Investigations of Hyperthyroidism

Case scenario

A 16 years old boy was referred by his general practitioner for assessment of suspected hyperthyroidism

Complains
•    Racing heart
•    Gastric reflux
Other
•    Good appetite
•    No apparent weight gain or loss
•    No diarrhoea

The parents reported that the boy had problems with behaviour and school performance and seemed to be hyperactive

Examination
Revealed a
•    Large smooth goitre
•    Thyroid bruit
•    Tachycardia
•    Sweaty plams
•    Proximal muscle weakness

Month	Nov	Dec	Jan	Feb	Mar	Unit	Ref Range
fT4	92	53	18	8	3	pmol/L	10-20
TSH	<0.1	<0.1	<0.1	0.2	1.1	mIU/L	0.5-4.0
Decreased fT4               with time Increased TSH             with time

Conclusion

Grave’s disease (autoimmune condition) where thyroid gland is stimulated by autoantibodies directed against TSH receptors on thyroid cells.

Impression
The patient had a
• Overt features of Graves disease (hypothyroidism and goitre)
• Ophthalmopathy
• Absent pretibial myxoedema detected
• Perform tests for thyroid hormone measurement (for confirmation)
• Patient was given carbimazole & TFT’s regularly checked
• Carbimazole act by blocking several TSH-stimulated stages in TH secretion
• Symptoms & signs improved