PBL 3 - Hyperthyroidism Flashcards
List some of the symptoms of hyperthyroidism. (10)
What are the symptoms specific to Grave’s disease? (4)
GENERAL HYPERTHYROIDISM
- Weight loss
- Heat intolerance
- Palpitations
- Dyspnoea
- Irritability
- Fatigue
- Sweating
- Tremor
- Tachycardia
- Hypertension
GRAVE’S DISEASE:
- Ophthalmopathy
a. Exophthalmus
b. Periorbital oedema
c. Lid retraction/lag
d. Diplopia
e. Nerve compression - Dermopathy
- Pretibial myxoedema
- Finger clubbing
List the causes of hyperthyroidism. Consider:
a) Primary hyperthyroidism (4)
b) Secondary hyperthyroidism (7)
PRIMARY HYPERTHYROIDISM: Graves' disease Toxic multinodular goitre Toxic adenoma Ectopic thyroid tissue, e.g. ---Metastatic follicular cancer ---Struma ovarii
SECONDARY HYPERTHYROIDISM: TSHoma Exogenous thyroid hormones Subacute de Quervain's thyroiditis (post-viral) Drug-induced (e.g. amiodarone) Pregnancy TB Thyroid hormone resistance syndrome
Define Grave’s disease.
Autoimmune hyperthyroidism caused by autoantibodies; features classic signs of hyperthyroidism as well as additional symptoms specific to Grave’s disease
Describe the pathophysiology of Grave’s disease. (3)
- High levels of circulating thyroid hormones.
- Effects of increased hormone levels:
a. Increased metabolism
b. Increased sympathetic nervous activity - Autoimmune antibodies:
a. TSH-receptor antibodies
- –Stimulate normal TSH receptors to increase stimulation of the thyroid gland
Describe the investigations that can be done for hyperthyroidism. (3)
- TSH levels
- Serum free T4 levels
a. Free T4 index
b. Measure of T4 protein binding
c. Thyroxine binding globulin levels - Serum/total T3 levels
What is thyrotoxicosis?
Hyperthyroidism
What is thyroid crisis/thyroid storm?
A life-threatening condition due to a severe worsening of previously undiagnosed or inadequately treated thyrotoxicosis; often presents with fever, agitation, nausea, vomiting and abdominal pain
List the causes of thyroid storm. (8)
- Infection
- Diabetic ketoacidosis
- Physical/emotional trauma
- Thyroidectomy
- Childbirth
- Surgery
- Trauma
- No obvious cause
List the clinical features of thyroid storm. (5)
- Very high fever
- Extreme cardiovascular effects
a. Tachycardia
b. Congestive heart failure
c. Angina - Severe CNS effects
a. Agitation
b. Delirium
c. Psychotic episodes
d. Coma - Altered liver function
- Biochemical features:
a. Hyperglycaemia
b. Hypercalcaemia
c. High WBC count
d. Anaemia
Describe the treatment of hyperthyroidism. (3)
- Thionamides
a. Carbimazole/methimazole
b. Propylthiouracil (PTU) - Radioactive iodine
a. Uses 131iodine - Thyroidectomy
What is the mechanism of action of thionamides?
- Inhibit thyroid peroxidase
a. Therefore there is no hormone synthesis - Inhibit peripheral T4 to T3 conversion
a. Especially PTU - this causes a more rapid effect
What are the side effects of thionamides? (2)
- Maculopapular pruritic rash
- Agranulocytosis
a. Presents with sore throat, fever
List the SWEATING mnemonic for symptoms of hyperthyroidism.
Sweating Weight loss Emotional lability Appetite increased Tremor/Tachycardia Intolerance to heat/Irregular menstruation/Irritability Nervousness Goitre/Gastrointestinal problems
List the THYROIDISM mnemonic for symptoms of hyperthyroidism.
Tremor/Tachycardia Heart rate increased Yawning (fatigue) Restlessness Oligomenorrhoea/amenorrhoea Intolerance to heat Diarrhoea Irritability Sweating Muscle wasting/weight loss
Which thionamide is used preferentially in pregnancy?
Propylthiouracil
Methimazole may cause aplasia cutis in foetus