Hypothyroidism Flashcards

1
Q

What will TFTs show in primary hypothyroidism?

A

TSH- high

T3/T4- low

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

What will TFTs show in secondary hypothyroidism?

A

TSH- low or normal

T3/T4- low

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

What is the definition of hypothyroidism?

A

Any disorder that results in insufficient secretion of thyroid hormones from the thyroid gland

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

What is myxoedema coma?

A

A hypothyroid emergency

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

In general, hypothyroidism is most common in which sex and of which age group?

A

Females, 65+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Hypothyroidism has a higher incidence in which race?

A

White populations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What environmental factor causes a higher incidence of hypothyroidism?

A

Areas of iodine deficiency

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

What are 5 causes of goitrous, primary hypothyroidism?

A
  • Hashimoto’s thyroiditis
  • Iodine deficiency
  • Drug induced
  • Maternally transmitted
  • Hereditary defects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What 2 drugs have a big effect on thyroid function?

A

Amiodarone and lithium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is hypothyroidism maternally transmitted?

A

If the mother is on anti-thyroid drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Is Hashimoto’s thyroiditis always goitrous?

A

No

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

What are 4 causes of non-goitrous, primary hypothyroidism?

A
  • Hashimoto’s thyroiditis
  • Post-ablative therapy
  • Post-radiotherapy
  • Congenital defects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are 3 examples of self-limiting hypothyroidism?

A
  • Following withdrawal of anti-thyroid drugs
  • Subacute thyroiditis
  • Post-partum thyroiditis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What causes secondary hypothyroidism?

A

Hypothalamic or pituitary disease

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

What are 6 causes of hypothalamic-pituitary disease?

A
  • Infiltrative disease
  • Malignancy
  • Infection
  • Cranial radiotherapy
  • Congenital disorders
  • Trauma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What effects can hypothyroidism have on the hair and skin?

A
  • Vitiligo
  • Coarse, sparse hair
  • Periorbital puffiness
  • Pale, cool, doughy skin
  • Hypercarotenaemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What effect does hypothyroidism have on thermogenesis?

A

Cold intolerance

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

What clinical sign appears in hypothyroidism as a result of abnormal fluid balance?

A

Pitting oedema

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

What effects can hypothyroidism have on the CV system?

A
  • Decreased HR
  • Cardiac dilatation
  • Pericardial effusion
  • Worsening of heart failure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What metabolic effects does hypothyroidism have?

A
  • Hyperlipidaemia

- Weight gain and decreased appetite

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

What GI effects can hypothyroidism cause?

A
  • Constipation
  • Intestinal obstruction
  • Ascites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What respiratory effects can hypothyroidism cause?

A
  • Deep, hoarse voice
  • Macroglossia
  • Sleep apnoea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What neurological/CNS effects can hypothyroidism have?

A
  • Depression, psychosis
  • Muscle stiffness, cramps
  • Peripheral neuropathy
  • Decreased visual activity
24
Q

What reproductive effects can hypothyroidism have?

A
  • Menorrhagia
  • Oligo/amenorrhoea (later)
  • Hyperprolactinaemia
25
Hypothyroidism causes macrocytosis. What is this and what test will show it?
Enlarged red blood cells, increased MCV
26
What does hypothyroidism do to creatinine kinase?
Increases it
27
What does hypothyroidism do to LDL cholesterol?
Increases it
28
What effect does hypothyroidism have on sodium concentration and why?
Hyponatraemia- decreases renal tubular water loss
29
Why does hypothyroidism cause hyperprolactinaemia?
Increased TRH increased PRL secretion
30
What type of disease is Hashimoto's thyroiditis?
Autoimmune
31
What are the two main antibodies involved in Hashimoto's thyroiditis? Which is the major one?
Anti-thyroglobulin (60%) and anti-thyroperoxidase (95%)
32
Is TRAb ever present in Hashimoto's thyroiditis?
Yes (10-20%)
33
Autoantibodies in Hashimoto's thyroiditis cause antibody mediated, cell dependent cytotoxicity via what cell?
CD8+ T cells
34
How does cytokine mediated cell death occur in Hashimoto's thyroiditis?
Gamma interferon from T cell activation recruits macrophages
35
What sex and age group is Hashimoto's most common in?
Females, 45-60
36
What may precede Hashimoto's thyroiditis?
Transient hyperfunction (hashitoxicosis)
37
What type of goitre will Hashimoto's usually cause?
Diffuse, firm, painless
38
There is an increased risk of what type of cancer in the gland affected by Hashimoto's thyroiditis?
B cell Non-Hodgkins Lymphoma
39
What other autoimmune conditions are most commonly affected with autoimmune thyroid disease?
Addison's disease, pernicious anaemia, Type 1 diabetes
40
What is the main treatment of hypothyroidism?
Levothyroxine
41
What is the main risk of levothyroxine increasing metabolic rate?
Cardiac arrhythmias
42
What is the normal dosage of Levothyroxine?
50-100 macrograms daily
43
When should the normal dosage of levothyroxine be changed and what to?
In the elderly or those with ischaemic heart disease it should be 25-50 macro grams initially and adjusted every 4 weeks depending on response
44
Once TSH is stabilised with Levothyroxine, how often should levels be checked?
Every 12-18 months
45
Is there proven benefit of T3/4 combined treatment?
No
46
When in the day is levothyroxine preferably taken?
Before breakfast
47
What happens to the dose of levothyroxine in pregnancy and why?
It increases (usually by 25-50%) since pregnancy increases thyroid binding globulin
48
What drugs interfere with Levothyroxine?
Ca++ and iron tablets and PPIs
49
Who is most commonly affected by myxoedema coma?
Elderly females with longstanding but unrecognised or untreated hypothyroidism
50
Why is the mortality rate of myxoedema coma so high?
Co-morbidities
51
What 4 things may an ECG of someone with myxoedema coma show?
- Bradycardia - Varying degrees of heart failure - T wave inversion - Prolonged QT interval
52
What type of respiratory failure will occur in myxoedema coma? What are the features of this?
Type 2- hypoxia, hypercapnia, respiratory acidosis
53
Co-existing failure of what is present in 10% of myxoedema coma patients?
Adrenals
54
How should patients with myxoedema coma be treated?
- ABCDE, intensive care | - Passively rewarmed
55
What is the major thing that should be monitored for in myxoedema coma?
Arrhythmias
56
What 4 things should be monitored in myxoedema come?
Oxygenation, urine output, fluid balance, blood sugars
57
What drugs should myxoedema coma patients be given?
Broad spectrum antibiotics and thyroxine (cautiously)