Thyroid

Question 1

What is hyperthyroidism?

Answer 1

Hypermetabolic state resulting from excess thyroid hormone

Question 2

What are the results of Hyperthyroidism?

Answer 2

↑ Metabolic rate
Excessive body heat generation
↑ Cardiac activity

Question 3

What are the causes of hyperthyroidism?

Answer 3

1. More common in Caucasian & Hispanic
populations
2. Females > males
3. Familial tendency
4. Autoimmune Dz 
5. Overexposure to iodine
A. Expectorants, amiodarone, seaweed, contrast dye

Question 4

What is grave’s dz?

Answer 4

1. Most common cause (80-90% of cases)
2. Diffuse toxic goiter
3. Autoimmune Dz

Question 5

What is toxic adenoma?

Answer 5

1. Single benign hyperfunctioning thyroid tumor resulting from a geneticmutation
2. “Hot” thyroid nodule

Question 6

What is Toxic Multinodular Goiter (Plummer’s Dz)?

Answer 6

2° to hyperplasticresponse of entire thyroid gland to a stimulus (iodine deficiency)

Question 7

What is Transient Thyroiditis?

Answer 7

1. Subacute thyroiditis
   A. Can causethyrotoxicosis&hypothyroidism
   B. De Quervain’s thyroiditis
   -Sudden, painful enlargement of thyroidgland w/fever,malaise& muscle aches (viral mediated)
2. Hashimoto’s thyroiditis
   A. Autoimmune disease

Question 8

What are the rare causes of hyperthyroidism?

Answer 8

1. ↑ Iodine ingestion w/preexisting thyroid hyperplasia or adenoma
2. Thyroid neoplasm
3. Amiodarone
4. Hydatidiform mole
5. Pituitary neoplasm
   A. Hypersecretes TSH

Question 9

What are the sxs of hyperthyroidism?

Answer 9

Wt. loss 
↑ Appetite 
Diarrhea
Anxiety
Irritability
Heat intolerance
Palpitations
Tremor
Hyperactivity
↓ Menses (oligomenorrhea,  	  	                       amenorrhea)
Hyperreflexia
Diaphoresis
Hyperactivity
Tachycardia
Systolic HTN
Tremor
Warm, moist skin
Thin, fine hair 
Lid lag
Stare
Muscle weakness

Question 10

What are the sxs of grave’s dz?

Answer 10

1. Exophthalmos
2. Lid retraction
3. Lid lag
4. Goiter
5. Painless pretibial swelling (myxedema)
6. Less common
   A. Diplopia
   B. Blurred vision
   C. Photphobia
   D. Increased lacrimatio

Question 11

What is thyroid storm/severe thyrotoxicosis?

Answer 11

1. Abrupt, severe exacerbation of thyrotoxicosis

2. Rare potentially fatal complication of hyperthyroidism

Question 12

What causes thyroid storm/severe thyrotoxicosis?

Answer 12

1. Occurs in patients with untreated (or undiagnosed) or undertreated hyperthyroidism
2. Precipitating event
   A. Trauma
   B. Infection
   C. Surgery
   D. Parturition

Question 13

What are the sxs of thyroid storm?

Answer 13

1. High fever
2. Tachycardia (>140)
3. CHF in elderly
4. N/V
5. Tremor
6. Mental status changes (psychosis, coma, seizures)

Question 14

What are the dx studies for hyperthyroidism?

Answer 14

1. ↓ TSH
2. ↑ Free Thyroxine (Free T4)
   A. Normal in subclinical hyperthyroidism
   -Pituitary adenoma secreting TSH
3. ↑ Free Triiodothyronine (Free T3)
4. Anti-TPO Ab (anti-thyroid peroxidase Ab)
   A. ↑ in Graves’ Dz
5. Anti-TSHR Ab (antithyrotropic receptor Ab)
   A. ↑ in Graves’ Dz

Question 15

What imaging and further studies are used in hyperthroidism?

Answer 15

1. Thyroid U/S
   A. If thyroid nodule or nodular goiter on exam
2. 24-hr radioiodine uptake (I-123) & scan
   A. Urine or serum HCG prior to testing
3. FNA & Bx if nodule confirmed

Question 16

What are the I-123 Uptake and scan results in Toxic adenoma?

Answer 16

1. Normal gland size
2. “Hot” nodule
3. Single focus of uptake

Question 17

What are the I-123 Uptake and scan results in graves’ disease?

Answer 17

1. Diffuse glandular enlargement

2. ↑ Homogenous I-123 uptake

Question 18

What are the I-123 Uptake and scan results in a multinodular goiter?

Answer 18

1. Diffuse enlargement w/ nodules

2. Areas of ↑ & ↓ I-123 uptake (heterogenous)

Question 19

What disorders require a thyroid biopsy?

Answer 19

All “cold nodules” require biopsy to R/O thyroid cancer

Question 20

How does radioactive Iodine treat hyperthyroidism?

Answer 20

1. Destroys gland
2. Most common treatment in non-pregnant adults, patients w/ large goiters, euthyroid not met after 1 yr of oral Tx, & when malignancy is likely (prior to surgery)
3. Single oral dose
4. Can worsen eye sx’s

Question 21

What are examples and functions of the thionamide drugs?

Answer 21

1. Methimazole/Tapazole (MMI) or Propylthiouracil (PTU)

A. Blocks production of thyroid peroxidase/inhibits new hormone synthesis

Question 22

What is the goal of hyperthyroid treatment?

Answer 22

1. euthyroid in 3-8 wks and cont. for 12 to 24 mo.

2. Useful in preparing patients for surgery or radioactive iodine treatment

Question 23

What is the drug of choice for hyperthyroidism in pregnant and breast feeding women?

Answer 23

Propylthiouracil (PTU)

Question 24

What are the benefits of Methimazole/Tapazole (preferred) over PTU?

Answer 24

Lower S/E, longer duration of activity

Agranulocytosis - rare complication

Question 25

What is the role of steroidsin the treatment of hyperthyroidism?

Answer 25

1. Inhibits peripheral T4->T3 conversion | 2. Ophthalmopathy responds best to IV methylprednisolone, or high-dose tapered prednisone Tx

Question 26

Why are beta blockers used in hyperthyroidism?

Answer 26

1. Propranolol controls palps, tachy, anxiety, tremors | 2. Initial treatment of choice for Thyroid Storm

Question 27

What are the surgical options for hyperthyroidism?

Answer 27

Thyroidectomy- partial vs total | requires thyroid hormone supplementation

Question 28

What are the indications for thyroid surgery?

Answer 28

1. Children (Graves’) 2. Pregnant women 3. Pts who refuse I-131 therapy 4. Pts w/ severe eye symptoms 5. Requires thyroid hormone supplementation

Question 29

What pt education needs to take place for hyperthyroidism?

Answer 29

1. Refer pt to Ophthalmologist A. Emergency care for eye pain, optic nerve compression, color vision loss 2. Smoking cessation-worsens eye symptoms 3. Medication compliance is important A. Risk of thyroid storm B. Patient education on symptoms/risk

Question 30

How is thyroid storm treated?

Answer 30

1. ICU 2. Treat underlying cause (infection, etc) 3. Tylenol 4. Beta Blocker 5. Tapazole/methimazole A. 80-100 mg PO or PR stat, then 30 mg PR q 8h 6. Inhibit thyroid hormone release A. Lugol’s sol’n: Iodide 10 gtts q 8h OR Sodium iodide 250 mg IV q 6h B. Corticoteroids: Hydrocortisone 100 mg IV Q8h

Question 31

define hypothyroidism

Answer 31

1. Inadequate secretion of thyroid hormone 2. > 90% of cases are primary caused by thyroid gland dysfunction 3. More common in caucasian females 4. ↑ prevalence w/ age

Question 32

What are the causes of primary hypothyroidism?

Answer 32

1. Autoimmune A. Hashimoto’s thyroiditis (most common cause > age 8) -Cell- & Ab-mediated destruction of thyroid tissue B. Previous thyroid surgery C. Radioactive iodine therapy D. External radiotherapy E. Meds such as lithium, amiodarone, sulfonamides, interferon, interleukin-2 F. Congenital ≈ 1 per 4000 births

Question 33

What are the causes of secondary hypothyroidism?

Answer 33

1. Pituitary dysfunction 2. Postpartum necrosis 3. Neoplasm

Question 34

What are the sxs of hypothyroidism?

Answer 34

1. Thinning, dry hair 2. Loss of outer 1/3 of brows 3. Skin A. Dry, coarse, cool, edema of eyelids & hands (myxedema) 4. Fatigue 5. Wt. gain 6. ↓ Appetite 7. Poor memory 8. Depression 9. Cold intolerance 10. Dulled expression 11. Macroglossia: uncommon unless longstanding untreated hypothyroid 12. +/- Thyromegaly 13. Bradycardia 14. Slow relaxation phase of DTR’s 15. Possible CTS (carpal tunnel syndrome) 16. Hyperlipidemia 17. Anemia 18. Hyponatremia

Question 35

What is the most common thyroid disorder in the US?

Answer 35

1. Hashimoto’s Thyroiditis 2. Affects 1% of the population & 5% over age 65 3. More common in women 7:1

Question 36

What is the etiology and precipitating factors for hypothyroidism?

Answer 36

1. Cause: combo of genetic & environmental factors 2. Precipitating factors: A. Stress B. Pregnancy C. Excess iodine intake D. Radiation exposure

Question 37

What are the early signs of hashimoto's thyroiditis?

Answer 37

1. Tender enlarged thyroid 2. Fever 3. Tachycardia 4. Diaphoresis 5. Palpitations 6. Wt. loss

Question 38

What are the late signs of hashimoto's thyroiditis?

Answer 38

1. +/- Nontender, enlarged thyroid 2. Fatigue 3. Wt. gain 4. Delayed reflexes

Question 39

What are the characteristics of subclinical hypothyroidism?

Answer 39

TSH high, T4 normal

Question 40

What are the characteristics of secondary hypothyroidism?

Answer 40

Inadequate TSH secretion from pituitary

Question 41

What are the characteristics of tertiary hypothyroidism?

Answer 41

Inadequate thyrotropin-releasing hormone(TRH) from hypothalamus

Question 42

What is the ddx for hypothyroidism?

Answer 42

1. Subclinical 2. Chronic fatigue syndrome 3. Secondary 4. Tertiary

Question 43

What are the diagnostic studies in hypothyroidism?

Answer 43

1. ↑ TSH A. Most sensitive screen (normal 0.50-5.0 mIU/L) 2. ↓ Free T4 A. Normal in subclinical hypothyroidism 3. Thyroid autoantibodies (Anti-thyroid antibodies) A. Anti-TPO Ab (anti-thyroid peroxidase antibodies) B. Anti-Tg Ab (anti-thyroglobulin antibodies) C. ↑ in Hashimoto’s thyroiditis but not always 4. Thyroid Scan A. Only for nodule B. Followed by FNA & Bx to R/O cancer

Question 44

How is hypothyroidism treated?

Answer 44

1. Synthetic thyroxine (T4) A. Levothyroxine daily am dose 2. Surgery A. Thyroidectomy if large gland compromises tracheoesophageal function or suspicious for malignancy

Question 45

What is myxedma coma?

Answer 45

1. Severe hypothyroidism leading to ↓ mental status & hypothermia 2. Medical Emergency w/ high mortality rate

Question 46

What causes myxedema coma?

Answer 46

1. Long standing undiagnosed or undertreated hypothyroidism 2. With additional insult A. Infection (pneumonia) B. Systemic disease C. Stroke/CHF/MI D. Medications: Sedatives, anesthetics, opiates, antidepressants) E. Cold exposure F. Trauma G. Surgery I. pregnancy

Question 47

What are the the sxs of myxedema coma?

Answer 47

1. General: Hypothermia ( < 95° F rectal) 2. HEENT: Myxedema facies, macroglossia 3. Neuro: Lethargy or stupor, areflexia 4. Cardiac: Hypotension/shock, bradycardia, low cardiac output 5. Vascular: ↓plasma volume, increased vascular permeability, fluid accumulation 6. Pulmonary: Depressed resp. drive, pleural effusions 7. Renal/GU: Bladder distention, hyponatremia 8. GI: Gastric atony, megacolon, ileus

Question 48

What is the treatment for myxedema coma?

Answer 48

1. ICU 2. Airway-if resp acidosis 3. T4 loading dose A. Levothyroxine 300-500 mcg IV over 15 min, then 100 mcg IV q 24 h 4. Hydrocortisone 100 mg IV bolus, then 50 mg IV q 12 h A. Give until adrenal insuff. is ruled out (normal serum cortisol) 5. Progressive rewarming of pt 6. Pan-culture then empiric Abx 7. IV hydration w/ D5NS 8. +/- Vasopressors

Question 49

What is the tx for hashimoto's thyroiditis?

Answer 49

1. Start thyroid hormone replacement Tx A. Prevents or corrects the hypothyroidism B. Halts thyromegaly

Question 50

What can hashimoto's thyroiditis initially present as? How do you managed this?

Answer 50

1. Can initially present as hyperthyroidism 2. Treatment-until initial hyperthyroid period resolves A. Bed rest & NSAIDs B. Some need steroids to ↓ inflammation & control palpitations C. Beta blocker to ↓ the HR & ↓ tremors

Question 51

What are the indications to treat myxedema-suspected pts before labs come back?

Answer 51

1. Thyroidectomy scar 2. Hx of I131 therapy 3. Hypothyroidism

Question 52

What are the dx studies for myxedema coma?

Answer 52

1. ↑↑ TSH 2. ↓ Free T4 3. CBC w/diff, UC, BC x 2 4. CXR 5. CMP 6. ABG’s 7. Serum cortisol (R/O adrenal insuff.) 8. ↑ CPK 9. Hyperlipidemia