Overview
This lecture covers the key differences between hyperthyroidism and hypothyroidism, including causes, symptoms, diagnostic strategies, nursing priorities, and main medications. It also provides memory tricks and NCLEX test tips to help with retention and exam success.
Hyperthyroidism (Graves Disease)
- Definition & Patho: High energy and metabolism due to excess T3 and T4. Think "hyper = high and hot."
- Main Causes: Graves disease (autoimmune, "Gains disease" = high energy), excess iodine, or overmedication with thyroid hormones (e.g., too much levothyroxine).
- Classic Symptoms:
- High blood pressure (hypertension: "over 140, the heart says oh lordy")
- Tachycardia (HR > 100), palpitations, possible atrial fibrillation
- Weight loss (not gain), despite increased appetite
- Heat intolerance, hot and sweaty skin (diaphoresis)
- Frequent diarrhea (not constipation)
- Insomnia, restlessness, agitation
- Key Physical Signs:
- Exophthalmos ("grape eyes"—bulging eyes; NCLEX term: exophthalmos)
- Goiter ("golf balls" in the throat—enlarged thyroid)
- Complication: Thyroid storm (thyrotoxicosis)—life-threatening. Watch for agitation, confusion, restlessness, very high fever (>105°F), high HR/BP. NCLEX tip: These are priority findings.
- Diet: High calorie, high protein, high carbohydrate, frequent meals/snacks (6–8/day). NCLEX tip: Avoid high fiber (unless constipated), caffeine (no coffee, soda, tea), and spicy foods.
- Mnemonic: "Hyper = High and Hot" and "Graves = Gains (energy)."
Hypothyroidism (Hashimoto's Disease)
- Definition & Patho: Low and slow energy/metabolism due to low T3 and T4. Think "hypo = low and slow."
- Main Causes: Hashimoto's disease (autoimmune), low iodine intake, thyroidectomy, pituitary tumor, or anti-thyroid treatments.
- Classic Symptoms:
- Fatigue, weakness, muscle aches
- Weight gain and water retention (edema in legs, under eyes)
- Bradycardia (HR < 60), hypotension
- Cold intolerance, dry skin (not sweaty), slow healing
- Constipation (not diarrhea)
- Hair loss (alopecia; NCLEX tip: not hirsutism)
- Depression, apathy, forgetfulness, low libido, infertility
- Irregular menstruation: amenorrhea (no period) or hypermenorrhea (heavy bleeding)
- Complication: Myxedema coma—severe, life-threatening. Watch for extremely low respirations, low BP, and need for airway support. NCLEX tip: Priority is airway management (endotracheal tube/tracheostomy at bedside).
- Diet: Low calorie, low cholesterol, low saturated fat. Encourage frequent rest periods.
- Mnemonic: "Hypo = Low and Slow" and "Hashimoto's = Heavy and Slow."
Diagnostics
- Test Order: Always check T3 and T4 first:
- High T3/T4 = hyperthyroidism
- Low T3/T4 = hypothyroidism
- TSH: Usually opposite of T3/T4 (high TSH in hypo, low TSH in hyper).
- NCLEX tip: Do not memorize lab values; focus on whether levels are high or low.
- Mnemonic: "T3/T4 first, TSH follows."
Pharmacology & Treatments
- Hypothyroidism:
- Levothyroxine: Only main drug.
- Mnemonic: "LEVO"
- L: Lifelong therapy (never stop abruptly)
- L: Long, slow onset (3–4 weeks for effect)
- E: Early morning, Empty stomach (30–60 min before breakfast, same time daily)
- V: Very hyper—report signs of hyperthyroidism (agitation, confusion, high HR/BP/temp)
- O: Oh, the baby's fine (pregnancy safe)
- NCLEX tips:
- No food with dose (empty stomach)
- No cure—only treats, not cures
- No double dosing—if missed, take ASAP
- Never stop abruptly (risk of myxedema coma)
- Avoid narcotics, sedatives, and benzos (risk of respiratory depression)
- Hyperthyroidism:
- Methimazole: Not pregnancy safe.
- PTU (Propylthiouracil): Pregnancy safe. Mnemonic: "PTU = Puts Thyroid Underground." Report fever/sore throat (risk of agranulocytosis).
- SSKI (Potassium Iodide):
- S: Shrinks thyroid before surgery
- S: Stains teeth (use straw, juice)
- K: Keep 1 hour apart from other anti-thyroid meds
- Beta Blockers (e.g., propranolol): Control symptoms (lower HR/BP). Mnemonic: "LOL = Lowers heart vitals."
- Radioactive Iodine Uptake: Destroys thyroid in one dose.
- NCLEX tips:
- Negative pregnancy test before
- Remove neck jewelry/dentures
- NPO 2–4 hours before, 1–2 hours after
- No anesthesia; patient is awake
- Avoid contact with others (especially pregnant people, children) for 1–7 days
- Separate bathroom, flush 3x, no shared utensils/laundry, no kissing/cuddling
- Expect hypo symptoms after
- Thyroidectomy:
- Priorities:
- Airway: Monitor for stridor, hoarseness, weak voice (keep endotracheal/tracheostomy supplies at bedside)
- Breathing: Monitor for noisy breathing, voice changes
- Circulation: Watch for bleeding (especially behind neck/pillow)
- Position: Neutral head/neck, HOB 30–45° (semi-Fowler's), no flexing/extension
- Calcium: Monitor for hypocalcemia (tingling/numbness, Chvostek's & Trousseau's signs)
- Mnemonic: "If you remove the T (thyroid), check the C (calcium)."
Key Terms & Definitions
- T3/T4: Active thyroid hormones controlling metabolism and energy.
- TSH: Thyroid Stimulating Hormone from pituitary; regulates thyroid.
- Graves Disease: Autoimmune hyperthyroidism ("Gains disease").
- Hashimoto's Disease: Autoimmune hypothyroidism ("Heavy and slow").
- Thyroid storm: Life-threatening hyperthyroid crisis (agitation, confusion, high temp/HR/BP).
- Myxedema coma: Life-threatening hypothyroid crisis (low RR, BP, temp).
- Goiter: Enlarged thyroid gland ("golf balls" in throat).
- Exophthalmos: Bulging eyes ("grape eyes").
- Chvostek's sign: Facial twitching when cheek tapped (hypocalcemia).
- Trousseau's sign: Arm spasm with BP cuff (hypocalcemia).
- Amenorrhea: No period ("amen = no period").
- Hypermenorrhea: Heavy periods ("hyper = heavy bleeding").
Action Items / Next Steps
- Review medication protocols and patient education for levothyroxine and antithyroid drugs.
- Memorize emergency signs and NCLEX priorities for thyroid storm and myxedema coma.
- Study physical assessment findings: exophthalmos, goiter, hypocalcemia signs (Chvostek's, Trousseau's).
- Practice NCLEX-style questions on thyroid disorders.
- Use provided mnemonics and memory tricks to reinforce key concepts for exams.