Chart — Endocrine
Thyroid Disorder Comparison Chart
Hypothyroidism vs hyperthyroidism vs thyroid storm vs myxedema coma — side-by-side comparison across temperature, cardiovascular, neurological, lab, treatment, and nursing priorities.
Educational use only. Thyroid storm and myxedema coma are life-threatening emergencies requiring ICU management. Clinical presentation varies — use clinical judgment and institutional protocols. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
| Feature | Hypothyroidism | Hyperthyroidism | Thyroid Storm | Myxedema Coma |
|---|---|---|---|---|
| Definition | Insufficient thyroid hormone production; TSH elevated (pituitary compensating), T3/T4 low | Excess thyroid hormone; TSH suppressed (negative feedback), T3/T4 elevated | Life-threatening extreme hyperthyroidism — exaggerated response to uncontrolled thyrotoxicosis plus physiologic trigger | Life-threatening extreme hypothyroidism — altered consciousness, hypothermia, respiratory failure in severely undertreated patients |
| Common Causes | Hashimoto's thyroiditis (most common), post-RAI, post-thyroidectomy, iodine deficiency, medications (amiodarone, lithium) | Graves' disease (most common), toxic multinodular goiter, toxic adenoma, excessive levothyroxine, iodine load (Jod-Basedow) | Surgery (thyroid or other), RAI, iodine contrast, infection, trauma — triggers in patient with pre-existing uncontrolled hyperthyroidism | Untreated or undertreated hypothyroidism + precipitating event: cold exposure, infection, sedatives, surgery, opioids |
| Temperature | Low — cold intolerance; decreased metabolic rate → heat loss > production | Elevated — heat intolerance; increased metabolic rate → excess heat production | Extreme hyperthermia (> 104°F / 40°C) — hallmark of thyroid storm | Extreme hypothermia — hallmark of myxedema coma; patient may be < 95°F (35°C) |
| Cardiovascular | Bradycardia, hypotension, pericardial effusion, elevated LDL and cholesterol | Tachycardia, palpitations, hypertension, atrial fibrillation (especially in elderly), widened pulse pressure | Severe tachycardia (> 140 bpm), atrial fibrillation, high-output heart failure — cardiovascular collapse risk | Bradycardia, hypotension, cardiomegaly, low cardiac output — cardiovascular collapse risk |
| Neurological / Mental Status | Depression, cognitive slowing, memory impairment, lethargy, delayed reflexes (delayed relaxation phase) | Anxiety, tremor, irritability, insomnia, emotional lability, hyperreflexia | Agitation, confusion, psychosis, then obtundation — progressive neurological deterioration | Obtundation → coma; seizures possible; very slow speech if responsive; delayed reflexes |
| Skin / Hair / Eyes | Dry skin, hair loss, brittle nails, periorbital edema (myxedema), pale/cool skin; no exophthalmos | Warm moist skin, fine hair, pretibial myxedema (Graves'), onycholysis; exophthalmos (Graves' only — not other causes) | Profuse diaphoresis (drenching sweats), flushing | Extreme dry/thick/cool skin; periorbital edema; generalized non-pitting edema from mucopolysaccharide accumulation |
| GI / Metabolic | Constipation, weight gain despite poor appetite, decreased metabolic rate, low BMR | Diarrhea, weight loss despite increased appetite, increased metabolic rate, hyperglycemia | Nausea, vomiting, diarrhea, jaundice (liver involvement — serious sign), hyperglycemia | Paralytic ileus (no bowel sounds), abdominal distension, hyponatremia (SIADH-like), hypoglycemia |
| Key Labs | TSH ↑, free T4 ↓, free T3 ↓; elevated cholesterol; possible anemia; hyponatremia in severe hypothyroidism | TSH ↓ (suppressed), free T4 ↑, free T3 ↑; possible mild hypercalcemia; elevated alkaline phosphatase | TSH near 0, markedly elevated free T4 and T3; elevated LFTs; elevated WBC (without true infection); hyperglycemia | TSH markedly ↑ (primary), T4 very low; hyponatremia; hypoglycemia; CO₂ retention (respiratory failure); possible elevated CK |
| Treatment Priority | Levothyroxine (start low, titrate); address cause; lifestyle adjustments | Antithyroid drugs (methimazole preferred; PTU in pregnancy/storm); beta-blockers for symptom control; RAI or surgery for definitive treatment | 1st: Beta-blocker (propranolol IV) → 2nd: PTU → 3rd: Potassium iodide (1h after PTU) → 4th: Hydrocortisone. Treat fever with acetaminophen (NOT aspirin). ICU care. | IV levothyroxine (400 mcg loading dose) + hydrocortisone (adrenal insufficiency commonly co-exists); warming blankets (PASSIVE — not active) or warmed IV fluids; mechanical ventilation prn; ICU care |
| Nursing Priority | Medication adherence (lifelong); monitor for cardiovascular complications; constipation management; fall prevention | Cardiac monitoring; cool environment; high-calorie diet; eye care (Graves'); report agranulocytosis signs (fever, sore throat) if on antithyroid drugs | ICU: continuous cardiac monitoring; cooling measures + acetaminophen (NOT aspirin); O₂; strict I&O; medication administration sequence (beta-blocker → PTU → iodide); thyrotoxic heart failure monitoring | ICU: airway management (intubation if respiratory failure); avoid sedatives/opioids (worsen CNS depression); careful fluid resuscitation (hyponatremia); warming; thyroid and cortisol replacement |
| NCLEX Memory Aid | SLOW: Slow heart, Low temp, Obesity/weight gain, Weight in hair loss. TSH HIGH = body begging for more thyroid hormone. | FAST: Fast heart, Anxiety, Sweating, Thin/weight loss. TSH LOW = body being flooded, feedback off. | S-T-O-R-M: Severe hyperthermia, Tachycardia extreme, Obtundation, Rx = beta-blocker FIRST + PTU + iodide, Must use acetaminophen (not aspirin) | COMA clue: Cold, Obtunded, Myxedema (skin/edema), A₃ (Airway + Adrenal support). Passive warm — never active (vasodilation causes cardiovascular collapse). |
Thyroid Lab Pattern Summary
Primary Hypothyroidism: TSH ↑↑, T4 ↓
Secondary Hypothyroidism: TSH ↓, T4 ↓ (pituitary failure)
Primary Hyperthyroidism: TSH ↓↓, T4/T3 ↑
TSH alone screens: Low TSH → hyperthyroid; High TSH → hypothyroid
Related Resources
Thyroid Disorders for NursesFull guide — thyroid physiology, hypothyroidism, hyperthyroidism, thyroid storm, and myxedema coma
Open →Thyroid Medications ReferenceLevothyroxine, PTU, methimazole, radioactive iodine, and potassium iodide
Open →Endocrine Crisis Management ReferenceThyroid storm and myxedema coma — priority interventions and do-not actions
Open →Standards & sources
Fact-checked Jun 20, 2026This page is written to align with American Diabetes Association (ADA) Standards of Care · American Association of Clinical Endocrinology (AACE). It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →