MEH 20 - Thyroid Dysfunction

Question 1

What are T3/4 + TSH levels in hyper and hypothyroidism and why?

Answer 1

Hyperthyroidism = T3/4 high, TSH low (as T3/4 provides neg feedback on TRH + TSH)

Hypothyroidism = T3/4 low, TSH high (as lack of neg feedback from T3/4)

• One way of assessing thyroid gland function + disorders.

Question 2

Apart from biochemical analysis, what are some other methods of thyroid assessment?

Answer 2

• Thyroid examination - check to see if enlarged
• Thyroid ultrasound - best for imaging thyroid
• Radio-isotope scan

Question 3

What are the typical signs + symptoms of hypothyroidism?

Answer 3

• Tiredness, weight gain, cold intolerance, change in appearance, constipation, dry hair/skin, puffy eyes.
• Myxeodema - loss of eyebrows, bradycardia, slow reflexes, cold peripheries.

Question 4

What are the common causes of hypothyroidism?

Answer 4

• Auto-immune atrophic (atrophy of thyroid gland)
• Hashimoto’s thyroiditis (TPO antibodies)
• Dyshormonogenesis (babies w/underactive thyroid)
• Iodine deficiency

Question 5

What is the treatment for hypothyroidism?

Answer 5

• Levothyroxine (T4) for life

Question 6

What are the signs + symptoms of hyperthyroidism?

Answer 6

Symptoms = Weight loss, irritability, restlessness, itching, sweating, tremor, palpitations etc

Signs = Tremor, tachycardia, warm peripheries, hypertension + lid lag/lid retraction (bulging eyes)

Question 7

What are the common causes of hyperthyroidism?

Answer 7

1) Graves’ disease - autoimmune stimulation of TSH receptor (TRAb). Most common cause.

2) Nodular thyroid disease
3) Thyroiditis. - e.g.: due to viral infection or medication

Question 8

What are the treatment options for hyperthyroidism?

Answer 8

• Carbimazole
• Surgery
• Radioactive iodine