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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EMERGENTID

Meningitis & Encephalitis

Bacterial meningitis has ~20% mortality even with treatment and doubles with every hour of antibiotic delay. Empiric antibiotics BEFORE LP if there will be ANY delay. Dexamethasone before or with first antibiotic dose.

🔍 Overview

CSF Patterns

Parameter	Bacterial	Viral	TB / Fungal
Opening pressure	↑↑ (> 25 cmH₂O)	Normal or mildly ↑	↑
WBC	> 1000 (PMN predominant)	10–500 (lymphocyte predominant)	10–500 (lymphocyte predominant)
Glucose	< 40 (or CSF/serum ratio < 0.4)	Normal	↓↓ (often < 20 in TB)
Protein	> 250 mg/dL	50–100	↑↑ (100–500)
Gram stain	Positive in ~60–90%	Negative	AFB smear low sensitivity (~20% in TB)

Organisms by Age

Age Group	Common Organisms	Empiric Coverage
Neonates (< 1 mo)	Group B strep, E. coli, Listeria	Ampicillin + cefotaxime (or gentamicin)
Children (1 mo–18 yr)	N. meningitidis, S. pneumoniae, H. influenzae	Vancomycin + ceftriaxone
Adults (18–50)	S. pneumoniae (#1), N. meningitidis	Vancomycin + ceftriaxone
Adults > 50, immunocompromised, alcoholics	S. pneumoniae, Listeria, N. meningitidis, gram-negatives	Vancomycin + ceftriaxone + ampicillin (Listeria coverage)

Add ampicillin for Listeria coverage if: age > 50, immunocompromised, alcoholics, pregnancy, chronic steroids. Listeria is NOT covered by cephalosporins.

When to Get CT Before LP

CT before LP ONLY if: immunocompromised, history of CNS disease, new-onset seizure, papilledema, altered consciousness, focal neurologic deficit
If CT needed → give antibiotics BEFORE CT AND LP. Do NOT delay antibiotics for imaging.
If none of these features → LP first, no CT needed

🚨 Management

Empiric Treatment

Antibiotics within 30–60 minutes. Every hour of delay increases mortality. Do NOT wait for LP results.

Drug	Dose	Role
Vancomycin (Vancocin)	15–20 mg/kg IV q8–12h	Covers penicillin-resistant S. pneumoniae (up to 30% resistance in some regions)
Ceftriaxone (Rocephin)	2g IV q12h	Covers S. pneumoniae, N. meningitidis, H. influenzae, gram-negatives. Meningitis dose = 2g q12h (not standard 1–2g daily).
Ampicillin (Principen)	2g IV q4h	Listeria coverage. Add if age > 50, immunocompromised, alcoholism, pregnancy.
Dexamethasone (Decadron) GIVE WITH FIRST ANTIBIOTIC	0.15 mg/kg IV q6h × 4 days	European Dexamethasone Meningitis Trial, 2002: reduced mortality and hearing loss in S. pneumoniae meningitis. Give before or with first antibiotic dose. Discontinue if NOT S. pneumoniae (no benefit for other organisms). Do NOT give if already received antibiotics -benefit lost.
Acyclovir (Zovirax)	10 mg/kg IV q8h	Add if encephalitis suspected (AMS, seizures, temporal lobe findings, behavioral changes). Covers HSV encephalitis -mortality ~70% without treatment, ~20% with acyclovir.

Chemoprophylaxis -Close Contacts

N. meningitidis confirmed: close contacts (household, kissing, shared utensils, healthcare workers with unprotected airway exposure) need prophylaxis
Rifampin 600 mg PO BID × 2 days, OR ciprofloxacin 500 mg PO × 1 dose (preferred -single dose), OR ceftriaxone 250 mg IM × 1
Not needed for S. pneumoniae

Swipe for more examples

📋 Case 1, Bacterial Meningitis Empiric Therapy

Patient: 22M, worst headache of life, fever 39.4°C, nuchal rigidity, photophobia, petechial rash on trunk/extremities.

Do NOT delay antibiotics for LP or CT:

Blood cultures × 2 → antibiotics IMMEDIATELY → then CT (if indicated) → then LP.
Antibiotics within 1 hour. Every hour of delay worsens mortality.

Empiric therapy (age 18–50):

Ceftriaxone (Rocephin) 2g IV q12h (covers N. meningitidis, S. pneumoniae, H. influenzae)
+ Vancomycin (Vancocin) 15–20mg/kg IV q8–12h (covers resistant S. pneumoniae -MIC > 0.1)
+ Dexamethasone (Decadron) 0.15 mg/kg IV q6h × 4 days -give BEFORE or WITH first antibiotic dose (reduces mortality in pneumococcal meningitis -Cochrane 2015). No benefit if given after antibiotics.

If age > 50 or immunocompromised: Add ampicillin (Amoxil) 2g IV q4h for Listeria coverage.

Petechial rash → highly suspicious for N. meningitidis → droplet isolation (not airborne). Chemoprophylaxis for close contacts: ciprofloxacin (Cipro) 500mg PO × 1 dose or rifampin (Rifadin) 600mg PO BID × 2 days.

CSF expected: WBC > 1000 (PMN predominant), protein > 250, glucose < 40, Gram stain + in ~60%.

📋 Case 2, HSV Encephalitis

Patient: 34F presents with 3 days of fever, headache, bizarre behavior, and new-onset seizures.

Imaging: CT head: temporal lobe hypodensity. MRI shows temporal lobe involvement (more sensitive than CT).

LP: Lymphocytic pleocytosis (WBC 120, 95% lymphs), elevated protein, normal glucose, RBCs present.

Diagnosis: HSV encephalitis until proven otherwise.

Treatment:

IV acyclovir 10 mg/kg q8h, START IMMEDIATELY, do not wait for PCR results.
HSV PCR is the confirmatory test (sensitivity 98%) but takes 24-48h.
Every hour of delay in acyclovir increases mortality and neurological damage.
Duration: 14-21 days IV acyclovir.

If PCR negative but high clinical suspicion: Repeat PCR at 3-5 days (can be false negative early).

Key lesson: Temporal lobe findings + fever + behavioral changes + seizures = acyclovir NOW. Treat first, confirm later. HSV encephalitis is fatal without treatment.

📋 Case 3, Meningitis in Immunocompromised Patient

Patient: 45M with HIV (CD4 count 65), presents with 2 weeks of progressive headache, low-grade fever, and neck stiffness. Subacute presentation suggests opportunistic infection, NOT typical bacterial meningitis.

LP: Opening pressure 32 cmH₂O (elevated), WBC 25 (lymphocytic), protein 80, glucose 30 (low). India ink: positive for encapsulated yeast. Cryptococcal antigen (CrAg): positive (titer 1:1024).

Diagnosis: Cryptococcal meningitis.

Treatment:

Induction: Amphotericin B liposomal 3-4 mg/kg/day + flucytosine 25 mg/kg QID × 2 weeks.
Serial LPs to manage elevated ICP (drain if OP >25, this is the #1 cause of death).
Consolidation: Fluconazole 400mg daily × 8 weeks.
Maintenance: Fluconazole 200mg daily until CD4 >200 × 6 months on ART.

Do NOT start ART immediately, wait 4-6 weeks (early ART causes IRIS → fatal cerebral edema).

Key lesson: Subacute meningitis + HIV + low CD4 = think crypto. Check CrAg. Serial LPs to manage pressure are lifesaving. Delay ART to avoid IRIS.

🔄 Updated Practice: Old teaching: dexamethasone is controversial in bacterial meningitis. Current evidence: dexamethasone (0.15 mg/kg IV q6h × 4 days) BEFORE or WITH the first antibiotic dose reduces mortality and hearing loss in PNEUMOCOCCAL meningitis (European Dexamethasone Meningitis Trial, 2002). Key: it must be given before or simultaneously with antibiotics -no benefit if given after. No proven benefit in meningococcal or gram-negative meningitis, but most centers give it empirically since you don't know the organism yet.

💊 Medications

Empiric Antibiotic Therapy -Bacterial Meningitis

Do NOT delay antibiotics. Give empiric therapy immediately after (or ideally with) blood cultures. Every hour of delay increases mortality. LP can follow antibiotics -CSF cultures remain positive for hours.

Drug	Dose	Indication	Key Notes
Ceftriaxone	2g IV q12h	Empiric coverage -S. pneumoniae, N. meningitidis, H. influenzae, GNRs	Higher dose than standard (meningeal dosing) -needed for adequate CSF penetration across BBB.
Vancomycin	15-20 mg/kg IV q8-12h	Empiric -covers penicillin-resistant S. pneumoniae (up to 30% resistance in some areas)	Target AUC/MIC 400-600 (AUC-guided dosing per 2020 ASHP/IDSA guidelines). Load with 25-30 mg/kg if severe.
Dexamethasone	0.15 mg/kg IV q6h × 4 days	Give BEFORE or WITH first antibiotic dose -reduces inflammation from bacterial lysis	Proven mortality benefit in pneumococcal meningitis de Gans, 2002. Discontinue if non-pneumococcal etiology confirmed. Must give before/with antibiotics -no benefit if given after.
Ampicillin	2g IV q4h	Add if age > 50, immunocompromised, pregnant, or alcoholic -covers Listeria monocytogenes	Listeria is intrinsically resistant to cephalosporins. Must add ampicillin for Listeria coverage in at-risk patients.
Acyclovir	10 mg/kg IV q8h	Add if HSV encephalitis suspected (temporal lobe findings, behavioral changes, seizures)	Adjust for renal function. Duration 14-21 days for HSV encephalitis. Maintain adequate hydration to prevent crystalluria.

Standard empiric regimen: Ceftriaxone + vancomycin + dexamethasone for all adults. ADD ampicillin if age > 50 or immunocompromised. ADD acyclovir if HSV suspected. Narrow based on culture and susceptibility results.

📋 On Rounds

Why give dexamethasone before antibiotics in bacterial meningitis?

When antibiotics lyse bacteria, cell wall fragments (lipoteichoic acid, peptidoglycan) are released → massive inflammatory cascade in the subarachnoid space → cerebral edema, increased ICP, neuronal damage. Dexamethasone dampens this inflammatory burst. European Dexamethasone Meningitis Trial, 2002: dex given before/with the first antibiotic dose in S. pneumoniae meningitis reduced mortality from 15% to 7% and hearing loss significantly.

Why is the ceftriaxone dose 2g q12h for meningitis instead of the usual 1–2g daily?

The blood-brain barrier limits antibiotic penetration into the CSF. Even with meningeal inflammation (which increases permeability), only a fraction of serum drug levels reach the CSF. To achieve adequate bactericidal concentrations in the CSF, you need higher and more frequent dosing than for systemic infections. Ceftriaxone 2g q12h achieves CSF levels that reliably exceed the MIC for S. pneumoniae and N. meningitidis.

When do you need a CT head before LP, and what happens if it delays treatment?

CT before LP is needed if: immunocompromised, history of CNS disease, new-onset seizure, papilledema, altered consciousness, focal neurologic deficit. These identify patients at risk for brain herniation from LP. If CT is needed: draw blood cultures → start empiric antibiotics + dexamethasone IMMEDIATELY → then CT → then LP when safe. Do NOT delay antibiotics for CT or LP.

How do you interpret CSF results to differentiate bacterial from viral meningitis?

Bacterial: WBC > 1,000 (PMN predominant > 80%), protein > 200, glucose < 40 (or CSF/serum glucose ratio < 0.4), gram stain positive in ~60-90%. Viral: WBC 10-500 (lymphocyte predominant), protein 50-100, glucose normal, gram stain negative. TB/fungal: WBC 10-500 (lymphocyte predominant), protein very high (> 200), glucose LOW (like bacterial). Pearl: early bacterial meningitis can have lymphocyte predominance (first 12-24h)

Clinical Examples

📋 Case 1, Community-Acquired Bacterial Meningitis

Patient: 42M, previously healthy, presents with 18 hours of severe headache, fever, neck stiffness, and photophobia. Found confused by coworkers.

Key findings: Temp 39.6°C, HR 112, BP 88/52, GCS 12. Nuchal rigidity, positive Kernig and Brudzinski signs, petechial rash on trunk. CSF: WBC 2,400 (95% PMN), protein 320, glucose 18 (serum 110), gram stain: gram-negative diplococci. Lactate 8.4.

Management:

Dexamethasone 0.15 mg/kg IV q6h x 4 days -- give BEFORE or WITH first antibiotic dose de Gans, 2002
Empiric: ceftriaxone 2g IV q12h + vancomycin 15-20 mg/kg IV q8-12h (covers resistant pneumococcus)
Gram-negative diplococci = Neisseria meningitidis. Narrow to penicillin G or ceftriaxone once confirmed
Droplet precautions x 24h of effective antibiotics. Chemoprophylaxis for close contacts (rifampin, ciprofloxacin, or ceftriaxone IM)

Teaching point: Dexamethasone must be given BEFORE or WITH antibiotics to be effective. If antibiotics have already been given, dexamethasone has no benefit. Do not delay antibiotics for LP.

📋 Case 2, Meningitis in an Immunocompromised Patient

Patient: 67F on chronic prednisone 15 mg daily for polymyalgia rheumatica, presents with 3 days of low-grade fever, progressive headache, and subtle personality changes. No classic meningismus.

Key findings: Temp 38.3°C, HR 88, BP 134/72. Oriented but slow to respond. Mild neck stiffness only. CSF: WBC 680 (78% PMN), protein 245, glucose 22 (serum 105), gram stain: gram-positive rods.

Management:

Gram-positive rods in immunocompromised = Listeria monocytogenes until proven otherwise
Empiric: ceftriaxone 2g IV q12h + vancomycin + ampicillin 2g IV q4h (cephalosporins do NOT cover Listeria)
Dexamethasone: controversial in Listeria; give empirically and discontinue once Listeria confirmed
Ampicillin x 21 days minimum for Listeria meningitis (longer than other organisms due to intracellular persistence)

Teaching point: Add ampicillin for Listeria coverage in age >50, immunocompromised, pregnant, or alcoholic patients. Cephalosporins do NOT cover Listeria. Listeria can present subacutely without classic meningeal signs.

📋 Case 3, Post-Neurosurgical Meningitis

Patient: 56M, post-op day 8 from craniotomy for meningioma resection, develops new fever, worsening headache, and declining mental status. External ventricular drain (EVD) in place.

Key findings: Temp 39.2°C, HR 108, GCS declining from 15 to 12 over 24h. CSF from EVD: WBC 1,800 (90% PMN), protein 380, glucose 12 (serum 98), gram stain: gram-positive cocci in clusters.

Management:

Gram-positive cocci in clusters post-neurosurgery = Staphylococcus. Empiric: vancomycin IV + cefepime 2g IV q8h (covers MRSA + Pseudomonas)
Consider intrathecal/intraventricular vancomycin (5-20 mg daily) if poor response to IV therapy alone
EVD removal or exchange if feasible -- source control is critical for device-related ventriculitis
Do NOT give dexamethasone in post-surgical meningitis (no evidence of benefit)

Teaching point: Post-neurosurgical meningitis has completely different microbiology (Staph, gram-negatives) than community-acquired. Vancomycin + anti-pseudomonal beta-lactam is the empiric regimen. Device removal is essential for cure.

⚡ Summary

Summary

Empiric Abx

Vancomycin + ceftriaxone + ampicillin (if > 50, immunocompromised, or pregnant -Listeria coverage). Start within 30 min.

Dexamethasone

0.15 mg/kg IV q6h × 4 days (typically ~10 mg in adults). Give before or with first antibiotic dose. Reduces mortality in S. pneumoniae European Dexamethasone Meningitis Trial, 2002.

CT Before LP?

Only if: immunocompromised, CNS disease, new seizure, papilledema, focal deficit, altered consciousness. Don't delay abx for CT.

CSF Findings

Bacterial: PMN > 1000, protein > 200, glucose < 40. Viral: lymphocytes, protein 50-100, glucose normal. TB/fungal: lymphocytes, very high protein, low glucose.

Duration

S. pneumoniae: 10-14 days. N. meningitidis: 5-7 days. Listeria: 21 days. HSV encephalitis (acyclovir): 14-21 days.

Chemoprophylaxis

N. meningitidis contacts: rifampin 600 BID × 2 days OR ciprofloxacin 500 × 1 OR ceftriaxone 250 IM × 1.

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Meningitis & Encephalitis -Quick Reference Card

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MENINGITIS & ENCEPHALITIS -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