Presentation

What is the thyroid gland and what is its primary role in the body?

• A butterfly-shaped endocrine gland located in the anterior neck

• Sits just below the larynx and straddles the trachea

• Highly vascular

• Produces hormones that regulate:

  • Metabolic rate

  • Thermoregulation

  • Cardiovascular function

  • Neurologic development

  • Energy utilization

How does the hypothalamic–pituitary–thyroid (HPT) axis regulate thyroid hormone production?

• Hypothalamus releases thyrotropin-releasing hormone (TRH)

• Anterior pituitary releases thyroid-stimulating hormone (TSH)

• Thyroid gland releases T3 and T4

• Increased T3 and T4 suppress TRH and TSH via negative feedback

• Maintains endocrine homeostasis

Why is TSH considered the most sensitive test for thyroid function?

• Responds quickly to small changes in thyroid hormone levels

• Becomes abnormal before T3 and T4 in many cases

• Used as the primary screening test for thyroid disorders

What is hyperthyroidism and what is happening physiologically?

• A condition caused by excess production of T3 and T4

• Leads to:

  • Increased basal metabolic rate

  • Increased oxygen consumption

  • Increased sympathetic nervous system activity

What is the most common cause of hyperthyroidism?

• Graves’ disease

• Autoimmune disorder

How does Graves’ disease cause hyperthyroidism?

• Thyroid-stimulating immunoglobulins (TSI) mimic TSH

• Causes continuous stimulation of the thyroid gland

• Results in excessive hormone production

What other conditions can cause hyperthyroidism?

• Toxic nodular goiter

• Thyroiditis

• Excess thyroid hormone intake

• Pituitary adenoma producing excess TSH

• hCG-secreting tumors

What metabolic signs and symptoms are seen in hyperthyroidism?

• Weight loss despite increased appetite

• Heat intolerance

• Excessive sweating

• Increased energy expenditure

What cardiovascular manifestations occur in hyperthyroidism?

• Tachycardia

• Palpitations

• Systolic hypertension

• Atrial fibrillation

• Risk for high-output heart failure

What neurologic and sympathetic nervous system findings are associated with hyperthyroidism?

• Anxiety

• Restlessness

• Insomnia

• Fine tremors

• Hyperreflexia

What gastrointestinal and skin findings are associated with hyperthyroidism?

• Diarrhea or frequent bowel movements

• Warm, moist skin

• Hair thinning

What eye findings are specific to Graves’ disease and what nursing intervention is important?

• Exophthalmos (bulging eyes)

• Lid lag

• Nursing care includes eye lubrication to prevent corneal damage

What laboratory findings are expected in hyperthyroidism?

• Decreased TSH

• Increased free T4 and/or T3

How does radioactive iodine uptake help diagnose hyperthyroidism?

• Diffuse uptake indicates Graves’ disease

• Patchy uptake suggests toxic nodular goiter

• Low uptake indicates thyroiditis or hormone overuse

What medications are used to treat hyperthyroidism and how do they work?

• Methimazole:

  • First-line for most patients

  • Inhibits thyroid hormone synthesis

• Propylthiouracil (PTU):

  • Used in first trimester of pregnancy

  • Used in thyroid storm

  • Blocks T4 to T3 conversion

Why are beta-blockers used in hyperthyroidism?

• Control tachycardia

• Reduce tremors and anxiety

• Propranolol also decreases T4 to T3 conversion

What definitive treatments are available for hyperthyroidism?

• Radioactive iodine ablation (curative)

• Thyroidectomy:

  • Large goiters

  • Malignancy

  • Medication failure or intolerance

What is thyroid storm?

• A life-threatening hyperthyroid crisis

• Occurs in untreated or inadequately treated hyperthyroidism

• Causes rapid multi-organ decompensation

What factors commonly precipitate thyroid storm?

• Infection

• Surgery or trauma

• Iodine exposure

• Sudden withdrawal of antithyroid medications

What clinical manifestations are seen in thyroid storm?

• Severe tachycardia

• Hyperthermia

• Hypertension progressing to heart failure

• Altered mental status (agitation, delirium)

• Gastrointestinal distress

• High mortality if untreated

How is thyroid storm managed medically?

• Beta-blockers (propranolol) first

• PTU to block hormone synthesis and conversion

• Iodine solution given AFTER PTU

• Corticosteroids

• ICU-level supportive care

• Aggressive cooling and IV fluids

• Treat underlying cause

What are the priority nursing assessments after thyroidectomy?

• Airway patency

• Bleeding or hematoma

• Voice quality

• Signs of hypocalcemia

Why is hypocalcemia a concern after thyroidectomy?

• Parathyroid glands may be damaged

• Leads to decreased calcium levels

• Can cause tetany and neuromuscular irritability

What positioning and assessments are important after thyroidectomy?

• Semi-Fowler’s position

• Avoid neck extension

• Perform whisper test to assess laryngeal nerve

• Hoarseness is expected; absence of voice is abnormal

• Monitor for stridor and respiratory distress

What is hypothyroidism and what is occurring physiologically?

• Inadequate production of thyroid hormones

• Decreased metabolic rate

• Slowed body systems

What is the most common cause of hypothyroidism?

• Hashimoto’s thyroiditis

• Autoimmune destruction of thyroid tissue

What are the differences between primary, secondary, and tertiary hypothyroidism?

• Primary: thyroid gland failure

• Secondary: pituitary failure (low TSH)

• Tertiary: hypothalamic failure (low TRH)

Why is congenital hypothyroidism dangerous if untreated?

• Leads to cretinism

• Causes severe intellectual disability

• Results in impaired physical growth

What signs indicate hypothyroidism in infants?

• Lethargy

• Poor feeding

• Cool skin

• Hypotonia (“floppy” infant)

How do you know levothyroxine therapy is effective in infants?

• Infant becomes alert and playful

• Improved muscle tone

• Warm skin temperature

What clinical manifestations are seen in adults with hypothyroidism?

• Fatigue and lethargy

• Depression

• Weight gain

• Cold intolerance

• Bradycardia

• Constipation

• Dry, coarse skin

• Hair thinning

• Menstrual irregularities and infertility

What laboratory findings support a diagnosis of primary hypothyroidism?

• Elevated TSH

• Decreased free T4

• Possible anemia

• Hyperlipidemia

• Hyponatremia in severe cases

How is hypothyroidism treated?

• Lifelong levothyroxine (synthetic T4)

• Dose individualized based on age, weight, and cardiac status

• Start low in elderly and cardiac patients

What important medication interactions occur with levothyroxine?

• Increases effects of warfarin

• Increases insulin and digoxin requirements

What patient education is essential for levothyroxine therapy?

• Take on an empty stomach

• Take in the morning

• Separate from calcium and iron

• Do not stop abruptly

• Regular TSH monitoring every 6–8 weeks during adjustment

What is myxedema coma?

• Life-threatening complication of severe hypothyroidism

• Medical emergency with high mortality

What factors commonly trigger myxedema coma?

• Infection

• Cold exposure

• Trauma

• Sedatives

• Abrupt discontinuation of thyroid medication

What clinical findings are seen in myxedema coma?

• Hypothermia

• Bradycardia

• Hypotension

• Hypoventilation

• Decreased level of consciousness or coma

• Non-pitting edema

How is myxedema coma treated?

• Airway and ventilation support

• IV levothyroxine (T4)

• Possible IV liothyronine (T3)

• IV hydrocortisone

• Active rewarming

• IV fluids (0.9% normal saline)

• Continuous cardiac and neurologic monitoring