What is the optimal, systematic format for presenting an infective endocarditis case, including patient demographics, risk factors, history of present illness, physical examination findings, laboratory and imaging results, microbiology, diagnostic criteria, treatment plan, monitoring, and surgical indications?

Systematic Format for Presenting an Infective Endocarditis Case

Present IE cases using a structured, algorithmic approach that prioritizes diagnostic criteria, risk stratification, and early identification of surgical indications to guide multidisciplinary team decision-making. 1, 2

Patient Demographics and Risk Factors

Begin with age, sex, and specific predisposing conditions that increase IE risk 1:

• Cardiac risk factors: Prosthetic valves, previous IE, congenital heart disease, valvular disease, intracardiac devices (pacemakers, defibrillators) 1
• Non-cardiac risk factors: Injection drug use, immunocompromised state (HIV, chemotherapy), chronic hemodialysis, recent invasive procedures with bacteremia 1, 3
• Healthcare-associated factors: Recent hospitalization, indwelling venous catheters, recent dental or surgical procedures 1

History of Present Illness

Document the clinical presentation systematically 1:

• Fever characteristics: Present in up to 90% of cases; may be absent in elderly, immunocompromised, or after antibiotic pre-treatment 1
• Constitutional symptoms: Chills, poor appetite, weight loss, night sweats 1, 4
• Cardiac symptoms: New or changing heart murmur, signs of heart failure (dyspnea, orthopnea, peripheral edema) 1
• Embolic phenomena: Stroke, transient ischemic attack, focal neurological deficits, limb ischemia, splenic/renal infarcts 1
• Duration and progression: Acute (days to weeks with virulent organisms like S. aureus) versus subacute (weeks to months with less virulent organisms) 1, 3

Physical Examination Findings

Document specific findings organized by system 1:

• Cardiac: New regurgitant murmur (present in majority), signs of heart failure (rales, elevated JVP, S3 gallop) 1
• Vascular phenomena: Janeway lesions (painless hemorrhagic macules on palms/soles), splinter hemorrhages, conjunctival hemorrhages 1
• Immunologic phenomena: Osler's nodes (painful nodules on finger/toe pads), Roth spots (retinal hemorrhages with pale centers), glomerulonephritis 1
• Neurological: Focal deficits suggesting stroke, altered mental status, meningismus 1
• Splenomegaly: May be present in subacute cases 1

Laboratory Results

Present microbiological and laboratory data systematically 1:

Blood Cultures

• Timing and technique: Three separate blood culture sets from different venipuncture sites before antibiotics 2
• Organism identification: Specify organism (S. aureus, viridans streptococci, enterococci, coagulase-negative staphylococci, HACEK organisms) 1, 4
• Culture-negative IE: Occurs in 2.5-31% of cases, most commonly from prior antibiotic use 1

Additional Microbiological Testing for Culture-Negative Cases

• Serological testing: Coxiella burnetii (IgG phase I >1:800), Bartonella, Brucella, Legionella 1
• PCR and immunohistology: From surgical specimens or embolic material 1

Other Laboratory Tests

• Inflammatory markers: Elevated ESR, CRP 1
• Complete blood count: Anemia, leukocytosis 1
• Renal function: Creatinine elevation suggesting immune complex glomerulonephritis or septic emboli 1
• Urinalysis: Hematuria, proteinuria 1
• Rheumatoid factor: May be positive 1

Imaging Results

Echocardiography (Cornerstone of Diagnosis)

Transthoracic Echocardiography (TTE) 1, 2:

• First-line imaging modality in all suspected IE cases 1, 2
• Document presence/absence of vegetations, location, size, mobility 1
• Assess valve function and degree of regurgitation 1
• Identify complications: abscess, pseudoaneurysm, fistula, valve perforation 1

Transesophageal Echocardiography (TOE) 1, 2:

• Mandatory when TTE is negative but clinical suspicion remains high 1, 2
• Required for all prosthetic valve cases and intracardiac device cases 2
• Sensitivity >85% for detecting vegetations and perivalvular complications 2
• Repeat TOE within 7-10 days if initially negative with high clinical suspicion 1

Additional Imaging for Complications

• Cerebral CT/MRI: Identify silent embolic events (occur in 35-60% of patients), hemorrhage, abscess, mycotic aneurysms 1, 2
• Abdominal CT: Detect splenic, renal, or hepatic emboli/abscesses 2
• Whole-body CT: Systematic screening for silent embolic events in 20-50% of patients 2
• 18F-FDG PET/CT or radiolabeled leukocyte SPECT/CT: For prosthetic valve endocarditis (>3 months post-implantation) to detect abnormal activity around prosthesis 1

Diagnostic Criteria Application

Apply Modified Duke Criteria systematically 1:

Major Criteria

1. Positive blood cultures:

   • Typical organisms (viridans streptococci, S. bovis, HACEK, S. aureus, community-acquired enterococci) from two separate cultures 1
   • Persistently positive cultures (≥2 positive cultures drawn ≥12 hours apart, or all of 3, or majority of ≥4 cultures with first and last ≥1 hour apart) 1
   • Single positive culture for Coxiella burnetii or phase I IgG >1:800 1

2. Imaging positive for IE:

   • Echocardiography: vegetation, abscess, pseudoaneurysm, valve perforation, new prosthetic valve dehiscence 1
   • Abnormal FDG-PET/CT or leukocyte SPECT/CT activity around prosthetic valve (>3 months post-implant) 1

Minor Criteria

• Predisposition (heart condition, injection drug use) 1
• Fever ≥38°C 1
• Vascular phenomena (emboli, pulmonary infarcts, mycotic aneurysm, hemorrhages, Janeway lesions) 1
• Immunologic phenomena (glomerulonephritis, Osler's nodes, Roth spots, rheumatoid factor) 1
• Microbiological evidence not meeting major criteria 1

Definite IE: 2 major criteria, OR 1 major + 3 minor criteria, OR 5 minor criteria 1

Risk Stratification and Prognostic Assessment

Identify high-risk features requiring urgent referral to reference center 1, 2:

Highest Risk Factors (79% mortality/surgery risk when all three present) 1:

• Heart failure 1, 5
• Periannular complications (abscess, pseudoaneurysm, fistula) 1, 5
• S. aureus infection 1

Additional Poor Prognostic Factors 1:

• High degree of comorbidity, diabetes 1
• Septic shock 1
• Moderate-to-severe ischemic stroke 1
• Brain hemorrhage 1
• Need for hemodialysis 1

Treatment Plan

Antimicrobial Therapy

Initiate empiric therapy immediately after blood cultures in unstable patients 1, 2:

• Native valve, community-acquired: Cover S. aureus, streptococci, enterococci 5
• Prosthetic valve or healthcare-associated: Cover methicillin-resistant staphylococci, enterococci, non-HACEK gram-negative pathogens 5

Targeted therapy based on organism 5:

• MSSA left-sided native valve: Nafcillin or oxacillin for 6 weeks (uncomplicated) or ≥6 weeks (complicated with abscess or metastatic complications) 5
• MRSA: Vancomycin 5

Temperature should normalize within 7-10 days; persistent fever requires investigation 2:

• Replace IV lines 2
• Repeat blood cultures 2
• Repeat echocardiography 2

Surgical Indications

Emergency surgery (within 24 hours) 5, 2:

• Severe acute aortic or mitral regurgitation with refractory pulmonary edema or cardiogenic shock 5, 2

Urgent surgery (within days) 5, 2:

• Severe regurgitation or obstruction causing symptomatic heart failure or poor hemodynamic tolerance on echocardiography 5, 2
• Locally uncontrolled infection: abscess, false aneurysm, fistula, enlarging vegetation 5, 2

Timing with neurological complications 1:

• After silent embolism or TIA: surgery without delay if indicated 1
• After stroke without coma or hemorrhage: surgery without delay if indicated for heart failure, uncontrolled infection, abscess, or persistent embolic risk 1
• After intracranial hemorrhage: postpone surgery ≥1 month 1

Monitoring Strategy

Inpatient Phase (First 2 Weeks - Critical Phase) 2:

• Daily clinical assessment for heart failure, embolic events, neurological complications 5, 2
• Serial echocardiography to monitor vegetation size and valve function 5
• Weekly blood cultures until sterile 2

Outpatient Parenteral Antibiotic Therapy (OPAT) 5, 2:

• Consider after week 2 if: Medically stable, no heart failure, no concerning echocardiographic features, no neurological signs, no renal impairment 5, 2
• Contraindications: Heart failure, concerning echo features, neurological complications, renal impairment 5

Structured Follow-Up 2:

• Visits at 1,3,6, and 12 months post-discharge (majority of events occur during this period) 2
• Clinical assessment at each visit 2
• Repeat echocardiography 2
• Monitor for relapse or complications 2

Multidisciplinary Team Involvement

All IE patients must be managed by an "Endocarditis Team" 1, 2:

Team Composition 1:

• Infectious disease specialists 1, 2
• Microbiologists 1, 2
• Cardiologists 1, 2
• Cardiac surgeons 1, 2
• Imaging specialists 1
• Specialists in valve disease, congenital heart disease, pacemaker extraction (when available) 1
• Neurologists and neurosurgery/interventional neuroradiology (for neurological complications) 1

Reference Center Criteria 1:

• Immediate access to TTE, TOE, CT, MRI, nuclear imaging 1
• On-site cardiac surgery capability 1
• Regular team meetings to discuss cases, surgical decisions, and follow-up plans 1

Complicated IE requires immediate referral to reference center: Heart failure, perivalvular abscess, embolic complications, neurological complications, congenital heart disease 1, 2