Hypothyroidism

Question 1

What is hypothyroidism?

Answer 1

The term used to describe 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 or hyperthyroidism 
medications
central causes

Question 3

Describe Hashimoto’s thyroiditis

Answer 3

The most common cause of hypothyroidism in the developed world. Caused by autoimmune inflammation of the thyroid gland. It is associated with antithyroid peroxidsase (anti-TPO) antibodies and antithyroglobulin antibodies
It initially causes a goitre after which there is atrophy of the gland

Question 4

Describe iodine deficiency

Answer 4

The most common cause of hypothyroidism in the developing world

Question 5

What treatments of hyperthyroidism can lead to hypothyroidism?

Answer 5

carbimazole
prophylthiouacil
radioactive iodine thyroid surgery

Question 6

What medications can cause hypothyroidism?

Answer 6

Lithium

amiodarone

Question 7

What are some of the central (secondary) cause s of hypothyroidism?

Answer 7

Tumours
infection
vascular (e.g. Sheehan syndrome)
Radiation

Question 8

How does hypothyroidism present and what are its features?

Answer 8

weight gain?
fatigue 
dry skin
coarse hair and hair loss
fluid retention
amenorrhiea
constipation

Question 9

How is hypothyroidism managed?

Answer 9

Replacement of thyroid hormone with oral levothyroxine.
The dose is titrated until TSH levels are normal, measure TSH monthly initially until stable then less frequently unless they become symptomatic