Graves Disease

Pregnant pt with h/o autoimmune disease presents with worsening heat intolerance, insomnia, and anxiety/restlessness. Reports recent onset diplopia, blurred vision, reduced color perception, and diarrhea. HTN, exophthalmos, goiter, periorbital edema, thyroid acropachy, pretibial myxedema, and vitiligo on exam.

  • TSH < 0.1 mIU/L with inappropriately elevated free T4 and total T3 levels

  • Positive anti-thyroid peroxidase (TPO) antibodies

  • Radioactive iodine uptake scan of thyroid shows high uptake with homogeneous radioactive iodine distribution

  • Treatment

    • 1st trimester of pregnancy: Start Propylthiouracil 50 mg TID and titrate to appropriate TSH

    • After 1st trimester: Methimazole 5-120mg in divided doses; pt counseled about dose-dependent risk for agranulocytosis

  • Pt advised that definitive treatment will include radioactive iodine ablation vs. surgical removal of thyroid gland

Notes

  • Thyroid acropachy

    • Clubbing of fingers/toes with swelling of hands/feet; considered pathognomonic for Graves disease

    • Rare: Occurs in only 0.3% of patients

  • Anti-thyroperoxidase (TPO) antibodies are markers of autoimmune destruction of thyroid tissue may be positive in Graves disease (hyperthyroidism) or Hashimoto’s thyroiditis (hypothyroidism)

  • Only hyperthyroid state with high, homogeneous uptake of radioactive iodine

Toxic Multinodular Goiter

Elderly pt presents with new onset palpitations and heat intolerance. Reports associated sweating, tremor, and anxiety. Pt has lived in Great Lakes region her entire life, keeps Kosher, and exclusively eats garden non-processed foods flavored with sea salt. Tachycardia and lid-lag on exam.

  • TSH < 0.1 mIU/L with elevated free T4 and T3 levels

  • Radioactive iodine uptake scan of the thyroid shows high uptake with nodular radioactive iodine distribution in multiple areas of accumulation

  • Treatment: Trial of medications to control symptoms including

    • Propranolol extended release 80 mg daily

    • Methimazole 5 mg TID; f/u labs in 6 weeks with titration to 20 mg TID as needed to maintain TSH, free T4 and T3 in appropriate ranges

  • Pt advised about risk for thyroid storm; instructed to contact provider for new onset fever, agitation, tachycardia, irregular heartbeat, diarrhea, and/or pedal edema

Notes

  • Second most common cause of hyperthyroidism after Graves disease

    • Pathophysiology: Hyperplasia of thyroid follicular cells that no longer respond to regulation by TSH

    • Most common in elderly patients living in iodine-deficient areas, e.g. those surrounding the Great Lakes in the United States (chronic iodine insufficiency = increased risk for hyperplasia)

    • Most salt in the U.S. is iodized, but unprocessed Kosher or “sea salts” may not contain iodine

  • A single toxic adenoma is referred to as Plummer disease; it will present as a single area of accumulation on radioactive iodine uptake scan

Transient Thyroiditis

Pt with h/o autoimmune disease s/p delivery presents with new onset episodes of palpitations and heat intolerance. Recently started on amiodarone, lithium. No goiter, thyroid tenderness, Graves' ophthalmopathy or pretibial myxedema on exam.

  • TSH > 0.1 mIU/L but < 0.4 mIU/L with elevated free T4 and T3 levels

  • Obtain anti-thyroperoxidase antibodies

  • Radioactive iodine uptake scan shows low uptake

  • Pt counseled that condition may progress to hypothyroidism

  • Pt encouraged to establish appointment with cardiologist and psychiatrist to discuss discontinuing amiodarone and lithium

  • Pt advised to follow-up for repeat TSH, FT4, and T3 testing in 6 weeks and again at 6 months

Notes

  • May be initiated by

    • Idiopathic autoimmune event (painless)

    • Childbirth (postpartum thyroiditis)

    • Medications, e.g. amiodarone, lithium

  • Categories of transient thyroiditis

    • Painless thyroiditis - May or may not be followed by hypothyroidism.

    • Hashimoto’s thyroiditis - Involves autoimmune destruction of thyroid gland that releases thyroid hormone; ultimately followed by hypothyroidism

    • Postpartum thyroiditis - Transient thyroiditis that occurs within 1 year postpartum

  • Diagnosis

    • Presence of anti-thyroperoxidase antibodies may indicate Hashimoto’s thyroiditis, but does not rule out Graves disease as they can be present in both conditions

    • A radioiodine thyroid scan may not be indicated in patients with a TSH > 0.1 mIU/L; follow-up with repeat laboratory testing is generally indicated

Subacute (de Quervain) Thyroiditis

Pt with h/o recent viral illness presents with acute onset thyroid tenderness. Reports recent fever. Pain with palpation of thyroid and vesicular rash present on posterior pharynx/hand/feet on exam.

  • TSH > 0.1 mIU/L but < 0.4 mIU/L with elevated free T4 and T3 levels

  • Obtain anti-thyroperoxidase antibodies

  • Radioactive iodine uptake scan shows low uptake

  • Naproxen 500 mg BID for pain and inflammation

  • Pt cousled that condition generally improves at 6 weeks and resolves at 6 months

  • Pt advised to present for repeat TSH, free T4, and T3 testing in 6 weeks and at 6 months

Notes

  • Etiology

    • Inflammation due to viral illness releases preformed T4 and T3 hormone

    • Cases have been associated with Coxsackie disease, however, adults may not display the classic viral exanthem

  • Presence of anti-thyroperoxidase antibodies indicates autoimmune etiology, i.e. the condition is due to transient instead of subacute thyroiditis