When to intubate in GCS?

GCS ≤ 8 requires intubation for airway protection. The patient cannot protect their own airway at this level of consciousness. Motor score is the most prognostically important component.

What is the best initial fluid for sepsis resuscitation?

Lactated Ringer's (LR) is the preferred resuscitation fluid. The SMART trial (2018) showed balanced crystalloids reduced death, new renal failure, and persistent renal dysfunction compared to normal saline.

When to start vasopressors in septic shock?

Start norepinephrine (first-line vasopressor) if MAP remains < 65 mmHg after initial 30 mL/kg crystalloid resuscitation, or earlier if patient is profoundly hypotensive. Do not delay pressors to complete full fluid resuscitation.

Why can serum uric acid be normal during acute gout?

During acute inflammation, IL-6 increases renal urate excretion and redistributes urate from plasma to tissues. Up to 40% of acute gout flares have normal serum uric acid. Joint aspiration with polarized microscopy is needed for definitive diagnosis.

How do you distinguish lupus flare from infection in SLE?

Key clues: CRP is low/normal in flare but elevated in infection. Complement (C3/C4) drops in flare but is normal/elevated in infection. Procalcitonin is elevated in bacterial infection but normal in flare. Anti-dsDNA rises in flare, stable in infection.

What is the difference between DKA and HHS?

DKA features acidosis (pH 600), hyperosmolality (> 320), and minimal ketosis -typically in Type 2 DM. DKA requires insulin drip; HHS requires aggressive fluid resuscitation first.

When to give tPA in acute ischemic stroke?

IV alteplase (tPA) can be given within 4.5 hours of last known well time in eligible patients. CT head must rule out hemorrhage first. For large vessel occlusion, mechanical thrombectomy can be performed up to 24 hours with favorable imaging.

What antibiotics for community-acquired pneumonia?

Inpatient non-ICU: ceftriaxone + azithromycin. ICU: ceftriaxone + azithromycin (add vancomycin if MRSA risk). Outpatient healthy: amoxicillin. Outpatient with comorbidities: augmentin + azithromycin or respiratory fluoroquinolone. Duration: 5 days if clinically stable for 48 hours.

How to interpret iron studies?

Iron deficiency: low ferritin (< 30), high TIBC, low iron, low transferrin saturation (< 20%). Anemia of chronic disease: normal/high ferritin (acute phase reactant), low TIBC, low iron. A ferritin of 50-100 in an inflamed patient may still represent iron deficiency.

What is the correction rate for hyponatremia?

Correct sodium no more than 8 mEq/L in 24 hours to avoid osmotic demyelination syndrome (ODS). For symptomatic severe hyponatremia with seizures, give 3% hypertonic saline 100-150 mL bolus over 10-20 minutes. If overcorrected, use D5W + DDAVP rescue protocol.

When to start antibiotics in meningitis?

Within 30-60 minutes. Do NOT delay antibiotics for LP or CT. Draw blood cultures, start empiric antibiotics (vancomycin + ceftriaxone ± ampicillin if > 50 or immunocompromised), then perform LP when possible. Dexamethasone should be given before or with the first antibiotic dose.

DOACs vs warfarin in antiphospholipid syndrome?

DOACs are contraindicated in APS. The TRAPS trial (2018) showed rivaroxaban was inferior to warfarin with more thrombotic events in triple-positive APS patients. Warfarin with INR target 2-3 is the standard for APS, indefinitely.

How to manage scleroderma renal crisis?

ACE inhibitors (captopril) are life-saving -start immediately and titrate aggressively. Do NOT hold for rising creatinine. Steroids > 15 mg prednisone per day precipitate scleroderma renal crisis. ARBs are NOT a substitute -evidence is only for ACEi.

What are the 4 pillars of heart failure treatment?

Guideline-directed medical therapy (GDMT) for HFrEF: (1) ARNI or ACEi/ARB, (2) beta-blocker (carvedilol, metoprolol succinate, or bisoprolol), (3) MRA (spironolactone or eplerenone), (4) SGLT2 inhibitor (dapagliflozin or empagliflozin). All four should be initiated and titrated to target doses.

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EmergentCardiologyID

Infective Endocarditis

Infection of the endocardial surface (usually valves). Diagnosis requires high clinical suspicion + blood cultures + echo. Delay in treatment = valve destruction, emboli, death. Get cultures before antibiotics -then don't wait.

🔍 Overview

Modified Duke Criteria

Definite IE: 2 major, OR 1 major + 3 minor, OR 5 minor. Possible IE: 1 major + 1 minor, OR 3 minor. Modified Duke, 2000

Major Criteria	Details
1. Positive blood cultures	Typical organisms from 2 separate cultures: Viridans strep, S. bovis, HACEK, S. aureus, or Enterococcus (without primary focus). OR persistently positive cultures (≥ 2 drawn > 12h apart, or 3/3 or majority of ≥ 4 cultures positive).
2. Endocardial involvement	Echo: vegetation, abscess, new prosthetic dehiscence. OR new valvular regurgitation (murmur change).

Minor Criteria
Predisposition: IV drug use, prosthetic valve, prior IE, structural heart disease
Fever ≥ 38°C
Vascular phenomena: septic emboli, mycotic aneurysm, Janeway lesions, conjunctival hemorrhage
Immunologic phenomena: Osler nodes, Roth spots, glomerulonephritis, positive RF
Microbiologic: positive cultures not meeting major criteria, or serologic evidence

Blood Culture Protocol

3 sets of blood cultures from 3 different venipuncture sites before antibiotics. Each set = 1 aerobic + 1 anaerobic bottle. Draw at least 20 mL per set. Space 30–60 min apart if possible (but do NOT delay antibiotics more than 1–2h for critically ill patients).

Organisms

Organism	% of IE	Key Association
S. aureus	~30–40%	Most common overall (especially IVDU and healthcare-associated). Acute, destructive. High embolic risk.
Viridans streptococci	~20–25%	Subacute. Dental procedures. Native valve. More indolent course.
Enterococcus	~10%	GI/GU source. Elderly patients. Requires synergistic therapy (ampicillin + gentamicin or ampicillin + ceftriaxone).
Coagulase-negative staph	~10%	Prosthetic valve IE (especially early < 1 year). S. epidermidis.
HACEK organisms	~3%	Gram-negative, slow-growing. May need prolonged incubation. Treat with ceftriaxone.
Culture-negative	~5–10%	Prior antibiotics (most common reason), Coxiella burnetii (Q fever), Bartonella, Brucella, fungi.

🚨 Management

Empiric Antibiotic Therapy

Setting	Empiric Regimen	Notes
Native valve, acute	Vancomycin (Vancocin) 15–20 mg/kg IV q8–12h + cefepime (Maxipime) 2g IV q8h	Covers MRSA + gram-negatives. Narrow based on cultures. Duration: 4–6 weeks.
Native valve, subacute	Vancomycin (Vancocin) + ceftriaxone (Rocephin) 2g IV q24h	Covers strep + staph. Add gentamicin if Enterococcus suspected. Enterococcal Endocarditis Trial, 2013
Prosthetic valve	Vancomycin (Vancocin) + gentamicin + rifampin (Rifadin) 300 mg PO q8h	Rifampin for biofilm penetration. Triple therapy × 6 weeks minimum. Gentamicin × 2 weeks only.
IVDU (right-sided)	Vancomycin (Vancocin) (covers MRSA -most common in IVDU IE)	Narrow to nafcillin/oxacillin if MSSA. Right-sided (tricuspid) has better prognosis than left-sided. POET, 2019

🔄 Updated Practice: Old teaching: add gentamicin to all endocarditis regimens for synergy. Current practice: gentamicin is no longer routinely recommended for native valve Staph aureus endocarditis, it adds nephrotoxicity without mortality benefit. For Enterococcus faecalis endocarditis, ampicillin + ceftriaxone is preferred over ampicillin + gentamicin (equally effective, less nephrotoxic, Enterococcal Endocarditis Trial, 2013). Gentamicin is still used for prosthetic valve endocarditis and some streptococcal regimens.

Surgical Indications -When to Operate

Early surgery (during initial hospitalization) reduces mortality in these scenarios: [EASE, 2012

Heart failure from severe valvular regurgitation -most common surgical indication
Uncontrolled infection -persistent bacteremia > 5–7 days despite appropriate antibiotics, perivalvular abscess, fistula
Large vegetation (> 10 mm) with embolic events despite antibiotics
Fungal endocarditis -almost always requires surgery
Prosthetic valve endocarditis with dehiscence, abscess, or persistent bacteremia
S. aureus prosthetic valve IE -consider early surgery regardless

📋 On Rounds

Why does S. bovis endocarditis require a colonoscopy?

S. gallolyticus (formerly S. bovis biotype I) bacteremia/endocarditis has a strong association with colorectal malignancy -up to 25–50% of patients have colon polyps or cancer. The mechanism is thought to involve bacterial translocation through disrupted colonic mucosa. Every patient with S. bovis/gallolyticus bacteremia needs a colonoscopy, even if asymptomatic.

When do you get a TEE vs TTE for endocarditis?

TTE first in most patients -sensitivity ~70% for vegetations. If TTE is negative but clinical suspicion remains high → TEE (sensitivity ~95%). Go straight to TEE in: prosthetic valves (TTE limited by acoustic shadowing), suspected perivalvular abscess, S. aureus bacteremia (high-risk, need definitive imaging), poor TTE windows (obese, ventilated). If initial TTE/TEE negative but suspicion persists → repeat in 5–7 days.

When does endocarditis require surgery instead of antibiotics alone?

Four major surgical indications: (1) Heart failure from valvular regurgitation (most common indication), (2) Uncontrolled infection (persistent bacteremia > 7 days despite appropriate abx, perivalvular abscess, mycotic/fungal endocarditis), (3) Large vegetation (> 10 mm on left-sided valve with embolic event, or > 15 mm even without embolism), (4) Prosthetic valve endocarditis with any of the above.

A patient with IVDU has tricuspid valve endocarditis. Does this change your antibiotic approach?

Right-sided endocarditis (TV) in IVDU has better prognosis than left-sided (mortality ~5% vs ~20-30%). If MSSA: nafcillin/oxacillin 2g IV q4h × 4 weeks (can shorten to 2 weeks if: uncomplicated, MSSA, no metastatic infection, vegetation < 2 cm, and clinical improvement). MRSA: vancomycin or daptomycin (daptomycin is an alternative for right-sided MRSA IE, but NOT left-sided -inactivated by surfactant in lungs).

Clinical Examples

📋 Case 1, Native Valve Endocarditis with Embolic Stroke

Patient: 58M with poorly controlled diabetes, presents with 3 weeks of fevers, malaise, and new-onset left arm weakness. Recent dental extraction 4 weeks ago without antibiotic prophylaxis.

Key findings: Temp 38.9°C, HR 105, new aortic regurgitation murmur, Janeway lesions on palms, splinter hemorrhages. Blood cultures 4/4 positive for Streptococcus gallolyticus. TEE: 1.4 cm vegetation on aortic valve with moderate AR. MRI brain: acute embolic infarct R MCA territory.

Management:

IV penicillin G 4 million units q4h + gentamicin 1 mg/kg q8h (synergy) x 4 weeks
Urgent CT surgery consult: large vegetation (>10 mm) + embolic event = surgical indication EASE Trial, 2012
Colonoscopy required: S. gallolyticus (bovis) has strong association with colorectal neoplasia (~60% have polyps or cancer)
Serial blood cultures q48h until clearance; repeat TEE at 1 week

Teaching point: S. gallolyticus endocarditis mandates colonoscopy regardless of GI symptoms. Embolic events with vegetations >10 mm warrant early surgery.

📋 Case 2, Prosthetic Valve Endocarditis with Paravalvular Abscess

Patient: 72F with mechanical aortic valve (replaced 8 months ago), presents with fever x 2 weeks, chills, and new heart failure symptoms. Central line placed 3 weeks ago for chemotherapy.

Key findings: Temp 38.5°C, HR 98, BP 100/55, bilateral crackles, JVD. Blood cultures 4/4 positive for methicillin-resistant Staphylococcus epidermidis. TEE: 8 mm vegetation on prosthetic AV, paravalvular abscess with new dehiscence.

Management:

Vancomycin (trough 15-20) + rifampin 300 mg PO q8h + gentamicin 1 mg/kg IV q8h x 2 weeks, then vanco + rifampin x 6 weeks total
Emergent surgical referral: PVE + paravalvular abscess + heart failure = absolute surgical indication
Heart failure management: diuresis, preload/afterload optimization while awaiting surgery
Rifampin added ONLY after blood cultures negative (induces resistance if started during active bacteremia)

Teaching point: PVE with paravalvular abscess has near-100% surgical indication. Rifampin is essential for biofilm penetration on prosthetic material but must be started after culture clearance.

📋 Case 3, Culture-Negative Endocarditis

Patient: 38F, no significant PMH, presents with 6 weeks of fevers, weight loss, arthralgias, and night sweats. Given azithromycin empirically 2 weeks ago at urgent care.

Key findings: Temp 38.2°C, new MR murmur, Osler nodes on fingertips. Blood cultures 4/4 negative (drawn on antibiotics). TTE: 6 mm vegetation on anterior mitral leaflet. Bartonella henselae IgG titer 1:1024. Patient has 3 cats.

Management:

Culture-negative workup: Bartonella, Coxiella (Q fever), Brucella, HACEK serologies, Tropheryma whipplei PCR
Bartonella IE confirmed: doxycycline 100 mg BID + gentamicin 1 mg/kg q8h x 2 weeks, then doxycycline alone x 6 weeks
Prior antibiotic exposure is the most common cause of culture-negative IE (~50% of cases)
Consider 16S rRNA PCR on excised valve tissue if serologies inconclusive

Teaching point: When cultures are negative, always ask about prior antibiotics. Bartonella is the most common cause of culture-negative IE in immunocompetent patients -- think cat exposure.

📣 Sample Presentation

One-Liner

"Mrs. Thompson is a 44-year-old with IVDU presenting with 2 weeks of fever, chills, and a new systolic murmur at the left sternal border. Blood cultures grew MSSA (4/4 bottles). TTE shows a 1.2 cm vegetation on the tricuspid valve."

Key Points to Cover on Rounds

Organism: MSSA on 4/4 blood cultures, sensitive to oxacillin. Antibiotics: nafcillin 2g IV q4h, day 5 of planned 6-week course. Echo: 1.2 cm TV vegetation, moderate TR, no abscess. No embolic complications -CT chest negative for septic emboli, UA clean. Surveillance cultures at 48h negative. ID following. CT surgery evaluated -no surgical indication yet. Plan: PICC line placed, continue IV abx, daily assessment for embolic events.

Monitoring During Treatment

Parameter	Frequency	Target / Action
Blood cultures	q24-48h until negative	Must document clearance. Persistent bacteremia → evaluate for abscess, source control
Vancomycin trough	Before 4th dose, then 1-2x/week	AUC/MIC-guided dosing preferred. Target AUC 400-600
Gentamicin levels	Peak and trough with first dose	Peak 3-5 mcg/mL (synergy). Trough < 1. Monitor Cr and hearing
Renal function	2-3x/week	Aminoglycosides and vancomycin are nephrotoxic. Adjust doses accordingly
CBC, ESR/CRP	Weekly	Trend WBC and inflammatory markers. Should decline with treatment
Repeat TTE/TEE	At completion of therapy	New baseline. Sooner if clinical deterioration, new murmur, or concern for abscess
Neuro checks	Daily	Embolic stroke in 20-40%. New focal deficit → urgent CT/MRI head
ECG	Daily initially	New PR prolongation → perivalvular abscess. New AV block is an emergency

New conduction abnormality (prolonged PR, new heart block) during IE = abscess until proven otherwise. Get urgent TEE and CT surgery consult.

🧪 Workup

Diagnostic Evaluation -Infective Endocarditis

Blood cultures BEFORE antibiotics. Obtain 3 sets from separate venipuncture sites, separated by at least 30 minutes. This is the single most important diagnostic step.

Test	Findings	Clinical Significance
Blood cultures ×3 ESSENTIAL	Persistent bacteremia (same organism in multiple sets)	Draw from 3 separate sites BEFORE antibiotics. Continuous bacteremia is a major Duke criterion. Identifies organism + susceptibilities.
TTE → TEE	Vegetations, abscess, valve perforation, regurgitation	Start with TTE. If negative but suspicion high → TEE (sensitivity 90-100% vs TTE ~60-75%). TEE mandatory for prosthetic valves.
CBC	Leukocytosis, anemia (chronic disease), thrombocytopenia	Anemia of chronic disease common in subacute IE. Thrombocytopenia suggests severe sepsis or DIC.
BMP	Cr (baseline + immune complex GN), electrolytes	Renal function -immune complex glomerulonephritis, aminoglycoside toxicity monitoring.
ESR / CRP	Elevated	Markers of inflammation. Trend to monitor treatment response.
Rheumatoid factor	Elevated in chronic IE	Minor Duke criterion. Immune complex formation in subacute endocarditis.
Complement levels (C3/C4)	Low	Consumed by immune complex deposition (glomerulonephritis).
Urinalysis	Microscopic hematuria, RBC casts, proteinuria	Immune complex GN or renal septic emboli. Hematuria in up to 50% of IE patients.

Modified Duke Criteria: Definite IE = 2 major, OR 1 major + 3 minor, OR 5 minor criteria. Major: (1) positive blood cultures (typical organism ×2, or persistently positive), (2) endocardial involvement on echo (vegetation, abscess, new dehiscence, new regurgitation).

💊 Medications

Key Medications -Infective Endocarditis

Scenario	Regimen	Duration	Notes
Empiric (native valve)	Vancomycin (AUC 400-600) + Ceftriaxone (Rocephin) 2g IV q24h	Pending cultures	Covers MRSA + streptococci + HACEK. Add gentamicin if considering enterococcal coverage.
MSSA -native valve	Nafcillin or Oxacillin 2g IV q4h	6 weeks	Anti-staphylococcal penicillins are preferred over vancomycin for MSSA (better outcomes). Cefazolin 2g IV q8h if penicillin allergy (non-anaphylactic).
MRSA -native valve	Vancomycin IV, AUC-guided dosing (target AUC 400-600)	6 weeks	Trough-based dosing is outdated. AUC-guided dosing reduces nephrotoxicity. Alternative: daptomycin 8-10 mg/kg IV daily (NOT for left-sided endocarditis with pulmonary involvement -inactivated by surfactant).
Prosthetic valve (empiric)	Vancomycin + Gentamicin 1 mg/kg IV q8h + Rifampin 300 mg PO q8h	≥6 weeks (vanco + rifampin), 2 weeks (gent)	Rifampin penetrates biofilm on prosthetic material. Do NOT start rifampin until blood cultures are negative (resistance develops rapidly).
Viridans streptococci (MIC ≤0.12)	Ceftriaxone 2g IV q24h	4 weeks	Can use 2-week short course with ceftriaxone + gentamicin if uncomplicated native valve. Penicillin G 12-18 million units/day IV continuous is alternative.
Enterococcus	Ampicillin 2g IV q4h + Ceftriaxone 2g IV q12h	6 weeks	Ampicillin + ceftriaxone preferred over ampicillin + gentamicin (avoids nephrotoxicity, similar efficacy). If VRE: linezolid or daptomycin.

Surgical indications: heart failure from valvular dysfunction, uncontrolled infection (persistent bacteremia >5-7 days, abscess, enlarging vegetation), prevention of embolism (vegetation >10 mm with embolic event, >15 mm regardless). Consult CT surgery early.

⚡ Summary

Summary

Modified Duke

2 major, or 1 major + 3 minor, or 5 minor. Major: positive blood cultures (typical organisms), echo vegetation.

Empiric Abx

Vancomycin + ceftriaxone (native valve). Vancomycin + gentamicin + rifampin (prosthetic valve). ID consult always.

Duration

Native valve: 4-6 weeks IV. MSSA TV in IVDU: may shorten to 2 weeks if uncomplicated.

Surgery

HF from valvular dysfunction, uncontrolled infection, large vegetation (> 10mm) with embolism, abscess.

Must Do

Blood cultures × 3 sets from different sites. TTE first → TEE if negative but suspicion high. CT head if neurologic symptoms.

Source

IVDU = tricuspid. Dental = strep viridans. GI/GU = enterococcus. Prosthetic = coag-neg staph early, S. aureus late.

📄 One Pager

Infective Endocarditis -Quick Reference Card

Print this page (Ctrl/Cmd + P) for a condensed reference card. All tabs will print on the same page for a complete topic summary.

INFECTIVE ENDOCARDITIS -AT A GLANCE

📋 Diagnose: See Overview tab for criteria
🧪 Workup: Focused labs + imaging → see Workup tab
⚡ Treat: Evidence-based algorithm → see Management tab
💊 Drugs: Key medications with dosing → see Medications tab
📣 Present: One-liner + key points → see Rounds tab

🧪 Workup

Diagnostic Workup

Blood cultures × 3 sets from separate sites BEFORE antibiotics. 20 mL per set (10 mL aerobic + 10 mL anaerobic). Sensitivity > 90% with 3 sets
CBC: Leukocytosis, anemia (normocytic, chronic disease), thrombocytopenia (if DIC)
BMP: Cr (renal emboli, drug-induced nephritis), electrolytes
ESR/CRP: Elevated in > 90%. Useful for monitoring treatment response
Urinalysis: Microscopic hematuria (renal emboli, immune complex GN) in 25-50%
RF (rheumatoid factor): Positive in ~50% of subacute IE
Procalcitonin: Supports bacterial etiology if elevated

Imaging

TTE first -sensitivity ~75% for native valves. Adequate if high quality and clinical picture clear
TEE if: TTE negative but high suspicion, prosthetic valve, poor TTE windows, suspected abscess/fistula. Sensitivity ~95%
CT chest/abdomen/pelvis: If concern for septic emboli (splenic infarct, renal infarct, mycotic aneurysm)
Brain MRI: If neurologic symptoms. Mycotic aneurysms, septic emboli, meningitis
PET/CT: Consider for prosthetic valve IE or cardiac implantable device infection when echo is equivocal

Modified Duke Criteria: 2 major, or 1 major + 3 minor, or 5 minor = definite IE. Major = positive blood cultures (typical organism × 2 OR persistently positive) + endocardial involvement on echo (vegetation, abscess, new dehiscence, new regurgitation).

💊 Medications

Antibiotic Therapy

Organism	Native Valve	Prosthetic Valve	Duration
Empiric (acute)	Vancomycin + cefepime (or gentamicin)	Vancomycin + cefepime + rifampin	Until cultures return
MSSA	Nafcillin/oxacillin 2g IV q4h	Nafcillin + rifampin 300mg PO q8h + gentamicin × 2 weeks	NV: 6 weeks. PV: ≥ 6 weeks
MRSA	Vancomycin 15-20 mg/kg IV q8-12h (trough 15-20) OR daptomycin 8-10 mg/kg IV daily	Vancomycin + rifampin + gentamicin × 2 weeks	6 weeks
Viridans Strep (MIC ≤ 0.12)	Ceftriaxone 2g IV daily OR penicillin G 12-18 MU/day	Same + gentamicin × 2 weeks	NV: 4 weeks. PV: 6 weeks
Enterococcus	Ampicillin 2g IV q4h + ceftriaxone 2g IV q12h (preferred for E. faecalis)	Ampicillin + ceftriaxone 6 weeks	6 weeks
HACEK	Ceftriaxone 2g IV daily	Ceftriaxone 2g IV daily	NV: 4 weeks. PV: 6 weeks
Culture-negative	Vancomycin + cefepime. ID consult for serologies (Bartonella, Coxiella, Brucella)	Same + rifampin	6 weeks

Key principles: Bactericidal agents only (not bacteriostatic). IV therapy for entire course. Aminoglycoside synergy duration varies. Monitor vanco troughs, gentamicin levels, renal function. ID consult for all IE.

⚡ Summary

Blood Cultures

3 sets from separate sites BEFORE antibiotics. Repeat q24-48h until clearance documented.

Duke Criteria

2 major OR 1 major + 3 minor OR 5 minor = definite IE. Blood cultures + echo findings are major criteria.

Echo

TTE first (sensitivity 75%). TEE if: prosthetic valve, negative TTE + high suspicion, or suspected abscess (sensitivity 95%).

Treatment Duration

Native valve: 4-6 weeks IV. Prosthetic valve: ≥ 6 weeks. Bactericidal agents only. ID consult for all.

Surgical Indications

Heart failure from valve dysfunction, uncontrolled infection/abscess, large vegetation (> 10mm) with embolic events, prosthetic valve dehiscence.

Complications

Embolic stroke (20-40%), mycotic aneurysm, splenic abscess, renal infarct, new heart block = abscess.

📄 One Pager

Cardiology / ID · One Pager

Infective Endocarditis

Blood cultures × 3 → empiric abx → echo → ID consult → 4-6 weeks IV. Surgery if HF, uncontrolled infection, or large vegetation.

🧪 Modified Duke Criteria

2 major = definite IE
1 major + 3 minor = definite IE
Major: typical organism on ≥ 2 cultures; vegetation/abscess on echo
Minor: predisposing condition, fever, vascular/immunologic phenomena, positive cultures not meeting major

🚨 Management

Blood cultures × 3 from different sites BEFORE antibiotics
Empiric: vancomycin + ceftriaxone (native valve)
Prosthetic valve: vancomycin + gentamicin + rifampin
TTE first → TEE if negative but high suspicion
ID consult always. Duration: 4-6 weeks IV

🔪 Surgical Indications

Heart failure from valvular dysfunction (most common indication)
Uncontrolled infection (persistent bacteremia > 7 days, abscess)
Large vegetation > 10mm with embolism EASE, 2012
Prosthetic valve IE with any of the above
Fungal endocarditis (almost always requires surgery)

💊 Key Drugs

Vancomycin15-20 mg/kg q8-12h

Ceftriaxone2g IV q12h

Nafcillin2g IV q4h (MSSA)

Gentamicin1 mg/kg q8h (PVE)

⚠️ Pitfalls

Antibiotics before blood cultures
Missing perivalvular abscess (need TEE)
Not consulting surgery early enough
Not checking for embolic complications (CT head, spleen)