Thyroid Flashcards

1
Q

Hypothylamus
Function

A
  • Function: Controls apptetite, Temperature, Sex drive, Weight, mood, Sleep, Thurst
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2
Q

Hypothalamus Controls by ?

A

Controls **Pituary Hormones **by releasing Hormones :
* Thyrotropic - releasing hormone (TRH)
* Grownth Hormone- Releasing Hormone (GHRH)
* Corticotropin - releasing Hormone (CRH
* Gonadotropin- releasing Hormone(GRH)

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3
Q

Pituary Gland
Another Name

A

Master Gland

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4
Q

Pituitary Gland
Anterior Pituatary

A

TSH
Prolactin
GH
ACTH
LH

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5
Q

Pituatary Gland
Posterior Pituatary

A

ADH
Oxytocin

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6
Q

Thyrotropin -Releasing Hormone (TRH)

A

Stimulates the release of thyroid-stimulating hormone (TSH) and prolactin from the anterior pituitary.

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7
Q

Growth Hormone-Releasing Hormone (GHRH):

A

Stimulates the secretion of growth hormone (GH) from the anterior pituitary.

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8
Q

Corticotropin-Releasing Hormone (CRH):

A

Adrenocorticotropic hormone (ACTH) from the anterior pituitary.

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9
Q

Gonadotropin-Releasing Hormone (GnRH):

A

Stimulates the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary.

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10
Q

Thyroid Gland
Function

A

Controller of metabolism
Energy use
Oxygen consumption
Heat Production

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11
Q

T4 another name

A

Thyroxine (another name )

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12
Q

Thyroxine (T4)

A
  • **Major Thyroid Hormone secreted
  • 4 Iodine Atoms
  • T4 more occurate Hormone measure for clinical significant**s
  • Iodine is element needed for production of hormone
  • Iodine is not produce by body, must be ingensted with diet
  • Thyroid has active mechanism that able to pick up iodine in blood stream
  • T4 active in tissues they pick up iodine untile it’s converted T3
  • T4 to T3
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13
Q

Triodothyronine

A

T3 ( anoter name )

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14
Q

T3 Triiodothyronine

A

T4 convereted to T 3 removal iodine atom in Liver

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15
Q

Thyroid Stimulating Hormone (TSH)

A
  • Activated in Pituatary
  • Less T4 more TSH
  • More T4 less TSH
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16
Q

Somatrostatin

A
  • Released from Hypothylamus
  • Ability to inhibit (stop) TSH release
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17
Q

THyroid Function
Thyroid Hormone Uses
T3 and T4

A
  • Facilitate normal growth and development
  • Increases metabolism
  • Increases catechlamine effects
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18
Q

TSH

A
  • Most useful marker for thyroid function
  • Follows a diurnal rhythms, peaks at midnight
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19
Q

Metablic Effects of T3

A
  • Stimulates lipolysis and release of free fatty acids and glycerol
  • Stimlates metabolism of chelesterol to bile acids
  • Induces expression of lipogenic enzymes
  • Facilatates rapid removal of LDL from plasma
  • Effects chelsterol metabolism
  • Stimulates aspect of carbohydrate metabolism and the pathway for protein degradation
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20
Q

Levels

A
  • Normal TSH 0.3/0.5 to 3.0/5.0
  • TSH level below 0.4 suggest Thyroid **overactive **
  • TSH above 5.0 thyroid is underactive
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21
Q

Primary Hypothyroidism

A
  • U.S.A most common cause : Autoimmune
    * World Wide: Iodine Dyfisiansy
  • **Second Most Common Cause **: Post-therapetic treatment
  • Thyroid Destructtion
  • Medacations : Amio, Lithium, Interferon Alpha
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22
Q

Secondary (central ) hypothyroidism

A
  • Deficient TSH Secretion
  • Rare
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23
Q

Tertiary (central ) hypothyroidism

A
  • Deficient TRH secretion
  • Even mroe rare
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24
Q

Hypothyroidism **Signs **

A
  • Hypotension/Bradycardia
  • Brittle nail
  • Hair Loss
  • Decrased DTR
  • Dry course skin
  • Myxedema in extremities
  • Puffiness of eyes/face (periorbital edema )
  • HYpglycemia
  • Decreased bowel sound/constipation
  • Goiter( not present in all pts )
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25
Hypothyroidism** Symptoms**
* Weight gain; inability to lose weight * Extreme fatigue * Forgetfulness * Prutitus * Depression * Cold intolerance * Menstual irregulatiriet * Muschle Cramps
26
Initiate Work Up
Not Bound = T4 : Able to enter body Tissue
27
Initial Work up : **TSH **
* **Normal Range: **0.47-4.68 * **Suppresed:** Hyperthroidism * **Elevated**: Hypothyroidism
28
Abnormal TSH what next
* Check FT 4 * Elevated T4 = Hyperthyrodism * Suppressed= Hypothyroidism **T3 : Check for Hyperthoidism or Determines Severtiy Hypothyroidism **
29
2 antibodies
* Antithyroglobulin antibodies * Antithryoidism Peroxidase antibodies
30
Subclinial Hypothyroidism Overview
* Rises with age, highter rate in females * Elevated TSH and **normal T3/T4** * Symptoms may be presen or absent
31
treament quidelins
* TSH> 10 mU/L : consider tx * TSH upper limit of normal to 9.9 : 1. <65 consider tx 2. > 65 tx with symptoms 3. >80 yrs : avoid tx
32
Hypothyroidism Treatment Plan **Target Goal**
* Replace thyroxine to mimix normal, physiologic leveles * Alleviate signs, symptoms, and biochemical abnormalities
33
Levothyroxine Initiate dose
At 1.6mg/kg/day
34
Recheck TSH
6 to 8 wks * Adjust Levopthyroxine by 12.5 to 25 mcg/day
35
Hypythyroidism/Myxedema Coma : **What is Hallmark Signs ?**
**Decreased LOC and Hypothermia**
36
Myxedema : Clinical Presentation ?
* Hyponatremia * Hypoglycemia * Hypoventilation * Hypotension * Bradycardia * CHF * Severe hypothyroidism W/High Mortality
37
Myxedema Labs
TSH, FT4, Cortisol (will be low ) , ABG
38
Pharmacology Reduction of Levothyroxine Effectivenss : **Malabsorption Syndromes **
* Postjejunoiletal Bypass Surgery * Short bowel Syndrme * Celiac Syndrome
39
Pharmacology Reduction of Levothyroxine Effectivenss : **Reduced Absorption **
* Colestipol Hydrochloride * Sucralfate * **Ferrous Sulfate** * Food ( soybean Formula) * Aluminum Hydroxide * Cholestyramine * Sodium Polystyrene Sulfonate
40
Pharmacology Reduction of Levothyroxine Effectivenss : **Drugs that Increase Clearance **
Rifampin Carbamazepine Phenytoin
41
Pharmacology Reduction of Levothyroxine Effectivenss : Factors That Reduced T4 to T 3 Clearance
Amiodarone Selenium Deficiency
42
Pharmacology Reduction of Levothyroxine Effectivenss : Other Mechanisms
Lovastatin Sertaline
43
Euthroid Sick
* Low Serum Levels of thyroid Hormones * Nonthroidal Systemic Illness (trauma, DKA, Anorexia, Cirrohois, Malnutrition, sepsis) * Most likely due to decreased peripheral conversion of T4 to T 3 , decrease clearance of reverse T 3 * ***Labs: Do not have Elevated TSH ; Cortisole* Level is Hight ; * * Where Hypothyroidism Cortisole Levels is Low **
44
Euthryroid Sick : Dx
* Excluson of Hypthyroidism * Check TSH * Directed toward underlying illness * Thyroid Hormone replacment DO NOT Indicated
45
Hyperthyroidism
46
Thyrotoxicosis VS Hyperthyroidism
***** **Thyrotoxicosis:*** Clinical Syndrome of expcess circulating thyroid hormones irrespective of source * Can be due to too much Levothyroxine . Too much thyrotoxicosis floating in body * **Hyperthyroidism**: * * Sustained increased in Thyroid hormone synthesis and secretion from the *thyroid gland *
47
Hyperthroroidism Cause
* **Autoimmune (Graves' disease) ** * **Toxic nodular goiter** * Thyroiditis * Exogenous Iodine * Amiodarone Toxicity * Excessive ingestion thyroid hormone replacement * TSH secreting pituitary adenoma
48
****Hyperthyroidism **Signs **
* Hypermetabolism ( classic symprom loosig weight and eating more ) * Hyperrreflexia * Tachycardia * Hypertension * Warm, moist, thinning of skin * **Fine/thin hair** * Goiter * Exophthalmos
49
Hyperthyroidism **Symptoms **
* Palpitations * Fatique * Sweating * Anxiety * Insomnia * Mentrual irregulatirties * Heat Intolerance * **Myalgias, Muschle weakness**
50
Hyperthoroidism : Grave's Desease
* Most common cause of hyperthyroidism in the uS * 7 to 8 times more common in women than men * Autoimmune Disease * **TRAb or TSI ** * Overactivity of the **thyroid gland **
51
GRave's Disease Clues ?
* Exopthalmos * Enlarged thyroid Gland * Family hx of autoimmune diseas
52
Hyperthyroidism: Exophthalmos
******Associated with Graves' Disease** * Inflammation of **retro-orbital tissues ** * Optic nerve compression and atrophy
53
Hyperthoroidism Exophthalmos **Symptoms **
* Eye discomfort, grittiness * Excess tear production * Phorophobia * Diplopia * Decreased Acuity
54
Hyperthoroidism Exophthalmos **Signs**
* Exophthalmos * Ophthalmoplegia ( weakness or paralysis of one or more of the muscles that control eye movement. ) * * Periorbital edema
55
Initiated Work Up TSH
* **TSH ** * Normal Range 0.47 to 4.68 * Supressed = Hyperthyroidism * Elevated= Hypothyroidism
56
Initiated Work Up TRAb
**TRAb **Positive = Graves' Disease Negative= Further Work up **
57
Initiated Work Up Elevated FT4 and T 3
* Total T 4: measure Bound /Free Hormone * FT4 : Not Bound / able to enter tissues for effectiness * Total T 3 : Support dx Hyperthyroidism / Dx Severity Hyperthyroidism **Elevated FT4 and T3 Elevated: Hyperthyroidism Suppressed: Hypothyroidism **
58
Thyroid Scan
* Find out if thyroid Glan is over reactive or toxic nodules goiter or thyroitis * Test if thyroid glan can collect iodien * T4 collect iodine Thyroid glan collect iodine for T 4
59
60
Radioactive Iodine Uptake
Aloud us to see where iodine goes Determin if glan is overreactive Hi Uptake Radiosity : Graves Disease Low Up take : HYpoactivity Contraindicating for pregnant women
61
Subclinical Hyperthyroidism
Exogenous ( originates from outside of the system ) Endogenous ( within system ) Low TSH and FT4 and T 3 WNl
62
Thyroid Storm causes
Surgery, Infection, Traume. Acute Iodine load . Abrupt cessatio of anti-thyroid medication
63
Thyroid Storm Symptoms
fever Agitation and confusion Tachycardia Hyperglycemia HTN RR distress N/V
64
TX of thyroid STorm
1. TX underlying Cause 2. BB (propranolol ) 3. Thionamide (PTU or Methimazole ) 4. Iodine Solution (SSKI or Lugol's solution ) 5. Glucocotroicoids (Hydrocortisone 100 mg Q 8 hr s) 6. Antipyretics 7. Supportive care 8. Admit to ICU