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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Herpes Zoster (Shingles)

VZV reactivation from dorsal root ganglia causes painful dermatomal vesicles. Treat within 72h of rash onset with valacyclovir to reduce severity and postherpetic neuralgia risk. Ophthalmology emergency if V1 (forehead/eye) involved. Shingrix vaccine is >90% effective and recommended for all adults ≥50.

🔍 Overview

Herpes Zoster, Key Concepts

Reactivation of VZV from dorsal root ganglia (latent since primary varicella/chickenpox infection)
Dermatomal distribution, unilateral, does NOT cross midline (except in immunocompromised with disseminated disease)
Most common dermatomes: T3–L3 (thoracic > lumbar > cervical). Can affect any dermatome including cranial nerves.
Risk factors: age >50 (most important), immunosuppression (transplant, HIV, chemo, steroids), stress, trauma
Lifetime risk: ~30% of all adults will develop shingles; increases with age
Infectious: vesicular fluid contains live VZV, can cause primary varicella (chickenpox) in non-immune contacts. Airborne + contact precautions until lesions crusted.

Clinical Syndromes & Complications

Syndrome	Presentation	Key Points
Classic dermatomal zoster	Prodrome of pain/burning/tingling 2–3 days before rash. Then grouped vesicles on erythematous base in a single dermatome, unilateral. Pain is often severe, burning, stabbing, lancinating.	Clinical diagnosis in most cases. Rash evolves: papules → vesicles → pustules → crusting over 7–10 days. Pain may precede rash by days (can be confused with MI, pleurisy, renal colic).
Herpes zoster ophthalmicus (HZO) EMERGENCY	V1 (ophthalmic division of trigeminal) involvement. Vesicles on forehead, eyelid, nose.	Hutchinson sign = vesicles on tip/side of nose (nasociliary nerve) → 76% risk of ocular involvement. Urgent ophthalmology consult. Can cause keratitis, uveitis, retinal necrosis, blindness.
Ramsay Hunt syndrome	VZV reactivation in geniculate ganglion (CN VII). Vesicles in ear canal/pinna + ipsilateral facial paralysis + hearing loss/vertigo.	Triad: ear vesicles + facial palsy + CN VIII symptoms. Worse prognosis than Bell’s palsy for recovery. Treat with valacyclovir + prednisone.
Postherpetic neuralgia (PHN)	Pain persisting >90 days after rash onset. Burning, allodynia (pain from light touch), lancinating.	Most common complication. Risk increases with age (>60 years), severity of acute pain, and extent of rash. Antivirals within 72h reduce PHN risk. Treatment: gabapentin, pregabalin, duloxetine, lidocaine patch, capsaicin.
Disseminated zoster	>20 vesicles outside the primary + adjacent dermatomes. Looks like varicella.	Occurs in immunocompromised (HIV, transplant, chemo). Treat with IV acyclovir. Can involve lungs, liver, CNS. Airborne + contact precautions.
VZV vasculopathy / stroke	Stroke weeks–months after zoster (especially ophthalmic zoster). VZV infects cerebral arteries.	Risk of stroke is 1.3x higher for 1 year after zoster. Consider in unexplained stroke after recent shingles. Treat with IV acyclovir.

Hutchinson sign = ophthalmology emergency. Vesicles on the tip or side of the nose indicate nasociliary nerve involvement (V1) and predict ocular complications in 76% of cases. Get urgent ophthalmology consult even if the eye looks normal, keratitis/uveitis can develop over days.

🧪 Workup

Diagnosis

Clinical diagnosis in most cases, unilateral dermatomal vesicular rash is classic. Lab confirmation rarely needed.
VZV PCR (swab of unroofed vesicle), gold standard when diagnosis is uncertain. Highly sensitive and specific. Also useful for disseminated zoster, atypical presentations, and immunocompromised patients.
DFA (direct fluorescent antibody), rapid but less sensitive than PCR. Can distinguish VZV from HSV.
Tzanck smear, multinucleated giant cells (same as HSV, cannot distinguish). Low sensitivity. Largely replaced by PCR.

When to confirm with lab testing: atypical presentations (no vesicles, unusual location, immunocompromised), disseminated disease, CNS involvement, zoster sine herpete (dermatomal pain without rash, diagnosed by VZV PCR of skin swab or CSF).

🚨 Management

Treatment

Scenario	Treatment	Duration	Notes
Uncomplicated zoster	Valacyclovir (Valtrex) 1g PO TID	7 days	Start within 72h of rash onset for best efficacy. Reduces pain duration, rash healing time, and PHN risk. Can still start after 72h if: new vesicles still forming, immunocompromised, or HZO.
HZO (ophthalmic zoster) URGENT	Valacyclovir 1g PO TID + ophthalmology consult	7–10 days	Start antivirals regardless of timing. Ophthalmology for slit-lamp exam, IOP check, fundoscopy. May need topical steroids + cycloplegics if uveitis.
Ramsay Hunt	Valacyclovir 1g PO TID + prednisone 60 mg PO daily × 5 days then taper	7 days antivirals	Combined antiviral + steroid improves facial nerve recovery. ENT referral. Worse prognosis than Bell’s palsy for complete recovery.
Disseminated / Immunocompromised	Acyclovir 10 mg/kg IV q8h	7–10 days (until no new lesions × 48h)	IV therapy for disseminated disease, CNS involvement, or severe immunosuppression. Transition to PO valacyclovir when improving and able to take PO.

Pain Management

Phase	Medications	Notes
Acute zoster pain	Acetaminophen + NSAIDs (first-line). Gabapentin 300–1200 mg TID for neuropathic component. Short-course opioids if severe.	Pain can be intense, don’t undertreat. Start gabapentin early to reduce risk of PHN transition.
Postherpetic neuralgia (PHN)	Gabapentin (Neurontin) 300–3600 mg/day Pregabalin (Lyrica) 75–300 mg BID Duloxetine (Cymbalta) 60 mg daily Lidocaine 5% patch (topical, up to 3 patches/12h) Capsaicin 8% patch (applied in clinic)	First-line: gabapentin or pregabalin. Lidocaine patch for localized pain. TCAs (amitriptyline 25–75 mg QHS) are effective but limited by side effects in elderly. Opioids are last resort.

Prevention, Shingrix Vaccine

Shingrix (recombinant adjuvanted VZV vaccine), 2 doses IM, 2–6 months apart
>90% effective at preventing shingles and PHN across all age groups ZOE-50, 2015
Recommended for all adults ≥50 regardless of prior shingles episode or prior Zostavax (old live vaccine)
Also recommended for immunocompromised adults ≥19 (transplant, HIV, autoimmune on immunosuppression), Shingrix is non-live and safe
Common side effects: injection site pain (78%), myalgia, fatigue, self-limited 1–3 days

Shingrix replaced Zostavax. Zostavax (live attenuated) was only ~51% effective and waned significantly after 5 years. Shingrix maintains >85% efficacy at 4+ years. Shingrix is safe in immunocompromised (non-live vaccine). No need to check varicella history before vaccinating, >99% of adults ≥50 are VZV seropositive.

Shingrix Vaccination Schedule

Detail	Recommendation
Vaccine	Shingrix (recombinant, adjuvanted), non-live subunit vaccine containing VZV glycoprotein E + AS01B adjuvant
Dose	2 doses, 0.5 mL IM (deltoid). Dose 1 at day 0, Dose 2 at 2-6 months later
Who	All adults ≥ 50 years (immunocompetent). Immunocompromised adults ≥ 19 years (HIV, transplant, chemo, biologics, chronic steroids)
Efficacy	97% effective in adults 50-69; 91% effective in adults ≥ 70 ZOE-50, 2015 ZOE-70, 2016
Duration of protection	>85% efficacy maintained at 4+ years. Long-term data still accumulating.
Common side effects	Injection site pain (78%), myalgia (45%), fatigue (45%), headache (38%), shivering (27%), fever (21%), GI symptoms (17%). Self-limited 1-3 days. Warn patients, reactogenicity is high but normal.
Missed dose 2?	If >6 months since dose 1, give dose 2 as soon as possible. Do NOT restart the series, any interval is acceptable.
Coadministration	Can be given with other vaccines (flu, pneumococcal, Tdap, COVID-19) at different injection sites. No minimum interval required.

When to Vaccinate vs. Defer

Scenario	Vaccinate?	Notes
Active zoster (open vesicular lesions)	DEFER	Wait until acute episode resolves and lesions have fully crusted. Vaccinating during active disease offers no benefit and may confuse clinical picture. Typically wait 2-3 months after episode to vaccinate.
Recent zoster (crusted, healing)	WAIT	Wait until rash has fully resolved. No minimum interval required after resolution, but most experts suggest 2-3 months to allow immune reconstitution and ensure the episode is truly over.
History of prior shingles (remote)	YES	Shingles can recur. Prior episode is NOT a contraindication. Vaccinate to prevent future episodes.
Prior Zostavax	YES	Shingrix is recommended regardless of prior Zostavax. Wait at least 2 months after Zostavax before giving Shingrix.
Immunocompromised (HIV, transplant, chemo, biologics)	YES	Shingrix is non-live and safe. Recommended for immunocompromised adults ≥ 19 years. Ideally vaccinate during periods of disease stability or low-intensity immunosuppression. May have reduced efficacy.
Pregnancy	DEFER	Insufficient safety data. Defer until postpartum.
Moderate-severe acute illness	WAIT	Defer until recovered. Minor illness (e.g., mild URI) is NOT a reason to delay.
Known allergy to vaccine component	CONTRAINDICATED	Anaphylaxis to a prior dose or known allergy to any component (e.g., polysorbate 80). This is the only true contraindication.

Open lesions = defer vaccination. Vesicular fluid contains live VZV and the patient is actively infectious. Vaccinating during active zoster does not treat the current episode (Shingrix is preventive, not therapeutic). Wait for full crusting, then vaccinate 2-3 months later to prevent recurrence. Meanwhile, ensure contact precautions until all lesions are crusted.

💊 Medications

Key Medications for Herpes Zoster

Drug (Brand)	Dose	Key Notes
Valacyclovir (Valtrex)	1g PO TID × 7 days	Preferred oral agent. Better bioavailability than acyclovir = more convenient dosing (TID vs 5x/day). Same efficacy. Dose-adjust for renal impairment.
Acyclovir (Zovirax)	Oral: 800 mg PO 5x/day × 7 days IV: 10 mg/kg q8h	Oral has poor bioavailability (requires 5x daily dosing, less convenient than valacyclovir). IV for disseminated disease, immunocompromised, CNS involvement. Hydrate aggressively to prevent nephrotoxicity.
Famciclovir (Famvir)	500 mg PO TID × 7 days	Alternative to valacyclovir. Similar efficacy. Use if intolerant to valacyclovir.
Gabapentin (Neurontin)	300–1200 mg PO TID	First-line for neuropathic pain (acute and PHN). Titrate slowly (start 300 mg QHS, increase every 3 days). Dose-adjust for renal function. Sedation, dizziness common initially.
Pregabalin (Lyrica)	75–150 mg PO BID	Alternative to gabapentin for PHN. Faster onset. More predictable pharmacokinetics. Schedule V controlled substance.

📋 On Rounds

What is the Hutchinson sign and why is it important?

Hutchinson sign = vesicles on the tip or side of the nose during herpes zoster. It indicates involvement of the nasociliary branch of V1 (ophthalmic division of trigeminal nerve), which also innervates the cornea and uvea. Positive Hutchinson sign predicts 76% risk of ocular complications (keratitis, uveitis, retinal necrosis). Requires urgent ophthalmology consult regardless of current eye symptoms.

When can you still start antivirals after 72 hours?

While antivirals are most effective within 72h of rash onset, you should still treat beyond 72h if: (1) New vesicles are still forming (active viral replication), (2) Immunocompromised patient (higher risk of dissemination and complications), (3) HZO (ophthalmic zoster) (risk of blindness justifies treatment at any time), (4) Ramsay Hunt (facial nerve at risk), (5) Disseminated zoster. The 72h window is a guideline, not an absolute cutoff.

How does Ramsay Hunt syndrome differ from Bell's palsy?

Ramsay Hunt = VZV reactivation in the geniculate ganglion causing the triad: (1) ear vesicles (external ear canal, pinna), (2) ipsilateral facial paralysis (LMN CN VII), (3) hearing loss or vertigo (CN VIII involvement). Bell's palsy = idiopathic (likely HSV-1-related) CN VII palsy without vesicles or hearing loss. Key differences: Ramsay Hunt has worse prognosis for recovery (complete recovery ~50% vs ~85% for Bell's), is treated with antiviral + steroid (vs steroid only for Bell's), and has visible vesicles in the ear.

What isolation precautions are needed for a hospitalized patient with shingles?

Localized zoster: Contact precautions + cover the lesions. Infectious until all vesicles are crusted. Keep away from immunocompromised patients, pregnant women (if non-immune), and neonates. Disseminated zoster: Airborne + contact precautions (VZV can spread via aerosol from disseminated lesions). The virus in vesicular fluid can cause primary varicella (chickenpox) in non-immune contacts, it does NOT cause shingles in others.

📣 Sample Presentation

One-Liner

"Mrs. Thompson is a 72-year-old woman presenting with 3 days of painful unilateral vesicular rash in a T6 dermatomal distribution, consistent with herpes zoster."

Key Points to Cover on Rounds

Herpes zoster, T6 dermatome, unilateral, does not cross midline. Onset 3 days ago with prodromal burning followed by vesicular eruption. Started valacyclovir 1g PO TID × 7 days (within 72h window). Pain management: acetaminophen + gabapentin 300 mg TID (titrating). No V1 involvement (no Hutchinson sign, no eye symptoms). Not immunocompromised, oral antivirals sufficient. Contact precautions until crusted. Shingrix vaccine after acute episode resolves (2–3 months). Monitoring for PHN development.

⚡ Summary

Summary

Treatment

Valacyclovir 1g PO TID × 7 days. Start within 72h. IV acyclovir if immunocompromised/disseminated.

Hutchinson Sign

Vesicles on nose tip = V1 nasociliary involvement. 76% risk of ocular complications. Urgent ophthalmology consult.

Ramsay Hunt

Ear vesicles + facial palsy + hearing loss/vertigo. Antiviral + prednisone. Worse recovery than Bell’s palsy.

PHN Prevention

Early antivirals reduce risk. Treat with gabapentin/pregabalin, lidocaine patch, duloxetine. Common in >60y.

Vaccine

Shingrix: 2 doses IM, >90% effective. All adults ≥50. Immunocompromised ≥19. Non-live = safe.

Isolation

Contact precautions (localized) or airborne + contact (disseminated) until crusted. Can cause chickenpox in non-immune.

📄 One Pager

Herpes Zoster (Shingles), Quick Reference Card

Print this page (Ctrl/Cmd + P) for a condensed reference card.

HERPES ZOSTER, AT A GLANCE

📋 Dx: Clinical (unilateral dermatomal vesicles). VZV PCR swab if uncertain.
⚡ Tx: Valacyclovir 1g PO TID × 7d (start within 72h). IV acyclovir 10 mg/kg q8h if disseminated/immunocompromised.
👁️ HZO: V1 involvement + Hutchinson sign → urgent ophthalmology. Treat regardless of timing.
👂 Ramsay Hunt: Ear vesicles + facial palsy + hearing loss → antiviral + prednisone.
🔥 PHN: Pain >90 days. Gabapentin/pregabalin first-line. Lidocaine patch for localized pain.
💉 Prevent: Shingrix × 2 doses for all ≥50. >90% effective. Non-live = safe in immunocompromised.