Hypothyroidism

Question 1

What is hypothyroidism?

Answer 1

Inadequate output of thyroid hormones by the thyroid gland

Question 2

What are the causes of hypothyroidism?

Answer 2

Hashimoto’s thyroiditis
Iodine deficiency
Secondary to treatment of hyperthyroidism
Medications
Secondary hypothyroidism

Question 3

What is Hashimoto’s thyroiditis?

Answer 3

Autoimmune inflammation of the thyroid gland
- Antithyroid peroxidase (anti-TPO) antibodies
- Antithyroglobulin antibodies

Causes goitre then atrophy

Question 4

What treatments of hyperthyroidism can cause hypothyroidism?

Answer 4

Carbimazole
Propylthiouracil
Radioactive iodine
Thyroid surgery

Question 5

What medications can cause hypothyroidism?

Answer 5

Lithium- inhibits TH production
Amiodarone- interferes with TH production

Question 6

What are the causes of secondary hypothyroidism?

Answer 6

Hypopituitarism- fails to produce enough TSH
- Tumours
- Infection
- Vascular (Sheehan syndrome)
- Radiation

Question 7

What is the presentation of hypothyroidism?

Answer 7

Weight gain
Fatigue
Dry skin
Coarse hair and hair loss
Fluid retention
Heavy or irregular periods
Constipation

Question 8

What are the investigations for hypothyroidism?

Answer 8

TSH
T3 and T4

Question 9

What does high TSH and low T3 and T4 indicate?

Answer 9

Primary hypothyroidism
Pathology is in thyroid gland

Question 10

What does low TSH and low T3 and T4 indicate?

Answer 10

Secondary hypothyroidism
Pathology in the pituitary gland

Question 11

What is the management of hypothyroidism?

Answer 11

Oral levothyroxine
- Synthetic T4 and metabolises to T3 in the body
- Dose is titrated until TSH levels are normal