NRSG 250: Exam 2 - Endocrine Disorders

How does the thyroid function?

1. hypothalamic-pituitary-thyroid (HPT) axis

   • hypothalamus → TRH

   • TRH → anterior pituitary → TSH

   • TSH → thyroid gland → T3 and T4

2. T3/T4 increase:

   • metabolism

   • HR

   • heat production

   • energy use

What is the negative feedback loop in the thyroid?

1. rising T3/T4 tells brain to slow stimulation

2. Hypothalamus decreases TRH

3. Pituitary decreases TSH

4. prevents overproduction of thyroid hormone

* High thryoid hormone → low TSH

Low thyriod hormone → high TSH

How does T3/T4 work and what do they do?

iodine needed to make T3/T4

• T4: main hormone released by thyroid

• T3: more active hormone

• T4 is converted → T3 in body tissues

thyroid hormone regulate cellular metabolism

What are the types of thyroid disorders classified by hormone activity?

1. hypothyroidism: decreased thyroid hormone activity

2. hyperthyroidism: increased thyoid hormone activity

What are the types of thyroid disorders classified by location?

1. Primary: thyroid gland problem

2. Secondary: pituitary problem

3. Tertiary: hypothalamus problem

What is hypothyroidism?

decreased thyroid hormone activity → slowed metabolism

What is the etiology of hypothyroidism?

1. Hashimoto thyroiditis / autoimmune thyroiditis (most common cause!!)

2. thyroidectomy or radioactive iodine

3. iodine deficiency

4. med-induced

5. pituitary or hypothalamic disease

What is goiter and how is it related to iodine?

Goiter: enlargement of the thyroid gland

• most common cause: iodine deficiency

Patho:

1. low iodine → low T3/T4

2. low T3/T4 → pituitary releases more TSH

3. high TSH → overstimulates thyroid tissue

4. thyroid enlarges

What are the manifestations of hypothyroidism?

1. fatigue/lethargy

2. cold intolerance

3. weight gain

4. dry skin, brittle nails, thinning hair

5. constipation

6. bradycardia

7. depression/slowed thinking

8. menstrral changes

What are the lab patterns of primary, secondary, and tertiary hypothyroidism?

1. Primary: problem is in thyroid gland

   • low T3/T4

   • high TSH

2. Secondary: problem in pituitary

   • low T3/T4

   • low or normal TSH

3. Tertiary: problem in hypothalamus

   • Low TRH

   • Low TSH

   • Low T3/Tr

What are the diagnostics for hypothyroidism?

Labs:

• TSH and free T4 = priority

• Hashimoto thyroiditis: check thyroid antibodies

  • TPOAb

  • TgAb

Imaging:

• thyroid ultrasound → enlarged gland or nodules

• fine needle aspiration → suspicious nodule

• CT / MRI → structural or pituitary concern

What tx is used for hypothyroidism?

Medication:

• levothyroxine

Considerations:

• usually lifelong therapy

• take on empty stomach

• take separate from calcium, iron, antacids, and vitamins

• monitor for signs of over-replacement:

  • tachycardia

  • palpitations

  • weight lost

  • heat intolerance

What nursing interventions are used for hypothyroidism?

1. Monitor heart rate, BP, temperature, weight

2. Assess fatigue, cognition, bowel pattern, skin changes

3. Teach medication timing and lifelong adherence

4. Track response to therapy over weeks

5. Watch older adults for cardiac stress after starting therapy

6. Assess for myxedema coma, a medical emergency

What is a complication of hypothyroidism?

myxedema coma

What is myxedema coma?

severe, life-threatening hypothyroidism often triggered by infection, trauma, surgery, or cold exposure

What are the S/S of myxedema coma?

1. Hypothermia

2. Bradycardia

3. Hypotension

4. Altered mental status

5. Hypoventilation

What is hyperthryroidism?

excess thyroid hormone production → hypermetabolic state (speeds body systems up)

What causes hyperthyroidism?

1. Graves disease (autoimmune) and most common

2. toxic nodules or goiter

3. thyroiditis

4. excess thyroid hormone replacement

Rare cause: pituitary tumor causing excess TSH

What diagnostics are used for hyperthyroidism?

Labs:

• TSH

• Free T4

• T3

Imaging:

• Thyroid US → nodules or enlarged thyroid

• Radioactive iodine uptake scan

• ECG → palpitations, tachycardia, or dysrhythmia risk

Other:

• TSH receptor antibodies/TRAb for Graves

What are the lab patterns in primary, secondary, and teritiary hyperthyroidism?

1. Primary: thyroid makes too much hormone

   • high T3/T4

   • negative feedback → low TSH

2. Secondary: pituitary releases too much TSH

   • high or normal TSH

   • high T3/T4

3. Tertiary: hypothalamus produces excess TRH

   • high TRH

   • high TSH

   • high T3/T4

What is Graves disease?

autoimmune disorder where antibodies simulate TSH receptors → excess T3/T4

• most common cause of hyperthyroidism in the US

What are the risk factors for Graves disease?

1. women

2. family hx

3. other autoimmune disease (T1DM, pernicious anemia, Addison’s dz)

What are the manifestations of Graves disease? (same for hyperthyroidism)

1. thyrotoxicosis (excess syndrome)

2. weight loss despite increased appetite

3. heat intolerance → sweating

4. tachycardia / palpitations

5. nervousness, anxiety, irritability

6. tremors; muscle weakness / wasting

7. insomnia

8. frequent stools / diarrhea

9. menstrual changes

10. enlarged thyroid → goiter

11. exophthalmos (bulging eyes)

What are the eye symptoms from Graves disease?

1. exophthalmos or proptosis (bulging eyes)

2. dry, irritated, or tearing eyes

3. red swollen conjuctiva

4. eyelid swelling

5. pretibial myxedema

What nursing interventions are used for Graves disease?

1. assess vision changes

2. encourage eye lubrication as prescribed

3. elevate HOB if edema

4. teach pt to report eye pain, diplopia, or worsening vision

How does hyperthyroidism affect pregnancy?

Risks for:

1. miscarriage

2. HTN complications

3. preterm birth

4. low birth weight

What tx is used for hyperthyroidism?

Medications:

• antithyroid meds (methimazole, PTU)

• beta blockers → reduce tachycardia, tremors, anxiety

Other/surgical:

• radioactive iodine ablation → destroys overactive thyroid tissue

• thyroidectomy → surgical removal

What nursing interventions are used for hyperthyroidism?

1. Assess all S/S (HR, rhythm, BP, temp, heat, weight, bowels, anxiety, eye symptoms)

2. Assess lab results

3. provide low-stimulation environment

4. monitor for dysrhythmias

5. administer meds as prescribed

6. teach med adherence and follow-up labs

7. encourage nutrition to meet increased metabolic needs

8. teach to report fever/sore throat → possible agranulocytosis

9. report worsening palpitations, chest pain, fever, or confusion

10. follow radiation safety instructions after radioactive iodone

11. lifelong thyroid hormone may be needed after ablation or surgery

What is a complication of hyperthyroidism?

thyroid storm

What is thyroid storm?

life-threatening worsening of thyrotoxicosis

What causes thyroid storm?

1. infection or acute illness

2. surgery / trauma

3. postpartum state

4. withdrawal of antithryoid meds

What are the manifestations of thyroid storm?

1. high fever

2. severe tachycardia or afib

3. HTN early → hypotension / shock later

4. agitation, delirium, confusion

5. N/V/D

6. HF

What tx/nursing interventions are used for thyroid storm?

Priority: ABCs + cardiac stabilization

• support airway & oxygenation

• monitor ECG, BP, temp, and mental status

Medications:

• beta blocker / cardiac med

• antithyroid med

• iodine after antithyroid

• glucocorticoids

Other:

• cooling measure → fever

• treat trigger → infection

• correct dehydration & electrolyte imbalance

What preoperative medications are used before a thyroidectomy and why?

1. antithyroid meds

   • methimazole or PTU → decrease T3/T4 production

   • PTU → blocks T4 to T3 conversion

2. iodine solution (after antithyroid meds)

   • SSKI or Lugol’s solution → decreases thyroid size and vascularity

   • reduces bleeding risk

3. beta blockers

   • propranolol or metoprolol → decrease HR, tremors, anxiety

What are nursing considerations for post-op thyroidectomy complications?

1. Priority: ABCs:

   • respiratory distress

   • laryngeal edema

   • vocal cord paralysis

   • keep trach tray & suction available

2. Hemorrhage:

   • check dressing behind neck

   • monitor drain output

   • watch for frequent swallowing

3. Hypocalcemia:

   • from parathyroid injury

   • S/S: tingling, tetant, Chvostek/Trousseau signs

   • keep calcium gluconate available

4. Thyroid storm:

   • S/S: fever, tachycardia, HTN, agitation

   • anticipate BB, antithryoid meds, cooling measyre