PANCE Blueprint Endocrinology (7%)

16 y/o with diaphoresis, weight loss, tremor, palpitations, and neck swelling

Patient will present as → a 37-year-old female with a 2-week history of a painful mass in her neck after having a sore throat and fever for 3 days. The patient reports the mass has slowly been enlarging over that time span and has become more painful to the touch. She also reports feeling hot, even when her coworkers feel cold, and reports loose stools over the past week. The patient’s vital signs are T 98.6F, BP 140/90, Pulse 110 bpm, and SpO2 100%. On exam, you note a diffusely enlarged thyroid that is painful to the touch. TSH is decreased, T4/T3 is elevated, and radioactive iodine uptake and scan at 24 hours reveals an uptake of 3% (normal 8-25%).

Thyroiditis is a general term that refers to inflammation of the thyroid gland and includes a group of individual disorders causing thyroidal inflammation but presenting in different ways

Hashimoto’s thyroiditis: an autoimmune form of thyroiditis ⇒ autoantibodies directed against thyroid ⇒ thyroid tissue is destroyed over time ⇒ chronic hypothyroidism

• The most common cause of hypothyroidism in the United States
• Hashimoto's thyroiditis may present similarly to subacute thyroiditis, but the presence of neck tenderness and a recent viral illness should make you think subacute thyroiditis.
• Goiter on PE
• High levels of anti-TPO antibodies
• TX depends on whether hypothyroidism is present
  • euthyroid: no treatment
  • chronic hypothyroidism: lifelong substitution with T4

Postpartum thyroiditis

• 2-12 months after giving birth
• Immune system diminished during pregnancy ⇒ after childbirth immune system is more active and might attack the thyroid
• Hyperthyroid phase 5-7 months after birth, followed by normal thyroid function

Subacute thyroiditis (Quervain's thyroiditis)

• The most common cause of thyroid pain and has a greater incidence in women
• Inflamed, painful thyroid, fever, and muscle aches
• The etiology is often post-infectious and viral in origin
• Usually following symptoms such as fever, myalgia, and pharyngitis
• Early in the course may be hyperthyroid, followed by a period of hypothyroidism
• Increased ESR (60-100)

Drug-induced: Thyroiditis can also be seen in patients taking certain drugs

• Antithyroid medications: methimazole and propylthiouracil
• Lithium - bipolar disorder
• Amiodarone - antiarrhythmic
• Interferon alpha
• Tyrosine Kinase Inhibitors (e.g., Sunitinib) - anti-cancer
• Checkpoint inhibitors (e.g., Nivolumab, Pembrolizumab)
• TSH should be checked every 6-12 months - T4 therapy given right away

Infectious bacterial thyroiditis (rare) is often due to the hematogenous spread of staph or strep

• Its signs are the classic ones of inflammation: fever, heat, pain, redness, and swelling
• ↑ WBC

Summary of thyroiditis:

Lab values depend on the cause of thyroiditis and may be euthyroid

• Other possibilities include ↑ ESR (subacute), ↑ WBC count (infectious), ↑ anti-TPO antibodies (Hashimoto's)
• TFTs (if abnormal) are usually hyperthyroid at presentation - ↓ TSH, ↑ T4, and ↑ T3

Ultrasound and radioactive iodine scanning have little value in this setting and are not warranted

• If performed, a radioactive iodine (RAI) scan will reveal diminished uptake

If there is PAIN think:

• Painful subacute - De Quervain's (granulomatous) usually post viral
• Infectious - bacterial mainly - strep or staph most common
• Radiation
• Trauma

If there is NO PAIN think

• Postpartum - 1-2 months of hyperthyroidism after delivery
• Drug-induced - the most common cause of drug-induced thyroiditis is Lithium or Amiodarone
• Hashimoto thyroiditis

Hashimotos: TX depends on whether hypothyroidism is present

• euthyroid: no treatment
• chronic hypothyroidism: lifelong substitution with T4

Subacute and postpartum thyroiditis usually resolve on their own after 12-18 months; often only need pain management

• Beta-blockers during hyperthyroid state
• T4 for several months during hypothyroid phase until TSH normalizes then can be stopped
• Occasionally permanent hypothyroidism
• Aspirin for pain and inflammation

Drug-induced: Stop offending drugs *lithium *Amiodarone - will usually return to euthyroid state once the meds are stopped

Infectious bacterial thyroiditis: The treatment is that for any febrile disease, including specific antibiotic drugs if the invading organism has been identified and its sensitivity to the drug established. Surgical drainage if abscess present