Bacterial Infective Endocarditis

Bacterial Infective Endocarditis

Pathology:                    Infection of the endocardium usuallylining the heart valves.

                                          Vegetationscomprising of fibrin, platelets and micro-organisms degrade valves.

Aortic valve most commonly affected followed by mitralthen tricuspid valves

Fever + new murmur = endocarditis until provenotherwise.


Aetiology:                     Normal heart valves: StreptococcusViridans

Risk factors for normal valves: diabetes,renal failure, immunosuppression


Abnormal valves: Staphylococcus Aureus from skin

Risk factors for abnormal valves: Valvedisease, prosthetic valve, IV drug use

(Tricuspidvalve most often affected), Cyanotic congenital heart failure


Other organisms: Staphylococcus epidermis, Enterococcus Faecalis,

HACEKorganisms (Haemophilus, Actinobacillus, actinomycetemcomitans, Cardiobacteriumhominis, Eikenella, Kingella), Mycobacteria, Chlamydia, Coxiella


Symptoms:                   Fever, rigors, night sweats, malaise,anorexia, anaemia, weight loss, stroke.


Signs:                              Clubbing,new murmur, splenomegaly, petechiae, Osler’s nodes (painful finger pulpnodules), Janeway lesions (painless palmar lesion), splinter haemorrhages, RothSpots (retinal haemorrhages), microscopic haematuria, glomerulonephritis.


Investigations:          Bloods: FBC, U&E, LFT, Clotting, CRP

Blood Cultures: 3 sets at differenttimes from different sites

Urine: microscopic haematuria

ECG: Prolonged PR interval or AV nodeblock

ECHO: Assess for vegetations, abscess,congenital lesions and LV function

Diagnosis: Based on ModifiedDukes Criteria

Definite – 2 major criteria,1 major and 3 minor criteria or 5 minor


Possible – 1 major and 1 minorcriteria or 3 minor criteria


Treatment:                  Streptococcus Viridans: 4weeks IV benzylpenicillin and gentamicin followed

by 2 weeks of oral penicillin

Staphylococcus Aureus: Flucloxacillin and gentamicin (MSSA) or Vancomycin

 and gentamicin (MRSA) in addition rifampicinis  

 required for prosthetic valves for MSSA orMRSA.

Surgical: Prosthetic valvedehiscence, fungal infections, poor antibiotic response

severe heart failure and aortic root abscess withheart block


Complications:          Septic emboli, acute heart failure,valve regurgitation, septic shock


Prognosis:                    30% mortality with Staphylococcal infections. 6% mortalitywith Streptococcus.

Text Box: 	Modified Duke’s Criteria For Infective Endocarditis
	Major Criteria
	Blood Cultures Positive – Typical Pathogen from at least 2 separate cultures
	Evidence of endocardial involvement on Echo – vegetations, perivalvular abscess, new regurgitation

Minor Criteria
Fever - ≥38°C
Evidence from single blood culture 
Vascular Phenomena –Mycotic aneurysm, Roth Spots, Janeway Lesions, Osler’s nodes.
Echo findings not consistent with major criteria
Risk Factors – IVDU or valvular disease

	Mnemonic ‘BE FEVER’


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