Thyroid

Question 1

Hypothyroidism

Answer 1

Weakness, forgetfulness, Cold intolerance, decreased sweating, brittle hair and nails, facial edema

Goiter (Hypertrophy due to Inc stimulation by TSH) Cretinism

Question 2

Primary Hypothyroidism

Answer 2

Autoimmune D/O; Antibodies target thyroid peroxidase; Sx, radiation, radioiodine induced; Iodine defficiency MC WW.

Hashimoto’s Disease (Chronic autoimmune D/O) Lack of Thyroid production; Tx-provide thyroid hormone

Question 3

Secondary Hypothyroidism

Answer 3

Hypothalamus or pituitary insufficiency (Lack TRH or TSH secretion) central hypothyroidism.

Drug induced (amiodorone, lithium, antithyroid) 
 Tx-provide exogenous Thyroid hormone

Question 4

Hypothyroidism Meds

Answer 4

Dose adjusted every 6 weeks; Monitor every 6-8 wks then every 6-12 mths (S/S improvement / Hyperthyroid)

Take w/ empty stomach in a.m to avoid insomnia; AE-worse cardiac fx, Dec. bone density; Lovothyroxine DOC

Question 5

Lovothyroxine DOC

Answer 5

stable and uniform potency; long 1/2 life 7 days, low allergy, T3 controlled benefit when fasting or ill.

> 65 y/o, cardiac disease should initiate 25mcg/day. Before meals 30 min. or post 1 hr Titrate every 6 wks

Question 6

Dessicated Thyroid

Answer 6

Tx-Hypothyroidism; Animal source; Greater risk for hypersensitivity rx. Potency varies ; Mad cow disease risk

Low initial; increase ever 2-4 wks

Question 7

Liothyronine

Answer 7

Tx-Hypothyroidism Rapid absorption an greater activity results in cardio tox t 1/2 life 1.5 days

Niche (Appeal to small population) role in patients who cannot convert T4 to T3

Question 8

Liotrix

Answer 8

Tx-Hypothyroidism; Mimic’s body’s natural 4:1 T4:T3 secretion ratio; offers no clinical advantage

Question 9

Myxedema coma

Answer 9

Medical ER; Result of untreated hypothyroidism mortality (30-60%) Loss of brain fx. Low thyroid in blood
Due to cold exposure, trauma, infection, HF, meds

Hypoventilation, Hypoglycemia, hypothermia, shock
Tx Levothyroxine IV daily; Hydrocortisone until R/O Adrenal suppresion

Question 10

Hyperthyroidism

Answer 10

Intolerance to heat, Eye bulging, facial flushing Tachycardia, Weight loss, anorexia, fatigue, confusion

Grave’s Disease (60-80%) T stimulating Ab mimic TSH stimulating T3 and T4; Drug induced 2nd MC; adenoma; Plummer’s Disease= Multiple adenoma

Question 11

Hyperthyroidism Tx of choice

Answer 11

Radioactive Iodine for non-pregnant pts;Cost effective, no exopthalmus (Grave’s); failed Pharmacotherapy; –> hypothyroidism

Surgery; Tx OC for severe hyperthyroidism; unwilling/ able to take radioactive iodine; pregnant women; Costly –> hypothyroidism

Question 12

Thiomide

Answer 12

Hyperthyroidism; inhibits thyroid peroxidase blocks iodination synthesis of T hormones; slow onset= weeks

Max effects may take 4-6 mths; Prego D; 20-30 % remission post 1 yr discontinue; Severe hepato failure Jaundice; Lupus like s/s Arthralgia; Leukopenia; DC prior to I131

Question 13

Methimazole

Answer 13

DOC for Grave’s disease adults and children

NOT Pregnancy 1st Trimester

Question 14

Propythiouracil (PTU)

Answer 14

DOC for Pregnancy 1st Trimester and nursing ; Thyroid Storm;; adverse reaction to Methimazole

Question 15

Iodides (K Iodide and Saturated Solution SSKI)

Answer 15

Short term Hyperthyroidism (1-2 wks) preoperative prep for thyroidectomy; protect from subsequent damage prior to radiation exposure

Caution; May exacerbate hyperthyroidism; DC anti-thryoid Rx least 3-4 days prior to I^131; AE w Lithium

Question 16

Radioactive Iodine I^131

Answer 16

Rapidly accumulates in thyroid ommits gamma and Beta radiation destroying thyroid tissue–> Hypothyroid

Full effects seen 2-6mths period; Require 2nd 6-12 mth after; Neg pregnancy confirm X48hrs prior; permanent hypothyroidism 80% of all pts 25 yrs post procedure

No pregnancy, nursing or Opthalmopathy

Question 17

Nonselective B blockers

Answer 17

Adjunt to Block B1 and B2 Recep. to controlhyperthyroid ; tachycardia, HTN tremor, may block T4 periph. conversion. HR> 90BPM

Monitor Adrenargic S/S< 90 BPM –> hypotension, bradycardia, sex dysfx, weakness

Caution; DM, asthma, lipid abnormalities drug withdrawal ; DI B2 Agonists and CCBs

Question 18

Propanolol

Answer 18

Most evidence of use; Dose >160 mg dec. T3 levels 20%

FDA indication for thyrotoxicosis

Question 19

Nadalol

Answer 19

Least evidence of use; May also inhibit peripheral conversion T4 to T3.

Question 20

Metoprolol

Answer 20

B1 Specific (Non specific BBs tend to be preferred) direct effect o hypermetabolism.

Question 21

Esmolol

Answer 21

Inection; Used in ICU for Tx of severe thyrotoxicosis or thyroid storm.

Question 22

Medications used when BBs are CI (e.g., Asthma)

Answer 22

Verapamil and Diltiazem

Question 23

Thyrotoxicosis

Answer 23

Refers to Thyroid Hormone excess; ingestion of hormone or Thyroiditis; Amiodorone induced

Obesity MC cause inappropriately used thyroid hormone

Question 24

Thyroid Storm

Answer 24

Acucte exacerbation of all s/s of thryotoxicosis (mortality 20%); Trauma, infection, antithyroid agent withdrawal

Fever >103 , tachycardia, tachypnea, delirum/coma

Question 25

Thyroid Storm Management

Answer 25

1. Propylthiouracil or Methimazole
2. Iodide solution therapy (SSKI)
3. Antiadrenargic Theraoy Propanolol- Esmolol (Asthma)
4. Acetaminophen
5. Hydrocortisone Corticosteroid (reduce T4-T3 conversion)
6. Cholestyramine ; Bile Acid sequestrant (Dec. enterohepatic thyroid hormone)