8. Thyroid disease: hyper, hypo and other Flashcards

Question

Graves disease

Answer 1

Autoantibody stimulates the TSH receptor, causing excess thyroid hormone production and thyroid growth (goitre) Accounts for 75% of cases • Typically women 30-50 yrs

Answer 2

Placental β-human chorionic gonadotrophin is structurally similar to TSH and TSH-like action on the thyroid likely if hyperemesis / twin pregnancy Settles after 1st trimester of pregnancy

Answer 3

Likely Graves disease: • Personal or family history of any autoimmune thyroid / endocrine disease • Goitre with a bruit = Graves disease • Thyroid eye disease = Graves disease (20%) Positive thyroid autoantibody titre

Answer 4

``` Thyroid autoantibodies May not need any imaging • clinical diagnosis may be clear Thyroid uptake scan (isotope scan) • Functional scan: darker areas of increased activity ```

Answer 5

``` • Medical • Radioiodine • Surgery • Symptom control ○ Beta-blockers (propranolol), not if asthmatic • Risk of no treatment ○ Symptoms worsening ○ Atrial fibrillation e.g. stroke ○ Osteoporosis e.g. fractures ```

Answer 6

``` Carbimazole or propylthiouracil (PTU) 18 months – 2 years Titrate or block-replace Rare side effect: agranulocytosis Approx one third long term cure rate Two thirds relapse • Usually first year • Cannot predict in advance ```

Answer 7

RADIOACTIVE IODINE TREATMENT (I-131) • Oral treatment, radioiodine concentrated in thyroid, radiation kills thyroid cells • Medical therapy first till euthyroid • Approx 40% risk permanent hypothyroidism after treatment • Not if pregnant / breast feeding • Need to avoid prolonged close contact with others for 1-2 weeks after treatment ○ Tricky if young children • Not if severe thyroid eye disease • Future pregnancies ○ Women advised to wait 6m, men 4m • Warn patients about airplane security systems!

Answer 8

• Sub-total thyroidectomy (“almost total”) • Patients must be euthyroid pre-operatively ○ Medical therapy first • Risks ○ Anaesthetic ○ Neck scar ○ Hypothyroidism ○ Hypoparathyroidism ○ Vocal cord palsy (recurrent laryngeal nerve damage)

Answer 9

• Initial treatment: short term medical therapy (to control thyroid function tests) Subsequent curative treatment: radioiodine

Answer 10

Reassurance that variety of Sx all relate to hyperthyroidism • E.g. swings in emotion, anxiety, panic, irritability May take time to feel 'normal' again • Even after TFTs normalise, may be ‘lag’ phase of few months due to ‘metabolic rollercoaster’ Treatments for thyroid do not help eye disease Risk of weight gain – watch dietary intake! Confirm ‘family’ plans / intentions – guide treatment

Answer 11

‘Active’ • Encourage smoking cessation • Steroids ○ Pulsed IV methylpred / oral prednisolone • Other immunosuppressive / steroid-sparing agents • Radiotherapy 'Burnt out’ • May be left with disfigurement causing impaired quality of life and social avoidance • Surgical treatment ○ Orbital decompression ○ Eyelid surgery

Answer 12

``` Who gets it? • Usually 2º Graves • Unrecognised • Incompletely treated ○ “start-stop” ○ erratic compliance ○ early on in course of treatment ○ Surgery / radioiodine treatment without adequate preparation • RARE! What triggers it? • Surgery (GA) • Childbirth • Acute severe illness ○ Infection ○ Trauma ○ Diabetic ketoacidosis ○ Stroke ○ Pulmonary embolus ```

Answer 13

``` • Multi-system • Graves ○ Goitre, thyroid eye disease • Hyperpyrexia • CNS ○ Agitation, delirium • Cardiovascular ○ Tachycardia >140 bpm ○ Atrial dysrhythmias ○ Ventricular dysfunction ○ Heart failure • GI ○ Nausea & vomiting ○ Diarrhoea ○ Hepatocellular dysfunction Degree of elevation of thyroid hormone concentrations does NOT distinguish uncomplicated thyrotoxicosis from thyroid storm High mortality rate ITU-level care ```

Answer 14

``` Usually self-limiting thyroid disease Transient mild thyrotoxicosis • Always resolves (1-2 m) • b-blockers if required • Isotope scan would be ‘cold’ • Anti-thyroid drugs will not work Longer hypothyroid phase (4-6 m) • 80% normal at 1 year • May require thyroxine treatment for a while Annual TFTs: 30% hypothyroid @ 1 yr, 50% @ 3 yr ```

Answer 15

Consider if: Patient is pregnant / within 1 year post-partum risk T1 diabetes, FHx thyroid disease, smoker Patient has very tender thyroid • May be raised inflammatory markers Clinical thyroid status does not fit with lab results • Rapidly changing thyroid function tests No diagnostic features of Graves disease Current / recent treatment with immunomodulatory medication

Answer 16

``` Other autoimmune endocrine diseases • Type 1 diabetes • Pernicious anaemia • Coeliac disease • Premature ovarian failure • Addison’s disease Syndromes • Turner syndrome • Down's syndrome Medication for other diseases • Lithium ○ Inhibits thyroid hormone synthesis & secretion • Amiodorone Annual thyroid functioning test screening recommended ```

Answer 17

``` Euthyroid Goitre • Common • More common in iodine-deficient areas • May be multinodular • Usually nothing to worry about Thyroid nodule • Thyroid nodule in euthyroid patient • Must exclude thyroid cancer - 5% • Ultrasound scan characteristics helpful • Fine needle aspiration biopsy for cytology ```