Endocrinology_Thyroid disease_Hypothyroidism

Question 1

Clinical Manifestation of hypothyroidism - Dermatologic

Answer 1

• Decreased blood flow leads to cool skin, coarse hair, and brittle nails.
• Accumulation of glycosaminoglycans in interstitial spaces causes nonpitting edema (myxedema).

Question 2

Clinical Manifestation of hypothyroidism - cardiovascular

Answer 2

• Decreased heart rate and contractility → decreased cardiac output → dyspnea on exertion.

Question 3

Clinical Manifestation of hypothyroidism - GIT

Answer 3

• Decreased motility leads to constipation

Question 4

Clinical Manifestation of hypothyroidism - Hematologic

Answer 4

Normocytic anemia

Question 5

Clinical Manifestation of hypothyroidism - Reproductive

Answer 5

• Amenorrhea
• menorrhagia
• decreased fertility

Question 6

Clnical manifestation of hypothyroidism - Neurologic

Answer 6

• Carpal tunnel syndrome and delayed deep tendon reflexes

Question 7

Clinical manifestation of hypothyroidism - Metabolic

Answer 7

• Increased cholesterol and triglycerides
• decreased free water clearance leads to hyponatremia
• decreased basal metabolic rate → weight gain

Question 8

What is cretinism?

Answer 8

• Congenital hypothyroidism causing mental retardation and impaired growth

Question 9

Intepret - Low free T4 and high TSH

Answer 9

• overt hypothyroidism

Question 10

Intepret - Normal free T4 and high TSH

Answer 10

• subclinical hypothyroidism

Question 11

Intepret - Low free T4 and low TSH

Answer 11

• Secondary hypothyroidism (rare)

Question 12

What are some conditions that can cause secondary hypothyroidism?

Answer 12

• pituitary macroadenoma
• Sheehan syndrome, which is a pituitary infarct secondary to postpartum hemorrhage.

Question 13

What is the most common cause of hypothyroidism?

Answer 13

• Hashimoto thyroiditis, which is a chronic autoimmune thyroiditis.

Question 14

which auto antibodies mediate destruction of thyroid tissue in Hashimoto thyroiditis?

Answer 14

• antithyroid globulin and anti thyroid peroxidase antibodies.

Question 15

What are risk factors for developing Hashimoto thyroiditis?

Answer 15

• female gender
• family history of autoimmune disorders.

Question 16

What are the iatrogenic causes of hypothyroidism?

Answer 16

• thyroidectomy
• external radiation therapy
• radioiodine therapy

Question 17

Which medications can cause hypothyroidism?

Answer 17

• Lithium
• Amiodarone
• interferon Alpha
• interleukin 2

Question 18

iodine deficiency can cause hypothyroidism.
True or False?

Answer 18

• True, less than 100 micrograms of iodine per day increases the risk of hypothyroidism

Question 19

Excess iodine can cause hypothyroidism.
True or False?

Answer 19

• True. Excess iodine can inhibit the organification of T4 and T3.
  This is called the Wolff-Chaikoff effect

Question 20

What percentage of patients with subclinical hypothyroidism progress to overt hyperthyroidism?

Answer 20

• 33% to 55%.

Question 21

The risk of progression to overt hypothyroidism is associated with higher TSH levels, > 12 and positive antithyroid peroxidase antibodies.

true or false?

Answer 21

True

Question 22

For patients with subclinical hypothyroidism, under what conditions maythyroid replacement treatment be considered.

Answer 22

• symptomatic patients.
• Patients with TSH >10 - Since treatment appears to prevent progression to overt hypothyroidism
• pregnant patients with TSH more than 4.5 since subclinical hypothyroidism is a risk factor for miscarriage, and low birth weight.
• Patients with goitre since replacement can decrease goiter size.

Question 23

How do you treat hypothyroidism?

Answer 23

• synthetic L-thyroxine (T4) supplement

Question 24

How do you measure response to hypothyroidism therapy?

Answer 24

• Check TSH every four to six weeks until euthyroid,
• symptoms can improve, after two weeks.

Question 25

How do you treat myxedama?

Answer 25

L-thryoxine IV