Sandbox RSGFire

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Farman Khan, MD, MRCP [2]; Mohamed Moubarak, M.D. [3]; Rim Halaby, M.D. [4]

Infective endocarditis Resident Survival Guide Microchapters
Overview
Causes
FIRE
Diagnosis
Treatment
Prophylaxis
Do's
Don'ts

Overview

Infective endocarditis is the infection of the endothelium of the heart including but not limited to the valves. While acute bacterial endocarditis is caused by an infection with a virulent organism such as staphylococcus aureus, group A or other beta-hemolytic streptococci, subacute bacterial endocarditis is an indolent infection with less virulent organisms like streptococcus viridans. Patients with unexplained fever for more than 48 hours and who are at high risk for infective endocarditis and patients among whom valve regurgitation is newly diagnosed should undergo a diagnostic workup to rule out endocarditis. The diagnosis of endocarditis depends on a thorough history and physical exam as well as on the results of the blood cultures and the findings on transthoracic echocardiogram or transesophageal echocardiogram. The modified Duke criteria is used to establish the diagnosis of endocarditis. Endocarditis is initially treated with empiric antibiotic therapy until the causative agent is identified.

Causes

Life Threatening Causes

Acute endocarditis is a life-threatening condition and must be treated as such irrespective of the underlying cause.

Common Causes

• Enterococcus infection
• Staphylococcus aureus infection
• Streptococcus viridans infection

FIRE:Focused Initial Rapid Evaluation

A Focused Initial Rapid Evaluation (FIRE) should be performed to identify patients in need of immediate intervention.

Boxes in salmon color signify that an urgent management is needed.

Abbreviations: CT: Computed tomography ; CTA: Computed tomography angiography; MRA: Magnetic resonance angiography; MRI: Magnetic resonance imaging; TEE: Transesophageal echocardiography; TTE: Transthoracic echocardiography

Antibiotic Prophylaxis

Shown below is a table depicting the prophylaxis antibiotic regimes for infective endocarditis.

Infective Endocarditis Antibiotic Prophylaxis Oral treatment is tolerated Not allergic to penicillin Allergic to penicillin ▸ Amoxicillin 2 g ▸ Ampicillin 2 g IM or IV OR ▸ Cefazolin 1 g IM or IV OR ▸ Ceftriaxone 1 g IM or IV Oral treatment is not tolerated Not allergic to penicillin Allergic to penicillin ▸ Cefalexin 2 g OR ▸ Clindamycin 600 mg OR ▸ Azithromycin 500 mg OR ▸ Clarithromycin 500 mg ▸ Cefazolin 1 g IM or IV OR ▸ Ceftriaxone 1 g IM or IV OR ▸ Clindamycin 600 mg IM or IV

Do's

• Elicit a full medical history to identify the minor Duke criteria for the diagnosis.
• Consider alternative diagnoses for bacteremia and fever by searching for focus of infections.
• Initiate antibiotic therapy after withdrawing blood for culture (Class I, level of evidence B).

• If the blood cultures are negative in a patient suspected to have infective endocarditis, suspect HACEK infection and ask the laboratory to retain the blood cultures for more than two weeks.

• If HACEK bacteremia is detected without any focus of infection, suspect the presence of infective endocarditis even in the absence of the typical signs and symptoms.

• Do a transesophageal echocardiography intraoperatively among patients scheduled for valve surgery for infective endocarditis (Class I, level of evidence B).

• Consider ordering a cardiac CT scan when echocardiography does not provide clear details about the cardiac anatomy in the context of suspected paravalvular infections (Class IIa, level of evidence B).

• Suspect intraventricular septal abscess as a complication of endocarditis when the ECG is significant for a gradual increase in the PR interval or a new left bundle branch block.

Don'ts

• Don't administer prophylaxis for infective endocarditis in patients with valvular heart disease who are at risk infective endocarditis for procedures such as transesophageal echocardiography, cystoscopy, esophagogastroduodenoscopy or colonoscopy without any evidence of active infection (Class III; level of evidence B).

• Do not administer infective endocarditis prophylaxis for the following dental procedures:
  • Anesthetic injections in noninfected tissue
  • Dental radiographs
  • Shedding of deciduous teeth
  • Placement of orthodontic brackets
  • Placement or removal of prosthodontic or orthodontic appliances
  • Adjustment of orthodontic appliances
  • Bleeding following trauma to the oral mucosa or lips

• Do not administer prophylaxis for infective endocarditis for procedures involving the respiratory tract unless they involve incision of the respiratory tract mucosa.

• Do not administer cephalosporins in subjects with a previous history of anaphylaxis, angioedema, or urticaria following penicillin or ampicillin use.

References

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