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Name:_________________________________________ General Medicine Endocrinology Hyperthyroidism Learning Objectives: Lecture 1 Discuss the aetiology, clinical manifestations, investigations & treatment of Hyperthyroidism Dr. J. Satish Kumar, MD, Department of Basic & Medical Sciences, AUST PRESENTING PROBLEMS IN THYROID DISEASE The most common presentations of thyroid disease are thyrotoxicosis (i.e. hyperthyroidism) hypothyroidism and goitre (i.e. enlargement of the thyroid). http://www.biologyinmotion.com/thyroid/thyroid.swf HYPERTHYROIDISM-Intro PREVALENCE AFFECTS 5% OF THE WOMEN MEN POPULATION 2% 0.2% 15% OF CASES OCCUR IN PATIENTS OLDER THAN 60 YRS OF AGE Hyperthyroidism Hormone excess-Summary Graves' disease 2. Multinodular goitre 3. Adenoma 4. Subacute thyroiditis 1. Etiology 1 Grave’s disease Autoimmune disease caused by antibodies to TSH receptors Can be familial and associated with other autoimmune diseases 2 Toxic multi-nodular goiter 5% of all cases 10 times more common in iodine deficient area Typically occurs in older than 40 with long standing goiter Etiology 3 Toxic adenoma More common in young patients Autonomically functioning nodule 4 Thyroiditis Subacute Abrupt onset due to leakage of hormones Follows viral infection Resolves within eight months Can re-occur 5Treatment Induced Hyperthyroidism Etiology Amiodarone (Anti arhythmic drug) Induced Thyroiditis Up to 12% of patients, especially in iodine deficient cases Most common cause of iodine excess in US. Two types: *Type I - due to excess iodine (Amiodarone contains 37% iodine). *Type II –– occurs in normal thyroid Etiology Thyroid Hormone Induced Factitious hyperthyroidism in accidental or intentional ingestion to lose weight Tumors -Metastatic thyroid cancer -Ovarian tumor that produces thyriod hormone (struma ovarii) -Trophoblastic tumor -TSH secreting tumor Smoking as an etiology Thiocyanate, one of the toxins contained in cigarettes, is especially dangerous to the thyroid gland in susceptible people. Cigarette smokers are also more likely to develop eye complications of Graves' disease. Patients who smoke increase their health risk by worsening their thyroid disease. Clinical Symptoms Depends on Age of patient Magnitude of hormonal excess Presence of co-morbid condition Mechanism of Clinical Symptoms The thyroid axis is involved in the regulation of cellular differentiation and metabolism in virtually all nucleated cells, so that disorders of thyroid function have diverse manifestations. 1. Catabolism 2. Enhancement of sensitivity to catecholamines Clinical Symptoms Older patient presents with lack of clinical signs and symptoms, which makes diagnosis more difficult. In younger patients, Graves' disease is the main manifestation. Middle-aged men and women most commonly have toxic nodular goiter. Thyroid storm is a rare presentation, occurs after stressful illness in under treated or untreated patient. Characteristics -Delirium -Dehydration -Severe tachycardia -Vomiting -Fever -Diarrhea THE THYROID GLAND IN OLD AGE Thyrotoxicosis Causes: commonly due to multinodular goitre. Symptoms: apathy, anorexia, proximal myopathy, atrial fibrillation and cardiac failure predominate. Non-thyroidal illness: thyroid function tests are performed more frequently in the elderly but interpretation may be altered by intercurrent illness. Clinical symptoms Psychiatric Hyperactivity Emotional lability Anxiety Decreased concentration Insomnia Clinical symptoms Eyes Stare, Lid lag *Due to sympathetic over activity *Only Grave’s disease has ophthalmopathy -Inflammation of extraocular muscles, orbital fat and connective tissue. -This results in exopthalmos Impaired eye muscle function (Diplopia) Periorbital and conjunctival edema Gritty feeling or pain in the eyes Corneal ulceration due to lid lag and proptosis Optic neuritis and even blindness Clinical symptoms Skin -Warm -May be erythematous (due to increased blood flow) -Smooth- due to decrease in keratin -Sweaty and heat intolerance -Onycholysis –softening of nails and loosening of nail beds Clinical symptoms Hyperpigmentation -Due the increased ACTH secretion Pruritis -mainly in graves disease Thinning of hair Vitiligo and alopecia areata -mainly due to autoimmune disease Infilterative dermopathy -Graves disease, most common on shins Clinical symptoms Cardiovascular System Increased cardiac output (due to increased oxygen demand and increased cardiac contractibility. Tachycardia Widened pulse pressure Atrial fibrillation Mitral valve problems LVH and cardiomyopathy High output – heart failure Lipid Profile Low total cholesterol Low HDL Low total cholesterol/HDL ratio Respiratory System Dyspnea on rest and with exertion Oxygen consumpation and CO2 production increases. Hypoxemia and hypercapnea, which stimulates ventilation Respiratory muscle weakness Decreased exercise capacity Tracheal obstruction May exacerbate asthma Increased pulmonary arterial pressure Clinical symptoms GI System -Weight loss due to increased calorigenesis -Hyperdefecation -Malabsorption -Steatorrhea -Celiac Disease (in Grave’s Disease) -Hyperphagia (weight gain in younger patient) -Anorexia- weight loss in elderly -Dysphagia -Abnormal LFT especially phosphate Clinical symptoms Hematological System Normochromic normocytic anemia Serum ferritin may be high Grave’s disese ITP Pernicious anemia Anti-neutrophiliac antibody Clinical symptoms GU System Urinary frequency and nocturia Enuresis is common in children Women High serum estradiol Low free estradiol High LH Reduce mid-cycle LH surge Oligomenorrhea and amenorrhea Anovulatory infertility GU System Men High total testosterone Low free testosterone High serum LH High serum estradiol Gynecomastia Decreased libido Erectile dysfunction Decreased or abnormal sperm Clinical symptoms Skeletal System Bone resorption Increased porosity of cortical bone Reduced volume of trabecular bone Serum alkaline phosphate is increased Increased osteoblasts Inhibit PTH secretions Decreased calcium absorption and increased excretion Osteoporosis, Fractures Clinical symptoms Skeletal System Grave’s disease is associated with thyroid acropathy -Clubbing of nails -Periosteal bone formation in metacarpal bone or phalanges Neuromuscular System Tremors-outstretched hand and tongue Hyperactive tendon reflexes Proximal muscle weakness in 50% pts. Decreased muscle mass and strength Clinical symptoms Endocrine Increased sensitivity of pancreatic beta cells to glucose Increased insulin secretion Antagonism to peripheral action of insulin Latter effects usually predominate leading to intolerance. Investigations It is important to confirm the presence of thyrotoxicosis biochemically by more than one test of thyroid function because of the need for prolonged medical treatment or destructive therapy. Serum T3 and T4 are elevated in the majority, but T4 is in the upper part of the normal range Further tests, which may be required to establish the aetiology of thyrotoxicosis, include measurement of TSH receptor antibodies. Thyrotoxicosis is an important cause of atrial fibrillation, hence ECG is useful Treatment Treatment depends upon -Cause and severity of disease -Patients age -Goiter size -Co-morbid condition -Treatment desired • The goal of therapy is to correct hyper-metabaolic state with fewest side effects and lowest incidence of hypothyroidism. Management Stress management plays a very important part in successful treatment of thyroid disease. Stress affects the thyroid gland negatively. Treating the thyroid without treating the stress can cause more problems. Incorporating regular relaxation exercise is critical to helping thyroid disease respond to the recommended medical treatment. Management Options Summary Anti-thyroid drugs Radioactive iodine Surgery Beta-blocker and iodides are adjuncts to above treatment Anti-thyroid Drugs-Methimazole Drug of choice for non-pregnant patients because of : Low cost Long half life Lower incidence of side effects Can be given in conjunction with beta-blocker Treatment Radioactive Iodine Treatment of choice for Grave’s disease and toxic nodular goiter Inexpensive Highly effective Easy to administer Safe Radioactive iodine has replaced surgery for Tx of hyperthyroidism Surgery Subtotal thyroidectomy is most common This limits incidence of hypothyroidism to 25% Total thyroidectomy in large goiter or severe disease Treatment Beta Blockers Prompt relief of adrenergic symptoms Any beta blocker can be used, but non-selectives have more direct effect on hyper-metabolism, Propranolol widely used Increase progressively until symptoms are controlled Iodide blocks peripheral conversion of T4 to T3 and inhibits hormone release. These are used as adjunct therapy Before emergency non-thyroid surgery Common oral findings in hyperthyroidism Increased susceptibility to dental caries Periodontal disease Maxillary or mandibular osteoporosis Accelerated dental eruption Burning mouth syndrome. In Graves' disease, Sjogren's syndrome and systemic lupus erythematosus can occur. A common side effect of many medications is xerostomia Dentists Role in Thyroid care Conducting an extraoral cancer examination for the thyroid is an important procedure for the dental professional to perform. The gland should first be inspected and then palpated; it is possible to palpate the gland standing in front of or behind the patient. Normal patients have thyroid glands that are difficult to feel. The dental professional should note any characteristics of the nodules or masses. Since the thyroid is the master gland of metabolism and energy, it is important to protect this gland whenever possible. Use a thyroid collar when taking patient X-rays. The thyroid is extremely sensitive to radiation and excessive radiation exposure is a known risk factor for various thyroid conditions. Exposure to a surgical antiseptic iodine (such as Povidone) can increase the risk of temporary thyroiditis, hypothyroidism or hyperthyroidism. Patients with underlying thyroid antibodies and a tendency toward autoimmunity appear to be at more risk. When there is excess of fluoride in the body it can interfere with the function of the thyroid gland. Fluoride has been linked to thyroid problems. Patients who wish to avoid the effect of fluoride on their thyroid can utilize a fluoride-free toothpaste such. Conclusion From medication to lifestyle, a patient challenged with thyroid disease can help their treatment be more effective and improve their well-being and quality of life. Dental professionals have a responsibility to be aware of the different dimensions of the disease and treatment that could affect a patient whose medical history reflects thyroid problems.