Hyperthyroidism

Question 1

Pharmacological therapy for primary hyperthyroidism

Answer 1

Severely symptomatic?
Carbimazole 30-45mg PO Daily in 2-3 divided doses.
Pregnant? Propylthiouracil 300-450mg PO Daily in 2-3 divided doses.
Mild or no syptoms
Carbimazole 10-20mg daily and propylthiouracil 100-200mg daily

AE: Agranulocytosis within first month of therapy.
- Propylthiouracil has rare cases of severe liver injury

Beta block to improve symptoms
- Atenolol 25mg PO OD
- Propranolol 10mg PO BD

beta blocker contraindicated? Give diltiazem 60mg PO QID.

Question 2

Indications for TSH investigation

Answer 2

Goitre or thyroid nodules identified
Monitoring of Thyroxine replacment therapy
Prior to and early in first trimester of women with risk factors for thyroid dysfunction
Basis of symptoms and risk factors for thyroid dysfunction.

Question 3

Indications for Radionuclide Thyroid Scan

Answer 3

Confirmatory of thyrotoxicosis if not evident on clinical examination or laboratory tests.

Question 4

Preference for Radioiodine or thyroidectomy for treatment of thyrotoxicosis

Answer 4

Radioiodine
- Severe Graves disease with large goitre. Recurrent severe disease. Older patient. Cause by toxic adenoma or toxic multinodular goitre. Young patients with high TSH-Recept Ab despite oral therapy.

Thyroidectomy
- As per above but include treatment of localised thyroid cancer.

Question 5

Approach to patient with goitre

Answer 5

1. TSH
   Low? Order thyroid scintigraphy
   Hot nodule? Toxic adenoma/multinodular goitre. Diffuse uptake? Graves. Not hot? Order thyroid US
   Normal? Order thyroid US
   High? Treat with levothyroxine and see if nodue regresses.

Question 6

Differential for Hyperthyroidism

Answer 6

• De Quervains Thyroiditis
• Infectious thyroiditis
• Graves disease
• Early phase of post-partum thyroiditis
• Excess Thyroid replacement
• Toxic adenoma