side by side comparison

Hypothyroidism vs Hyperthyroidism: Everything Slow vs Everything Fast

The NCLEX hands you a set of vitals and a symptom cluster — bradycardia with constipation or tachycardia with diarrhea — and expects you to pick the correct thyroid disorder in seconds. Reversing even one finding (like temperature intolerance) leads you to the wrong diagnosis and the wrong intervention.

Comparison

Side-by-side2 compared
Dimension
Hypothyroidism
Hyperthyroidism (Graves')
Pathophysiology & risk
  • ↓ thyroid hormone — metabolism slows
  • Hashimoto's, post-RAI/thyroidectomy
  • ↑ thyroid hormone — metabolism accelerates
  • Graves' autoimmune (TSI antibodies)
Signs & symptoms
  • Bradycardia, weight gain, cold intolerance
  • Constipation, fatigue, depression
  • Dry coarse skin, hair loss, periorbital edema
  • ★Exophthalmos (bulging eyes) — Graves'
  • Tachycardia/AFib, weight loss, heat intolerance
  • Diarrhea, anxiety, tremor, insomnia
Diagnostics & labs
  • ★↑ TSH (primary)
  • ↓ T3, ↓ T4
  • ★↓ TSH (suppressed)
  • ↑ T3, ↑ T4
Nursing priorities
  • Provide warmth; monitor for slowed vitals
  • Prevent constipation; pace activity
  • Cool, low-stimulation environment
  • Cardiac monitoring (AFib); eye protection
Treatment & meds
  • Levothyroxine daily, empty stomach
  • Lifelong replacement
  • Methimazole or PTU; beta-blocker for symptoms
  • Radioactive iodine or thyroidectomy
Patient teaching
  • Same time daily, 30–60 min before food
  • Lifelong; do not stop abruptly
  • ★Report sore throat/fever — agranulocytosis
  • RAI radiation precautions; protect eyes
Red flags — escalate
  • Myxedema coma: hypothermia, bradycardia, ↓ LOC
  • Warm slowly; IV levothyroxine
  • Thyroid storm: temp > 104°F, severe tachycardia
  • Cooling, beta-blocker, PTU, iodine
Complications
  • Myxedema coma; pericardial effusion
  • AFib, heart failure, osteoporosis
Pathophysiology & risk

Hypothyroidism

  • ↓ thyroid hormone — metabolism slows
  • Hashimoto's, post-RAI/thyroidectomy

Hyperthyroidism (Graves')

  • ↑ thyroid hormone — metabolism accelerates
  • Graves' autoimmune (TSI antibodies)
Signs & symptoms

Hypothyroidism

  • Bradycardia, weight gain, cold intolerance
  • Constipation, fatigue, depression
  • Dry coarse skin, hair loss, periorbital edema

Hyperthyroidism (Graves')

  • ★Exophthalmos (bulging eyes) — Graves'
  • Tachycardia/AFib, weight loss, heat intolerance
  • Diarrhea, anxiety, tremor, insomnia
Diagnostics & labs

Hypothyroidism

  • ★↑ TSH (primary)
  • ↓ T3, ↓ T4

Hyperthyroidism (Graves')

  • ★↓ TSH (suppressed)
  • ↑ T3, ↑ T4
Nursing priorities

Hypothyroidism

  • Provide warmth; monitor for slowed vitals
  • Prevent constipation; pace activity

Hyperthyroidism (Graves')

  • Cool, low-stimulation environment
  • Cardiac monitoring (AFib); eye protection
Treatment & meds

Hypothyroidism

  • Levothyroxine daily, empty stomach
  • Lifelong replacement

Hyperthyroidism (Graves')

  • Methimazole or PTU; beta-blocker for symptoms
  • Radioactive iodine or thyroidectomy
Patient teaching

Hypothyroidism

  • Same time daily, 30–60 min before food
  • Lifelong; do not stop abruptly

Hyperthyroidism (Graves')

  • ★Report sore throat/fever — agranulocytosis
  • RAI radiation precautions; protect eyes
Red flags — escalate

Hypothyroidism

  • Myxedema coma: hypothermia, bradycardia, ↓ LOC
  • Warm slowly; IV levothyroxine

Hyperthyroidism (Graves')

  • Thyroid storm: temp > 104°F, severe tachycardia
  • Cooling, beta-blocker, PTU, iodine
Complications

Hypothyroidism

  • Myxedema coma; pericardial effusion

Hyperthyroidism (Graves')

  • AFib, heart failure, osteoporosis

★ marks the fact that sets a column apart.

Clinical Pearl

Hypo = cold, slow, heavy, constipated. Hyper = hot, fast, thin, diarrhea — opposites across every system.

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Component Topics

Hyperthyroidism & Graves' DiseaseHypothyroidism
See all Endocrine topics