Thyroid Disease Blake Briggs, Class of 2017

Introduction Remember the 4 B’s of the Thyroid Brain development in utero Increased Basal metabolism Increased Beta adrenergic effects Increased bone resorption Noncancerous thyroid disease can be broken up into whether it is hyper or hypothyroid (AKA does it produce/release hormones or not)

Hyperthyroid diseases Grave’s disease Toxic multinodular goiter Subacute thyroiditis Struma ovarii Presentation: remember that thyroid hormones increase beta adrenergic effects and basal metabolism. So all the symptoms and signs are based off these 2 concepts. Tachycardia, palpitations, tremors, diaphoresis Weight loss, diarrhea, polyuria

Grave’s Disease Autoimmune disease where thyroid-stimulating immunoglobulins bind to TSH receptor and stimulate it, allowing for excess thyroid hormone production. Unique sign: Exophalmos (bulging eyes) Diagnosis: diffuse iodine uptake on nuclear imaging.

Grave’s Disease Complication: Thyroid Storm. Massive release of thyroid hormones causes severe beta adrenergic effects. The most concerning complication is an arrhythmia. Other signs are high fever, agitation, nausea, and vomiting. Tx: beta blockers, steroids, and PTU can save the patient’s life.

Grave’s Disease Treatment Medical therapy: propylthiouracil (PTU) and methimazole block thyroid hormone production by inhibiting peroxidase. Radioiodine ablation: best option. Administration of radioactive iodine that destroys follicular cells. Contraindicated in pregnancy. Thyroidectomy: if ablation fails.

Toxic Multinodular goiter ”hot” nodules in thyroid release thyroid hormone. Due to Iodine deficiency  decreased T4  TSH induces thyroid cell hyperplasia and rapid “catch up” T4 production. Dx: “patchy”, nondiffuse uptake of radioactive iodine tracer on nuclear imaging.

Subacute Thyroiditis (DeQuervain’s) Post-viral infection; transient inflammation of thyroid gland. Patient presents with fever and gland is painful to touch Diagnosis: high serum thyroid hormone with negative radionucleotide uptake

Struma Ovarii Very rare. Ovarian teratoma produces thyroid hormone. Diagnosis: high serum thyroid hormone with negative radionucleotide uptake. Thyroid is not enlarged and not painful to touch.

Hypothyroid diseases Hashimoto’s Iodine deficiency Riedel’s thyroiditis Lithium toxicity Cretinism Ablation The opposite symptoms and signs of hyperthyroidism. Decreased beta adrenergism: bradycardia, delayed reflexes, dry skin Decrease basal metabolism: mental sluggishness, weight gain, constipation

Hashimoto’s disease Autoimmune destruction of thyroid tissue. It is marked by hyperthyroidism at first, due to the targeting and destruction of follicular cells which release preformed thyroid hormone. Eventually, the cells are destroyed and less and less hormone is produced until no functional follicular cells are left. Special findings: carpal tunnel syndrome, myxedema (pretibial and periorbital swelling) Complication: Myxedema Coma- profound AMS  coma, hypotension, and hypoventilation. Mainly from often untreated disease. Tx: hormone replacement, +/- intubation.

Riedel’s Thyroiditis Progressive, irreversible inflammation and fibrosis of thyroid. Firm, hard, painless gland. Classically in young people. Due to autoimmune destruction and fibrosis.

Others Cretinism: almost nonexistent in the US. Hypothyroidism in utero due to maternal hypothyroidism. Poor brain development  mental retardation, umbilical herniation, short stature, delayed reflexes and hypotonia, jaundice, and macroglossia.

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