Hyperthyroidism

Hyperthyroidism is an increase in T3 and T4 hormones by the thyroid gland. It has a variety of causes and effects on the body.

Etiology and Phisiology
Hyperthyroidism affect five time more women than men. Onset for both groups is usually between the ages of thirty and fourty. Onset is usually slow and the condition can go undiagnosed for years. It is possible to have spontaneous remission especially if the cause is infection or dietary but is usually a lifelong condition.

The secretion of thyroid horomones T3 and T4 is controlled by thyroid stimulating hormone (TSH) which is produced and secreted in the pituitary gland. T3 is the more active form of the hormone and is made when the body converts T4 into T3. Table 50-5 p. 1264 in the text has a list of the effects of thyroid hormone but in general thyroid hormone is stimulating. Too much will cause excess action in almost all bodily systems. In a healthy person TSH will increase when T3 and T4 levels decrease which stimulates increased production of T3 and T4 which in turns reduces the amount of T3 and T4 released. This negative feedback loop is disrupted in persons with Hyperthyroidism.

Graves Disease

Graves disease is an autoimmune disorder wherein the immune system creates antibodies to thyroid tissue. In the early stages these antibodies attach to thyroid tissue leading to an increase in T3 and T4 production. TSH production decreases as a result but this does not affect T3 and T4 production. In the later stages antibodies can cause the destruction of thyroid tissue leading to hypothyroidism. It is usually caused by a lack of iodine, infection or stressful life events.

Goiter

Goiter is a term used for an enlarged thyroid. It is usually caused by a lack of iodine in the diet although can be seen with graves disease or from eating foods that contain goitergens. They can be associated with hyper or hypo thyroidism or normal thyroid function.

Another type of goiter is called toxic nodular goiters and are associated with increased T3 and T4 production that doesn't respond to TSH. In this condition nodules of thyroid tissue grow on the thyroid and secrete thyroid hormone but do so independantly of the action of TSH.

Hashimoto's Thyroiditis

This condition has an acute onset and is often associated with pain in the neck and throat, unlike other forms of hyperthyroidism, It is caused when thyroid tissue is replaced by fibrous tissue. In the acute phase the patient is hyperthroid and in the chronic phase they are hypothroid. Don't confuse with Graves.

Signs and Symptoms
Thyroid hormone can exert its action on every cell in the body/ accordingly the effects can be seen almost anywhere. Table 50-5 p. 1264 has a more complete list but in general hyperthroidism is marked by an increase in bodily functions. Some of the more specific and unusual ones are below.

Thyroid hormone stimulates the metabolism directly but also increases the number of binding sites for epinephrine and norepinephrine. Epi and norepi are both hormones and neurotransmitters and stimulate the sympathetic nervous system.
 * Increased basic metabolic rate
 * Expothalmus (bulging of the eyes)
 * Diaphoretic
 * Enlargement of the gland
 * Bruit and thrill over the thyroid upon auscultation.
 * Amenorrhea
 * Fine thin hair
 * Heat intolerance
 * Thin
 * Eats a lot, never gains weight. (So annoying)
 * Always moving, restless.
 * Agitated easily.
 * Tremors of the hands.
 * Easily fatigued, muscle weakness
 * Tachycardia, atrial fib, increased blood pressure and respirations.

Thyroid Storm (Thyrotoxic Crisis)

This is a medical emergency and requires immediate intervention and notification of the care provider. In general all the symptoms of hyperthyroidism are greatly increased. Pulse is >130, temp >100 (37.7), N/V/D, severly agitated and restless, seizurecomadeath.

Labs

TSH will be decreased while free T4 levels will be elevated. T3 levels may be measured and are usually elevated along with T4. RAIU (radioactive iodine uptake) test is used to tell which kind of hyperthroidism is present. In graves disease uptake will be between 35% and 95%, in thyroiditis uptake will be about 2% while those with a nodulare goiter will show an uptake in the high normal range.Normal range for this test is 15% - 25% uptake of iodine.

Normal lab values
 * TSH (Thyrotropin) - 0.4-4.2 mIU/L
 * T4 (Thyroxine) - Males 4-12 ug/dl Females 5-12 ug/dl. < 2 = Myxedema. > 20 = Thyroid Storm
 * T3 (Triodothyronine) - 70-205 ng/dl ages 20-50. Decreases with age.

Medical Treatment
Radioactive Iodine

This is the treatment of choice for hyperthyroidism when remission is impossible and is also used to treat those in thyrotoxic crisis. Radioactive iodine destroys thyroid tissue with the goal being destruction of enough tissue to prevent hyperthyroidism while leaving enough intact to still produce adequate amounts of thyroid hormone. Effects take 2-3 months to be seen and patients may be treated with antithyroid medications until the effectiveness of treatment is known. It is possible to overtreat and kill all of the thyroid. Nurse and patient should both be aware of sign and symptoms of hypothyroidism. Thyroiditis and parotiditis are complications and usually subside in a few days. Ice chips, sips of water and salt and soda gargle will help with the discomfort.

Thyroidectomy

Used for rapid reduction in thyroid hormone levels, when there is a large goiter, or if someone is not a canidate for iodine therapy (ie. pregnancy). Subtotal is preferred with removal of 5/6 of the thyroid. Antithyroid drugs and and potassium iodine are given prior to surgery to reduce thyroid size and vascularity thereby reducing hemorrhage and side effects. Post op patient will need humidified O2, support for the head and neck to avoid flexion, monitor for bleeding, swelling (patent airway), whisper (nerve damage).

Accidental removal of the parathyroid gland is a possible complication and an emergency. This causes a decrease in serum calcium levels. Signs are tingling in extremities and mouth, Chvostek's sign (tap angle of jaw and observe for twitch), and Trousseau's sign (B/P cuff causes hand to cramp severly if inflated to 250+ for three minutes). Treatment is 10% calcium gluconate given slowly, 0.5ml/min. Rapid administration can cause vasodilation, cardiac dysarrythmia and death.

Medication PTU and methimazole (Tapazole) both block the creation of T3 and T4 in the thyroid. PTU reduces the conversion rate of T4 to T3. Improvement starts in 1-2 weeks with maximal relief seen after 4-8 weeks. Therapy lasts for 6-15 months after which it is discontinued to check for spontaneous remission which happens in 20% - 40% of cases. Generally used prior to surgery along with iodine to reduce size and vascularity. Glucocorticoids are also are also used to block the conversion of T4 to T3. Generally medications will be used prior to surgery, during pregnancy, in children, or when someone is not a good canidate for surgery.

Thyroid Storm

This can occur seperately or after a thyroidectomy. It is a medical emergency and requires physician notification and nursing intervention. Iodine, PTU, Tapazole and glucocorticoids are used to reduce the levels of thyroid hormone while propranolol (Inderol) is used for symptom relief. IV fluids will be need if patient is dehydrated. Other interventions are assessment for cardiac problems, patent airway, tempreture and emotional status. Interventions are aimed at relieving these problems.

Nursing Considerations
Assessment

Assessment will involve looking for the signs and symptoms listed above. Enlarged thyroid, expothalmus, bruit and thrills over the thyroid are especially indicitative of hyperthyroidism. Interventions Thyroid Storm
 * Dehydration if vomiting, diarrhea and diaphoresis present.
 * Signs of hypocalcemia (tingling, Trousseau's and Chevostok's) if surgerical removal was done.
 * Signs and symptoms of hypothyroidism.
 * Whisper as it could indicate nerve damage
 * Bleeding or swelling that could comprimise the airway or is uncontrolled.
 * If radioactive iodine used assess for swelling in the mouth, salivation, nausea, vomiting and skin reactions.
 * Patent airway
 * Lyrangeal stridor (wheezing). May be related to hypocalcemia or nerve damage.
 * If expothalmus is present: eye drops, elevate head of bed, low sodium diet, tape eyelids shut for sleep, and dark glasses to prevent glare and protect from irritants.
 * Cool quiet room if inpatient.
 * I&O
 * Assist with exercises with muscle tremors present
 * Humidified O2 if thyroidectomy was done.
 * Support head and neck if thyroidectomy was done.
 * Ice chips, sips of water and salt and soda gargle if sore throut or mouth.
 * Surgical patients may be NPO or have partial restrictions regarding intake. Sodium may also be restricted.

This can occur seperately or after a thyroidectomy. It is a medical emergency and requires physician notification and nursing intervention. Iodine, PTU, Tapazole and glucocorticoids are used to reduce the levels of thyroid hormone while propranolol (Inderol) is used for symptom relief. IV fluids will be need if patient is dehydrated. Other interventions are assessment for cardiac problems, patent airway, tempreture and emotional status. Interventions are aimed at relieving these problems.

Patient Education
If surgery performed: If radioactive iodine is used educate about dry mouth and how to relieve as above. Also swelling of the mouth, salivation, nausea and vomiting. These are signs of iodine toxicity and the provider should be notified.
 * Signs and symptoms of hypocalcemia
 * Signs and symptoms of nerve damage
 * Support head
 * Adequate iodine intake but not too much. Table salt not sea salt. Seafood twice a week.
 * Exercise
 * Signs and symptoms of hypothyroidism. May be temporary or permanent.
 * If replacement therapy needed explain the need for compliance especially of there is no thyroid function.
 * Patient education when using preop meds to shrink thyroid is also important as noncompliance is a problem and can lead to negative outcomes postop.