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
Q

Hypothyroidism** Symptoms**

A
  • Weight gain; inability to lose weight
  • Extreme fatigue
  • Forgetfulness
  • Prutitus
  • Depression
  • Cold intolerance
  • Menstual irregulatiriet
  • Muschle Cramps
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26
Q

Initiate Work Up

A

Not Bound = T4 : Able to enter body Tissue

27
Q

Initial Work up :
**TSH **

A
  • **Normal Range: **0.47-4.68
  • Suppresed: Hyperthroidism
  • Elevated: Hypothyroidism
28
Q

Abnormal TSH what next

A
  • Check FT 4
  • Elevated T4 = Hyperthyrodism
  • Suppressed= Hypothyroidism

**T3 : Check for Hyperthoidism or Determines Severtiy Hypothyroidism **

29
Q

2 antibodies

A
  • Antithyroglobulin antibodies
  • Antithryoidism Peroxidase antibodies
30
Q

Subclinial Hypothyroidism Overview

A
  • Rises with age, highter rate in females
  • Elevated TSH and normal T3/T4
  • Symptoms may be presen or absent
31
Q

treament quidelins

A
  • 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
Q

Hypothyroidism Treatment Plan
Target Goal

A
  • Replace thyroxine to mimix normal, physiologic leveles
  • Alleviate signs, symptoms, and biochemical abnormalities
33
Q

Levothyroxine
Initiate dose

A

At 1.6mg/kg/day

34
Q

Recheck TSH

A

6 to 8 wks
* Adjust Levopthyroxine by 12.5 to 25 mcg/day

35
Q

Hypythyroidism/Myxedema Coma :
What is Hallmark Signs ?

A

Decreased LOC and Hypothermia

36
Q

Myxedema : Clinical Presentation ?

A
  • Hyponatremia
  • Hypoglycemia
  • Hypoventilation
  • Hypotension
  • Bradycardia
  • CHF
  • Severe hypothyroidism W/High Mortality
37
Q

Myxedema Labs

A

TSH, FT4, Cortisol (will be low ) , ABG

38
Q

Pharmacology Reduction of Levothyroxine Effectivenss :
**Malabsorption Syndromes **

A
  • Postjejunoiletal Bypass Surgery
  • Short bowel Syndrme
  • Celiac Syndrome
39
Q

Pharmacology Reduction of Levothyroxine Effectivenss :
**Reduced Absorption **

A
  • Colestipol Hydrochloride
  • Sucralfate
  • Ferrous Sulfate
  • Food ( soybean Formula)
  • Aluminum Hydroxide
  • Cholestyramine
  • Sodium Polystyrene Sulfonate
40
Q

Pharmacology Reduction of Levothyroxine Effectivenss :
**Drugs that Increase Clearance **

A

Rifampin
Carbamazepine
Phenytoin

41
Q

Pharmacology Reduction of Levothyroxine Effectivenss :
Factors That Reduced T4 to T 3 Clearance

A

Amiodarone
Selenium Deficiency

42
Q

Pharmacology Reduction of Levothyroxine Effectivenss :
Other Mechanisms

A

Lovastatin
Sertaline

43
Q

Euthroid Sick

A
  • 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
Q

Euthryroid Sick : Dx

A
  • Excluson of Hypthyroidism
  • Check TSH
  • Directed toward underlying illness
  • Thyroid Hormone replacment DO NOT Indicated
45
Q

Hyperthyroidism

A
46
Q

Thyrotoxicosis VS Hyperthyroidism

A

**** 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
Q

Hyperthroroidism
Cause

A
  • **Autoimmune (Graves’ disease) **
  • Toxic nodular goiter
  • Thyroiditis
  • Exogenous Iodine
  • Amiodarone Toxicity
  • Excessive ingestion thyroid hormone replacement
  • TSH secreting pituitary adenoma
48
Q

**Hyperthyroidism **Signs **

A
  • Hypermetabolism
    ( classic symprom loosig weight and eating more )
  • Hyperrreflexia
  • Tachycardia
  • Hypertension
  • Warm, moist, thinning of skin
  • Fine/thin hair
  • Goiter
  • Exophthalmos
49
Q

Hyperthyroidism
**Symptoms **

A
  • Palpitations
  • Fatique
  • Sweating
  • Anxiety
  • Insomnia
  • Mentrual irregulatirties
  • Heat Intolerance
  • Myalgias, Muschle weakness
50
Q

Hyperthoroidism :
Grave’s Desease

A
  • 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
Q

GRave’s Disease Clues ?

A
  • Exopthalmos
  • Enlarged thyroid Gland
  • Family hx of autoimmune diseas
52
Q

Hyperthyroidism:
Exophthalmos

A

**Associated with Graves’ Disease
* Inflammation of **retro-orbital tissues **
* Optic nerve compression and atrophy

53
Q

Hyperthoroidism
Exophthalmos
**Symptoms **

A
  • Eye discomfort, grittiness
  • Excess tear production
  • Phorophobia
  • Diplopia
  • Decreased Acuity
54
Q

Hyperthoroidism
Exophthalmos
Signs

A
  • Exophthalmos
  • Ophthalmoplegia ( weakness or paralysis of one or more of the muscles that control eye movement. )
    *
  • Periorbital edema
55
Q

Initiated Work Up
TSH

A
  • **TSH **
  • Normal Range 0.47 to 4.68
  • Supressed = Hyperthyroidism
  • Elevated= Hypothyroidism
56
Q

Initiated Work Up
TRAb

A

**TRAb
**Positive = Graves’ Disease
Negative= Further Work up **

57
Q

Initiated Work Up
Elevated FT4 and T 3

A
  • 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
Q

Thyroid Scan

A
  • 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
Q
A
60
Q

Radioactive Iodine Uptake

A

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
Q

Subclinical Hyperthyroidism

A

Exogenous ( originates from outside of the system )
Endogenous ( within system )
Low TSH and FT4 and T 3 WNl

62
Q

Thyroid Storm causes

A

Surgery, Infection, Traume. Acute Iodine load . Abrupt cessatio of anti-thyroid medication

63
Q

Thyroid Storm Symptoms

A

fever
Agitation and confusion
Tachycardia
Hyperglycemia
HTN
RR distress
N/V

64
Q

TX of thyroid STorm

A
  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