Updated: 2/7/2020

Endocarditis

Topic
Review Topic
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Questions
10 10
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Evidence
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Snapshot
  • A 25-year-old woman presents to the emergency room for a fever. She has a history of intravenous drug use and had previously been treated for osteomyelitis. On physical exam, she is febrile, and heart auscultation reveals a new systolic murmur at the lower left sternal border. An echocardiogram reveals tricuspid valve vegetations.
Introduction
  • Clinical definition
    • inflammation of the heart valve, typically secondary to infection, most commonly by staphylococci or streptococci
  • Epidemiology
    • location
      • mitral valve > tricuspid valve
      • tricuspid valve disease is associated with intravenous (IV) drug use
        • Staphylococcus aureus, Pseudomonas, and Candida
    • risk factors
      • rheumatic heart disease
      • IV drug use
      • immunosuppression
      • prosthetic heart valve
      • congenital heart disease
  • Etiology
    • acute endocarditis
      • Streptococcus pneumoniae
      • Streptococcus pyogenes
      • Staphylococcus aureus
        • IV drug users
        • large vegetations seen on the valves
      • Neisseria gonorrhea
    • subacute bacterial endocarditis is characterized by slower onset and less severe symptoms
      • Streptococcus galloyticus
        • in the setting of colon cancer
        • must perform colonoscopy 
      • enterococcus
        • in the setting of gastrointestinal/genitourinary procedures
      • Streptococcus viridans
        • often a complication of dental procedures
        • can also occur with upper respiratory infections
        • makes dextrans, which binds to fibrin-platelet aggregates on the heart valves
      • Staphylococcus epidermidis
        • often in the setting of prosthetic valves
      • Candida albicans
        • IV drug users
    • non-infectious endocarditis
      • Libman-Sacks endocarditis
        • from systemic lupus erythematosus
        • mitral or aortic valve involvement
      • non-bacterial thrombotic (marantic) endocarditis 
        • from inflammatory states
        • very poor prognosis
        • thrombi made of platelets with fibrin without organisms or neutrophils
  • Pathogenesis
    • endothelial damage on the surface of the cardiac valve can cause a thrombus to form
      • factors include turbulent blood flow that can damage endothelium or deposition of fibrin-platelet aggregate on damaged endothelium
    • bacteria can then adhere to thrombus
    • vegetations are caused by further depositions of fibrin and platelets
  • Prognosis
    • often presents as fever of unknown origin
    • endocarditis prophylaxis may be required before dental procedures
Presentation
  • Symptoms
    • persistent fevers (the most common symptom)
    • shortness of breath
    • systemic symptoms
      • weakness
      • fever
      • malaise
  • Physical exam
    • new murmur on auscultation
      • tricuspid valve in IV drug users 
        • a systolic murmur along the left lower sternal border in tricuspid regurgitation
    • from emboli
      • Roth spots
        • retinal hemorrhages on funduscopy
      • Janeway lesions
        • erythematous and nontender macules on palms or soles
      • nail bed splinter hemorrhages
    • from immune complex deposition
      • Osler nodes
        • tender nodules on fingers or toes
      • glomerulonephritis
Imaging
  • Echocardiography   
    • indication
      • for all patients
    • findings
      • vegetations on valves
Evaluation
  •  Making the diagnosis
    • based on clinical presentation and Duke criteria
      • pathologic criteria
        • blood culture of the organism (best initial step)   
          • drawn at least 12 hours apart OR
          • multiple positive cultures (at least 3 of 4) with the first and last drawn at least 1 hour apart
        • histologic evidence of endocarditis from vegetation or intracardiac abscess
      • clinical criteria: one of the following
        • 2 major criteria
        • 1 major and 3 minor criteria
        • 5 minor criteria
    • if blood cultures are negative but echocardiography shows endocarditis, consider one of the causes of culture-negative endocarditis (CNE)
      • Coxiella burnetii
      • Bartonella spp
      • HACEK organisms
        • Haemophilus
        • Aggregatibacter
        • Cardiobacterium
        • Eikenella
        • Kingella
 
Duke Criteria
Major Minor
  • Positive blood cultures from 2 separate blood cultures drawn > 12 hours apart, 3 out of 4 blood cultures that are positive, with first and last samples drawn 1 hour apart, single positive blood culture for Coxiella burnetti, or antiphase I IgG antibody titer > 1:800
  • Abnormal echocardiogram with vegetation or abscess or partial dehiscence of prosthetic valve
  • Fever
  • Presence of risk factors, including intravenous drug use, structural heart disease, prosthetic heart valve, dentla procedures, or history of endocarditis
  • Vascular phenomena, including Janeway lesions, emboli, mycotic aneurysm, and conjunctival hemorrhage
  • Immunologic phenomena, including glomerulonephritis, Osler nodes, and Roth spots
  • Positive blood cultures not meeting major criterion
  • Echocardiographic findings consistent with endocarditis but not meeting major criterion
 
Differential
  • Osteomyelitis
    • distinguishing factor
      • although this can present as fever of unknown origin, it typically lacks other findings of endocarditis and will not have vegetations on echocardiography
Treatment
  • Management approach
    • choice of antibiotics ultimately depend on causative agent and susceptibility as well as presence of prosthetic material in the heart
    • all anitbiotics should given intravenously
  • Medical
    • vancomycin plus ceftriaxone or gentamicin
      • indications
        • empiric antibiotic therapy for patients with no prosthetic valve
        • often for 4-6 weeks
    • vancomycin plus gentamicin and rifampin
      • indications
        • empiric antibiotic therapy for patients with prosthetic valve
        • often for 4-6 weeks
  • Operative
    • surgical valve replacement 
      • indications
        • heart failure
        • patients who are refractory to medical therapy
        • abscess formation
Complications
  • Cardiac complications
    • perivalvular abscess
    • arrhythmias
    • heart failure
  • Splenic abscesses
  • Renal infarction due to septic emboli
  • Neurologic complications
    • stroke from septic emboli 
 

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Questions (10)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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(M2.CV.4691) A 43-year-old man with a history of hepatitis C and current intravenous drug use presents with 5 days of fever, chills, headache, and severe back pain. On physical exam, temperature is 100.6 deg F (38.1 deg C), blood pressure is 109/56 mmHg, pulse is 94/min, and respirations are 18/min. He is thin and diaphoretic with pinpoint pupils, poor dentition, and track marks on his arms and legs. A high-pitched systolic murmur is heard, loudest in the left sternal border and with inspiration. He is admitted to the hospital and started on broad-spectrum antibiotics. One of the blood cultures drawn 12 hours ago returns positive for Staphylococcus aureus. Which of the following is the most appropriate next step to confirm the diagnosis? Review Topic | Tested Concept

QID: 107643
1

Repeat blood cultures now

0%

(0/2)

2

Repeat blood cultures 24 hours after initial cultures were drawn

100%

(2/2)

3

Repeat blood cultures 36 hours after initial cultures were drawn

0%

(0/2)

4

Repeat blood cultures 48 hours after initial cultures were drawn

0%

(0/2)

5

Do not repeat blood cultures

0%

(0/2)

M2 A

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(M2.CV.18) A 37-year-old man with a history of IV drug use presents to the ED with complaints of fevers, chills, and malaise for one week. He admits to recently using IV and intramuscular heroin. Vital signs are as follows: T 40.0 C, HR 120 bpm, BP 110/68 mmHg, RR 14, O2Sat 98%. Examination reveals a new systolic murmur that is loudest at the lower left sternal border. Initial management includes administration of which of the following regimens? Review Topic | Tested Concept

QID: 104903
1

IV Vancomycin

30%

(23/76)

2

IV Vancomycin, IV levofloxacin

1%

(1/76)

3

IV Vancomycin, IV ceftriaxone

42%

(32/76)

4

IV Vancomycin, IV gentamycin, PO rifampin

8%

(6/76)

5

IV Vancomycin, IV ceftriaxone, IV fluconazole

17%

(13/76)

M2 A

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(M2.CV.50) A 63-year-old gentleman with a history of mitral valve prolapse presents to his internist with a 2-week history of fever, night sweats, and general malaise. Three weeks ago, he underwent periodontal surgery for gingival hyperplasia, for which he did not receive antibiotic prophylaxis. He denies a history of drug abuse. His physical exam is notable for a temperature of 39 deg C and a faint pansystolic murmur loudest at the cardiac apex. His nails are shown in Figure A, and painful lesions on his fingers are shown in Figure B. What is the most likely causative organism in this case? Review Topic | Tested Concept

QID: 104935
FIGURES:
1

Staphylococcus aureus

4%

(1/26)

2

Staphylococcus epidermidis

4%

(1/26)

3

Streptococcus viridans

85%

(22/26)

4

Streptococcus pneumoniae

0%

(0/26)

5

Enterococcus faecalis

0%

(0/26)

M2 A

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