53. Diseases with thyroid hyperfunction

Question 1

Hyperthyroidism: Definition

Answer 1

Disease characterized by increased T3, T4 secretion by thyroid

Question 2

Hyperthyroidism: etiopathophysiology

Answer 2

PRIMARY HYPERTHYROIDISM

• Graves disease ( Auto-immune —> thyroid stimulating AB and thyroperoxidase AB —> Stimulate follicular cells —> Increased T3, T4
• Iodine overdose ( Increased T3, T4 production )
• Thyroid adenoma —> Increased no. follicular
• L-Thryoxine overdose
• Mcune Albright syndrome ( Rare genetic disorder —> Fibrous dysplasia of bone + stimulates thryoid —> Increased T3, T4

SECONDARY:

• Pituitary adenoma
• hCG producing tumor ( Increased hCG mimics TSH —> Increased T3, T4 )

Question 3

Hyperthyroidism: CF

Answer 3

GENERAL

• Weight loss ( ^ metabolism )
• Hyperthermia
• Diarrhea ( Increased GIT motility )
• Tachycardia, HTN, tremors, sweating ( ^ SNS activity )
• Anxiety, irritability ( Neuropsychic )
• Early closure of fontanelle ( Quick development )

GRAVES

• Triad = Exophthalmos, Tibial myxedema ( red, purplish waxy skin ), Acropathy ( clubbing )

Question 4

Diagnosis

Answer 4

1) ^ T3, T4

2) Decreased TSH = Primary:

• MRI —> thyroid Adenoma
• Pt history —> Iodine, L-thyroxine
• X-ray —> ground glass bones = McCune Albright syndrome
• Thyroperoxidase and thryoid stimulating AB —> Graves

3) Increased TSH = secondary:

• MRI —> Pituitary adenoma
• hCG levels —> hcG producing tumor

Question 5

Treatment

Answer 5

GENERAL

• Thyreostatic therapy = Carbimazole for 2-4 yrs
• Systemic therapy = Beta blockers
• If thyroid adenoma = Radiation Iodine ( shrinks thyroid ) / Thyroidectomy

If thyreostatic therapy fails = Very high dose Iodine ( Blocks iodine uptake by thyroid ) + thionamide