Drug-Induced Hyperthyroidism Flashcards
What drug commonly causes hyperthyroidism and why
AMIODARONE
High iodine content - hyperthyroidism
Inhibits conversion of T4 to T3 (hypothyroidism
Role of AMIODARONE
Anti-arrythmic
What elements can cause hyperthyroidism if found in a drug
Iodine
Lithium
What are the clinical presentations of drug-induced hyperthyroidism
- Palpatations
- Diarrhoea
- Weight LOss
- Heat Intolerance
- Tremors
- Warm
- Hyperkinesis
- Anxiety
- Diffuse Goitre
DIFFUSE GOITRE and WASTING are the biggest signs
In elderly how can drug-induced hyperthyroidism be caused
- Atrial Fibrillation
2. Heart Failure
In children, how can drug-induced hyperthyroidism be caused
- Excessive height or GR
2. Behavioural problems (ADHD)
How is Hyperthyroidism treated
- PROPRANOLOL (controls symptoms)
- PROPYLTHIOURACIL (stops conversion of T4 to T3)
- ORAL Carbimazole and THYROXINE which reduces hypothyroidism risk
Why do half of those with Graves’ relapse after 2 years
Discontinue treatment after two years
What is the main side-effect of treating hypothyroidism
Agranulocytosis - leads to Low white blood cells count (leukopenia)
Rash (less common)
When should drugs stop being given to patients with Graves’ or hypothyroidism
If they get throat, mouth ulcers
Fevers
When should radioactive iodine be given
4 days after anti-thyroid drugs have been stopped
How long does 131-I take for normal thyroid to function
4-12 weeks after radioactive iodine
When can radioactive iodine be contraindicated
Pregnancy and breast feeding
Side-effects of giving radioactive iodine
Discomfort in the ne ck and hyperthyroidism initially
When should surgery be given to individuals with hyperthyroidism
- Those with large goitre, poor response to drugs or experiencing severe side-effects from treatment
What is subtotal thyroidectomy
Leaves a bit of thyroid (nota ll removed) to preserve function
When is subtatotal thyroidectomy given
When patient is euthyroid
When is a total thyroidectomy given
Those with large goitre, malignancy in nodule or Graves’
What should we do before surgery occurs
Stop antithyroid drugs 10-14 days before
GivePotassium Iodide to reduce vascularity of gland
Side-Effectt of surgery for hyperthyroidism
Hypothyroid
Tracheal compression from post-operative bleeding
Laryngeal nerve paslsy (sore throat)
Trnasient hypocalcaemia (removal of PTH gland)
How can Hashimoto’s thyroiditis be treated
Levothyroxine therapy to shrink goitre even when patient is not hypothyroid
How is a thyroid crisis treated
1. LARGE DOSES OF: Oral CARBIMAZOLE ORAL PROPRANOLOL ORAL POTASSIUM IODIDE IV HYDROCORTISONE
Role of ORAL POTASSIUM IODIDE
Block acutely the release of thyroid hormone from glands
Role of IV HYDROCORTISONE
Inhibits T4 to T3
Signs of children with hypothyroidism
Slow growth velocity
Poor School performance
How are papillary and follicular carcinomas treated
Total thyroidectomy
Ablative radioactive iodine
Problem with anapaestic carcinomas
- Does not respond to radioactive iodine
External radiotherapy provides brief respite
How to treat medullary carcinoma
Thyroidectomy and lymph node removal
How is hypothyroidism treated
Oral LEVOTHYROXINE
What should we look out for in patients with ischaemic heart disease who are hypothyroid
Start on lower dose
What do we increase the risk of if we give LEVOTHYROXINE
AF and Osteoporosis if we suppress TSH completely
How is primary hypothyroidism treated
- Those titrated until TSH normalises
2. Check T4 levels 6-8 weeks after dose adjustment
Why can’t we check TSH levels in secondary hypothyroidism
TSH will always be low
What do we monitor in secondary hypothyroidism
T4
How do we treat Myxoedema Coma and what people does this usually effect
IV T3 and Glucose infusion
Old people - confusion
How is myxoedema coma caused
EXTREMELY LOW T4
What in blood tests would indicate hypothyroidism
- Normocytic or microcytic anaemia or microcytic in women due to coeliac’s
- Raised serum aspartate transferase levels
- Increased serum creatinine kinase levels
- Hypercholesterolaemia
- Hyponatraemia due to increased ADH
Where is iodine deficiency common
Netherlands, India, Russia and Africa
Role of Thyroid peroxides
Production and storage of thyroid hormones
Problem with Postpartum thyroiditis
Can be misdiagnosed as postpartum depression (Temporary phase after pregnancy)
Four ways hypothyroidism can be drug-induced
- CARBIMAZOLE
- LITHIUM
- AMIODARONE
- INTERFERON
What often causes Goitre
Iodine Deficiency