Thyroid Disease Dr John McDermott Consultant Endocrinologist Connolly Hospital Blanchardstown Hermitage Medical Clinic Royal College of Surgeons in Ireland

Thyroid Hormones Thyroid gland manufactures and releases thyroid hormones Thyroid hormones are iodine containing amino acids 3, 5, 3’ triiodothyronine = T3 3, 5, 3’,5’ tetraiodothyronine = T4

Thyroid Hormones ‘Maintain the level of metabolism in the tissues that is optimal for their normal function’ Small amounts secreted continuously

Thyroid Hormones Deficiency or excess of thyroid hormones:  wide and varied symptoms and physical signs involving any organ system

Thyroid Case 33 year old woman Gaining weight Tired – busy job and 2 young children Rows over thermostat

Thyroid Case T4: 6 (normal 9 – 22) TSH: 36 (normal 0.4 – 4) Diagnosis: Hypothyroidism

Other symptoms of hypothyroidism Constipation Heavy periods Cold dry skin, dry hair, hair loss Muscle pains/stiffness

Hypothyroidism Joseph Fourier, a French mathematician ‘began to suffer from a strange disease, whose main effect was to render him extremely sensitive to cold….caused him to wrap up in many layers of heavy clothing, and live in a highly heated room from which he seldom ventured forth, even in summer heatwaves’. Paul Strathern, Napoleon in Egypt

Treatment of Hypothyroidism Thyroid hormone, T4 (Eltroxin) Aim to abolish symptoms Aim to achieve a high normal T4 and low-normal TSH NB Pregnancy issues

Thyroid Case [2] 26 year old woman Noticed prominence of right eye x 3 weeks Increased appetite – but weight decreasing Difficulty getting out of the bath

On Examination Pulse 120 regular Tremulous, sweaty hands Enlarged, rubbery thyroid

Thyroid Case [2] T4: 37 (normal 8 – 22) TSH < 0.01 (normal 0.4 – 4) Anti-TSH receptor antibodies ++ Diagnosis: Graves Disease causing hyperthyroidism, ophthalmopathy

Graves Disease Autoimmune condition Antibodies against TSH receptor – stimulate excess thyroid hormone Antibodies attack back of eye - proptosis

Treatment of Hyperthyroidism Antithyroid drugs: Carbimazole (Neomercazole) Propylthiouracil (PTU) Radioactive Iodine Surgery - thyroidectomy

Radioactive Iodine Commonly prescribed treatment for hyperthyroidism Orally-administered I131 Concentrated in thyroid gland, radiation destroys thyroid tissue

Radioactive Iodine Precautions after dose Long-term hypothyroidism

Surgery ‘Subtotal’ thyroidectomy Hypothyroidism Potential other complications

Diseases of the Thyroid Disorders of function: Hyperthyroidism Hypothyroidism Disorders of structure: Goitre Thyroid nodules/cancer

Goitre Enlarged thyroid Symptoms: Cosmetic concerns, obstructive symptoms Toxic Multinodular Goitre: hyperthyroidism

Thyroid nodules 5% of population have palpable thyroid nodules 30-40% of popn have non-palpable nodules detectable on ultrasound Thyroid cancer in 8% of palpable thyroid nodules Differentiated cancers: slow growing, good prognosis

Thyroid nodules Risk stratify: risk factors, u/s characteristics, hot or cold Fine needle aspiration Observation, surgery

Summary Thyroid disease common but treatable, wide and varied complaints Disorders of function: Hypo/Hyper, diagnosis TFTs Disorders of structure: Goitre, nodules