Thyroid disease

Question 1

What are the thyroid hormones and which is the most active?

Answer 1

T3 and T4

T4 is converted peripherally to T3 which is the most active form is T3

Question 2

what is the role of thyroid hormones?

Answer 2

They increase cell metabolism so are essential for growth

Question 3

What is the useful form of thyroid hormone to measure?

Answer 3

Free thyroid levels because total thyroid hormone is affected by the level of throxine binding globulin

Question 4

In hyperthyroidism which hormones will be raised?

Answer 4

T4 will be raised and TSH should be decreased

In 1% of cases T3 will be raised without T4

Question 5

In hypothyroidism which hormones should be requested?

Answer 5

Only T4 and TSH because T3 does not add any extra information

Question 6

What is sick euthyroidism?

Answer 6

This TFTs becoming deranged that may occur in any systemic illness

Question 7

Which antibodies may be increased in autoimmune thyroid disease e.g. graves or hashimotos?

Answer 7

Antithyroid peroxidase (TPO) 
antithyroglobulin antibodies

Question 8

What disease may have a raised TSH receptor antibody?

Answer 8

Graves disease

Question 9

What is ultrasound useful for in thyroid disease?

Answer 9

Distinguishing between cycstic and from solid (possibly malignant) nodules

Question 10

What are isotope scans used for?

Answer 10

These are useful for determining the cause of hyperthyroidism and to detect retrosternal goitre

Question 11

What are the symptoms of thyrotoxicosis?

Answer 11

Diarrhoea
Sweating
Decreased weight
Increased appetite
Heat intolerance
Palpatation
tremor
Irritability

Question 12

What tests should be done for thyrotoxis?

Answer 12

TSH will be supressed and will be increased T3

Check thyroid autoantibodies

Question 13

What are the causes of thyrotoxicosis?

Answer 13

Graves disease
Toxic multinodular goitre - iron deficient and elderly
Toxic adenoma - hot nodule on isotope scan
Ectopic thyroid tissue e.g. metastatic thyroid cancer
Exogenous - iodine excess, levothyroxine

Question 14

What is the treatment of hyperthyroidism?

Answer 14

Drugs:
-beta blockers - rapid symptom control
-Anti-thyroid:
-Titrate up carbimazole 20-40mg depending on TFTs
OR
-Give carbimazole and levothyroixne simultaneously
Radioiodine treatment - risk of thyroid storm
Thyroidectomy - damage to recurrent laryngeal

Question 15

What are the side effects of carbimazole?

Answer 15

Agranulocytosis so need to watch for infection

Sore throat/mouth ulcers

Question 16

What are the signs and symptoms of hypothyroidism?

Answer 16

Tiredness, sleepy, lethargic, low mood, increased weight, constipation
Signs:
Bradycardic
reflexes relax slowly
ataxia
dry thin hair/skin
yawning
cold hands
ascites
round face
defeated demenour
immobile
CCF
Proximal myopathy - raised ck
Weight gain
Bradycardia - due to reduce beta adrenergic receptors

Question 17

What tests should be done for hypothyroid?

Answer 17

Will have low TSH and T4 or High LSH and low T4 in rare secondary hypothyroid

Question 18

What are the causes of hypothyroid?

Answer 18

Primary atrophic hypothyroidism - most common cause, lymphocytic infiltration of the thyroid causing atrophy - no goitre
Harshimotos thyroiditis - goitre
Iodine deficiency is cheif cause worldwide

Question 19

What is the treatment of hypothyroidism?

Answer 19

Healthy and young - levothyroxine (T4)

Heart disease - levothyroxine prescribed with caution as may cause MI

Question 20

What is the treatment of tyrotoxic storm?

Answer 20

A-E IV tube, fluids
Take blood for T3 T4 and TSH, cultures if infection suspects
Give beta blocker (propanolol IV) caution in CHD
May give digoxin to slow heart with cardiac monitoring
Antithyroid drugs carbimazole 15-25mg
Hydrocortisone to prevent peripheral t4 conversion to t3