Infective endocarditis resident survival guide

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]

Definition

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.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. Endocarditis can be a life-threatening condition if it is left untreated, and it must be treated as such irrespective of the causes.

Common Causes

• Enterococcus
• Staphylococcus aureus
• Streptococcus viridans

Management

Shown below is an algorithm depicting the management of infective endocarditis.

Characterize the symptoms: ❑ Onset of the symptoms ❑ Acute ❑ Subacute ❑ Fever ❑ Chills ❑ Rigors ❑ Sweats ❑ Weakness ❑ Myalgias ❑ Arthralgias ❑ Anorexia ❑ Fatigue ❑ Shortness of breath ❑ Hemoptysis ❑ Sputum ❑ Cough ❑ Pleuritic chest pain ❑ Seizures ❑ Symptoms suggestive of stroke ❑ Symptoms suggestive of transient ischemic attack

Identify existing risk factors: ❑ History of rheumatic heart disease ❑ Prosthetic valves ❑ Intravenous drug users ❑ Previous infective endocarditis ❑ Cardiac transplant recipients with valves abnormality ❑ Congenital heart diseases ❑ Unrepaired cyanotic congenital heart diseases ❑ Completely repaired defect with prosthetic material or device ❑ Repaired with residual defects at the site or adjacent to the site of a prosthetic material

Examine the patient: Vital signs ❑ Temperature ❑ Fever ❑ Blood pressure ❑ Wide pulse pressure (sign of aortic insufficiency) ❑ Narrow pulse pressure (sign of left ventricular failure) Skin ❑ Petechiae ❑ Splinter hemorrhages ❑ Osler's nodes ❑ Janeway lesions Dental examination ❑ Teeth ❑ Gingiva Eyes ❑ Conjunctival hemorrhage ❑ Roth's spots in the retina Heart ❑ Heart murmur ❑ Aortic insufficiency ❑ Tricuspid regurgitation ❑ Mitral regurgitation Lungs ❑ Rales as a sign of heart failure Abdomen ❑ Reduced bowel sounds (sign of mesenteric embolization or ileus) ❑ Abdominal pain ❑ Flank pain (sign of embolus to the kidney) ❑ Left upper quadrant pain (sign of splenic infarct) ❑ Splenomegaly Extremities ❑ Janeway lesions (painless hemorrhagic cutaneous lesions on the palms and soles) ❑ Gangrene of fingers ❑ Splinter haemorrhages ❑ Osler's nodes (painful subcutaneous lesions in the distal fingers) Neurologic ❑ Full neurological exam ❑ Focal deficits (suggestive of stroke or brain abscess)

Does the patient have any of the following: ❑ Unexplained fever for more than 48 hours and high risk for infective endocarditis ❑ Congenital or acquired valvular heart disease ❑ Previous infective endocarditis ❑ Prosthetic heart valve ❑ Congenital heart malformation ❑ Immunodeficiency ❑ History of drug injection ❑ Newly diagnosed valve regurgitation

Order tests: ❑ Blood culture (at least two sets) ❑ Order a TTE ❑ Order a TEE if one or more of the following is present ❑ Non diagnostic TTE in a suspected infective endocarditis (Class I, level of evidence B) ❑ Clinical complications (Class I, level of evidence B) ❑ Intracardiac device leads (Class I, level of evidence B) ❑ Staphylococcus aureus bacteremia without a known cause (Class IIa, level of evidence B) ❑ Prosthetic valve with persistent fever without bacteremia (Class IIa, level of evidence B) ❑ Prosthetic valve with a new murmur (Class IIa, level of evidence B) ❑ Nosocomial Staphylococcus aureus bacteremia with known extra-cardiac port of entry (Class IIb, level of evidence B)

Evaluate the Modified Duke Criteria for infective endocarditis: Probability of infective endocaritis Characteristics Definite diagnosis by pathological criteria ❑ Microorganisms demonstrated by culture or histological examination of a vegetation, OR ❑ Pathological lesions; vegetation or intracardiac abscess confirmed by histological examination showing active endocarditis Definite diagnosis by clinical criteria ❑ 2 major criteria, OR ❑ 1 major criterion and 3 minor criteria, OR ❑ 5 minor criteria Possible diagnosis ❑ 1 major criterion and 1 minor criterion, OR ❑ 3 minor criteria Rejected diagnosis ❑ Firm alternative diagnosis explaining evidence of IE, OR ❑ Resolution of IE syndrome with antibiotic therapy for 4 days, OR ❑ No pathological evidence of IE at surgery or autopsy, with antibiotic therapy for 4 days, OR ❑ Does not meet criteria for possible IE as above

❑ Begin antibiotic treatment (look below for details) ❑ Order blood cultures very 24-48 hours until no bacteremia can be detected ❑ Temporarily discontinue anticoagulation in case of ❑ Signs and symptoms of CNS involvement consistent with embolism or stroke (Class IIa, level of evidence B) ❑ Vitamin K antagonist administration (Class IIb, level of evidence B) ❑ Schedule early surgery during hospitalization before completion of the antibiotics course in case of ❑ Heart failure due to the valve dysfunction (Class I, level of evidence B) ❑ Left sided infective endocarditis due to staphylococcus aureus, fungal or highly resistant organisms (Class I, level of evidence B) ❑ Heart block, annular or aortic abscess or destructive lesions (Class I, level of evidence B) ❑ Persistent bacteremia or fever 5 to 7 following the initiation of the antibiotics (Class I, level of evidence B) ❑ Remove the pacemaker of the defibrillator system in case of ❑ Documented infection of the device or leads (Class I, level of evidence B) ❑ Valvular infective endocarditis by Staphylococcus aureus or fungi in the absence of documented infection of the device or leads (Class IIa, level of evidence B) ❑ Patient scheduled for valve surgery (Class IIa, level of evidence C) ❑ Persistent vegetations and recurrent emboli despite the antibitioc regimen (Class IIa, level of evidence B)

❑ Consult an infectious disease specialist ❑ Consult a cardiologist ❑ Consult a cardiac surgeon

Reevaluate the patient with TTE and/or TEE ❑ Change in clinical signs and symptoms ❑ New murmur ❑ Embolism ❑ Persistent fever ❑ Heart failure ❑ Abscess ❑ Atrioventricular heart block ❑ High risk of complications ❑ Large vegetations on echocardiogram ❑ Staphylococcus, enterecoccal, or fungal infections

Modified Duke Criteria

Shown below is a table summarizing the major and minor Modified Duke Criteria.

Major criteria

Minor criteria

1- Positive Blood Culture for Infective Endocarditis ❑ Typical microorganism consistent with infective endocarditis from 2 separate blood cultures, in the absence of a primary focus: ❑ Viridans streptococci, streptococcus bovis ❑ HACEK group ❑ Community-acquired staphylococcus aureus ❑Enterococci OR ❑ Microorganisms consistent with infective endocarditis from persistently positive blood cultures defined as: ❑ At least 2 positive cultures of blood samples drawn >12 hours apart, or ❑ All of 3 or a majority of 4 separate cultures of blood (with first and last sample drawn 1 hour apart) OR ❑ Single positive blood culture for Coxiella burnetii or anti–phase 1 IgG antibody titer >1:800 2-Echocardiographic evidence of endocardial involvement ❑ Oscillating intracardiac mass on valve or supporting structures, in the path of regurgitant jets, or on implanted material in the absence of an alternative anatomic explanation, or ❑ Abscess, or ❑ New partial dehiscence of prosthetic valve, or ❑ New valvular regurgitation

1- Predisposition ❑ Predisposing heart condition or intravenous drug use 2- Fever ❑ Temperature > 38.0° C (100.4° F) 3- Vascular phenomena ❑ Major arterial emboli ❑ Septic pulmonary infarcts ❑ Mycotic aneurysm ❑ Intracranial hemorrhage ❑ Conjunctival hemorrhage ❑ Janeway lesions 4- Immunologic phenomena ❑ Glomerulonephritis ❑ Osler's nodes ❑ Roth spots ❑ Rheumatoid factor 5- Microbiological evidence ❑ Positive blood culture but does not meet a major criterion as noted above OR ❑ Serological evidence of active infection with organism consistent with infectious endocarditis

Prophylaxis

Shown below an algorithm depicting the general prophylactic approaches of infective endocarditis.

Identify high risk patients: (Class IIa, Level of evidence B) ❑ Prosthetic valves patients ❑ Previous infective endocarditis ❑ Cardiac transplant recipients with valves regurgitation due to structurally abnormal valve ❑ Congenital heart diseases ❑ Unrepaired cyanotic congenital heart diseases ❑ Completely repaired defect with prosthetic material or device ❑ Repaired with residual defects

Identify high risk procedures: ❑ Dental procedures ❑ Manipulation of gingival tissue, or ❑ Manipulation of the periapical region of teeth, or ❑ Perforation of the oral mucosa ❑ Procedures on infected skin or musculoskeletal tissue ❑ Respiratory tract procedures ❑ Gastrointestinal and genitourinary procedures ❑ Patients undergoing cardiac surgery

❑ Administer prophylaxis ❑ Infective endocarditis prophylaxis regimens, or ❑ Prophylaxis regimens if the patient is penicillin or pmpicillin allergic, or ❑ Prophylaxis regimens if the patient is penicillin or ampicillin allergic and cannot take oral medications

Do's

• Elicit a full medical history to help detecting the minor Duke criteria for the diagnosis.
• Consider alternative diagnoses for bacteremia and fever.
• 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 TEE 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).

Dont's

• Don't administer prophylaxis for infective endocarditis in patients with valvular heart disease who are at risk infective endocarditis for procedures such as TEE, 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

References

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