Thyroid

Question 1

Causes of hyperthyroidism?

Answer 1

1.stimulation of TSH receptors
-graves disease
-TSH secreating pitutary adenoma
-high levels of HCG (3)

2.unregulated thyroid secretion
-TMN
-toxic adenoma

3.follicle destruction
-hashimoto’s thyroiditis
-de quervani’s thyroiditis (sub acute thyroiditis)

4.extrathyroid sources of thyroid hormone
-iatrogenic causes
-factitious hyperthyroidism
-strauma ovarii

Question 2

What causes the clinical features of hyperthyroidism?

Answer 2

Increased BMR and other metabolic activities
Increased sensitivity of beta adrenergic receptors

Question 3

Clinical features of hyperthyroidism?

Answer 3

12

Question 4

Ix of hyperthyroidism?

Answer 4

8

1.TSH (3rd gen)
2.Ft3 Ft4
3.isolated t3
4.thyroid peroxidase ab,thyroglobulin ab
5.TSH receptor ab
6.isotope uptake scan
7.USS
8.FNAC

Question 5

Mx of hyperthyroidism?

Answer 5

03 principals
1.anti thyroid medication
(1st line for graves and until definite tx for toxic MNG and toxic adenoma, to get euthyroidism before sx and radiotherapy)
-carbimazole (active form thiamazole/methimazole)
Immunosuppressive (good for graves)
Fetal defects rare
Tsh take 6w-3m to normalize,so monitor effect with ft3/ft4
SE- agranulocytosis, NV, athralgia,jaundice
- PTU
addition block conversation of t4 to t3
SE- liver toxicity
Indications- T1, allergic to carbemazole, severe thyrotoxicosis

2. Radioactive iodine tx (T 131)
   Relapsed graves
   Toxic adenoma and MNG
   contraindicated preg in 6m ,breast feeding
   Euthyroidism should achieve prior
   Worsening of eye dx
3. Thyroid sx
   Indications-5M

Question 6

presentation of thyrotoxic crisis?

Answer 6

7

Question 7

Precipitating factors of thyrotoxic crisis?

Answer 7

5
Infection
Surgery
Childbirth
Radioactive iodine
Withdrawal of anti thyroid tx

Question 8

Mx of thyrotoxic crisis?

Answer 8

8

Question 9

Causes of hypothyroidism?

Answer 9

Primary causes
1.hashimoto’s thyroiditis
2.subacute thyroiditis
3.postpartum thyroiditis
4.iatrogenic causes (sx,radioidodine,radiation)
5.SEs of drugs (anti thyroid, li, amiodarone,interferon alpha, thyrosine kinase inhibitors, checkpoint inhibitors) should check tsh every 6-12 months
6.iodine deficiency
7.iodine excess
Congenital hypothyroidism

Secondary hypothyroidism
Pituitary tumor (beware of an adrenal crisis)
Head trauma
Sheehan’s xd
Hypophysitis
Non pituitary tumor

Question 10

Reasons for clinical features in hypothyroidism?

Answer 10

Reduction of BMR and thermogenesis
Reduced sensitivity to beta receptors

Question 11

Clinical features of hypothyroidism?

Answer 11

15

Question 12

Ix of hypothyroidism?

Answer 12

Serum TSH (confirms diagnosis)
Thyroid and organ specific Ab
Hupercholesterolemia, hyponatremia, increased cpk, anemia

Question 13

Tx of hypothyroidism?

Answer 13

T4 replacement and rarely T3
1-1.5 microgram/kg/d (low dose start and then increase
Start low dose in pt >50yrs and cardiac disease
Beware of adrenal crisis

Question 14

Myxedema coma causes?

Answer 14

In old people, in cold
Severe hypothyroidism

Question 15

Clinical features of myxedema coma?

Answer 15

7
1.decrease body temp
2.respiratory depression
3.brandy arrhythmia
4.cardiac failure
6.hyponatremia
7.come

Question 16

Tx of myxedema coma?

Answer 16

6

Supportive care
Gradual rewarming
Correct electrolytes imbalance
Antibiotics
steroid-IV hydrocortisone
T3/T4 high dose via NG