Treatment

Medication to control elevated heart rate and/or high blood pressure caused by the hyperthyroidism.

• Examples include Propranolol, Metoprolol, etc.

Should be considered in all symptomatic patients with overt or subclinical hyperthyroidism, especially in older patients, patients with resting hear rate > 90 beats per minute, or pre-existing cardiovascular disease.

Antithyroid Drugs (ATD’s).

• Examples:
  • Methimazole
    • First line option due to lower risk of side effects.
    • Contraindicated during pregnancy.
  • Propylthiouracil (PTU)
    • Safe during pregnancy.
    • Has higher risk of side effects.
• Advantages:
  • Results in rapid improvement in symptoms.
  • Good for poor surgical candidates.
  • Good for patients who do not have access to an experienced, high volume thyroid surgeon.
  • Patients who do not have the time or space for post RAI quarantine in their homes.
• Disadvantages:
  • Potential side effects:
    • Rare but life-threatening liver failure (higher with PTU).
    • Rare but life-threatening agranulocytosis (low white blood cells, higher with PTU).
    • Rash and/or itching (higher with methimazole).
  • Requires routine blood draws to measure thyroid hormone levels (to ensure medication is effective and at the correct dose), liver function, and white blood cells counts.
  • Does not cure hyperthyroidism (helps to obtain remission, or no signs of Graves’ disease) and often requires indefinite treatment.
    • Up to 30% of Graves’ disease may go into remission over time with ATD treatment.
      • Thyrotropin Receptor Antibody (TRAb) can be measured over time to determine remission (return to normal range).
  • Treatment can sometimes be ineffective or not tolerable due to above side effects.

Radioactive Iodine (RAI).

• A one-time radioactive iodine pill (I-131) that is swallowed and kills overactive thyroid cells.
• Advantages:
  • Potentially one-time curative treatment.
  • Good for poor surgical candidates.
  • Good for patients who do not have access to an experienced, high volume thyroid surgeon.
  • Good for patients who experienced side effects on ATD.
• Disadvantages:
  • Requires a special diet prior to taking the pill.
  • Requires a period of quarantine following ingestion.
    • Necessary space at home, ability to take time off work / work from home, and have appropriate childcare.
  • Potential side effects of RAI:
    • Dry mouth and eyes, salivary gland inflammation / infection, increased dental cavities.
  • Contraindicated in pregnant women, women planning on becoming pregnant in the following 6 months, and women breastfeeding.
    • Can result in cretenism of the baby (complete loss of thyroid function).
  • Contraindicated if there is known or high suspicion for thyroid cancer.
  • Often results in permanent hypothyroidism (low thyroid hormone) requiring a lifelong, once daily thyroid hormone replacement medication.
  • Can potentially make orbitopathy (bulging eyes or Thyroid Eye Disease) worse.
  • Chance for recurrence requiring repeat RAI treatment.
    • Varies from 15 – 40%, depending on the dose of RAI given.
    • Higher the RAI dose, less likely chance of recurrence, but also higher risk of side effects.
  • Less effective on large goiters.
  • Contraindicated in smokers.
  • Increased risk for developing Primary Hyperparathyroidism later in life due to radiation effects on the parathyroid glands.

Surgery.

• Total thyroidectomy.
  • Removal of the entire thyroid gland.
    • The patient must first have their hyperthyroidism well controlled with ATD’s prior to performing surgery.
  • Advantages
    • Only 100% definitive curative treatment option.
    • Can resolve co-existing goiter causing compressive symptoms.
    • Can address concurrent thyroid cancer, suspicion for thyroid cancer, and primary hyperparathyroidism.
    • Good for women planning pregnancy in < 6 months.
    • Good for patients with orbitopathy (bulging eyes) and smokers.
    • Good for patients who experienced side effects on ATD.
    • Does not require special diet to prepare for RAI or a period of quarantine following the RAI.
  • Disadvantages
    • Patients must be healthy enough to undergo general anesthesia.
    • Results in permanent hypothyroidism (low thyroid hormone) requiring a lifelong, once daily thyroid hormone replacement medication.
    • Permanent scar in a natural horizontal crease in the neck.
    • If no access to an experienced, high-volume surgeon, the below surgical risks may be higher.
    • Risk for temporary (5%) or permanent (1%) recurrent laryngeal nerve damage.
      • Resulting in a hoarse and weak voice.
    • Risk for permanent hypoparathyroidism (~2%) causing hypocalcemia (low calcium levels).
      • Requires lifelong daily calcium and Vit D supplements.
    • Life-threatening bleeding in the neck (hematoma) following surgery (1%).
      • Requires urgent return to the operating room to control bleeding.

American Thyroid Association (ATA) generally recommends RAI or thyroidectomy.

• ATD’s may be considered on occasion as well.

Advantages and Disadvantages for ATD’s, RAI, and surgery is generally the same as for Graves’ disease with the following exceptions.

• The risk for retreatment (additional dose of RAI) is higher (up to 20%) following initial RAI for toxic multinodular goiter and single toxic nodule.
• If there is a single toxic nodule or multiple hot nodules that are all in the same lobe (same side) of the thyroid, a hemithyroidectomy should be the surgical treatment of choice.
  • Reduces risk of needing to be on life-long daily thyroid hormone replacement from 100% with total thyroidectomy to 30% for hemithyroidectomy.
  • Completely eliminates the risk for permanent hypoparathyroidism / hypocalcemia given that two parathyroid glands will not be manipulated.
    • Only one parathyroid gland is needed to keep calcium levels in the normal range.
  • Only one recurrent laryngeal nerve is at risk for temporary or permanent injury resulting in hoarse / weak voice changes, instead of both nerves.
• If there are multiple hot nodules in contralateral (opposite sides) thyroid lobes, then a total thyroidectomy is required.
  • 100% the patient will need to be on a once daily thyroid hormone medication for the rest of their life, started the day following surgery.
  • Risks are similar to total thyroidectomy for Graves’ disease as previously discussed.

Thyroid Ultrasound should be obtained to identify any coexisting thyroid nodules.

• If nodules are ‘hot’ on corresponding uptake scan, only those with high-risk features require a biopsy.
• If nodules are ‘cold’ on corresponding uptake scan or within a Graves thyroid gland, they should be assessed and biopsied according to the TIRAD’s guidelines.

Hyperthyroidism must be controlled with ATD’s +/- beta blockers prior to surgery.

• Limits the risk of life-threatening thyroid storm during surgery (uncontrollable heart rate and blood pressure).
  • If hyperthyroidism cannot be controlled adequately with ARD’s, use of beta blockers, KI (potassium iodine), glucocorticoids, and/or cholestyramine should be considered.

Calcium and Vitamin D levels should be checked prior to surgery.

• Correct Vitamin D deficiency and start calcium supplements (1,000 mg three times per day for 2 weeks) prior to surgery to limit severity of potential hypoparathyroidism / hypocalcemia (low blood calcium levels) following surgery.

KI (Potassium Iodine, aka SSKI or Lugol’s solution) drops can be given 10 days before surgery.

• Dosing 5-7 drops Lugol’s solution (8 mg iodide / drop) or 1-2 drops SSKI (50 mg iodide / drop) three times per day mixed with water or juice.
• Ingesting extra Iodine inhibits thyroid hormone production (Wolf Chaikoff effect).
• Can reduce the risk for thyroid storm in patients whose hyperthyroidism is difficult to control with ATD’s or cannot tolerate ATD’s.
• Some studies suggest it can reduce the amount of blood loss during surgery which can allow for a cleaner surgical field during dissection.

ATD’s are stopped following surgery, beta blockers are slowly weaned off with the help of the referring Endocrinologist.

A once daily thyroid hormone replacement medications is started the morning following surgery.

• The dose of this medication is based on the patient’s weight (1.6 mcg x weight in Kg’s) and may need to be adjusted overtime based on objective lab values and subjective symptoms.

Increased surgical risks associated with Hyperthyroidism compared to standard thyroidectomy risks:

• During surgery:
  • Injury to the recurrent laryngeal nerve
  • Increased blood loss.
• After surgery:
  • Bleeding in the neck (hematoma) possibly requiring return to the operating room to control.
  • Hypoparathyroidism (low blood PTH) / Hypocalcemia (low blood calcium)
    • Increased inflammation of the thyroid gland and surrounding tissues is associated with higher risks for accidental parathyroid gland removal along with the thyroid gland and manipulation of the parathyroid glands causing temporary or permanent dysfunction.
    • Hungry bone syndrome.
      • Bones are starved of calcium because of Hyperthyroidism (suppressed / low TSH levels).
      • Once the hyperthyroidism is cured, the bones are very hungry for calcium, and will absorb it from the blood rapidly, increasing the risk for temporary hypocalcemia.
      • Low threshold to start on Calcium before surgery, and aggressively treat hypocalcemia following surgery with Calcium and Calcitriol.

Due to these increased risks associated with surgery for Hyperthyroidism, surgical outcomes are the highest and complication rates are the lowest when surgery is performed by a high-volume surgeon (> 50 thyroidectomy surgeries per year).

To read more about Thyroid surgeries including what to expect, as well as details regarding recovery and risks:

• Hemithyroidectomy.
• Total Thyroidectomy.