Infective endocarditis - Internal medicine Flashcards
Etiology and pathogenesis of infective endocarditis (C)
- Predisposing heart condition
A: High risk group
▪ Prosthetic heart valves
▪ Prior episode of endocarditis
▪ Cyanotic congenital heart diseases
▪ After transcatheter occlusion of intracardial shunt in the following conditions
* Within the first 6 months of occlusion
* If there is residual shunt after device insertion
▪ IV drug addiction
B; Moderate risk group (other heart diseases)
▪ Valvular heart diseases (for example, rheumatic mitral stenosis)
▪ Acyanotic congenital heart disease - Procedures that could lead to infective endocarditis
o Dental extraction.
o Cardiac surgery.
o IV drug abuse (right sided endocarditis is more common, especially tricuspid valve
o ESRD patient receives hemodialysis via dialysis catheter and other Instrumentation (IV canula, CV line, cardiac catheterization).
3: Causative organisms and rout of entry
A) Streptococcal viridans …. dental procedures
B) Staphylococcal aureus …. Skin procedures / open heart surgery
C) Enterococci …. Genitourinary tract infections / procedure
D) Streptococcal bovis …. GIT infections / procedures
E) HACEK group …. Upper respiratory tract infections / procedures
▪ Search about names of HACEK organisms
F) Other rare organisms
▪ Mycoplasma
▪ Legionella
▪ Fungal
- Pathology / pathophysiology
o Endothelial damage in the endocardium lead to formation of platelet-fibrin thrombi
o Microorganism invasion of such thrombi lead to formation of infected vegetation
o Vegetation is a small solid mass composed of platelet, fibrin, and organism, occurring at the site of endothelial damage in the valve or endocardium. It may result in embolism
o Dislodgment of such vegetation from the heart will lead to septic embolism
Clinical presentation of infective endocarditis (B)
o Infective endocarditis could present with one or more of the following
▪ Persistent fever of unknown origin with constitutional symptoms [Anorexia, weight loss, malaise, weakness, night sweat, and arthralgia] especially if prolonged more than 21 days.
▪ Heart failure symptoms due to heart affection (see HF)
▪ Symptoms of embolic complications
* Stroke
* Visual disturbance
* Abdominal pain and/or hematuria
Management of Infective endocarditis patient (Diagnostic work-up) (C)
- Admission to hospital
- Examination
o General examination to search for fever and skin signs of infective carditis
o Local examination to pick up murmur of valve lesion - Investigations
o Blood culture
- 3 blood samples from 3 different sited with the interval between each sample 1 hour
- Each sample is divided into three containers (aerobic, anerobic, and fungi)
- Empirical antibiotics are started after blood culture samples
- causes of culture negative endocarditis
a. Prior antibiotic treatment
b. Atypical organism: Fungal or yeast.
c. Non infective endocarditis “Libmann Sac’s” in SLE and marantic fever in malignancy
o Echocardiography to pick up underlying heart condition and/or evidence of heart infection
- Small vegetations couldn’t be detected with transthoracic echo …therefore, transesophageal echo is mandatory in suspected cases when transthoracic echo is free
o Investigations to detect embolic / immunological / Toxic complications
- CBC / ESR / CRP / urine analysis
- Pelviabdominal ultrasound / CT abdomen and pelvis
- Chest x ray / CT chest
- CT / MRI brain
- Fundus examination
Management of Infective endocarditis patient (Diagnostic criteria) (A++)
1- Required criteria
a) Definite: 2 major or (1 major + 3 minor) or 5 minor
b) Possible: (1 major + 1 minor) or 3 minors
c) Rejected: resolution of fever within 4 days of antibiotics or confirming other diagnosis for the cause of fever
2- Major criteria
a) Typical echocardiography (using transthoracic and/or transesophageal echocardiography) when you pick one or more of the following
▪ Vegetation
▪ Valve ring abscess
▪ New valvular regurgitation
▪ Valve perforation or aneurysm
▪ New partial dehiscence of prosthetic valve (suture dislodge)
b) Typical blood culture
▪ Three or more positive cultures one hour apart
▪ Typical organism in two cultures
▪ Positive two cultures 12 hours apart
3- Minor criteria
a) Atypical echocardiography
▪ Echo findings not meeting typical echo criteria (e.g., pericardial effusion)
b) Atypical blood culture
▪ Positive blood culture not meeting typical criteria (e.g., 1/3 positive cultures)
c) IV drug addiction
d) Predisposing heart condition
e) Toxic manifestations …. Fever, toxic clubbing, and splenomegally
f) Embolic manifestations
▪ Janeway lesions: micro-abscess of the dermis, appearing as nontender, erythematous macules or nodules on the palms and soles
▪ Splinter hemorrhage: linear hemorrhagic streaks under the nails
▪ Stroke / brain abscess
▪ Mycotic aneurysm in brain
▪ Septic pulmonary embolism
g) Immunological (vasculitis) manifestations
▪ Ostler nodules: painful, erythematous, and raised lesions on the palms and soles
▪ Roth spots: retinal hemorrhages with pale canters.
▪ Glomerulonephritis
▪ Splenomegaly
▪ Pale clubbing
Management of Infective endocarditis patient (treatment) (A++)
1- Treatment of acute phase
a) Supportive measures
▪ Bed rest in patients with carditis and arthritis till control of HF and normalization of ESR
▪ Low salt diet in heart failure
▪ Antipyretics for fever and fever chart
b) Empirical antibiotics after withdrawal of blood culture samples
- Native valve endocarditis or late prosthetic valve endocarditis
* Ampicillin + flucloxacillin + gentamycin
* Or vancomycin + gentamycin
- Prosthetic valve endocarditis
* Vancomycin + gentamicin + rifampicin
c) General principles of antibiotic treatment of infective endocarditis
▪ IV antibiotic
▪ Bactericidal antibiotic
▪ High concentration of antibiotic
▪ Prolonged duration (4 weeks in native valve endocarditis / 6 weeks in prosthetic valve endocarditis
▪ Only 2 weeks for gentamycin for fear of renal toxicity
d) Antibiotic treatment according to blood culture
▪ Causes of culture negative endocarditis
* Start of antibiotics before blood culture
* Atypical organism
2- Indications of surgical management of infective endocarditis (complications)
a) Heart failure
▪ Acute pulmonary edema / cardiogenic shock due to acute valve regurgitation or obstruction
▪ Heart failure resistant to medical treatment
b) Uncontrolled infection
▪ Abscess
▪ large vegetation
▪ Persistent positive culture
c) Recurrent septic embolism
d) Infected prosthesis
Management of Infective endocarditis patient (Primary prevention) (A++)
1 Population indicated for prophylaxis against infective endocarditis
o Prosthetic heart valves
o Prior episode of endocarditis
o Cyanotic congenital heart diseases
o After transcatheter occlusion of intracardial shunt in the following conditions
▪ Within the first 6 months of occlusion
▪ If there is residual shunt after device insertion
2 Procedures indicated for prophylaxis against infective endocarditis
o Dental procedures with gingival manipulations
3 Antibiotic regimen
o No penicillin allergy: ampicillin or amoxicillin oral or IV 1 hour before the procedure
o Penicillin allergy: Clindamycin oral or IV 1 hour before the procedure
Poor prognosis features of infective endocarditis
-Old age
-Prosthetic valve
-DM
-Heart failure
-Neurological complications
-Large vegetation
