Hyperthyroidism Dr. Januchowski 2012 Picture courtesy: Hyperthyroidism Stephanie L Lee, MD, PhD; Chief Editor: George T Griffing, MD, Medscape reference library

Objectives Name the most common causes of hyperthyroidism Distinguish between the different causes by use of labs and imaging List the clinical features associated with hyperthyroidism Name the treatment options for hyperthyroidism Identify complications of hyperthyroidism

Etiology Autoimmunity (Graves disease) Toxic multinodular goiter (Plummers disease) Toxic adenoma Subacute thyroiditis (deQuervains thyroiditis) Struma ovarii Iodide induced thyrotoxicosis (Jod-Basedow) Molar pregnancy Metastatic follicular thyroid carcinoma

Comparing the most common causes Cause%SexPeak Age Graves50-60%  7.5>  Higher thyroid levels seen Subacute15-20%  2>  1VariesTenderness noted / decreased uptake on scan Toxic MN goiter15-20%  3>  1>50More common if iodine def. Toxic adenoma3-5%  3>  Single nodule

Graves Disease Most common cause Autoimmune modulated – Thyroid stimulating immunoglobulin (TSI) – Anti thyroid peroxidase (anti-TPO) Diffusely enlarged gland Can be associated with other autoimmune disease Can remit with oral medications***

Subacute thryoiditis Destructive release of preformed thyroid hormone No 123 I uptake in thyrotoxic phase Granulomatous infiltration noted*** Can have spontaneous remission

Toxic multinodular goiter Usually in older individuals with long standing goiter Usually only mild elevation in thyroid hormones Can be worsened with iodine exposure (contrast / amiodarone) – Can set off thyroid storm apathetic hyperthyroidism No spontaneous remission

Toxic adenoma Single hyperfunctioning follicular thyroid adenoma 123 I usually shows the hot nodule Does not remit spontaneously

Clinical Presentation Symptoms – Nervousness – Anxiety & Hyperactivity – Diarrhea – Increased perspiration – Heat intolerance – Tremor – Palpitations – Weight loss despite increased appetite – Reduction in menstrual flow or oligomenorrhea Signs – Hyperactivity – Tachycardia or atrial arrhythmia – Systolic hypertension – Warm, moist, smooth skin – Lid lag – Stare – Tremor – Muscle weakness

Physical Exam General – Anxious – Tachycardia – Elevated blood pressure – Tremor Derm – Thickening of skin Neck exam – Enlarged thyroid – Pain vs. no pain – Bruits HEENT – Periorbital edema – Proptosis

Evaluation – Labs Thyroid Stimulating Hormone (TSH) – most reliable screening method for assessing thyroid function T4, T3 – 99% protein bound – Used to estimate degree of thyrotoxicosis Anti-Thyroid peroxidase (TPO) Thyroid stimulating Immunoglobulin (TSI) – More impt than TPO if thinking about graves disease

Goldman’s Cecil Medicine, 24 th Ed. Figure 233-3

Evaluation - Imaging Common Forms (85-90% of cases)Radioactive iodine uptake Diffuse toxic goiter (Graves disease)Increased Toxic multinodular goiter (Plummer disease)Increased Thyrotoxic phase of subacute thyroiditisDecreased Toxic adenomaIncreased Less Common Forms Iodide-induced thyrotoxicosisVariable Thyrotoxicosis factitiaDecreased Uncommon Forms Pituitary tumors producing thyroid-stimulating hormoneIncreased Excess human chorionic gonadotropin (molar pregnancy/choriocarcinoma)Increased Pituitary resistance to thyroid hormoneIncreased Metastatic thyroid carcinomaDecreased Struma ovarii with thyrotoxicosisDecreased

Imaging Views

Complications Non-specific changes – Weight loss – Fatigue Cardiac – Atrial fibrillation – High output cardiac failure – Right heart failure – Pulmonary HTN Eyes – Proptosis – Extraocular muscle dysfunction Pretibial edema (pain)

Subclinical hyperthyroidism No symptoms Low TSH, normal T4 Risks – Osteoporosis – Atrial fibrillation – Hypercalcemia

Treatment Medications – Symptomatic relief – Antithyroid drugs Surgery Radioactive 131 I Note the difference for treatment: – Subclinical thyroiditis – Subacute thyroiditis (DeQuervain’s)

Treatment – Symptomatic care Tachycardia, tremors –  -blockers or Calcium channel blockers Eyes – Artificial tears, protection – Corticosteroids, surgery and radiation for severe cases

Antithyroid medications Methimazole – More potent and longer acting Propylthiouracil (PTU) – Can be used during pregnancy (1 st trimester) – Severe liver problems noted – Usually second line drug Titrated every 4 weeks

Surgery Severe hyperthyroidism in children Pregnant women who are noncompliant or intolerant of antithyroid medication Patients with very large goiters or severe ophthalmopathy Patients who refuse radioactive iodine therapy Refractory amiodarone-induced hyperthyroidism Patients who require normalization of thyroid functions quickly, such as pregnant women, women who desire pregnancy in the next 6 months, or patients with unstable cardiac conditions

Surgery Preoperatively – Antithyroid medications until stable TSH –  -blockers for heart rate < 80 – Iodine (as super saturated potassium iodide SSKI) Risks – Recurrent laryngeal nerve damage Damage 1 – trouble talking Damage both – pt gonna die by suffocation – Damage to parathyroid glands Hypoparathyroidism – low calcium in the blood

Radioactive 131 I Most common treatment in US Single oral dose Expected to become hypothyroid with treatment Cannot use in pregnancy or breastfeeding Can worsen eye disease if present – reduced by glucocorticoid therapy Can exacerbate thyrotoxicosis transiently

Thyroid Storm Thyrotoxicosis Acute, life-threatening hypermetabolic state Adult mortality is ~90% untreated (20%) Bimodal peak year old and year olds

Presentation of thyroid storm Fever Sweating Weight loss Respiratory distress Diarrhea Jaundice Anxiety Mental status change Seizures High output CHF Hypertension to hypotension (shock)

Causes of thyroid storm Bodily stressors – Sepsis – Surgery – Anesthesia induction – Radioactive iodine (RAI) therapy – DKA Drugs (anticholinergic and adrenergic drugs such as pseudoephedrine; salicylates; nonsteroidal anti-inflammatory drugs [NSAIDs]; chemotherapy) Excessive thyroid hormone (TH) ingestion Withdrawal of or noncompliance with antithyroid medications Direct trauma to the thyroid gland Vigorous palpation of an enlarged thyroid Toxemia of pregnancy and labor in older adolescents; molar pregnancy

Differential of thyroid storm Anxiety Disorder or Panic Disorder Congestive Heart Failure Hypertension Hyperthyroidism Pheochromocytoma Supraventricular Tachycardia, Atrial Ectopic Tachycardia

Evaluation of thyroid storm TSH will be low T4 will be high Other studies to rule things out

Treatment of thyroid storm Stabilize the patient’s CV status Control hyperthermia as needed Antiadrenergic drugs (beta blockers) – Propranolol High dose PTU – Blocks T4 output and T4-T3 conversion SSKI to block thyroid hormone release (start after anti- thyroid medicine) Glucocorticoids to decrease peripheral conversion

References Goldman’s Cecil Medicine, Chapter overview 07-overview