic findings of vegetations
    • New valvular regurgitation

Minor criteria

  • Predisposing valvular or cardiac abnormality
  • Intravenous drug misuse
  • Pyrexia ≥ 38°C
  • Embolic phenomenon
  • Vasculitic phenomenon
  • Blood cultures suggestive: organism grown but not achieving major criteria
  • Suggestive echocardiographic findings

Diagnosis

  • Definite endocarditis = two major, or one major and three minor, or five minor
  • Possible endocarditis = one major and one minor, or three minor
* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 627
Treatment
Tell the emperical therapy of infective endocarditis?
  • Acute—Flucloxacillin and gentamicin.
  • Subacute or indolent—Benzyl penicillin and gentamicin. In those with penicillin allergy, a prosthetic valve or suspected methicillin-resistant Staph. aureus (MRSA)
  • Infection—Triple therapy with vancomycin, gentamicin, and oral rifampicin.
* Pre-exam preparation for medicine, HN Sarker
What are the indications of cardiac surgery in infective endocarditis?

Indications for cardiac surgery in infective endocarditis

  • Heart failure due to valve damage
  • Failure of antibiotic therapy (persistent/uncontrolled infection)
  • Large vegetations on left-sided heart valves with evidence or ‘high risk’ of systemic emboli
  • Abscess formation

N.B. Patients with prosthetic valve endocarditis or fungal endocarditis often require cardiac surgery.

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 629
Complications
Notes
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