Updated: 2/25/2018

Endocarditis

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Snapshot
  • A 50-year-old man presents to the emergency room for a fever that has persisted for several days. He denies any history of intravenous drug use or any congenital heart disease. Physical exam reveals nailbed splinter hemorrhages, Osler nodes on his fingers, and Janeway lesions on his palms and soles. Heart auscultation reveals a new murmur. An echocardiogram shows vegetations on the mitral valve, and blood cultures that were drawn 12 hours apart were positive for Streptococcus bovis. Antibiotic therapy is started and he is scheduled for a colonoscopy. 
Introduction
  • Clinical definition
    • inflammation of the heart valve, typically secondary to infection
  • Epidemiology
    • location
      • mitral valve > tricuspid valve
      • tricuspid valve disease is associated with intravenous (IV) drug use
        • Staphylococcus aureus, Pseudomonas, Candida
    • risk factors
      • rheumatic heart disease
      • IV drug use
      • immunosuppression
      • prosthetic heart valve
      • congenital heart disease
  • Etiology
    • acute endocarditis
      • Streptococcus pneumoniae
      • Streptococcus pyogenes
      • Neisseria gonorrhea
      • Staphylococcus aureus
        • IV drug users
        • large vegetations seen on valves
    • subacute bacterial endocarditis is characterized by slower onset and less severe symptoms
      • Streptococcus bovis (gallolyticus) 
        • in the setting of colon cancer
      • Enterococcus
        • in the setting of gastrointestinal/genitourinary procedures
      • Streptococcus viridans
        • often a complication of dental procedures
          • 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
      • marantic endocarditis
        • from metastatic cancer seeding to the valves
        • very poor prognosis
  • 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
    • 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
  • Labs 
    • positive blood cultures 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
    • complete blood count
      • anemia
    • serum creatinine
      • to evaluate renal function (glomerulonephritis)
  • Making the diagnosis
    • based on clinical presentation and Duke criteria 
      • pathologic criteria
        • culture of organism
        • histologic evidence of endocarditis from vegetation or intracardiac abscess
      • clinical criteria: 1 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 1 of the causes of Culture-Negative Endocardidtis (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, or 3 out of 4 blood cultures that are positive, with first and last samples drawn 1 hour apart
  • Abnormal echocardiogram with vegetation, abscess ,or partial dehiscence of prosthetic valve
  • Fever
  • Presence of risk factors, including intravenous drug use, structural heart disease, prosthetic heart valve, dental 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 the presence of prosthetic material in the heart
    • all antibiotics should be given intravenously
  • Medical
    • vancomycin plus ceftriaxone or gentamicin
      • indications
        • for patients with no prosthetic valve
        • empiric antibiotic therapy
    • vancomycin plus gentamicin and rifampin
      • indications
        • for patients with prosthetic valve
        • empiric antibiotic therapy
  • Operative
    • surgical valve replacement
      • indications
        • heart failure
        • patients who are refractory to medical therapy
        • abscess formation
        • conduction disturbance
Complications
  • Cardiac complications
    • perivalvular abscess
    • arrhythmias
    • heart failure
  • Neurologic complications
    • stroke
 

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Questions (6)
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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(M1.CV.45) A 32-year-old African American woman presents to her family physician complaining of fevers, fatigue, weight loss, joint pains, night sweats and a rash on her face that extends over the bridge of her nose. She has also had multiple sores in her mouth over the past few weeks. She recently had a root canal procedure done without complications. She has no significant past medical history, but has recently had a urinary tract infection. She denies tobacco, alcohol, and illicit drug use. Laboratory evaluation reveals hemolytic anemia. If she were found to have a cardiac lesion, what would be the most likely pathogenetic cause? Review Topic

QID: 100561
1

Bacteremia secondary to a recent dental procedure

0%

(0/3)

2

Abberent flow causing platelet-fibrin thrombus formation secondary to hypercoagulability and malignancy.

0%

(0/3)

3

Bacteremia secondary to a urinary tract infection

0%

(0/3)

4

Immune complex deposition and subsequent inflammation

67%

(2/3)

5

Left atrial mass causing a ball valve-type outflow obstruction

0%

(0/3)

M1

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PREFERRED RESPONSE 4

(M1.CV.44) A 58-year-old man presents to the doctor with recurring fevers, night sweats and malaise. On exam he is found to have a holosystolic murmur heard loudest over the apex. His dermatologic exam is notable for painless skin lesions shown in Figure 1. Which of the following heart conditions most likely predisposed him to his current condition? Review Topic

QID: 100560
FIGURES:
1

Bicuspid aortic valve

18%

(2/11)

2

Aortic stenosis

0%

(0/11)

3

Mitral stenosis

0%

(0/11)

4

Mitral valve prolapse

45%

(5/11)

5

Rheumatic heart disease

36%

(4/11)

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(M1.CV.125) A 35-year-old woman with a medical history significant for asthma, hypertension, and occasional IV drug use comes to the emergency department with fever. On physical exam, there are findings depicted in figure A, for which the patient cannot account. What test will be most helpful to establish the diagnosis? Review Topic

QID: 100641
FIGURES:
1

Echocardiography

67%

(4/6)

2

Chest X-ray

0%

(0/6)

3

Pulmonary function tests

0%

(0/6)

4

Electrocardiogram (EKG)

17%

(1/6)

5

CT pulmonary angiography

0%

(0/6)

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(M1.CV.134) A 25-year-old man presents to the emergency room with shortness of breath. He has no past medical history and takes no medications. On physical exam, vital signs are temperature 38.1° C, heart rate 110/min, blood pressure 118/76 mm Hg, respiratory rate 22/min, and oxygen saturation 98% on room air. He appears malnourished and has poor dentition. Physical exam also reveals the markings along the cubital fossa as shown in Figure A and a low frequency pansystolic murmur best heard on the lower left sternal border. The murmur increases with inspiration and decreases with expiration and Valsalva maneuver. The patient is treated for his illness but later presents with hematuria, hypertension, and an elevated creatinine. What is the most likely cause of this patient's subsequent renal disease? Review Topic

QID: 100650
FIGURES:
1

Dilation and blunting of the renal calyces with cortical thinning

4%

(4/94)

2

Immune complex deposition

38%

(36/94)

3

Vascular damage to renal vessels secondary to benign nephrosclerosis

16%

(15/94)

4

Hereditary nephritis caused by a mutation in glomerular basement membrane

4%

(4/94)

5

Renal papillary necrosis secondary to infarctions of the medulla

29%

(27/94)

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