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CLINICAL ASPECTS OF THYROID DISORDERS A 30-year-old woman Her eyes bulge. Nervousness, irritability, palpitations and heat Diffuse enlargement thyroid gland. intolerance. Carbimazole and propranolol are prescribed. Lost 9.1 kg despite a good appetite. WHAT ARE HORMONES? Chemicals That Are Released Into the Bloodstream Regulators of Specific Body Functions Two main hormones: Tetraiodothyronine (Thyroxin) T4 & Triiodothyronine T3 Where to look for Thyroid Gland? CLINICAL EXAM. OF THYROID Have patient seated on a chair Inspect neck before & after swallowing Examine with neck in relaxed position Palpate from behind the patient Remember the rule of finger tips Use the tips of fingers for palpation Palpate firmly down to trachea Aspects That Will Be Addressed • Hyperthyroidism • Hypothyroidism • Thyroiditis Clinical Anatomy of Thyroid GOITRE A swollen thyroid gland Assessment; how big, how quickly has it developed, is it smooth or nodular, is it painful, any associated lymph nodes, any sudden changes, is it big enough to cause local symptoms (e.g. breathing problems) HYPERTHYROIDISM SYMPTOMS Hyperactivity/ irritability Heat intolerance and sweating Palpitations Fatigue and weakness Weight loss with increase of appetite Diarrhoea Polyuria Oligomenorrhoea, loss of libido Most common causes Graves disease Toxic multinodular goiter Autonomously functioning nodule SIGNS Tachycardia (AF) Tremor Goiter Warm moist skin Proximal muscle weakness Lid retraction or lag Gynecomastia CAUSES Rarer causes Thyroiditis or other causes of destruction Thyrotoxicosis factitia Iodine excess (Jod-Basedow phenomenon) Secondary causes (TSH or ßHCG) GRAVES DISEASE Autoimmune disorder Abs directed against TSH receptor with intrinsic activity. Thyroid and fibroblasts Responsible for 60-80% of Thyrotoxicosis More common in women HYPERTHYROID EYE DISEASE HYPERTHYROIDISM (ANY TRUE GRAVES’ OPHTHALMOPATHY CAUSE) Proptosis Lid lag, lid retraction and Diplopia stare Inflammatory changes Due to increased adrenergic 1. Conjunctival injection tone stimulating the levator 2. Periorbital edema palpebral muscles. 3. Chemosis Due to thyroid autoAb’s that cross-react w/ Ag’s in fibroblasts, adipo-cytes, + myocytes behind the eyes. Periorbital edema and chemosis Occular muscle palsy EYE SIGNS(OPHTHAMOPATHY) N - no signs or symptoms O - only signs (lid retraction or lag) no symptoms S - soft tissue involvement (peri-orbital oedema) P - proptosis (>22 mm)(Hertl’s test) E - extra ocular muscle involvement (diplopia) C - corneal involvement (keratitis) S- sight loss (compression of the optic nerve) Signs of Graves’s ophthalmopathy are divided into two components: SPASTIC: MECHANICAL: Stare, lid lag and lid Proptosis of varying degrees retraction which Ophthalmoplegia account for the congestive occulopathy characterized by “frightened” facies. chemosis, conjunctivitis, periorbital swelling the potential complications of corneal ulceration,optic neiritis and optic atrophy DERMOPATHY Usually occurs over the dorsum of the legs or feet and is termed localized or pretibial myxedema. It is usually a late phenomenon The affected area is usually demarcated from the normal skin by being raised and thickened and having a peau d’ orange appearance;it may be pruritic and hyperpigmented. The most common presentation is non pitting oedema,but lesions maybe plaque like,nodular or polypoid. Clubbing of the fingers and toes accompanies and is termed thyroid acropachy INVESTIGATIONS Thyroid function test: • TSH- Undetectable • T4 - Raised • T3 - Raised • • TSH-receptor antibodies (TRAb) elevated in Graves’s disease Isotope scanning- Increased uptake THYROTOXICOSIS- TREATMENT Three modalities: Radioactive iodine, Antithyroid drugs & Surgery 1) β-blockers 2) 131-RAIA (symptom control) (70% thyroidologists prefer) • Pregnancy should be deferred • Dosing for at least 6 months following 1. Graves: 10-15 mCi therapy with radio-active 131 2. Toxic MNG/Adenoma: 20-30 mCi • It is advisable to avoid 131-Rdio• Absolute contraindications active iodine therapy in patients - Pregnancy and lactation with active moderate severe (excreted in breast milk)! Graves’ ophthalmopathy. 3) Antithyroid Drugs 4) Surgery (30% thyroidologists prefer) (sub-total thyroidectomy) Indications 1. Propylthiouracil (PTU) – Patient preference – Large or symptomatic goiters 100 mg bid-tid to start – When there is question of malignancy 2. Methimazole – Need to be euthyroid prior to surgery 10X more potent the PTU – To ↓ the risk of arrhythmias during induction of 10 mg bid-tid to start anesthesia – To ↓ the risk of thyroid storm post operatively Complications of ATD’s – ATD’s + β-blockers 1. Agranulocytosis (1/200-500) 2. usually presents w/ acute pharyngitis/ tonsilitis Risks or pneumonia. – Permanent hypoparathyroidism 3. Rash – Recurrent laryngeal nerve problems 4. Hepatic necrosis, Cholestatic jaundice – Permanent hypothyroidism Arthralgia Propranolol (Inderal ®) HYPOTHYROIDISM SYMPTOMS Tiredness and weakness Dry skin Feeling cold Hair loss Difficulty in concentrating and poor memory Constipation SIGNS Weight gain with poor appetite Hoarse voice Menorrhagia, later oligo and amenorrhoea Paresthesias Impaired hearing CAUSES Dry skin, cool extremities Puffy face, hands and feet Delayed tendon reflex relaxation Carpal tunnel syndrome Bradycardia Diffuse alopecia Serous cavity effusions LAB INVESTIGATIONS TSH , free T4 Ultrasound of thyroid – little value Thyroid scintigraphy – little value Anti thyroid antibodies – anti-TPO S-CK , s-Chol , sTrigliseride TREATMENT Normochromic or macrocytic Levothyroxine anemia If no residual thyroid function 1.5 μg/kg/day ECG: Bradycardia with small Patients under age 60, without cardiac disease can be started on QRS complexes 50 – 100 μg/day. Dose adjusted according to TSH levels In elderly especially those with CAD the starting dose should be much less (12.5 – 25 μg/day) Autoimmune hypothyroidism (Hashimoto’s, atrophic thyroiditis) Iatrogenic (I123treatment, thyroidectomy, external irradiation of the neck) Iodine deficiency Drugs: iodine excess, lithium, antithyroid drugs. Infiltrative disorders of the thyroid: 1. amyloidosis, 2. sarcoidosis, 3. haemochromatosis, 4. scleroderma THYROIDITIS ACUTE rare and due to suppurative infection of the thyroid SUB ACUTE also termed de Quervains thyroiditis/ granulomatous thyroiditis – mostly viral origin CHRONIC THYROIDITIS mostly autoimmune (Hashimoto’s) The most common form of thyroiditis is Hashimoto thyroiditis, this is also the most common cause of long term hypothyroidism The outcome of all other types of thyroiditis is good with eventual return to normal thyroid function