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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EmergentNeuro

Heat Stroke

Core temperature >40°C (104°F) with CNS dysfunction (altered mental status, seizures, coma). A true medical emergency -mortality 10–50% depending on delay to cooling. The single most important intervention is rapid cooling to <39°C within 30 minutes. Every minute counts.

🔍 Overview

Classification

Type	Setting	Mechanism	Key Features
Classic (non-exertional)	Elderly, chronic illness, medications, heat waves	Failure of thermoregulation -body cannot dissipate environmental heat	Develops over days. Skin often hot and dry (sweat glands exhausted). Elderly on anticholinergics, diuretics, beta-blockers at highest risk.
Exertional	Young, healthy individuals -athletes, military, laborers	Metabolic heat production overwhelms dissipation during intense physical activity	Develops over hours. Skin may still be diaphoretic. Often in hot, humid environments. Can occur even in cool conditions with extreme exertion.

Heat Stroke vs Heat Exhaustion

Feature	Heat Exhaustion	Heat Stroke
Core Temp	< 40°C (104°F)	> 40°C (104°F)
Mental Status	Normal or mild confusion	Altered -confusion, delirium, seizures, coma
Sweating	Present (profuse)	May be absent (classic) or present (exertional)
Organ Damage	Absent	Present -rhabdomyolysis, DIC, liver failure, AKI, ARDS
Treatment	Rest, oral rehydration, passive cooling	Aggressive cooling + ICU

The defining feature of heat stroke is CNS dysfunction -not the temperature alone. A patient with temp 40.5°C and normal mentation has heat exhaustion. A patient with temp 40.1°C and confusion/seizures has heat stroke. Treat the brain, not the thermometer.

Risk Factors & Medications

Anticholinergics -impair sweating (diphenhydramine, TCAs, antipsychotics)
Diuretics -volume depletion impairs sweating
Beta-blockers -blunt cardiac output response to heat stress
Stimulants -amphetamines, cocaine, MDMA increase metabolic heat production
Antipsychotics -impair thermoregulation centrally (especially in NMS overlap)
Extremes of age -elderly (impaired thermoregulation) and infants (high surface area:volume)
Obesity, deconditioning, dehydration

🚨 Management

Cooling -The Single Most Important Intervention

Target: core temperature < 39°C (102.2°F) within 30 minutes. Every minute of delay increases mortality and neurological injury. Start cooling BEFORE full workup. Do NOT wait for labs.

Method	Technique	Effectiveness	Notes
Cold water immersion GOLD STANDARD	Immerse body (neck down) in ice water bath (1–3°C)	Cooling rate ~0.2°C/min -fastest available method	Gold standard for exertional heat stroke. Near-zero mortality if applied within 30 min. Logistically challenging in ED -need large tub. Monitor for shivering (counterproductive).
Evaporative cooling	Undress patient, mist with lukewarm water, fan continuously	Cooling rate ~0.05°C/min	Most practical in ED/ICU. Less effective than immersion but widely available. Combine with ice packs to axillae, groin, neck.
Ice packs	Apply to axillae, groin, neck, and scalp (high blood flow areas)	Adjunct -slow as standalone	Use in combination with other methods. Cover large surface area. Rotate frequently.
Cold IV fluids	4°C normal saline bolus (not iced -just refrigerated)	Adjunct -modest cooling effect	Addresses volume depletion AND provides some cooling. Give 1–2L bolus. Do not use as sole cooling method.
Invasive cooling	Peritoneal lavage, bladder irrigation with cold saline, endovascular cooling catheter	Variable -reserved for refractory cases	Consider if temp >41°C and not responding to external cooling. Endovascular catheter allows precise temperature control.

Stepwise Approach

ABCs first -secure airway if GCS ≤ 8, intubate if needed
Remove from heat -move to cool environment, remove clothing
Begin cooling immediately -cold water immersion if available, otherwise evaporative + ice packs
IV access + fluids -cold NS or LR 1–2L bolus. LR is safe even in liver disease (lactate is metabolized by kidneys and skeletal muscle, not just liver).
Continuous core temperature monitoring -rectal or esophageal probe (NOT oral or axillary -inaccurate)
Stop cooling at 39°C -overshoot hypothermia is a real risk
Treat seizures -benzodiazepines (lorazepam 2–4 mg IV). Avoid phenytoin (ineffective for hyperthermia-related seizures).
Avoid antipyretics -acetaminophen and NSAIDs do NOT work. Heat stroke is not a fever (no prostaglandin-mediated set point elevation). Antipyretics may worsen hepatic/renal injury.

Do NOT give antipyretics (acetaminophen, NSAIDs). Heat stroke is a failure of thermoregulation, not a prostaglandin-mediated fever. The hypothalamic set point is normal -the body simply cannot dissipate heat. Antipyretics are useless and hepatotoxic in this setting.

🧪 Workup

Diagnostic Evaluation

Core temperature -rectal or esophageal probe. Oral/axillary/temporal are unreliable. Must be >40°C for diagnosis.
CBC -leukocytosis common. Thrombocytopenia suggests DIC.
BMP -hyperkalemia (rhabdo, cell lysis), AKI (elevated Cr), hypoglycemia (liver failure).
LFTs -AST/ALT elevation is universal. Hepatic injury peaks at 48–72h. Fulminant liver failure is a major cause of death.
CK (creatine kinase) -rhabdomyolysis (CK >5× ULN). Peak at 24–72h. Check q6–12h.
Coagulation panel -PT/INR, PTT, fibrinogen, D-dimer. DIC is common and a major cause of death.
Lactate -marker of tissue hypoperfusion and anaerobic metabolism.
UA with myoglobin -dark urine, positive blood on dipstick but no RBCs on microscopy = myoglobinuria.
ABG/VBG -mixed acid-base disturbances common (respiratory alkalosis from tachypnea + metabolic acidosis from lactic acid).
CT head -if focal neurological deficits or seizures to rule out structural cause.

LFTs may be initially normal. Hepatic injury from heat stroke peaks at 48–72 hours. Recheck LFTs daily for 3–5 days. Fulminant hepatic failure requiring transplant can occur.

💊 Medications

Key Medications

Drug	Dose	Role	Notes
Normal Saline (cold, 4°C) 1ST LINE	1–2 L IV bolus	Volume resuscitation + adjunct cooling	Most patients are severely volume depleted. LR or NS are both acceptable -LR is safe even in liver disease (lactate is metabolized by kidneys and muscle, not just liver). Titrate to UOP 1–2 mL/kg/h (especially if rhabdo).
Lorazepam (Ativan)	2–4 mg IV PRN	Seizures, shivering	Shivering during cooling is counterproductive (generates heat). Benzos suppress shivering. Also first-line for heat stroke seizures.
Dantrolene CONSIDER	1–2.5 mg/kg IV	Refractory hyperthermia	Skeletal muscle relaxant. Consider if NMS or malignant hyperthermia cannot be excluded. Evidence for pure heat stroke is limited, but may help if significant muscle rigidity/rhabdo.
Sodium Bicarbonate	150 mEq in 1L D5W	Urine alkalinization for rhabdomyolysis	Target urine pH >6.5 to prevent myoglobin-induced AKI. Use if CK >5,000 and rising.

Medications that are CONTRAINDICATED or USELESS: Acetaminophen (no effect, hepatotoxic), NSAIDs (no effect, nephrotoxic), aspirin (no effect, worsens DIC), phenytoin (ineffective for hyperthermic seizures -use benzos).

📋 On Rounds

Pimp Questions

Why don't antipyretics work in heat stroke?

Fever is caused by prostaglandins raising the hypothalamic set point -antipyretics (acetaminophen, NSAIDs) work by blocking prostaglandin synthesis. In heat stroke, the hypothalamic set point is normal -the body simply cannot dissipate the heat load fast enough (overwhelmed thermoregulatory system). Since there is no prostaglandin-mediated set point elevation, antipyretics have zero effect.

What is the key difference between heat stroke and heat exhaustion?

CNS dysfunction. Heat exhaustion can cause fatigue, nausea, headache, and even syncope -but mental status remains intact. Heat stroke is defined by altered mental status (confusion, delirium, seizures, coma) + core temp >40°C. Heat exhaustion is a clinical continuum that can progress to heat stroke if not treated. The moment a patient develops AMS in the setting of hyperthermia, it's heat stroke until proven otherwise.

What is the gold standard cooling method and what cooling rate does it achieve?

Cold water immersion (ice water bath, 1–3°C) is the gold standard. Cooling rate ~0.2°C/min, which means a patient at 42°C can reach target (39°C) in ~15 minutes. Near-zero mortality when applied within 30 minutes. Compare with evaporative cooling (~0.05°C/min) -significantly slower. The military and sports medicine literature strongly supports ice water immersion as first-line.

How do you differentiate heat stroke from neuroleptic malignant syndrome (NMS)?

NMS presents with hyperthermia + AMS + lead-pipe rigidity + autonomic instability, typically after starting or increasing a dopamine antagonist (antipsychotics, metoclopramide). Key distinguishing features: (1) NMS has prominent muscle rigidity (heat stroke has flaccidity or mild rigidity), (2) NMS develops over days (exertional heat stroke over hours), (3) NMS has markedly elevated CK from rigidity

📣 Sample Presentation

One-Liner

"Mr. Thompson is a 22-year-old Army recruit who collapsed during a 10-mile run in 95°F heat, found unresponsive with rectal temp 41.8°C, GCS 7, tachycardic to 140, and diffusely diaphoretic."

Key Points to Cover on Rounds

Exertional heat stroke -core temp 41.8°C on arrival, GCS 7. Ice water immersion initiated in field within 15 min, continued in ED. Core temp down to 39.2°C at 20 min, cooling stopped at 38.8°C. Now GCS 11 (E3V3M5), improving. CK 12,400 and rising -aggressive IVF at 250 mL/hr with bicarb drip for urine alkalinization, target UOP >200 mL/h. LFTs: AST 320, ALT 180 -will recheck daily (peaks at 48–72h). Coags normal, no DIC. Lactate 6.2 → 3.1 trending down. Plan: ICU, continuous core temp monitoring, CK q6h, LFTs daily, neuro checks q2h, hold all nephrotoxins.

Monitoring Parameters

Continuous core temperature -rectal or esophageal probe. Stop active cooling at 39°C to prevent overshoot hypothermia.
Continuous telemetry -arrhythmias from hyperkalemia, hyperthermia-induced myocardial injury.
Urine output -target 1–2 mL/kg/h (especially with rhabdomyolysis). Foley catheter essential.
CK q6–12h -trend for rhabdomyolysis. Peak 24–72h. Aggressive IVF if CK rising.
LFTs daily × 3–5 days -hepatic injury peaks at 48–72h. Watch for coagulopathy, hypoglycemia as signs of liver failure.
Coags q12–24h -DIC panel (PT, PTT, fibrinogen, D-dimer). Fibrinogen < 150 = ominous.
BMP q6–12h -hyperkalemia (rhabdo), AKI, hypoglycemia (liver failure).
Neuro checks q1–2h -GCS trending. Persistent AMS after cooling suggests brain injury.

⚡ Summary

Definition

Core temp >40°C + CNS dysfunction (AMS, seizures, coma). The key distinguishing feature from heat exhaustion is altered mental status, not the temperature.

Cooling

Cold water immersion = gold standard (~0.2°C/min). Target <39°C within 30 min. Stop at 39°C to prevent overshoot. Evaporative + ice packs if no tub available.

Do NOT Give

Antipyretics (acetaminophen, NSAIDs) -useless and harmful. Not a prostaglandin-mediated fever. Phenytoin for seizures -use benzos instead.

Complications

Rhabdomyolysis (CK, IVF, bicarb), DIC (coags q12h, fibrinogen), hepatic failure (LFTs peak 48–72h), AKI, ARDS, cerebral edema.

Classic vs Exertional

Classic: elderly, medications, heat wave, develops over days, skin dry. Exertional: young, exercise, develops over hours, may still be diaphoretic.

Monitoring

Core temp (rectal/esophageal), CK q6–12h, LFTs daily × 3–5d, coags q12–24h, UOP 1–2 mL/kg/h, neuro checks q1–2h.