Modified Duke Criteria
Definite IE requires 2 major criteria, 1 major + 3 minor, or 5 minor criteria; bacteremia on 2 separate blood cultures + vegetation on Echo.
Endocarditis Etiologies
Native valve: Staph aureus (IVDU, tricuspid) vs. Viridans strep (dental). Prosthetic valve: Staph epidermidis (< 1 yr) vs. Viridans (> 1 yr).
Meningitis LP Profile
Opening pressure > 200 mm H2O, PMNs > 80%, Protein > 100 mg/dL, Glucose < 40 mg/dL (CSF/serum glucose ratio < 0.4).
Dexamethasone Rule
Administer IV Dexamethasone prior to or concurrent with first antibiotic dose in suspected Strep pneumoniae meningitis to prevent sensorineural hearing loss.
Modified Duke Criteria & Physical Exam Stigmata
Infective endocarditis (IE) diagnosis utilizes the clinical Modified Duke criteria:
Major Criteria
- Positive Blood Cultures: Typical microorganism in 2 separate cultures, or persistently positive cultures > 12 hours apart.
- Endocardial Involvement: Transesophageal Echocardiogram (TEE) showing oscillating intracardiac mass/vegetation, abscess, or new valvular regurgitation.
Minor Criteria
- Predisposing heart condition or IV drug use
- Fever ≥ 38.0°C (100.4°F)
- Vascular Phenomena: Septic emboli, Janeway lesions (painless erythematous macules on palms/soles), splinter hemorrhages
- Immunologic Phenomena: Osler nodes (painful nodules on pads of fingers/toes), Roth spots (retinal hemorrhages with pale centers), Glomerulonephritis, positive RF
Cerebrospinal Fluid (CSF) Analysis Master Grid
| Etiology | Opening Pressure | WBC Count & Predominance | Glucose (CSF:Serum) | Protein |
|---|---|---|---|---|
| Bacterial | Elevated (> 200-300 mm H2O) | Markedly elevated (> 1,000 / μL); > 80% PMNs | Markedly decreased (< 40 mg/dL, ratio < 0.4) | Markedly elevated (> 100-500 mg/dL) |
| Viral (Aseptic) | Normal to slightly elevated | Mildly elevated (10-500 / μL); Lymphocytic | Normal (> 60 mg/dL, ratio > 0.6) | Normal to mildly elevated (< 100 mg/dL) |
| Fungal / TB | Markedly elevated (> 250 mm H2O) | Elevated (100-500 / μL); Lymphocytic | Decreased (< 40 mg/dL) | Markedly elevated (> 100-500 mg/dL) |
| Guillain-Barré | Normal | Normal (< 5 / μL); Albuminocytologic dissociation | Normal | Markedly elevated (> 100 mg/dL) |
OMM Board Correlate: Meningeal Tensions & Cranial OCF
- Dural Reciprocal Tension Membrane (RTM): In recovering meningitis, persistent nuchal rigidity represents dura mater irritation. The dura firmly attaches to the foramen magnum, C2, C3, and S2. Sacral rocking and suboccipital release alleviate longitudinal dural tension.
- Contraindication in Acute Infection: OMT should never delay antibiotics. HVLA is contraindicated during acute meningitis.
- Cardiac Autonomics: T1-T5 thoracic spine and sympathetic chain. Normalize somatic dysfunctions to optimize cardiac chronotropic and inotropic reserve.
Board Traps & Common Distractors
- Never delay empiric antibiotics for meningitis to perform an LP or head CT; if a head CT is required prior to LP (focal deficits, papilledema, immunocompromise, seizure), immediately draw blood cultures and start IV Vancomycin + Ceftriaxone + Ampicillin (+ Dexamethasone) first.
- In patients with native valve endocarditis presenting with sudden-onset neurological deficits, avoid therapeutic anticoagulation (heparin/warfarin); anticoagulation increases the risk of fatal intracranial hemorrhage from mycotic aneurysm rupture.
- Patients with Staph aureus bacteremia must ALWAYS undergo echocardiography (TEE preferred) to evaluate for infective endocarditis, even if murmurs or physical signs are absent.