Chapter 49: Hyperthyroidism Flashcards
Cite the name of the most common form of hyperactivity of the thyroid gland.
graves disease
Define thyrotoxicosis and what circulating hormones are found in excess with this condition.
- thyrotoxicosis refers to the physiologic effects or clinical syndrome of hypermetabolism resulting from excess circulating levels of T4, T3, or both
- Hyperthyroidism and thyrotoxicosis usually occur together
Describe Graves’ disease and its characteristics.
(what, what causes, what antibodies, progression, associated with, s/s)
- an autoimmune disease of unknown cause characterized by diffuse thyroid enlargement and excess thyroid hormone secretion
- accounts for 75% of the cases of hyperthyroidism.
- Causative factors such as lack of iodine, smoking, infection and stressful life events, may interact with genetic factors to cause graves disease
*In graves disease the patient develops antibodies to the TSH receptor
*These antibodies attach to the receptors and stimulate the thyroid gland to release T3 T4 or both
*characterized by remissions and exacerbations, with or without treatment
*may progress to destruction of the thyroid tissue, causing hypothyroidism.
*Graves disease is associated with the presence of other autoimmune disorders including rheumatoid arthritis, pernicious anemia, systemic lupus erythematosus, addison’s disease, celiac disease, and vitiligo.
*Clinical manifestations:
They are related to the effect of excess circulating thyroid hormone
*It directly increases metabolism and tissue sensitivity to sympathetic NS stimulation
*Palpation: may reveal goiter & auscultation may reveal bruits (d/t ^^ blood supply) - Ophthalmopathy: Example → exophthalmos
*Things “speed up” so increased:
*Rate and force of cardiac contractions
*Cardiac output
*Appetite and thirst
*Peristalsis → diarrhea
*Fatigue (cause ur going crazy going stupid)
*Deep tendon reflexes
*Depression, nervousness, lability of mood
Explain exophthalmos and why does it occur.
Protrusion of eyeballs.
*Caused by increased fat deposits and fluid (edema) in the orbital tissues and ocular muscles. Increased pressure forces eyeballs outward.
Describe problems associated with exophthalmos.
*When the eyelids do not close completely, the exposed corneal surfaces become dry and irritated
*Corneal ulcers and loss of vision can occur
*Changes in the ocular muscles result in muscle weakness, causing diplopia (double vision)
Explain what are 2 conditions that are usually present when a thyroid storm (acute thyrotoxicosis) occurs.
*Acute thyroiditis is thought to result from stressors in a patient with preexisting hyperthyroidism
*Patients having a thyroidectomy are at risk because manipulation of the hyperactive thyroid gland results in an increase in hormones released.
Describe manifestations and severity of thyroid storm (11)
Severe tachycardia
Heart failure
Shock
Hyperthermia (up to 106 f)
Agitation
Delirium
Seizures
Abdominal pain
Vommitting
Diarrhea
Coma
Describe lab values and diagnostic studies that indicate hyperthyroidism. (4)
*Low or undetectable TSH levels (under 0.04)
*Increased free thyroxine (Free T4)
*Total T3 & T4 levels also may be assessed, bu they are not as definitive
*The Radioactive Iodine Uptake (RAIU) test can distinguish graves disease from other forms of thyroiditis
Cite the goals of managing hyperthyroidism and list the 3 treatment options.
three goals and three tx options
Goals: (1) block the adverse effects of excess thyroid hormone, (2) suppress over secretion of thyroid hormone, and (3) prevent complications
Treatment:
Antithyroid medications
Radioactive iodine therapy
Surgical intervention
Discuss the effects of antithyroid drugs, iodine, and B-adrenergic blockers.
They are not curative
First line antithyroid drugs (4)
what, 4 reasons to give, 1st line therapy for…, blocks what, how long
*inhibit thyroid hormone synthesis
*Reasons to use include graves disease in the young patient, hyperthyroidism during pregnancy, and the need to achieve a euthyroid state before surgery or radiation therapy
*It is the first line therapy in the thyrotoxicosis since it blocks the peripheral conversion of t4 to t3
*Therapy is continued for 6 to 15 months
Iodine (7)
used w/, for 2, large vs small dose, lowers what, max effect, span, mix
*Used with other antithyroid drugs to prepare the patient for thyroidectomy or for treatment of thyrotoxicosis
*Rapidly giving large doses of iodine inhibits synthesis of T3 and T4 and blocks the release of these hormones into circulation
*It also decreases the vascularity of the thyroid gland, making surgery safer and easier
*Maximal effect seen in 1 to 2 weeks
*Long term iodine not effective
*Iodine mixed with water or juice and given after meals = sip through straw so no staining occurs.
*Sign of iodine toxicity: Swelling of buccal mucosa and other mucous membranes
B-Adrenergic Blockers
uses, how it works, given w/, perfered BB for asthma and heart disease
*Used for symptom relief of thyrotoxicosis
*These drugs block the effect of SNS stimulation thereby decreasing tachycardia, nervousness, irritability, and tremors
*Propranolol is usually given with antithyroid agents
*Atenolol is the preferred Beta blocker for use in the hyperthyroid patient with asthma or heart disease
Describe the action of radioactive iodine in treating hyperthyroidism. (3)
(who for, how does it work, max effect when)
*Treatment of choice for non-pregnant adults
*It damages or destroys thyroid tissue, thus limiting thyroid hormone secretion
*RAI has a delayed response. The maximum effect may not be seen for 3 months
Describe indications for surgical therapy of hyperthyroidism (4)
- A large goiter causing tracheal compression
- A lack of response to antithyroid therapy
- Thyroid cancer
- May also be done when a patient is not a candidate for RAI
