Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHCY 310 > L 45. Thyroid Disorder > Flashcards

L 45. Thyroid Disorder Flashcards

1
Q

4x functions of the thyroid gland

A
  • Hormone production
  • Growth
  • Development
  • Regulation of energy metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Epidemiology of thyroid function x3

A
  • More common in women
  • Hypo prevalence increases with pregnancy and age
  • Most common dysfunctions = hypothyroidism and hyperthyroidism.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Patient assessment for thyroid dysfunction.

A

Is routine screening/asymptomatic testing recommended?
1. Patient history
2. Physical examination
3. TSH measures.
Routine screening/asymptomatic testing is not recommended.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

High suspicion symptoms of hypothyroidism x2?

A

Goitre, delayed reflexes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Intermediate suspicion symptoms of hypothyroidism x7

A 
Fatigue
Weight gain
Cold intolerance
Dry/rough/pale skin
Constipation
Facial swelling
Hoarseness.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Low suspicion/non-specific symptoms of hypothyroidism x7

A 
Dry hair/hair loss
Muscle cramps/aches
Depression
Irritability
Memory loss
Abnormal menstrual cycles
Decreased libido
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

High suspicion symptoms of hyperthyroidism x4

A

Goitre
Thyroid bruit (sound)
Eyelid lag/droop (Ptosis)
Eye bulging (proptosis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does ptosis and proptosis mean?

A

Ptosis: eyelid droop
Proptosis: bulging eyes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Intermediate suspicion symptoms of hyperthyroidism x7

A 
Fatigue
Weight loss
Heat intolerance/sweating
Fine tremor
Increased bowel movements
Fast heart rate/palpitations
Staring gaze
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Low suspicion/non specific symptoms of hyperthyroidism x7

A 
Nervousness
Insomnia
Breathlessness
Light/absent menstrual periods
Muscle weakness
Warm/moist skin
Hair loss
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Symptoms of hypothyroidism (x3)

A

Fatigue/lethargy/sleepiness
Cold intolerance
Dry skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Hypothyroidism treatment goals x3

A

Replace missing hormones
Relieve signs and symptoms
Achieve euthyroid state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a euthyroid state

A

Normal thyroid function/TSH within the reference range

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

… is the synthetic form of T4.

… is converted into the more active form, … in the peripheral tissue via peripheral……

A

Levothyroxine is the synthetic form of T4.

T4 is converted into the more active form, T3, in the peripheral tissue via peripheral deiodination.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why is levothyroxine the drug of choice for hypothyroidism?

A

It is reliable, it relieves symptoms, it is safe, and it stabilises thyroid function tests.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Potential issues with elderly or IHD patients with levothyroxine.
Therefore how must we approach the dosing?

A

Increased metabolic activity = increased cardiac stimulation = arrythmias, angina, MI
TTherefore need to do initial low dose and then titrate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Dosing of levothyroxine

A

Adult: 500-100mcg od before breakfast. Titrate 25-50mcg every 3-4 weeks according to response.
In cautioned patients, consider 25mcg of and adjust by +25mcg every 4 weeks.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is maintenance dose for levothyroxine in adults in and patients with cautions?

A

100-200 mcg daily in adults

50-200mcg daily in cautioned patients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Dose adjustments occur for levothyroxine when…

Monitoring timeframes.

A

Dose is titrated according to blood test results
Monitor TSH 6-8 weeks after initiating treatment.
Adjust if necessary, recheck in 6-8 weeks and check symptoms.
If patient stable, monitor TSH every 6-12 months.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why is the monitoring of levothyroxine only every 6-8 weeks?

A

Steady state takes 6-8 weeks to reach therefore show clinical benefit. Must wait until then to determine the effects of the medicine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

ADRs of levothyroxine (at excessive doses)

A

Hyperthyroidism symptoms:
Diarrhoea, headache, flushing, sweating, fever, heat intolerance
Increased appetite but weight loss
Tachycardia, arrhythmias, palpitations, hypertension
Tremor, restlessness, excitability
Insomnia, muscle cramp, muscular weakness
Menstrual irregularities, impaired fertility

22
Q

Food/diet interactions of levothyroxine

A

Many foods/ions decrease the gut absorption of levothyroxine (e.g calcium, iron, antacids, cholestryamine). Therefore should take it on an empty stomach.
Drug-food interactions: soy, high fibre diet.

23
Q

Drug interactions with Levothyroxine x4

A 
The following CYP inducers increase the metabolism of levothyroxine, therefore an increased dose is required:
Phenytoin
Carbamazepine
Oestrogen (HRT)
Rifampicin
24
Q

Levothyroxine brands x3

A

Synthroid
Eltroxin
Levothyroxine (mercury Pharma)

25
Q

IMP POINT WHEN CONSIDERING LEVOTHYROXINE BRANDS

A

Brands are NOT interchangable.
They have the same active ingredient
Different excipients –> diff absorption –> diff bioavailability

26
Q

What is a section 29 (unfunded) drug used for severe hypothyroidism?

A

Liothyronine (T3)

Is used to treat myxedema coma (severe hypothyroidism, life threatening).

27
Q

PK of liothyronine (onset, t0.5 - not values but describing words)

A

Rapid onset, short t0.5 therefore reaches therapeutic concs.

28
Q

Dosing for liothyronine in myxedema coma

A

IV injection if in coma.

10-20mg/day increased to 20mcg tds.

29
Q

Hyperthyroidism is considered to be a … disease

A

Hyperthyroidism is considered to be a subclinical disease

30
Q

What are the differences between subclinical and overt hyperthyroidism?

A

Subclinical: mild form, TSH is below normal but free T4/T3 is within the normal range. Few or no symptoms.

Overt hyperthyroidism: TSH lower than normal, free T3 and or T4 are above normal, hyperthyroidism symptoms will always be present (e.g sweating, weight loss etc)

31
Q

Treatment goals for hyperthyroidism x4

A

Relieve signs and symptoms
Decrease thyroid production
Achieve euthyroid state
Prevent complications

32
Q

Complications of hyperthyroidism x3

A

Loss of bone density, CVD, graves (opthalmopathy and dermopathy)

33
Q

Management of hyperthyroidism is dependent on: (x5)

A 
Cause and severity of disease
Age
Goitre size
Concurrent medications/co-morbidities
Patient preference
34
Q

MoA of thionamides

A

Competitively inhibit thyroid peroxidase –> decreased oxidation and binding of iodine (!!) –> decreased T4/T3 synthesis.
NOTE: PTU also inhibits the conversion of T4 to T3

35
Q

What does MMI and PTU stand for?

A 
MMI = metabolite methimazole
PTU= propylthiouracil
36
Q

Initial carbimazole/methimazole dosing.

How long is therapy normally continued for?

A

Adult: 15-40mg/day (divided) for 4-8 weeks then until euthyroid.
Reduce dose gradually and adjusted according to response.
Therapy normally continued for 12-18 months

37
Q

PTU initial dosing

A

200mg-400mg daily (divided) until euthyroid, then gradually reduce dose to 50-150mg daily (divided)

38
Q

Can PTU or methimazole be used in pregnancy?
Which has a shorter t0.5?
Which has 10 fold lower activity?

A

PTU can be used in pregnancy.
PTU has a shorter half life.
PTU has 10 fold lower activity than methimazole.

39
Q

Advantages of both carbimazole (x2) vs PTU (x4)?

No clear advantage of one over the other.

A

Carbimazole is most common. Can be given OD, may have better overall safety profile (less hepatoxicity)
PTU additionally inhibits T4 –> T3 conversion, can be used in pregnancy, short t0.5, but can cause severe liver injury.

40
Q

What does “block and replace” mean in terms of thyroid treatment?

A

High doses of carbimazole to block thyroid function
+ levothyroxine and titrate until euthyroid.
Given for 18 months, not suitable during pregnancy.

41
Q

ADRs of thionamides (minor + serious)

A

Minor: rash, fever, GI upset (treat symptoms)
Serious: bone marrow suppression –> agranulocytosis (low WBC count) = DISCONTINUE DRUG!

42
Q

Patient counselling of ADRs for thionamides?

A

Report symptoms of: fever, sore throat, or infection

43
Q

What is the serious side effect of thionamides? What should occur in this case?

A

AGRANULOCYTOSIS.

Discontinue drug immediately.

44
Q

Why are B blockers used for thyroid treatment?

A

They provide relief of adrenergic symptoms, and can inhibit the conversion of T4 to T3 (but don’t reduce synthesis).

45
Q

When do you start a thyroid patient on B blockers and when do you stop?
What are the most common B blockers given to thyroid patients?

A

Start when diagnosed for hyperthyroidism for symptomatic relief.
Continue until euthyroid occurs.
Most common: propanolol and nadolol.

46
Q 
Radioactive iodine:
What does it do?
What % is euthyroid after a single dose?
Whomst can it be used for?
Is it better or worse when compliance is an issue? Why?
What is the risk of it?
A

Removal of body tissue (thyroid) without surgery = thyroid ablation
90% euthyroid after a single dose
Can be used for all ages, those with cardiac disease or when having a relapse after partial thyroidectomy.
Good when compliance is an issue - one dose!
Risk: permanent hypothyroidism (lifelong monitoring required)

47
Q

Non-pharm options for hyperthyroidism

What are the usual indications for this method?

A

Partial thyroidectomy
- if failure to respond to medical treatment, intolerance to anti-thyroid meds, pressure of goitre onto trachea/oesophagus, or cosmetic issues.

48
Q

Summer of hyperthyroidism treatment

  • 1st line for Grave’s disease
  • Additional drugs to first line
  • 2nd line
  • Non-pharm option
A

1st line: Carbimazole
Additional drugs: B blockers for symptomatic relief (and propanolol inhibits T4 to T3)
2nd line: radioactive iodine (also for relapse after drug treatment)
NP option: thyroidectomy

49
Q

Which drugs can induce thyroid dysfunction?

A

Amiodarone and lithium

50
Q

What is the MoA of amiodarione inducing thyroid dysfunction?

A

Amiodarione has a high iodide content and a toxic effects on the thyroid. It also decreases peripheral conversion of T4 to T3.

51
Q

What is the MoA of lithium inducing thyroid dysfunction?

What parameters need to be monitored?

A

Decreases synthesis and secretion of thyroid hormones.

Need to monitor: TSH, free T4 and free T3

PHCY 310 (65 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions