Thyroid Disease Flashcards
What is the lifetime risk of thyroid disease in women?
20%
When is it especially important to consider thyroid disease?
Pregnancy/peripartum
Cardiac disease
List 11 symptoms of hypothyroidism
Bradycardia
Cold intolerance and hypothermia
Constipation
Delayed tendon reflexes
Depression
Effusions (pleural, pericardial)
Malaise
Myalgia and generalised myopathy (can be assoc. with increased CK)
Myxoedema
Voice change (e.g. hoarseness)
Weight gain
List 6 causes of primary hypothyroidism
ACIDIC:
AI
Congenital
Iodine deficiency
Drugs
Infiltrative disorders
Cures (iatrogenic: Px thyroidectomy, neck irradiation for lymphoma or other cancer)
List 4 causes of transient hypothyroidism
Silent thyroiditis (including postpartum)
Subacute thyroiditis
Withdrawal of thyroxine treatment in individuals with an intact thyroid
After radioactive iodine treatment or thyroidectomy
List 2 types of AI hypothyroidism. How are these distinguished clinically?
Hashimoto’s thyroiditis: goitre
Atrophic thyroiditis: atrophic, no goitre
List 6 drugs which may cause hypothyroidism
Drugs producing iodine excess (e.g. iodine-containing contrast media, amiodarone)
Lithium
Anti-thyroid drugs
p-aminosalicyclic acid
Interferon and other cytokines
Aminoglutethmide
List 4 congenital causes of hypothyroidism
Absent or ectopic thyroid gland
Dyshormonogenesis
TSH-R mutation
Iodine deficiency
List 6 infiltrative disorders which may cause hypothyroidism
Sarcoidosis
Amyloidosis
Haemochromatosis
Cystinosis
Riedel’s thyroiditis
Scleroderma
List 3 causes of secondary hypothyroidism
Hypopituitarism (tumours, trauma, surgery or irradiation, infiltrative disorders, Sheehan’s syndrome, genetic pituitary hormone deficiencies)
Isolated TSH deficiency or inactivity
Hypothalamic disease (tumours, trauma, infiltrative disorders, idiopathic)
How is hypothyroidism diagnosed?
Elevated TSH
Low FT4
Anti-thyroid Abs (e.g. anti-TPO) may be helpful
When should a thyroid U/S be considered?
If there is a palpable goitre (to check for nodules)
What is the relationship between hypothyroidism and IHD, OSA and HF?
Can cause hyperlipidaemia
How is hypothyroidism treated?
Usually 75-150 mcg/day thyroxine, single dose (some patients e.g. elderly or with IHD, start with 25-50 mcg/day)
Adjust dose after 6-8 weeks (has a half-life of ~1 week, takes 5-6 half lives to reach steady state), unless pt is pregnant (test every few hrs - better to overtreat)
How is treatment for hypothyroidism monitored? What is the aim of treatment?
TSH; aim for low normal in young people of child-bearing age (may be naturally higher in the elderly)
What medications may reduce thyroxine absorption and need to be taken separately?
Iron tablets
Calcium tablets
Antacids
Cholestyramine (bile acid sequestrant)
Is a nuclear scan necessary in hypothyroidism?
No
List 10 symptoms of hyperthyroidism
Loss of weight
Increased appetite
Increased sweating
Heat intolerance
Anxiety, sleep disturbance
Tremor
Hair loss
Palpitations
Diarrhoea
Oligomenorrhoea or amenorrhoea, menstrual irregularity
List 5 causes of hyperthyroidism
Graves’ disease
Toxic nodular goitre
Iodine-induced
Factitious (surreptitious thyroxine use)
Transient (assoc. with thyroiditis)
How does thyroiditis cause a transient hyperthyroidism?
Hormone is released from destroyed cells (produces hyperthyroidism initially; following death of cells less hormone is produced)
List 2 types of toxic nodular goitre
MNG
Adenoma (single toxic nodule)
List 3 causes of iodine-induced hyperthyroidism
Radiographic contrast
Dietary (e.g. kelp)
Amiodarone
NB Lithium can also cause hyperthyroidism as it acts similarly to iodine
Who is at risk of iodine-induced hyperthyroidism?
Those with pre-existing thyroid autonomy (e.g. Graves’, goitre due to iodine deficiency, etc)