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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EMERGENTEndocrineICU

Myxedema Coma

Life-threatening decompensated hypothyroidism. Mortality 25-60%. Classic: hypothermia + AMS + precipitating event in a patient with untreated hypothyroidism.

🔍 Overview

Overview

Myxedema coma is the most severe form of hypothyroidism, representing decompensation of long-standing untreated or undertreated disease. Despite the name, actual coma is present in only ~20% -most present with AMS, obtundation, or extreme lethargy. Mortality is 25-60% even with treatment. Classic triad: (1) altered mental status, (2) hypothermia (often < 95°F/35°C), (3) precipitating event. Triggers: infection (#1), cold exposure, sedatives/opioids, surgery, MI, stroke, medication non-compliance. Almost exclusively affects elderly women in winter. Think of it as multi-organ failure from severe thyroid hormone deficiency: decreased cardiac output, hypoventilation (CO₂ retention), hypothermia, hyponatremia (impaired free water excretion), hypoglycemia, and ileus.

🧪 Workup

Workup

TSH -markedly elevated in primary hypothyroidism (most cases). Low/normal TSH = central (pituitary) hypothyroidism.
Free T4 -very low. Free T3 also low but less reliable.
AM cortisol -MUST check before giving levothyroxine. Concomitant adrenal insufficiency is common (either autoimmune polyendocrine syndrome or central hypothyroidism with secondary AI). Giving T4 without cortisol replacement → adrenal crisis.
BMP -hyponatremia (impaired free water excretion → dilutional), hypoglycemia, elevated Cr (decreased renal perfusion)
ABG/VBG -respiratory acidosis (CO₂ retention from hypoventilation). May need intubation.
CBC -anemia (chronic disease), possible leukocytosis if infection triggered
CK -rhabdomyolysis from hypothyroid myopathy

Monitoring

🚨 Management

Management

Step 1 -Stress-dose steroids FIRST: Hydrocortisone 100 mg IV before or simultaneously with T4. Never give T4 alone -may precipitate adrenal crisis if concomitant AI (which you won't know until cortisol results return). [Endocrine Society]
Step 2 -IV levothyroxine (T4): Loading dose 200-400 mcg IV × 1, then 50-100 mcg IV daily. Must be IV -GI absorption is unreliable in myxedema (ileus, edema). Some experts add IV T3 (liothyronine) 5-20 mcg IV q8h for faster onset (T4 takes days to convert to active T3).
Step 3 -Supportive care:
- Passive rewarming -warm blankets, warming to room temperature. Do NOT actively rewarm aggressively (causes vasodilation → cardiovascular collapse).
- Mechanical ventilation if hypercapnic respiratory failure (CO₂ narcosis)
- Fluid resuscitation -cautious (impaired cardiac function). Avoid free water (worsens hyponatremia).
- Vasopressors if hypotension refractory to fluids + steroids
- Glucose -D50 for hypoglycemia
Step 4 -Treat the trigger: Broad-spectrum antibiotics if infection suspected (low threshold -hypothermia masks fever).

⚠ The most dangerous mistake: giving levothyroxine without cortisol coverage. T4 increases metabolic rate → increases cortisol demand → if adrenals can't respond → adrenal crisis → death.

💊 Medications

Medications

Drug	Dose	Route	Notes
Hydrocortisone	100 mg IV bolus → 50 mg IV q8h	IV	GIVE BEFORE OR WITH T4. Stress-dose steroids until AI is ruled out. Endocrine Society, 2014
Levothyroxine (Synthroid/T4)	200-400 mcg IV load → 50-100 mcg IV daily	IV	Must be IV (GI absorption unreliable). Onset: days. T4→T3 conversion impaired in critical illness.
Liothyronine (T3)	5-20 mcg IV q8h	IV	Optional -faster onset than T4. Use cautiously in elderly/cardiac patients (arrhythmia risk). Stop once clinically improving.
D50W	25g (50 mL) IV PRN	IV	For hypoglycemia (common in myxedema due to decreased gluconeogenesis).
Broad-spectrum antibiotics	Per clinical suspicion	IV	Low threshold -infection is #1 trigger and hypothermia masks fever. Empiric coverage until cultures return.

🏥 Rounds

Pimp Questions

❓ Why must you give steroids BEFORE levothyroxine in myxedema coma?

Many myxedema patients have concomitant adrenal insufficiency -either autoimmune polyendocrine syndrome (Hashimoto's + Addison's) or central hypothyroidism with secondary AI. Giving T4 increases metabolic rate → increases cortisol demand. If the adrenals can't respond → acute adrenal crisis → cardiovascular collapse → death. Always give hydrocortisone 100 mg IV first or simultaneously. [Endocrine Society]

❓ Why must levothyroxine be given IV in myxedema coma?

Myxedema causes impaired GI absorption from: (1) intestinal mucosal edema, (2) ileus/decreased motility, (3) decreased blood flow to the gut. Oral bioavailability of T4, which is already ~70% in normal patients, drops further. IV levothyroxine bypasses all of these issues and provides 100% bioavailability.

❓ Why is aggressive rewarming dangerous in myxedema coma?

Active rewarming causes peripheral vasodilation → drops preload → cardiovascular collapse in a patient who already has decreased cardiac output and contractility from hypothyroidism. Passive rewarming (warm blankets, raising room temperature) is safer. Target warming rate: 0.5°C per hour maximum.

❓ Why does myxedema coma cause hyponatremia?

Hypothyroidism causes hyponatremia through impaired free water excretion: (1) decreased cardiac output → decreased renal perfusion → increased ADH secretion, (2) decreased GFR → decreased free water delivery to collecting duct, (3) direct effect of thyroid hormone deficiency on aquaporin channels. The hyponatremia improves with T4 replacement -do NOT fluid restrict or give hypertonic saline (risks cerebral edema from too-rapid correction).

❓ What is the role of IV T3 (liothyronine) in myxedema coma?

T3 is the active thyroid hormone (T4 is a prohormone that must be converted to T3). In critical illness, peripheral T4→T3 conversion is impaired (sick euthyroid/non-thyroidal illness). IV T3 provides the active hormone directly, with onset in hours (vs days for T4). However, T3 is more likely to cause arrhythmia -use cautiously in elderly patients with cardiac disease. Most experts use combination T4 + low-dose T3.

❓ How do you differentiate myxedema coma from other causes of hypothermia + AMS?

Key clues for myxedema: (1) history of hypothyroidism or thyroidectomy scar, (2) periorbital/non-pitting edema, (3) macroglossia, (4) delayed relaxation phase of DTRs (pathognomonic), (5) hyponatremia + hypoglycemia + hypercapnia triad, (6) bradycardia disproportionate to hemodynamics. TSH and Free T4 confirm, but treatment should NOT wait for lab results if clinical suspicion is high.

Sample Presentation

Mrs. Thompson is a 82-year-old woman with known hypothyroidism (ran out of levothyroxine 2 months ago) brought from home by family for progressive lethargy × 5 days, now barely arousable. VS: T 93.6°F (34.2°C), HR 48, BP 88/52, RR 10. Exam: periorbital edema, macroglossia, dry skin, delayed DTRs, non-pitting edema of extremities. Labs: TSH > 100, Free T4 < 0.1, Na 118, glucose 52, cortisol pending, pCO₂ 68.

Key Points: Classic myxedema coma -hypothermia + AMS + bradycardia + hyponatremia + hypoglycemia + CO₂ retention in untreated hypothyroid. IMMEDIATE: hydrocortisone 100 mg IV → then T4 200-400 mcg IV. D50 for glucose. Passive rewarming. Consider intubation for hypercapnic respiratory failure (pCO₂ 68). ICU. Treat infection empirically.

Core temperature q2-4h -low-reading thermometer. Warming should be gradual. Target: rise of 0.5°C per hour maximum.
Cardiac telemetry -continuous. Watch for bradycardia, heart block, QTc prolongation, torsades. T3 replacement can cause tachycardia/arrhythmia.
TSH + Free T4 -recheck at 24-48h (T4 should be rising). TSH takes weeks to normalize -don't chase it.
AM cortisol result -if < 18 mcg/dL → confirmed AI → continue hydrocortisone. If normal → can taper steroids.
BMP q6-12h -Na⁺ (should improve with T4), glucose (hypoglycemia risk), K⁺
ABG -CO₂ trending (hypercapnia should improve). Intubate if pCO₂ rising or AMS worsening.
Mental status -should improve over 24-72h with treatment. If not → re-evaluate for missed trigger (sepsis, stroke).
CK trending -rhabdomyolysis from myxedema myopathy (aggressive IVF + monitor renal function)

Monitoring

📋 Summary

Summary

Triad

AMS + hypothermia + precipitant in untreated hypothyroidism

Step 1

Hydrocortisone 100 mg IV FIRST -rule out concomitant AI before T4

Step 2

T4 200-400 mcg IV load → 50-100 daily. ± T3 5-20 mcg IV q8h.

Labs

TSH sky-high, Free T4 undetectable, Na low, glucose low, pCO₂ high

Mortality

25-60% even with treatment. Elderly women in winter.

Danger

T4 without steroids → adrenal crisis. Active rewarming → cardiovascular collapse.

📄 One Pager

One-Pager

Myxedema Coma

Decompensated Hypothyroidism

Protocol

Step 1: Hydrocortisone 100 mg IV (BEFORE T4). Step 2: T4 200-400 mcg IV load ± T3 5-20 mcg IV q8h. Step 3: Passive rewarming. Step 4: Treat trigger. Step 5: ICU monitoring.

Classic Features

Hypothermia (< 95°F). Bradycardia. AMS → obtundation. Hyponatremia. Hypoglycemia. Hypercapnia. Non-pitting edema. Macroglossia. Delayed DTRs. Periorbital puffiness.