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Thyroid Disease Surface Anatomy • Anterior neck, below the thyroid Thyroid Anatomy cartilage • Located in the visceral compartment of the neck • C5 – T1 Gland structure • Two lobes (left and right) • Connected by a central isthmus • 4 parathyroid glands Arteries, veins, lymphatics A: Superior thyroid artery (external carotid) Inferior thyroid artery (subclavian) V: Sup., mid., inf., thyroid veins – thyroid venous plexus L: paratracheal and deep cervical nodes Innervation Sympathetic trunk Close relation to R. laryngeal nerve! Functions of thyroid hormones Thyroid physiology • Heart • Increases heart rate and blood pressure - High T3/T4 • Liver Hypothalamus • Increased glycogenolysis – increases blood glucose • Adipocytes • Lipolysis TRH • Thermoregulation • Dilation of blood vessels in the skin + • GI - T3 • Increased gastric secretions and TSH + peristalsis Anterior pituitary • Muscle T4 • Maintains muscle metabolism • Bone • Maintains osteoclast/osteoblast balanceQuestion A 45-year-old woman presents to the GP with a one-month history of weight loss, diarrhoea and worsening tremor. She also reports discomfort in both eyes but no other visual symptoms. She has a past medical history of vitiligo and type 1 diabetes mellitus. On examination, she has exophthalmos, lid lag, a fine tremor and pretibial myxoedema. What is the likely diagnosis? a) Parkinson’s disease b) IBD c) Graves disease d) De Quervain’s thyroiditis e) Anorexia NervosaQuestion A 45-year-old woman presents to the GP with a one-month history of weight loss, diarrhoea and worsening tremor. She also reports discomfort in both eyes but no other visual symptoms. She has a past medical history of vitiligo and type 1 diabetes mellitus. On examination, she has exophthalmos, lid lag, a fine tremor and pretibial myxoedema. What is the likely diagnosis? a) Parkinson’s disease b) IBD c) Graves disease d) De Quervain’s thyroiditis e) Anorexia NervosaHyperthyroidism: clinical presentation Metabolic Cardiovascular Neuropsych Ocular • Heat intolerance/sweating • Anxiety • Exopthalmos • Weight loss • Tachycardia • Hyperactivity • Periorbital oedema • Palpitations • Insomnia • Chest pain • Fine tremor • Lid retraction Skin/hair • HTN • Warm and moist skin • Brisk reflexes • Fine hair • Onycholysis Reproductive • Pretibial myxedema • Abnormal/heavy PMH/FH • Autoimmune GI menstruation disease • Gynaecomastia • Diarrhoea • Subfertility • Increased appetite Goitre MSK • Smooth/diffuse • Thyrotoxic myopathy – proximal weakness • Nodular • Osteoporosis/increased fractures – T3 = bone resorptionHyperthyroidism: causes and types Primary Hyperthyroidism Secondary Hyperthyroidism Pathology of theyroid Pathology of thepothalamus or Production of excessive thyroid pituitary hormone Excessive stimulation of the thyroid, resulting in overproduction of thyroid hormone Causes of primary hyperthyroidism – Differential diagnosis • Graves disease • Toxic multinodular goitre • Solitary toxic nodule • De Quervain’s thyroiditis –associated with pain! • Thyroid storm – emergency • Thyroid cancer – must rule out if patient is presenting with a neck lump!Graves disease Pretibial myxoedema • Deposits of mucin in pre-tibial area Most common cause of primary • Discolored, waxy, hyperthyroidism oedematous • Reaction to TSH Pathophysiology autoantibodies • Production of autoantibodies to the TSH receptor • Stimulates TSH receptors on the thyroid gland • Increased production of thyroid hormone Graves specific symptoms Thyroid eye disease Exopthalmos Diffuse goitre Inflammation/hypertrophy of tissues behind the eye due to thyroid autoantibodies • Lid retraction/lag • Opthalmoplegia • Irritation/redness of the eye surfaceHyperthyroidism: Investigation Examination Thyroid examination Lymph node examination Consider cardio + abdo based on symptoms e.g., palpitations, tachycardia, GI symptoms Observations – BP, HR, O2 sats Bedside Blood glucose ECG Bloods TFTs Hyperthyroidism: low TSH, raised T3 + T4 Thyroid autoantibodies – present in Graves • TSH receptor antibodies • TPO - thyroid peroxidase • Thyroglobulin Rule out other causes - FBC, UE’s, LFTs Imaging Radionuclide imaging • Uptake of technetium helps to differentiate between causes • CI in pregnancy Neck lump = USS!Hyperthyroidism: management Symptom control & lifestyle Beta blockers – e.g., propanolol Smoking cessation Thyroid eye disease – artificial tears, opthal input Antithyroid drugs Decrease output of thyroid hormones – reducing action of peroxidase enzyme 2 regimes: • Dose titration to maintain normal thyroid levels • Block and replace with levothyroxine Carbimazole o 10-30mg daily o Repeat TFTs after 4 weeks, then 3-6 months when euthyroid o SE: agranulocytosis - fever, sore throat, rashes. o Contraception/pregnancy planning – congenital abnormalities Propylthiouracil o Indicated in 1 trimester or pregnancy Radioiodine Single dose of radioactive iodine drink Iodine taken up by the thyroid, and radiation destroys thyroid cells o Patients can by hypothyroid and require replacement with levothyroxine o Cannot get pregnant for 6 months o Avoid close contact with children and pregnant women for 3 weeks o Limited contact with anyone several days after dose Surgical Thyroidectomy with lifelong levothyroxine replacementQuestion A 43 year old woman newly arrived from the Middle East presents to her GP complaining of tiredness, constipation and a swelling in her neck. On examination there is a large, diffuse, non-tender goitre. Thyroid function tests come back as follows: TSH 13.1mU/L (0.5-5.7) T3 5pmol/L (9-22) T4 62mmol/L (70-140) Anti-TPO negative Anti-thyroglobulin negative What is the most likely cause of this patient’s presentation? a) Graves disease b) Thyroid cancer c) Congenital hypothyroidism d) Hashimoto’s disease e) Iodine deficiencyQuestion A 43 year old woman newly arrived from the Middle East presents to her GP complaining of tiredness, constipation and a swelling in her neck. On examination there is a large, diffuse, non-tender goitre. Thyroid function tests come back as follows: TSH 13.1mU/L (0.5-5.7) T3 5pmol/L (9-22) T4 62mmol/L (70-140) Anti-TPO negative Anti-thyroglobulin negative What is the most likely cause of this patient’s presentation? a) Graves disease b) Thyroid cancer c) Congenital hypothyroidism d) Hashimoto’s disease e) Iodine deficiencyHypothyroidism: clinical presentation Metabolic • Cold intolerance Reproductive Cardiovascular • Weight gain • Oligo/amenorrhea • Bradycardia • Subfertility • Dyspnoea on exertion • Low libido Skin/hair • Dry, cool skin Goitre • Coarse and brittle hair Neuropsychiatric • Smooth • Brittle nails • Hypoactivity • Hair loss • Lethargy • Fatigue GI • Weakness • Constipation – reduced gastric • Depression motility • Reduced reflexes • Reduced appetite PMH/FH MSK • Autoimmune • Hypothyroid myopathy – proximal disease muscle weakness • Carpal tunnel syndromeHypothyroidism: causes and types Primary hypothyroidism Secondary hypothyroidism Pathology within the thyroid itself – inability to produce Pathology within the pituitary resulting in low thyroid hormone production of TSH T3/T4 are low T3/T4 are low TSH is high TSH is low Causes: Causes: • Hashimoto’s thyroiditis • Tumour • Thyroid attacked by T-cells • Infection • Initial hyperthyroid, followed by hypothyroid • Vascular – Sheehan syndrome • + Goitre • Radiation • High levels of TPO • Atrophic hypothyroidism • Like Hashimoto’s, but X goitre • Iodine deficiency • Secondary to treatment of hyperthyroidism • Medications – interfere with thyroid hormone production • Lithium • AmiodaroneHypothyroidism: Investigation Examination Thyroid examination Lymph node examination Consider cardio, abdo and resp depending on symptoms Bedside Observations: BP, HR, O2 sats ECG Blood glucose Bloods TFTs Primary hypothyroidism • TSH – high • Free T4 – low Secondary hypothyroidism • TSH – low • Free T4 – low Subclinical hypothyroidism • TSH – high • Free T4 – low Other baseline bloods: FBC, U&E’s, LFTS Imaging/other Any patient presenting with neck lump/goitre should have this investigated – consider USS/biopsyHypothyroidism: Management Medical management Levothyroxine (T4) Start on a low dose Typical dose is 1.6 micrograms/Kg TSH checked every 6 weeks, and titrate dose in 25-50 microgram increments until TSH within normal range Treatment is usually lifelong SE – symptoms of hyperthyroidism due to dose being too high. Advise patients to return to GP so dose can be adjusted. o Palpitations o Diarrhoea o Anxiety o Tremor Subclinical hypothyroidism • Lots of dispute whether to treat • Treat when TSH >10, or TSH >5 and symptomaticCCAs/Progress – top tips History taking Explanation/counselling • Hyperthyroid history • Explain a diagnosis of hyper or • Hypothyroid history hypothyroidism • Goitre/neck lump • Explain hyperthyroidism treatment • Cardiac history – palpitations • Carbimazole • Always have hyperthyroidism as a • PTU differential, and always say you would • Explain hypothyroidism treatment like to check TFTs to rule out! • Levothyroxine – remember to tell the patient treatment is likely lifelong! Examination • Thyroid examination • Lymph node/reticuloendothelial Data interpretation • Learn exactly what it says in the workbook! • Thyroid function tests