infective endocarditis and rheumatic fever 2

Question 1

Principles of antibiotic therapy

Answer 1

Target organism isolated from positive blood culture test

Empiric antibiotic therapy given to suspected cases who are acutely ill. Antibiotics should be given after the blood cultures have been taken
Should cover staphylococci (methicillin-susceptible and methicillin resistant), streptococci and enterococci

Duration of treatment:
Native valve is 4-6 weeks & prosthetic valves is 6 weeks
Calculate fromfirstday of negative blood culture

Question 2

empiric therapy treatment of native valve

Answer 2

all IV
>Benzylpenicillin
>Gentamicin
> IF STAPH infection - cefazolin- 2g- 8 hrs

Question 3

Empiric Therapy for prosthetic valve.

Answer 3

Vancomycin, IV, 20 mg/kg 12 hourly for 6 weeks.
AND
Rifampicin, oral, 7.5 mg/kg 12 hourly for 6 weeks.
AND
Gentamicin, IV, 1.5 mg/kg 12 hourly for 2 weeks

Question 4

IF it is a staphylococcus infection?

Answer 4

introduce
Cefazolin, 2g, 8 hourly and 4 weeks

and gentamicin, IV, 6 mg and 2 weeks

Question 5

Staphylococcal (cloxacillin/methicillin resistant) or methicillin sensitive
with significant beta-lactam allergy

Answer 5

s. Aureus - Vancomycin, Iv, 20, 12 hourly and 4 weeks.

Coagulase-negative
staphylococci - consult an expert on correct on antibiotic choice.

Question 6

Antibiotic Options- Directed Therapy Options (Prosthetic Valve)

Answer 6

Duration- minimum of 6 weeks

Expert opinion on antibiotic choice

Need for repeat cardiac surgery to control source of infection

Question 7

Prevention of Endocarditis

Answer 7

Antibiotic prophylaxis prior to invasive dental or oral procedures
Which patients? Co-morbid conditions or implanted devices
Which antibiotic? Oral amoxicillin 2g. If allergic to penicillin, azithromycin
Timing: 30-60 minutes prior to procedure

Other measures
Maintaining oral hygiene, refer to dental clinic/dental therapist for assessment and on-going dental care.
Treatment of infection with pathogens that can cause IE
Antibiotic prophylaxis for surgical site infection
Closure of PDA (patent ductus arteriosus) or VSD (ventricular septal defect

Question 8

what is an acute rheumatic fever

Answer 8

is an nonsuppurative sequela of group A streptococcus pharyngitis occurring 24 weeks following an infection.

Question 9

Rheumatic Heart Disease

Answer 9

Long term damage to the heart due to single severe episode or multiple recurrent episodes of ARF
Complication of ARF

Question 10

Epidemiology of Rheumatic Fever

Answer 10

Occur at any age- more common in children 5-15 years of age

Environmental factors: Increased risk in overcrowded household settings, poverty, malnutrition

Genetic susceptibility e.g. HLA-DR7 alleles

Routine use of antibiotics for acute pharyngitis will reduce risk of ARF

Question 11

what causes Rheumatic fever

Answer 11

GAS Pharyngeal Infection

Activation of the Innate Immune System

If left untreated, GAS antigen presented to T cells

B & T cells produce IgG and IgM antibody and activation of CD4+ cells

Antibodies that target the M-protein of certain streptococci shares antigenic determinants with proteins found on the heart, muscle, skin, CNS, heart valve (Read Murray p.g.193 on streptococcus structure and M-protein)

Question 12

Clinical Manifestations “Jones Criteria.

Answer 12

Jones Criteria.
J- joint involvement
O- O looks likes a heart= myocarditis
N- nodules and subcutaneous
E- erythema marginatum
S- Sydenham chorea

C- Crp increased
R- Arthralgia
F- Fever
E- elevated ESR

p-prolonged Pr interval
A- anamnesis of rheumatism
L- leukocytosis.

Question 13

Diagnosis of Rheumatic Fever

Answer 13

Evidence of recent S. pyogenes infection
Positive throat culture or specific molecular test
Rapid streptococcal antigen test
Elevated antistreptococcal antibody titre (ASO), anti-DNase B or anti-hyaluronidase antibodies

Question 14

if Group A streptococcal or rheumatic fever is left untreated it causes?

Answer 14

Rheumatic heart disease
Can occur 10-20 years after original illness
Most common cause of acquired valvular disease and more severe
Mitral valve more common than aortic
Often presents with mitral regurgitation than mitral stenosis

Jaccoud arthropathy
Benign, chronic arthropathy
Involves loosening and lengthening of periarticular in the hands and/or feet
Painless correctable deformities that do not cause functional impairment

Question 15

goals of treatment ?

Answer 15

Eradicate GAS
Relieve acute symptoms such as fever, arthritis
Manage rheumatic heart disease if present
Manage chorea if present
Prophylaxis against possible recurrence to prevent disease progression
Educate patient and patient’s caregivers
Trace household contacts- do throat swabs and give full course of antibiotics if throat swab is positive
For arthritis and fever, Ibuprofen, oral, 400mg 8 hourly

Question 16

Antibiotic choice: Rheumatic fever

Answer 16

Penicillin G benzathine- long acting IM- 1.2 MU as single dose OR Phenoxymethylpenicillin, oral, 500mg 12 hourly for 10 days
If severe penicillin allergy- Azithromycin oral, 500mg 12 hourly for 10 days

Question 17

primary prevention

Answer 17

prompt diagnosis and treatment of group A streptococcus pharyngitis.

Question 18

Secondary Prevention.

Answer 18

All patients with confirmed rheumatic fever and no persistent rheumatic valvular disease:
» Treat for 10 years or until the age of 21 years, whichever is longer

Question 19

TREATMENT of all patients with rheumatic fever and persistent rheumatic vulvar disease.

Answer 19

Treat lifelong.
Benzathine benzylpenicillin (depot formulation), IM, 1.2 MU every 3–4 weeks (preferred treatment).
OR Phenoxymethylpenicillin, oral, 250 mg 12 hourly.
Severe penicillin allergy: Azithromycin, oral, 250 mg daily