H_Review_Hyperthyroidism

Question 1

Sign and Symptoms

Answer 1

Amenorrhea

Decreasesed libido

Gynecomastia

proximal muscle weakness and hyperreflexia

Onycholysis

Palpitation

Osteopenia

Hypercalcemia

Hyperdefication

Question 2

Non Hyperthyroid thyrotoxicosis etiologies

Answer 2

**Ingestio of hormone:

*pharmacologic

LT4

Liothyronine (Cytome)

Armour (mix)

* non pharmacologic

Dietary supplements

Meat products in the past

**Inflammation causing release of endogenous thyroid hormone

Question 3

Hyperthyroid etiologies

Answer 3

*Antibody mediated

** Graves Disease

*Atuonomously functioning orthotopic thyroid tissue

** Toxic MNG

** Toxic adenoma

**Iodine exposure

* Autonomously functioning heterotopic thyroid tissue

**Struma ovarii

**Metastatic thyroid cancer

Question 4

Most common

88%

10%

1 %

< 1%

Question 5

Grave’s Disease

Answer 5

Atuoimmune Thyroid stimulating immunoglobulins

• Interferon therapy could cause it.

Complication

Graves ophthalmopathy

Dermopathy (pretibial myxedema)

Question 7

Toxic Adenoma

Answer 7

Plummer’s disease

Single autonomously functioning

Nodule is usually larg

Tx: resection, antithyroid, RAI

Question 8

Toxic MNG

Answer 8

Multiple autonomously functioning hyperplastic thyroid nodule

May be due to precipitated by I exposure

More common in elderly

Tx: RAI, surgical resection, antithyroid meds

Question 9

Sensitive index of thyroid function :

TSH vs FT4 vs FT3

Answer 9

TSH

Question 10

Radioactive tracers how are they different

I 123

Tc 99

Question 11

Uptake study

Question 12

Thyroid Scan

Answer 12

Used to generate images that reflect distributio of activity

I123 or Tc99 used / Gamma camera used to aquire images

works with looking at the distribution of the gamma radiation.

Question 13

Low uptake < 2%

Answer 13

• Inhibition of I uptake due to inflamation (damage)
• exogenous thyroid hormone ingestion
• Thyroglobulin levels

if low - injextion of exogenous thyroid

if high - inflammitory picture

Question 14

Hyperthyroid treatment:

Antithyroid Drug

Answer 14

30-60% remission rate within 12-18 montsh

• Rash
• Agranulocytosis
• Hepatitis and liver failure

PTU T4-T3 inhibition

• inhibits the enzyme thyroperoxidase, which normally acts in thyroid hormone synthesis by oxidizing the anion iodide (I-) to iodine (I0), facilitating iodine’s addition to tyrosine residues on the hormone precursor thyroglobulin, a necessary step in the synthesis of triiodothyronine(T3) and thyroxine (T4).

Question 15

Random facts

Which is used most?

which one is good for pregnancy (1st trimaster)?

Answer 15

MMi most commonly used

PTU 1st trimaster / hyperthyroidism with high FT3

Question 16

RAI and Pregnancy

Answer 16

Avoid pregnancy and breast feeding

avoid prenancy for 6 post treatment

Question 17

GRAVEs and RAI

Answer 17

Eye Dz may exacerbate

transient increase thyrotoxicosis

Question 18

Wolff–Chaikoff effect

Answer 18

Autoregulatory phenomenon that inhibits organification in the thyroid gland, the formation of thyroid hormones inside the thyroid follicle, and the release of thyroid hormones into the bloodstream.

This becomes evident secondary to elevated levels of circulating iodide. Lasts several days (around 10 days), after which it is followed by an “escape phenomenon”,[7] which is described by resumption of normal organification of iodine and normal thyroid peroxidase function. “Escape phenomenon” is believed to occur because of decreased inorganic iodine concentration secondary to down-regulation of sodium-iodide symporter (NIS) on the basolateral membrane of the thyroid follicular cell.

Question 19

RAI of toxic adenoma and toxic MNG