Clinical manifestations of thyroid disease

Clinical manifestations of thyroid disease Robert Schmidli MB ChB, MRCP, FRACP, PhD Consultant endocrinologist http://www.schmidli.com.au Overview • • • • • Goitre Thyrotoxicosis Hypothyroidism Thyroid tumours Thyroiditis (not covered) Goitre • Enlargement of the thyroid gland • Endemic goitre> 200 million people worldwide • Iodine deficiency major cause in developing countries Geographical areas • Iodine leached out of soil by flooding, glaciation • Newly-formed soil relatively iodine deficient • “Although Noah saved the animals from extinction, the flood left their descendents susceptible to goitre” Classification • Endemic – Iodine deficiency – Dietary goitrogens • Sporadic – Congenital defect in thyroid hormone biosynthesis – Chemical agents • Uninodular/multinodular (causes as above) – Functional/nonfunctional Mechanism  T4  TSH  T4 synthesis Clinical examination • Patient sitting • Observe neck, slightly extended, swallowing • Palpate from behind patient • Swallowing • Note size, consistency, irregularities Thyrotoxicosis • Syndrome that results when tissues are exposed to excessive thyroxine • 0.2-0.3 per 1000 people • Female : male 4-10 : 1 • May involve T4, T3 or both Causes of thyrotoxicosis • Graves’ disease • Toxic multinodular goitre • Thyroiditis – Painful – Painless • Exogenous • Ectopic • TSH excess Graves’ disease • Commonest cause of thyrotoxicosis • Multisystem immune disorder – – – – – Thyrotoxicosis Diffuse goitre Ophthalmopathy Myxoedema Acropachy • Hyperthyroidism due to antibodies which stimulate TSH receptor Clinical features • • • • • • • • Symptoms Nervousness Irritability Sweating Heat intolerance Palpitations Fatigue Weight loss  appetite Signs • • • • • • • • • Goitre Warm sweaty skin Lid retraction Hyperactivity Tremor Tachycardia Brisk reflexes Myopathy Atrial fibrillation Ophthalmopathy • • • • May not accompany thyrotoxicosis Clinically apparent disease 20-40% Mild disease in most Forward displacement: proptosis/exophthalmos • Periorbital swelling • Conjunctivitis, tearing • Limitation of extraoccular movement Other features • • • • • Localised myxoedema Generalised: hypothyroidism Pretibial myxoedema commonest site Acropachy Rare Finger clubbing Fibrosis, new bone in hands & feet Graves’ disease: treatment • Antithyroid drugs – Carbimazole – Propylthiouracil – less placental transfer – Adverse effects: • Bone marrow suppression • Rashes • Hepatitis – High chance of recurrence • Thyroidectomy • Radioactive iodine } Permanent Hypothyroidism • Syndrome resulting from lack of thyroid hormone • Female : male – 2-8 : 1 • Newborns: cretinism Causes • Primary (thyroidal) hypothyroidism – Autoimmune: cell-mediated thyroid destruction – 131I therapy – Thyroidectomy • Defective hormone synthesis – Congenital – Antithyroid drugs – Iodine deficiency • Central/secondary – TSH/TRH deficiency Clinical features • • • • • • Symptoms Dry skin Cold intolerance Weight gain Constipation Weakness, fatigue Hoarseness • • • • Signs Coarse skin, hair Cold skin Slow reflex relaxation Bradycardia Treatment • • • • Thyroxine replacement Lifelong usually Long half-life Usually 100-200 g/day Thyroid cancer • Risk factors – Solitary nodule – Female gender – Head and neck irradiation (children) • History – Enlarging neck mass – Dysphagia, dyspnoea • Examination – Hard, irregular thyroid nodule Investigations: thyroid cancer • Ultrasound – Solid nodule – Cystic nodule with solid areas • Isotope scan – Reduced uptake ( differentiation) • Fine needle biopsy • Histology at surgery Classification • Benign tumours – Follicular adenoma • Malignant – Papillary carcinoma – Follicular carcinoma – Anaplastic carcinoma – Medullary cell carcinoma