Hyperthyroidism Flashcards
1
Q
What is the definition of hyperthyroidism?
A
Over activity of the thyroid
2
Q
What is the pathophysiology of hyperthyroidism?
A
- TRH (Thyroid releasing hormone) is produced in the hypothalamus
- = pituitary gland secretes thyroid stimulating hormone (TSH)
- = THS stimulates growth and activity of the thyroid follicular cells
- Inorganic iodine → T3 (active) and T4 (prohormone) is released
- More T4 is produced but converted in peripheral tissue
- T3 binds to specific nuclear receptors on target cells
- Primary: disease of the thyroid – more common
- Secondary: hypothalamic-pituitary disease
3
Q
What are the risk factors/aetiology of hyperthyroidism?
A
- Woman
- Commonly between the ages of 20-40
- Other autoimmune disorders
- Graves’ disease – most common cause, autoimmune. Serum IgG antibodies bind to TSH receptors in the thyroid and behave like TSH
- Toxic multinodular goitre
- Solitary toxic nodule/adenoma
- Acute thyroiditis: viral (de Quervains), autoimmune, post irradiation
- Gestational/postpartum/neonatal
- Drugs: amiodarone
- Tumours
4
Q
What are the signs/symptoms of hyperthyroidism?
A
- Weight loss
- Restlessness/mania/psychosis
- Itching
- Sweating/heat intolerance/vasodilated peripheries
- Tall
- Palpitations/tachycardia/AF
- Systolic hypertension
- Muscle weakness/proximal myopathy/proximal muscle wasting
- Vomiting/diarrhoea
- Oligomenorrhea – infrequent/light periods
- Loss of libido
- Goitre
- Exophthalmos (Graves only)
- Ophthalmoplegia (Graves only) – paralysis of muscles within/around the eye
- Lid lag and stare
- Conjunctival/preorbital oedema
- Onycholysis – painless separation of nail from nail bed
- Palmar erythema
- Graves dermopathy aka Pretibial myxoedema (Graves only)
- Thyroid acropachy – clubbing (Graves only)
5
Q
What diseases present similarly to hyperthyroidism?
A
- Anxiety
* Phaeochomocytoma
6
Q
What investigations are carried out when hyperthyroidism is suspected?
A
- TFTs – immunoasssays for free T4, T3 and TSH
- ECG
- Autoantibodies – most commonly seen in Graves
- Thyroid US
- CRP/ESR ↑
7
Q
What are the surgical treatments for hyperthyroidism?
A
• Thyroidectomy – if large goitre, persistent drug side effect, poor compliance, recurrent hyperthyroidism
8
Q
What are the pharmacological treatments for hyperthyroidism?
A
- Anti-thyroid drugs: Carbimazole/PTU
- Radioactive iodine – if large goitre, persistent drug side effect, poor compliance, recurrent hyperthyroidism
- Beta blockers – symptom control
