Hyperthyroidism Flashcards
What is hyperthyroidism?
Increased thyroid hormone synthesis and secretion from the thyroid gland
What is thyrotoxicosis?
The clinical syndrome of excess circulating thyroid hormones
What is the most common cause of hyperthyroidism?
Grave’s disease
What is the 2nd most common cause of hyperthyroidism?
Multinodular goitre
What is the 3rd most common cause of hyperthyroidism?
Solitary toxic nodule
What are the causes of hyperthyroidism
- Grave’s disease
- Multinodular goitre
- Solitary toxic nodule
- Drugs
Interferon, amiodarone - Acute thyroiditis
- Gestational thyrotoxicosis
What causes Grave’s disease?
Autoimmune process that causes Antibody stimulation of TSH receptor
What is the most common cause of hyperthyroidism in the younger population?
Grave’s disease
What are the risk factors for Grave’s disease?
- Females
- +ve family Hx
- Smoking
- Low iodine intake
- Other autoimmune diseases
- T1DM
- Pernicious anaemia
- Coeliac
How may Grave’s disease present?
Diffusely symmetrical enlarged thyroid gland without nodules, and there may be a bruit
What is a multinodular goitre?
Multiple thyroid nodules that become independent of TSH regulation
What is the most common cause of hyperthyroidism in the older population?
Mulinodular goitre
How may multinodular goitre present?
Non-tender, firm thyroid nodules
What is solitary toxic nodule?
Solitary benign adenoma
How may solitary toxic nodule present?
Unilateral, non-tender thyroid mass
What is acute thyroiditis?
Inflammation of the thyroid gland which leads to release of thyroid hormones
What symptoms are associated with acute thyroiditis?
- Fever
- Neck pain
- Tenderness
- Dysphagia
How may acute thyroiditis present?
Tender, firm, irregular, diffusely enlarged thyroid gland which may be asymmetrical
How does gestational thyrotoxicosis occur?
High concentrations of hCG can stimulate TSH receptors and suppress TSH
When does gestational thyrotoxicosis occur?
1st Trimester
What are the universal symptoms of hyperthyroidism?
- Anxiety and agitation
- Sweating
- Heat intolerance
- Tachycardia
- Weight loss despite good appetite
- Loss of libido
- Diarrhoea
- Fatigue
What are the universal signs of hyperthyroidism?
- Palmar erythema
- Fine tremor
- Oncholysis
- Proximal myopathy
- Hyperreflexia
- Eyelid retraction
- Lid lag
What are the signs only seen in Grave’s disease?
- Acropachy
- Pretibial myxoedema
- Eye disease:
Proptosis/exophthalmos
Ophthalmoplegia
Oedema
Double vision
What is acropachy?
Soft tissue swelling of the hands and clubbing of the fingers
What is pretibial myxoedema?
o Deposits of mucin under the skin in the pretibial area
o Discoloured, waxy, oedematous appearance to the skin
What is Proptosis/exophthalmos?
Protrusion of eyeball
What is eyelid retraction?
Sclera is visible above the superior corneal limbus
What is the main risk factor of thyroid eye disease?
Smoking
How do you treat thyroid eye disease?
- Steroids
- Immunosuppression
- Surgery
What additional test would you order for Grave’s disease?
TRAbs (TSH-receptor antibodies)
What additional test would you order for thyroiditis?
ESR and CRP
How do you treat hyperthyroidism?
- Propanolol
- Antithyroid drugs = Carbimazole (1st), Propylthiouracil (2nd)
Others:
- Radioactive iodine
- Thyroidectomy
How can you give antithyroid drugs?
- Titration = start with high dose, and lower dose until lowest one is most effective
- Block-replace = High dose of antithyroid drug until hypothyroidism, then you give levothyroxine as a replacement
What do you need to warn a patient of when taking antithyroid meds?
• Agranulocytosis
- Report signs of infection, especially a sore throat
- WBC count should be performed
- Drug stopped if evidence of neutropenia
What can cause neonatal hyperthyroidism?
In Graves’ disease, thyroid stimulating antibodies can cross the placenta and stimulate the thyroid gland of the foetus
What is a thyrotoxic crisis/ thyroid storm?
End of the spectrum of thyrotoxicosis and is characterised by compromised organ function
How would you treat acute thyroiditis?
o Propranolol
Don’t need to give antithyroid medications
What is type 1 amiodarone induced thyrotoxicosis (AIT)?
- Excess thyroid hormone synthesis
- Enlarged goitre
- Managed with carbimazole or potassium perchlorate
- Stop amiodarone
What is type 2 amiodarone induced thyrotoxicosis (AIT)?
- Amiodarone-related destructive thyroiditis
- No Goitre
- Corticosteroids
- Stop amiodarone
