Guide — Endocrine
Thyroid Disorders for Nurses
Hypothyroidism, hyperthyroidism, thyroid storm, and myxedema coma — pathophysiology, assessment findings, labs, medications, nursing priorities, and NCLEX pearls.
12 min read · Endocrine
Educational use only. Thyroid disorder management varies by patient and clinical context. Always follow institutional protocols and provider orders. 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.
Thyroid Physiology Overview
The hypothalamic-pituitary-thyroid (HPT) axis regulates thyroid hormone production through negative feedback:
- Hypothalamus releases TRH (thyrotropin-releasing hormone)
- Pituitary releases TSH (thyroid-stimulating hormone)
- Thyroid gland produces T4 (thyroxine — inactive, majority) and T3 (triiodothyronine — active, more potent)
- T4 is converted to T3 in peripheral tissues (liver, kidney)
- Rising T3/T4 inhibits TSH release (negative feedback)
TSH interpretation rule: TSH and thyroid hormones move in opposite directions. High TSH = hypothyroidism (pituitary working hard to stimulate a failing thyroid). Low TSH = hyperthyroidism (pituitary suppressed by excess hormone).
Hypothyroidism
| Category | Details |
|---|---|
| Causes | Hashimoto's thyroiditis (most common — autoimmune), thyroidectomy, radioactive iodine treatment, medications (amiodarone, lithium), iodine deficiency (rare in US), pituitary failure (secondary) |
| Signs & Symptoms | SLOW DOWN: fatigue, weight gain, cold intolerance, constipation, dry skin, brittle hair/nails, bradycardia, hypotension, depression, slowed reflexes ("hung reflexes"), facial/periorbital edema, hoarseness, goiter |
| Labs | TSH ↑ (primary hypothyroidism), free T4 ↓; also: elevated cholesterol, elevated CK, anemia common; Anti-TPO antibodies elevated in Hashimoto's |
| Treatment | Levothyroxine (T4 replacement) — lifelong in most cases; start low and go slow in cardiac patients and elderly; titrate by TSH monitoring every 6–8 weeks |
| Nursing Priorities | Monitor cardiac status (bradycardia); assess for constipation; prevent hypothermia (warming measures); administer levothyroxine on empty stomach 30–60 min before breakfast; educate about lifelong therapy; caution with sedatives (exaggerated effects) |
Hyperthyroidism
| Category | Details |
|---|---|
| Causes | Graves' disease (most common — autoimmune, TSH receptor antibodies), toxic multinodular goiter, thyroid adenoma, excessive thyroid hormone intake, amiodarone, subacute thyroiditis |
| Graves' Disease Features | Exophthalmos (proptosis) — bulging eyes (unique to Graves'); pretibial myxedema (non-pitting lower-leg edema); diffuse goiter; positive TSI (thyroid-stimulating immunoglobulins) |
| Signs & Symptoms | SPEED UP: tachycardia/palpitations, hypertension, weight loss despite increased appetite, heat intolerance, diaphoresis, anxiety/nervousness, tremor, diarrhea, insomnia, exophthalmos (Graves'), goiter |
| Labs | TSH ↓ (suppressed), free T4 ↑, free T3 ↑; elevated TSI in Graves'; may have elevated liver enzymes |
| Treatment | Antithyroid drugs (PTU, methimazole); beta-blockers (propranolol) for symptom control; radioactive iodine (definitive in many); thyroidectomy; post-RAI/thyroidectomy requires lifelong levothyroxine |
| Nursing Priorities | Monitor cardiac (tachycardia, atrial fibrillation risk); cool environment; high-calorie diet; eye care for exophthalmos (artificial tears, dark glasses, elevate HOB); monitor for agranulocytosis with antithyroid drugs (WBC/fever); no ASA (displaces T4) |
Thyroid Storm (Thyrotoxic Crisis)
Life-threatening emergency — mortality 10–30%
Triggers: Surgery, infection, trauma, iodine load, abrupt antithyroid drug discontinuation, labor/delivery, severe physiologic stress
Classic presentation: Temperature > 38.5°C (often > 40°C), severe tachycardia (may have A-fib), agitation/delirium, nausea/vomiting, heart failure
Burch-Wartofsky scoring: Diagnostic scoring based on temperature, HR, CNS changes, GI symptoms, and precipitating event
| Intervention Order | Agent | Purpose |
|---|---|---|
| 1st | Beta-blocker (propranolol IV) | Controls heart rate; also inhibits T4→T3 conversion |
| 2nd | PTU (NOT methimazole) | Blocks new hormone synthesis AND inhibits T4→T3 conversion (methimazole lacks this conversion-blocking property) |
| 3rd (1h after PTU) | Potassium iodide (Lugol's solution) | Blocks hormone RELEASE (Wolff-Chaikoff effect). Must give PTU first — iodine given alone provides substrate for more hormone synthesis |
| Supportive | Corticosteroids, cooling, fluids | Inhibit conversion; manage fever with acetaminophen (NOT aspirin — ASA displaces T4 from binding protein, worsening crisis) |
Myxedema Coma
Definition: Extreme, life-threatening hypothyroidism — mortality 20–50%. Rare but important NCLEX topic.
Triggers: Cold exposure, infection, surgery, sedatives/opioids, inadequate thyroid replacement, undiagnosed hypothyroidism
Clinical features: Severe hypothermia (hallmark), altered mental status/coma, bradycardia, hypotension, hypoventilation, hypoglycemia, hyponatremia, periorbital edema
Treatment: IV levothyroxine (T4) and/or T3; IV hydrocortisone (rule out adrenal insufficiency before thyroid replacement); active warming; supportive care; may require mechanical ventilation
NCLEX Key
Hypothermia + bradycardia + AMS + history of thyroid disease = myxedema coma until proven otherwise. Never actively rewarm too fast — may trigger cardiovascular collapse. Passive external warming preferred.
Levothyroxine Administration — Key Points
| Topic | Key Information |
|---|---|
| Timing | 30–60 minutes BEFORE breakfast on an empty stomach — food significantly reduces absorption |
| Drug Interactions | Iron supplements, calcium supplements, antacids, sucralfate — separate by at least 4 hours; cholestyramine: 4–6 hours; amiodarone and lithium affect thyroid function |
| Monitoring | TSH is the primary monitoring test; recheck 6–8 weeks after dose changes; stable patients: annual TSH |
| Overdose signs | Signs of hyperthyroidism — tachycardia, palpitations, anxiety, weight loss, heat intolerance; report to provider |
| Pregnancy | Thyroid requirements increase ~30–50% during pregnancy — TSH monitoring every trimester; untreated hypothyroidism risks fetal neurodevelopment |
| Elderly/Cardiac patients | Start at low dose; titrate slowly — abrupt full replacement can precipitate angina or MI in those with coronary artery disease |
NCLEX Pearls
TSH inversely reflects thyroid hormone: High TSH = low thyroid hormone (hypo). Low TSH = high thyroid hormone (hyper). TSH is the BEST screening test.
Levothyroxine timing: ALWAYS on an empty stomach 30–60 min before food. Iron and calcium separate by at least 4 hours.
Thyroid storm fever treatment: Acetaminophen ONLY — aspirin is contraindicated (displaces T4 from protein binding, worsens toxicity).
PTU preferred in thyroid storm (not methimazole): PTU blocks both synthesis AND T4→T3 conversion. Methimazole only blocks synthesis.
Iodine AFTER PTU in thyroid storm: Give PTU at least 1 hour before potassium iodide — iodine given first provides substrate for more hormone production.
Myxedema vs thyroid storm: Myxedema = hypothermia + bradycardia + coma (hypo). Thyroid storm = hyperthermia + tachycardia + agitation (hyper). Same disease, opposite ends.
Agranulocytosis risk: Both PTU and methimazole — educate patients to report fever, sore throat, mouth sores immediately; WBC with differential required before starting.
Related Resources
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 →