Hyperthyroidism

Question 1

Do the cards in patho on thyroid, this is less than half of the important info

Question 2

What causes toxic diffuse goiter and toxic multinodular goiter?

Answer 2

Toxic diffuse goiter = graves disease

Toxic multinodular goiter= toxic goiter acquired from chronic iodine deficiency.

Question 3

Graves’and concomittant autoimmune disorders

Answer 3

Type 1 diabetes mellitus

Pernicious anaemia

Connective tissue diseases

Polyglandular deficiencies Clinical course: can remit as the other autoimmune diseases.

Question 4

What causes exopthalmos in hyperthyroidism, when does it occur in the disease?

Answer 4

Immunoglobulins directed against the receptors in the orbital fibroblasts and adipocytes and accumulation of glycosaminoglycans and inflammation.

• Result: proptosis,ophtalmoplegia (muscular weakness), conjuctivitis, corneal ulceration, optic neuritis and atrophy.
• May be unilateral, or bilateral
• Onset before and as late as 20 years afterward the manifestation of hyperthyroidism

Question 5

Describe the dermopathy in hyperthyroidism

Answer 5

Pretibial myxoedema (confusing term, because suggest hypothyroidism) • Nonpitting infiltration by proteinaceosus substance usually in the pretibial area • Often pruritic, and erythematous in early stages, subsequently becomes brawny • Cause –unknown • May appear years before or after hyperthyroidism

Question 6

What are some rare causes of hyperthyroidism?

Answer 6

• TSH secreting anterior pituitary adenoma. α-subunit of TSH is high.
• Molar pregnancy, choriocarcinoma and hyperemesis gravidarum - human chorionic gonadotropin(hCG) a week thyroid (FT4) stimulator. (High hCG serum and urin level)
• Drug induced- from amiodaron, interferon, lithium can induce thyroiditis
• Excess iodine ingestion (amiodaron, contrast agents, expectorans)- nontoxic goiter with autonomous areas- FT4 production
• Extrathyroid source of hormone: Thyrotoxicosis factitia (overingestion of thyroid hormon)

Struma ovarii- ovarian teratomas contain thyroid tissue

RAIU in the pelvis, thyroid is suppressed

Question 7

What are atypical sings of hyperthyroidism? What patients do they usually present in?

Answer 7

Elderly patients in fact present with atypical symptoms more frequently than the classic ones.

• apathetic
• no tremor
• Atrial fibrillation
• syncope
• heart failure and weakness

Question 8

Treatment for hyperthyroidism

Answer 8

Beta-blockers to control acute symptoms. Decrease tachycardia, tremor, mental symptoms, sweating/temperature, proxymal myopathy. Also, Propranolol decreases peripheral T4/T3 conversion.

Iodine - Inhibits T3/T4 release and decreases vascularity of the gland. Effect lasts from a few days to a week. Used for emergency managment of thyroid storm, or for patients with hyperthyroidism undergoing emergency surgery.

Propylthiouracil or Carbimazole/Methimazol and Thyroxine - TPO inhibitors, decrease T3/T4 syntehsis, and also inhibits peripheral conversion of T4 to T3. The inhibitors halt endogenous production, and exogenous thyroxine prevents hypothyroidism.

Radioiodine - ablation

Surgery if there are compression symptoms to surrounding neck structures.

Question 9

Diagnostic tests

Answer 9

Measure TSH and T4/T3 levels

Radioiodine uptake assay, scintiography

Ultrasound

Question 10

What type of Iodine is used to ablate toxic goiters?

Answer 10

Radioactive Sodium Iodine 131

Most common treatment for Graves and toxic nodular goiter for all ages, fine to use in children.

No indication that it increases tumor incidence.

BUT not used in pregnancy.

Question 11

Treatment for thyroid storm

Answer 11

Thyroid storm:

• Propylthiouracil, iodine, propanolol,
• IV dextrose to correct dehydration and fluids/electrolyte imbalance, that occurs after the hyperthyroidism is inhibited.
• antiarrhythmic drugs, verapamil voltage dependent calcium channel blocker, adenosine, beta blockers,
• Corticosteroids to prevent low cortisol due to thyroxine inhibition.
• After crisis is managed, ablation with raio iodine 131 or surgery.