Thyroid & Parathyroid Cheat Sheet
Hypothyroidism vs hyperthyroidism, levothyroxine, life-threatening crises, thyroidectomy care and parathyroid/calcium balance — high-yield for the NCLEX-RN.
What's in this cheat sheet
The thyroid governs metabolic rate, and TSH always moves opposite to T3/T4. This cheat sheet contrasts hypothyroidism and hyperthyroidism head to head, details levothyroxine and antithyroid drug teaching, covers the two emergencies (myxedema coma and thyroid storm), walks through thyroidectomy care and complications, and finishes with parathyroid disorders and their effect on serum calcium.
Pathophysiology & Diagnostics
The hypothalamus-pituitary-thyroid axis, negative feedback, and the lab pattern where TSH moves opposite T3/T4.
Hypo & Hyperthyroidism
Head-to-head assessment findings, nursing care, levothyroxine and antithyroid medications plus RAI safety.
Emergencies & Thyroidectomy
Myxedema coma, thyroid storm, and pre/post-op thyroidectomy care including hypocalcemia from parathyroid damage.
Parathyroid Disorders
PTH actions on calcium and the contrast of hyper- vs hypoparathyroidism.
Key Takeaways
High-yield facts most likely to appear on the NCLEX-RN.
TSH moves opposite to T3/T4: hypothyroid = ↓ T3/T4 with ↑ TSH; hyperthyroid = ↑ T3/T4 with ↓ TSH.
Give levothyroxine on an empty stomach each morning, it's taken for life, and never stop it abruptly (myxedema coma risk).
Do NOT palpate a goiter in hyperthyroidism — it can trigger a thyroid storm.
Antithyroid drugs (methimazole, PTU): report sore throat or fever (agranulocytosis) and watch for hepatotoxicity.
After thyroidectomy, position semi-Fowler's, keep emergency airway equipment ready, and watch for hypocalcemic tetany (Trousseau/Chvostek).
↑ PTH = ↑ calcium: hyperparathyroidism causes hypercalcemia; hypoparathyroidism (often post-thyroidectomy) causes hypocalcemia.
1. Pathophysiology & Diagnostics
The thyroid produces T3 and T4, which govern metabolic rate and influence every organ system.
The feedback axis
- Hypothalamus releases TRH → anterior pituitary releases TSH → thyroid releases T3 and T4
- High T3/T4 suppress TSH; low T3/T4 stimulate TSH
- Remember: TSH moves OPPOSITE to T3/T4
Diagnostic labs at a glance
| Lab | Hypothyroidism | Hyperthyroidism |
|---|---|---|
| T3 & T4 | ↓ Decreased | ↑ Elevated |
| TSH | ↑ Elevated | ↓ Decreased |
| Thyroid ultrasound | Nodules, goiter, masses | Structural assessment |
2. Hypothyroidism vs Hyperthyroidism
Assessment findings — head to head
| Feature | Hypothyroidism ("low & slow") | Hyperthyroidism |
|---|---|---|
| Labs | ↓ T3/T4, ↑ TSH | ↑ T3/T4, ↓ TSH |
| HR & BP | ↓ Bradycardia, ↓ BP | ↑ Tachycardia, palpitations, ↑ BP |
| Temperature | Cold intolerance | Heat intolerance, diaphoresis |
| Weight / GI | Weight gain, constipation | Weight loss, diarrhea |
| Energy / mood | Fatigue, lethargy (mimics depression) | Agitation, restlessness, insomnia |
| Hallmark | Dry skin, hair thinning, goiter | Exophthalmos (Graves'), goiter |
Hypothyroidism — nursing care
- Levothyroxine (synthetic T4): empty stomach each morning, 30–60 min before food
- Titrate dose slowly to prevent cardiac strain; monitor TSH
- Notify provider if HR > 100, chest pain, or palpitations (overtreatment)
- Drug is taken for life; NEVER stop abruptly → myxedema coma risk
Hyperthyroidism — nursing care
- Do NOT palpate the goiter — can trigger thyroid storm
- High-calorie diet to offset hypermetabolism; cool, quiet environment
- Eye care for exophthalmos: artificial tears, dark glasses, tape lids at night
- Antithyroid meds (methimazole, PTU): report sore throat/fever (agranulocytosis), monitor for hepatotoxicity
3. Emergencies & Thyroidectomy
Myxedema coma
From untreated hypothyroidism or stopping levothyroxine. Coma, extreme bradycardia, hypothermia, hypoventilation. Support ABCs, IV thyroid hormone, warm the patient.
Thyroid storm
Thyrotoxic crisis: high fever, severe tachycardia, agitation, HTN, seizures. Antithyroid meds + beta-blockers, IV fluids, acetaminophen (not aspirin), cooling.
Thyroidectomy care
- Pre-op: antithyroid meds to reach euthyroid state; potassium iodide reduces gland vascularity
- Post-op: position semi-Fowler's, avoid neck flexion, give levothyroxine (hormone must be replaced)
- Reassure that hoarseness is temporary; monitor for fever (early thyroid storm sign)
Post-thyroidectomy complications
| Complication | Signs & nursing action |
|---|---|
| Airway obstruction | Stridor, choking, frequent swallowing, blood behind neck → keep suction & emergency trach kit at bedside |
| Thyroid storm | High fever, tachycardia, agitation → beta-blockers, cooling, cardiac monitoring |
| Hypocalcemia (parathyroid damage) | Tetany, perioral/fingertip tingling, positive Trousseau or Chvostek → IV calcium gluconate, seizure precautions |
4. Parathyroid Disorders
The 4 parathyroid glands produce PTH, the primary regulator of serum calcium. Remember: ↑ PTH = ↑ calcium.
PTH actions (when calcium is low)
- Stimulates bone resorption → releases calcium into the blood
- Increases renal calcium reabsorption (less excreted in urine)
- Activates vitamin D → enhances intestinal calcium absorption
Hyper- vs hypoparathyroidism
| Hyperparathyroidism | Hypoparathyroidism | |
|---|---|---|
| PTH level | ↑ Elevated (often a tumor) | ↓ Decreased (often thyroidectomy damage) |
| Calcium | ↑ Hypercalcemia | ↓ Hypocalcemia |
| Watch for | Bone pain, stones, weakness | Tetany, Trousseau/Chvostek, seizures |
Thyroid & Parathyroid Self-Test
6 quick questions — answers reveal after you submit.
Q1. A client's labs show decreased T3 and T4 with an elevated TSH. Which condition do these results indicate?
Q2. Which instruction is correct for a client newly prescribed levothyroxine?
Q3. A client with Graves' disease has an enlarged thyroid. Which action should the nurse AVOID?
Q4. After a thyroidectomy, a client reports tingling around the mouth and in the fingertips. What complication does the nurse suspect?
Q5. A client taking methimazole for hyperthyroidism develops a sore throat and fever. What is the priority action?
Q6. A client has hyperparathyroidism. Which serum laboratory value does the nurse expect?
Answered 0 / 6 — unanswered count as incorrect.