Hyperthyroidism Flashcards
What is a Goitre?
Painless enlargement of the thyroid gland
What are the key characteristics of a goitre to comment on?
Diffuse vs nodular
Simple vs toxic (secreting)
Benign vs malignant
What is the ddx for a diffuse goitre?
Physiological - Puberty, pregnancy Autoimmune - Grave's, Hashimoto's Thyroiditis - De Quervain's , Riedel's Endemic - Iodine deficiency Drugs - Anti-thyroid drugs, lithium, amiodarone, iodine excess
What is the ddx for a nodular goitre?
Multinodular - Toxic multinodular, subacute thyroiditis
Solitary - Follicular adenoma, benign nodule, malignancy, lymphoma met
Infiltration - TB, sarcoid
What is the main local complication of a goitre?
Retrosternal extension
Pressure sx on trachea, oesophagus or vv
What investigations are appropriate when a pt presents with a goitre?
FBC (anaemia) ESR TFTs Thyroid autoantibodies CT USS FNAC
What determines the management of a goitre?
Whether the pt is hyper/hypothyroid
If eu-thyroid do not need to treat
What is Thyrotoxicosis?
Clinical disorder resulting from raised circulating levels of thyroid hormone
How common is Thyrotoxicosis?
1% of population
5:1 female preponderance
What are the common causes of Thyrotoxicosis?
Grave’s disease
Toxic multinodular goitre
What are the less common causes of Thyrotoxicosis?
Solitary toxic adenoma (Plummer's) Thyroiditis Drug induced (Amiodarone, levothyroxine) Excess iodine Hashitoxicosis
What are the rare causes of Thyrotoxicosis?
2o causes
- TSH secreting pituitary adenoma
- Resistance to thyroid hormone
What is Grave’s disease?
Autoimmune condition where IgG autoantibodies stimulate thyroid follicular cells
Out of control of normal feedback mechanism
What is Toxic Multinodular Goitre?
Several hyperactive nodules develop
Outside of TSH control
Common in older women
What are the sx of Thyrotoxicosis?
Anxiety/irritability Heat intolerance/sweating Increased appetite Palpitations Wt loss Tremor Loose motions Fatigue/weakness
What are the signs of Thyrotoxicosis?
Lid retraction/lag Systolic HTN Tachycardia/AF Tremor Hyper-reflexia Warm peripheries Proximal weakness
What signs of Thyrotoxicosis are unique to Grave’s disease?
Grave’s ophthalmopathy
Goitre/bruit
Acropachy
Pre-tibial myxoedema
What is Grave’s ophthalmopathy?
Lagopthalmos (unable to close eyes completely)
Exopthalmos/proptosis (bulging eyes)
Ophthalmoplegia (up & lat)
Periorbital oedema
What is acropachy?
Dermopathy associated w/ Graves
Soft tissue swelling of hands
Clubbing of fingers
What is pre-tibial myxoedema?
Dermopathy associated w/ Graves
Swelling of lower legs
What is Thyroid crisis/storm?
Rare presentation occurring in periods of stress in people w/ untreated hyperthyroidism
How does Thyroid crisis/storm present?
Hyperpyrexia Severe tachycardia Profuse sweating Confusion/psychosis Coma/death
How should Thyroid crisis/storm be managed?
Propylthiouracil
Propranolol
Sodium Iodide
High dose steroids
What investigations are appropriate in suspected Thyrotoxicosis?
TSH (suppressed) T3/T4 (elevated) TRAb (elevated in Grave's) Technetium uptake scan CT/MRI of orbit
What are the management options for Thyrotoxicosis in primary care?
Non-selective B-blocker (propranolol)-
-20-40mg t.d.s.
Refer to endocrinologist
What are the management options for Thyrotoxicosis in secondary care?
Antithyroid drugs
Radioacive Iodine
Surgical management
What antithyroid drugs are available?
Carbimazole (1st line)
Propylthiouracil (2nd line)
What is the main complication of Propylthiouracil?
Risk of severe liver injury (1/10000)
How do antithyroid drugs work?
Act as substrates for TPO
Prevent thyroid hormone synthesis
What are the main s/e of antithyroid drugs?
Skin rashes Severe agranulocytosis (mouth ulceration, sore throat, fever)
What is the main complication of Carbimazole?
Can cause cholestatic jaundice
How are antithyroid drugs introduced?
Intermediate course to induce remission (6-18mo)
Titration (starting high, titrating down to euthyroid)
Block & replace (maintain high, add thyroxine once T3/T4 controlled)
What is the success rate of anithyroid medications?
50%
When are antithyroid drugs most commonly used?
Grave’s disease mainly
When is Radio-active Iodine (RAI) therapy used?
1st line in non-Grave’s pathology
Grave’s where drug therapy failed
How does RAI therapy work?
Taken up by thyroid cells
Induces DNA damage & cell death
When is RAI contraindicated?
Pregnancy
Active Grave’s ophthalmopathy
If anti-thyroid drugs not discontinued/discontinued <1wk
What are the complications of RAI treatment?
Initial worsening of sx/thyroid storm (rare)
Small increased risk of thyroid cancer
What advice should pts receiving RAI be given re. children?
Avoid prolonged contact w/ children for 3/52 after treatment
Avoid conceiving for 6mo
No effect on fertility/congenital malformations
What are the surgical options for Thyrotoxicosis?
Total/sub-total thyroidectomy
When is surgical management indicated?
When drug therapy/RAI have failed or are contraindicated
If there is a suspicion of malignancy
If there is a large, toxic goitre
What are the potential post-op complications of surgical management for Thyrotoxicosis?
Haematoma causing asphyxia (emergency removal of sutures required)
Hypothyroidism (10%)
Hypocalcaemia (transient, due to hypoparathyroidism)
Vocal cord paresis (damage to recu larnygeal)
