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Flashcards in Endocrine - Online MedEd - thyroid Deck (18):
1

What does T4 do?

Movement
Mental
Metabolic active
*Can't live without T4

2

Excess of T4 does what?

Turn off TRH and TSH

3

TSH inhibits...

TRH

4

Hyperthyroid/thyroxicosis - symptoms

Tachycardia
Diarrhea
Heat intolerant (feels hot)
Increased DTR
Weight loss
Afib

5

Screen hyperthyroid with

TSH, then confirm with free T4
Hyperthyroid, TSH will be low and T4 high

6

First test of thyroid is always

TSH

7

Central hyperthyroid - pathophys

Elevated TSH drives T4

8

Know how to interpret Radioactive Iodine Uptake Scan (RAIU)

1) Graves disease - normal thyroid, TSH antibodies are made that activate TSH receptors --> thyroid gets bigger - whole thyroid will light up (TSH receptors everywhere on thyroid)
2) Thyroiditis - preformed T4, some iditis causes thyroid to fracture so now 2 thyroids --> cause transient hypothyroid state --> either thyroid will heal or shrivel up and die --> hashimotos. So in thyroiditis, won't light up on scan
3) Multinodular goiter --> many little lesions are secreting T4, will light up
4) Toxic adenoma --> one big lesion secreting T4, will light up
5) Factitious - exogenous T4 ingested
6) Stroma ovarii - ovarian lesion producing T4, will have a cold thyroid. will need a sestamibi scan of ovaries

9

Grave's disease - presentation and diagnosis, treatment

Exophthalmos
Preorbital myxoedema
Dx: Thyroid stimulating antibodies
Treatment: responds well to medical therapy, PTU and methimazole. Can use radioactive iodine ablation.
But if have exophthalmos and preorbital myxoedema, will need steroid and surgery because medical therapy can worsen

10

Thyroid storm - presentation

Afib/Shock
Fever
Hypotensive
AMS - altered mental status

11

Thyroid storm - treatment

IVF
Temperature under control
1) Propranolol - reduce autonomic symptoms
2) PTU or methimazole
3) Steroid - reduce conversion of T4 to T3

12

Treatment of hyperthyroid

1) Medical
2) Surgery - generally for Graves disease as radioactive iodine can cause exophthalmos etc.
3) Radioactive iodine - for multi nodular loiter, toxic adenoma, stroma ovarii
*Surgery and radioactive iodine are definitive treatment, whereas medical is to control symptoms

13

Hypothyroid - symptoms

Bradycardia
Constipation
Cold intolerance - patient feels cold
Decreased DTRs
Weight gain

14

Lab values for hypothyroid

TSH is high , T4 low
(Unless central lesion, both low)

15

Treatment of hypothyroid

Levothyroxine

16

Causes of hypothyroid

1) Iatrogenic - treated Graves
2) Hashimoto's - get TPO antibodies to confirm
*Doesn't matter too much about cause because same tx...except in...
3) Subclinical hypothyroid - treat if there are symptoms of hypothyroid

17

Myxoedema coma - what is it?

1) Coma
2) Hypothermic
3) Hypotension (due to drop in weight)

18

Treatment of myxedema coma

IVF
Blankets
IV T4/T3