M&n Week 5: Baker Thyroid Diseases And Therapeutics

Front 1

How is the production and release of thyroid hormones regulated?

Back 1

By TSH and TRH in the hypothalamic-pituitary-thyroid axis.

Front 2

How can trophoblastic tumors (molar pregnancy) result in hyperthyroidism?

Back 2

Excess HCG will occupy TSH receptor

Front 3

What percentage of Grave's patients will have clinical signs of opthalmopathy?

What percentage of patients with thyroid-related opthalmopathy have Grave's disease?

Back 3

50%

*Remainder will have subclinical evidence (extraocular muscle enlargement on orbital imaging)

90% patients with opthalmopathy have Grave's disease.

Front 4

If a patient presents with opthalmopathy without signs of hyperthyroidism, what should you check for?

Back 4

Immunoglobulins

Front 5

Describe the pathogenesis of opthalmopathy seen with Grave's disease.

Back 5

Autoimmune response against orbital autoantigen shared by thyroid
(fibroblast activation, extraocular edema, fibrosis)

Front 6

Thyroid acropachy or dermopathy are signs that are sometimes associated with which condition?

Back 6

Grave's disease

Front 7

What levels of thyroid hormone are expected in the diagnosis of hyperthyroidism?

Back 7

1. Suppressed TSH
2. Elevated free T4

Front 8

What sort of lab values or clinical signs are useful for making the diagnosis of hyperthyroidism?

Back 8

1. Elevated free T4, suppressed TSH
2. Goiter
3. Opthalmopathy
4. Dermopathy
5. TSH-receptor antibodies (TSI), Anti-TPO, anti-Tg <--- NOT clinically necessary to make diagnosis
6. Radioactive uptake and scan

Front 9

List 2 antithyroid treatments used for hyperthyroidism.

Back 9

1. Methimazole
2. Propylthiouracil (PTU)

Front 10

Why is PTU more efficacious than Methimazole?

Back 10

It has two function rather than one.
1. Blocks thyroid hormone synthesis
2. Blocks T4 to T3 conversion

Front 11

How long does it usually take to control symptoms of hyperthyroidism with antithyroid medication?

Back 11

2 - 3 weeks
(Propanolol given for symptomatic treatment)

Front 12

Why is Methimazole usually not used in pregnancy?

Back 12

Due to fetal aplasia cutis

(However, due alternative risks of PTU, sometimes Methimazole is still used during pregnancy)

Front 13

Why should you monitor patients for persistent sore throat, fever, or mouth ulcers after prescribing an antithyroid medication?

Back 13

Due to a rare, adverse side effect of thioamides --> agranulocytosis

Front 14

Why has the use of PTU been limited in the clinic?

What is PTU now used for?

Back 14

Due to recent reports of hepatic necrosis

*Now reserved for use in thyroid storm due to its dual effects and increased efficacy

Front 15

What type of treatments should you consider for hyperthyroid patients with atrial fibrillation?

Back 15

1. Warfarin or aspirin
2. Higher doses of digoxin

Front 16

Once administering radioactive iodine, women should be warned to hold-off pregnancy for at least how long?

Back 16

At least 4 months after treatment

Front 17

What conditions may occur within the first few days of radioactive iodine therapy?

Back 17

1. Acute thyroiditis
2. Sialadenitis
3. Opthalmopathy may worsen or appear (especially in smokers)

*Pre-treat with steroids

Front 18

When should a thyroidectomy be considered for a patient with hyperthyroidism?

Back 18

1. If the patient refuses radioactive iodine
2. Large, compressive goiters
3. Severe thyroid storm patients

Front 19

What are some complications that can arise from a thyroidectomy?

Back 19

1. Hypothyroidism
2. Hypoparathyroidism
3. Damage to Recurrent laryngeal N
4. Laryngeal edema secondary to hemorrhage

Front 20

How should a toxic nodule be treated?

Back 20

RAI

Front 21

How should a toxic multinodular goiter be treated?

Back 21

1. RAI
2. Surgery (if recurrent)

Front 22

How should thyroiditis be treated?

Back 22

Antithyroid medication

Front 23

Chronic lymphocytic or Chronic autoimmune thyroiditis is also known as...?

Back 23

Hashimoto's thyroiditis

Front 24

What type of immunity is associated with Hashimoto's thyroiditis?

What type of immunity is associated with Grave's disease?

Back 24

Hashimotos --> cellular immunity

Grave's disease --> humoral immunity

Front 25

What type of pathological findings are associated with Painful subacute thyroiditis?

Back 25

Giant cells and granulomas

Front 26

What type of pathological findings are associated with Hashimoto's thyroiditis?

Back 26

1. Lymphocytic infiltration
2. Germinal centers
3. Fibrosis

Front 27

Compare the thyroid function seen in Hashimoto's thyroiditis with that seen in Painful subacute thyroiditis.

Back 27

Hashimotos --> hypothyroidism

Painful subacute--> thyrotoxicosis, hypothyroidism, or both

Front 28

Compare the TPO antibody titers seen in Hashimoto's thyroiditis with that seen in Painful subacute thyroiditis.

Back 28

Hashimotos --> high titer, persistant

Painful subacute --> low titer, or absent, transient

Front 29

What sort of ESR rate is expected in Hashimoto's thyroiditis?

Back 29

Normal

Front 30

What sort of ESR rate is expected in Painful subacute thyroiditis?

Back 30

High

Front 31

What type of individuals are more susceptible to Hashimoto's thyroiditis? What about Painful subacute thyroiditis?

Back 31

Women are more susceptible to both

Front 32

Compare the age of onset typical of Hashimoto's thyroiditis with that of Painful subacute thyroiditis.

Back 32

Hashimoto's --> 30 - 50 yo

Painful subacute --> 20 - 60 yo

Front 33

If an adolescent patient presents with a goiter, what is the most likely cause?

Back 33

Hashimoto's thyroiditis
(most common cause of pediatric goiter or enlarged gland)

Front 34

Which 2 antibodies can be associated with Hashimoto's thyroiditis?

Back 34

1. Antithyroid microsomal (antithyroid-TPO)
2. Anti-thyroglobulin

Front 35

When comparing subacute thyroiditis and Grave's disease, how will the thyroid hormone levels be different?

Back 35

In subacute thyroiditis, T4 levels will be higher than T3

Front 36

By palpating a patient's thyroid gland, how can you differentiate between subacute thyroiditis and Grave's disease?

Back 36

Subacute thyroiditis results in a tender gland with minimal enlargement

Front 37

How can hypothyroidism lead to hypogonadism?

Back 37

TRH stimulates prolactin, and prolactin inhibits GnRH (decreased levels of LH and FSH).

Front 38

What is the half life of T4?

Back 38

7 days

Front 39

How often should you measure TSH levels after administration of T4 replacement therapy for hypothyroidism?

Back 39

Meausere TSH 8-12 weeks after starting Rx, then adjust dose and measure TSH yearly.

Front 40

Doses of thyroid replacement medications should be INCREASED for patients with what sort of conditions?

Back 40

1. Pregnancy
2. GI disease
3. Nephrotic syndrome

Front 41

Why should hypothyroid medications be increased for pregnant women?

The goal is to have what sort of TSH levels?

Back 41

Estrogen induces an increase in TBG, lowering free T4 in the serum.

*Want normal to low TSH levels (better to be slightly hyperthyroid-- ensure healthy brain maturation).

Front 42

What is central hypothyroidism?

Back 42

Thyroid hormone deficiency secondary to disorders of the pituitary, hypothalamus, or hypothalamic-pituitary portal circulation.

Front 43

What levels of thyroid hormone are seen in central hypothyroidism?

Back 43

Low T4
Any level of TSH (high, low, normal)

Front 44

How is the diagnosis of central hypothyroidism made?

Back 44

1. MRI of pituitary
2. TRH stimulation test

Front 45

What is Sick euthyroid syndrome?

Back 45

Non-thyroidal illnesses that modify peripheral metabolism of T4

Front 46

What sort of metabolic abnormality results in Sick euthyroid syndrome?

Back 46

Inhibition of 5'-deiodination of T4 to T3
(Inner ring deiodinases activated leading to rT3 rather than T3)

Front 47

What sort of lab values are expected in Sick euthyroid syndrome?

Back 47

1. TSH normal
2. Total T4 normal or increased, free T4 slightly increased
3. T3 decreased
4. Reverse T3 increased