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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EMERGENTEM

Anaphylaxis

IgE-mediated systemic allergic reaction. Epinephrine is the ONLY first-line treatment -everything else is adjunctive. The most common mistake: giving diphenhydramine and steroids instead of epinephrine. Epi first, always.

🔍 Overview

Diagnostic Criteria -Any ONE of Three

Criterion 1: Acute onset (minutes–hours) of skin/mucosal involvement (hives, flushing, angioedema) PLUS respiratory compromise (dyspnea, stridor, wheeze, hypoxia) OR hypotension/end-organ dysfunction
Criterion 2: ≥ 2 of the following after exposure to LIKELY allergen: skin/mucosal symptoms, respiratory compromise, hypotension, persistent GI symptoms (cramping, vomiting)
Criterion 3: Hypotension alone after exposure to KNOWN allergen for that patient

Up to 20% of anaphylaxis has NO skin findings. Don't wait for hives to give epinephrine. Isolated hypotension or bronchospasm after allergen exposure = anaphylaxis.

Common Triggers

Foods: peanuts, tree nuts, shellfish, milk, eggs (#1 cause in children)
Medications: antibiotics (penicillin, cephalosporins), NSAIDs, contrast dye, anesthetic agents (#1 cause in perioperative setting)
Insect stings: Hymenoptera (bee, wasp, hornet) -#1 cause of fatal anaphylaxis in adults
Latex
Idiopathic (~20% -no identifiable trigger)

Biphasic Anaphylaxis

Up to 20% of anaphylaxis cases have a biphasic reaction -recurrence of symptoms 1–72 hours after initial resolution (most within 8–10h). This is why ALL patients require a minimum 4–6 hour observation period, and severe reactions warrant 12–24h observation. Steroids (methylprednisolone 125 mg IV) are given empirically to prevent biphasic reactions, though evidence is limited.

Clinical Example

Case

28F with known shrimp allergy presents from a restaurant with lip swelling, diffuse urticaria, audible wheezing, and BP 82/48 within 15 minutes of eating shellfish. HR 124, SpO₂ 91% on RA. This is anaphylaxis (Criterion 2: skin + respiratory + hypotension after known allergen).

🚨 Management

Treatment Protocol

EPINEPHRINE is the ONLY first-line treatment. There is NO contraindication to epinephrine in anaphylaxis -not age, not pregnancy, not cardiac disease. The risk of NOT giving epi is always greater than the risk of giving it. IM Epinephrine Pharmacokinetics Trial, 2004 WAO, 2020

Step	Drug	Dose	Notes
1. EPINEPHRINE	Epinephrine 1:1000 (1 mg/mL) GIVE FIRST	0.3–0.5 mg IM (0.3–0.5 mL) in anterolateral thigh. Repeat q5–15 min if no improvement.	IM (not SubQ) -faster absorption IM Epinephrine Pharmacokinetics Trial, 2004. Anterolateral thigh (not deltoid) -better blood flow. Autoinjector: EpiPen 0.3 mg adult, 0.15 mg pediatric (< 30 kg). Most common error: not giving epi, giving it too late, or giving it SubQ. WAO Anaphylaxis Guidelines, 2020
2. Position	Supine with legs elevated (improves venous return). If vomiting → recovery position. If respiratory distress → sitting up. Do NOT have the patient stand or sit upright if hypotensive -can cause fatal "empty ventricle syndrome."
3. IV access + fluids	NS bolus	1–2 L rapid bolus (20 mL/kg peds)	Anaphylaxis causes massive vasodilation + capillary leak → distributive shock. Aggressive fluids needed.
4. Adjuncts	Diphenhydramine 50 mg IV + famotidine (Pepcid) 20 mg IV	H1 + H2 blockers	Adjunctive ONLY -do NOT give instead of epinephrine. Antihistamines treat hives but do NOT reverse bronchospasm or hypotension.
5. Steroids	Methylprednisolone 125 mg IV	Or dexamethasone 10 mg IV	Does NOT help acute anaphylaxis (takes 4–6h to work). May prevent biphasic reaction (occurs in ~5–20%, usually 1–72h later) Biphasic Anaphylaxis Review, 2015. Observe ≥ 4–6h after resolution.
Refractory	Epinephrine drip	1–10 mcg/min IV	If ≥ 2 doses of IM epi fail → start epi drip. Glucagon 1–5 mg IV if on beta-blockers (epi may be ineffective due to β-blockade). Vasopressin for refractory hypotension.

IM epinephrine is the ONLY life-saving treatment. Antihistamines and steroids are ADJUNCTS -they do NOT treat anaphylaxis. Delay in epinephrine = death.

NEVER give IV epinephrine push for anaphylaxis (unless cardiac arrest). IV push epi in a patient with a pulse causes fatal arrhythmias. Use IM or IV drip only.

Updated Practice: Old teaching: give IV Benadryl and steroids first, then epi if not improving. WRONG -epinephrine is FIRST, immediately. Every minute of delay increases mortality. WAO, 2020

🧪 Workup

Laboratory Workup

Tryptase level -draw within 1–2h of onset (peaks at 1h). Confirms mast cell degranulation. A normal tryptase does NOT rule out anaphylaxis.
CBC -baseline hematocrit, WBC
BMP -renal function, electrolytes (epinephrine can cause hypokalemia)
ECG -arrhythmias from epinephrine administration or myocardial involvement (Kounis syndrome -allergic MI)
Trigger identification -detailed timeline of exposures (food, drugs, insect stings, latex, exercise)
Allergist referral -4–6 weeks post-event for skin-prick testing and component testing

Clinical diagnosis. Do NOT delay treatment waiting for labs. Tryptase is confirmatory, not diagnostic. If it looks like anaphylaxis, treat like anaphylaxis.

📋 On Rounds

Why give glucagon in anaphylaxis for patients on beta-blockers?

Epinephrine works primarily through β₁ (increased HR, contractility) and β₂ (bronchodilation, vasodilation in muscle) receptors. In patients on beta-blockers, these receptors are occupied/blocked → epinephrine is less effective → refractory anaphylaxis. Glucagon bypasses the β-receptor entirely -it activates adenylyl cyclase directly via the glucagon receptor → increases cAMP → positive inotropy + chronotropy + smooth muscle relaxation.

Why is IM epinephrine given in the anterolateral thigh and not the deltoid?

The anterolateral thigh (vastus lateralis) provides faster and higher peak epinephrine absorption than the deltoid, with peak plasma levels at ~8 minutes vs ~34 minutes for subcutaneous. This is because the thigh has rich vasculature and large muscle mass for IM absorption. Never give epi IV push for anaphylaxis (unless in cardiac arrest) -IV bolus can cause fatal arrhythmia. The dose is 0.3–0.5 mg of 1:1000 (1 mg/mL) IM, repeat q5–15 min.

A patient had an anaphylactic reaction 4 hours ago and feels fine. Can you discharge them?

Observe for biphasic reaction. Biphasic anaphylaxis occurs in 1-20% of cases (most estimates ~5%), typically 1-72 hours after the initial reaction (most within 8-10h). Risk factors for biphasic: severe initial reaction, delayed epinephrine, required > 1 dose of epi, unknown trigger. Minimum observation: 4-6 hours for mild reactions.

What are the diagnostic criteria for anaphylaxis?

Anaphylaxis is diagnosed when any 1 of 3 criteria is met: (1) Acute skin/mucosal involvement (hives, flushing, angioedema) + respiratory compromise (wheeze, stridor, hypoxia) OR hypotension. (2) ≥ 2 of the following after exposure to a likely allergen: skin/mucosal symptoms, respiratory compromise, hypotension, persistent GI symptoms (cramping, vomiting). (3) Hypotension alone after exposure to a known allergen for that patient.

Clinical Examples

📋 Case 1, Antibiotic-Induced Anaphylaxis

Patient: 42F, no known drug allergies. First dose IV piperacillin-tazobactam. Within 15 min: diffuse urticaria, lip swelling, wheeze, BP 72/38.

Key findings: Skin + respiratory + hypotension after allergen. HR 128, SpO2 91%, stridor developing.

Management:

Epinephrine 0.5 mg IM anterolateral thigh (1:1000), FIRST, do not delay
Stop offending antibiotic immediately
NS 1-2L bolus; diphenhydramine 50 mg IV + famotidine 20 mg IV
Methylprednisolone 125 mg IV; albuterol neb for bronchospasm
Repeat epi q5-15 min if no improvement; epi drip if refractory

Teaching point: Most deaths from anaphylaxis result from delayed or withheld epinephrine. IM epinephrine has NO absolute contraindications. Antihistamines treat hives but do NOT reverse hypotension or airway obstruction. WAO, 2020

📋 Case 2, Refractory Anaphylaxis on Beta-Blockers

Patient: 67M, PMH CAD on metoprolol 100 mg BID. Bee sting 20 min ago. Flushing, tongue swelling, wheeze, BP 68/40, HR 52.

Key findings: Refractory hypotension despite 2 IM epi doses. HR blunted by beta-blocker.

Management:

Glucagon 1-5 mg IV bolus, then 5-15 mcg/min, bypasses beta-receptor
Epinephrine IV drip 1-10 mcg/min (ICU monitoring)
Aggressive IVF 2-3L; have suction ready (glucagon causes vomiting)

Teaching point: Beta-blockers blunt the cardiac response to epinephrine. Glucagon bypasses the beta-receptor via direct adenylyl cyclase activation, producing positive inotropy and chronotropy independent of beta-receptors.

📋 Case 3, Biphasic Anaphylaxis

Patient: 25F with peanut allergy. Accidental exposure 6h ago. Initial reaction treated with EpiPen. Resolved. Now: recurrent urticaria, throat tightness, wheezing.

Key findings: Biphasic anaphylaxis (~5% of cases, within 1-72h). Risk factors: severe initial reaction, > 1 epi dose needed, delayed treatment.

Management:

Repeat epinephrine 0.5 mg IM immediately
Admit for extended observation (12-24h minimum)
Continue H1 + H2 blockers and steroids
Discharge with EpiPen, allergist referral, action plan, medical alert bracelet

Teaching point: Biphasic reactions are why all anaphylaxis patients need minimum 4-6h observation (12-24h if severe). All patients need an EpiPen prescription and allergist referral at discharge.

📣 Sample Presentation

One-Liner

"Ms. Williams is a 35-year-old who developed diffuse urticaria, throat tightness, wheezing, and hypotension (BP 78/42) within 10 minutes of IV cefazolin administration. Consistent with anaphylaxis."

Key Points to Cover on Rounds

Anaphylaxis to cefazolin (probable cephalosporin allergy). Epinephrine 0.5 mg IM anterolateral thigh given × 1 → BP improved to 102/64. Additional: diphenhydramine 50 mg IV, famotidine 20 mg IV, methylprednisolone 125 mg IV, NS 1L bolus. Wheezing resolved with albuterol neb. Observed for biphasic reaction × 6 hours -no recurrence. Tryptase level drawn at 1h. Allergy documented: cephalosporins → anaphylaxis. EpiPen prescribed. Plan: allergist referral, avoid cephalosporins and high-cross-reactivity penilcillins, discharge with anaphylaxis action plan.

💊 Medications

Anaphylaxis Medications

Drug	Dose	Route	Role
Epinephrine (1:1000)	0.3–0.5 mg	IM anterolateral thigh	FIRST-LINE -repeat q5–15 min. No contraindications in anaphylaxis.
Diphenhydramine	50 mg	IV	H1 blocker -adjunct for urticaria/pruritus. Does NOT treat hypotension or bronchospasm.
Famotidine (Pepcid)	20 mg	IV	H2 blocker -adjunct. Combined H1+H2 blockade more effective than H1 alone.
Methylprednisolone	125 mg	IV	Prevents biphasic reaction (theoretical -weak evidence). Takes 4–6h to work. NOT for acute treatment.
Albuterol	2.5 mg neb	Nebulized	For bronchospasm refractory to epinephrine. Continuous neb if severe.
Glucagon	1–5 mg bolus, then 5–15 mcg/min	IV	For patients on beta-blockers. Bypasses β-receptor blockade → direct cAMP activation. Side effect: vomiting.
Epinephrine drip	1–10 mcg/min	IV infusion	Refractory anaphylaxis (failed ≥2 IM doses). ICU-level monitoring required.

⚡ Summary

Summary

Diagnosis

Rapid onset (min to hours) + skin/mucosal involvement + respiratory compromise or hypotension. 10-20% have NO skin findings.

First-Line

Epinephrine 0.5 mg IM anterolateral thigh. Repeat q5-15 min if needed. NO substitute -epi is the ONLY first-line treatment.

Adjuncts

H1 blocker (diphenhydramine 50 mg IV), H2 blocker (famotidine 20 mg IV), steroids (methylprednisolone 125 mg IV), NS bolus for hypotension.

Biphasic

Occurs in ~5% of cases, 1-72h after initial reaction. Observe 4-6h minimum (12-24h if severe). Steroids may help prevent.

Discharge

EpiPen prescription + teach auto-injector. Allergist referral. Anaphylaxis action plan. Medical alert bracelet. Avoid identified trigger.

Common Triggers

Foods (#1 in children: peanuts, tree nuts, shellfish). Medications (#1 in adults: antibiotics, NSAIDs). Hymenoptera stings. Latex.