Thyroid Flashcards
1
Q
Where is the TSH receptor located?
A
- surface of thyroid epithelial cells
2
Q
What is used to control the production of T3 and T4?
A
- Inhibitory feedback loops
3
Q
Explain thyroiditis?
A
- inflammation of the thyroid gland
4
Q
Cause of thyroiditis?
A
- Autoimmune (Hashimotos, Graves)
- De Quervains
- Infection
5
Q
What causes the symptoms of hyperthyroidism?
A
- Increased T3 and T4
6
Q
Hyperthyroidism is also known as what?
A
- Thyrotoxicosis
7
Q
What are some causes of hyperthyroidism?
A
- Graves
- Adenoma
- Thyroiditis
- Ectopic production
8
Q
What are some symptoms of hyperthyroidism?
A
- anxiety
- palpitations
- weight loss
- loose stool
- heat intolerance
9
Q
What investigations should be done for hyperthyroidism?
A
- TSH
- T3 and T4
10
Q
What investigation can be performed to test for Grave’s disease?
A
- TSH receptor antibodies
TRAb
11
Q
What is the first line treatment for hyperthyroidism?
A
- carbimazole
12
Q
What treatments can be used for hyperthyroidism?
A
- carbimazole
- propylthiouracil
- radioactive iodine
- b blockers
13
Q
Grave’s disease is what type of condition?
A
- autoimmune
14
Q
What antibodies are associated with Grave’s disease?
A
- TSH receptor antibodies
15
Q
What triad of features of hyperthyroidism can be seen?
A
- exophthalmos
- pretibial myxoedema
- acropathy
16
Q
Symptoms of de quervain’s thyroiditis?
A
- fever
- neck pain
- dysphagia
17
Q
What is the phases of de quervains thyroiditis?
A
- initial hyperthyroidism
- followed by hypothyroidism
18
Q
What is a thyroid storm?
A
- rare presentation
- acute increased production of thyroid hormone
- admission
19
Q
Hashimoto’s thyroiditis is what condition?
A
- autoimmune
- hypothyroidism
20
Q
What are some causes of hypothyroidism?
A
- Hashimotos
- iodine deficiency
- drugs for hyperthyroidism
- post-surgery
21
Q
Symptoms of hypothyroidism?
A
- weight gain
- fatigue
- hair loss
- oedema
22
Q
Treatment for hypothyroidism
A
- levothyroxine
23
Q
What age group does Hashimoto’s thyroiditis typically effect?
A
- 40-50
24
Q
What autoimmune sign is seen in Hashimoto’s thyroiditis?
A
- anti-thyroid antibodies
25
Hashimoto's thyroiditis increases the risk of other auto-immune conditions? True or false
- True
26
Goitre describes what?
- any enlargement of the thyroid gland
| - hyper or hypothyroidism can cause
27
What often causes a goitre?
- lack of dietary iodine
28
Diffuse goitre?
- iodine deficiency
| - usually normal thyroid function
29
Multi-nodular goitre?
- evolution from long standing simple goitre
| - low risk of malignancy
30
What are the different carcinomas of the thyroid?
- papillary
- follicular
- medullary
- anaplastic
31
What is an example of a thyroid adenoma?
- follicular adenoma
32
What may cause a papillary carcinoma?
- ionising radiation
33
What may cause a follicular carcinoma?
- iodine deficiency
34
What is the most common form of thyroid cancer?
- papillary carcinoma
35
What does papillary carcinoma arise from?
- follicular cells
36
What spread would papillary carcinoma tend to spread via?
- lymphatic
37
What are symptoms of papillary thyroid carcinoma?
- lesion
- hoarseness
- dysphagia
38
What is the 2nd most common type of thyroid cancer?
- follicular carcinoma
39
What is the spread route of follicular carcinoma?
- haematogenous
40
What cell type does medullary thyroid carcinoma arise from?
- c-cells
41
Explain anaplastic carcinomas of the thyroid?
- undifferentiated
| - aggressive
42
When does the thyroid gland begin to develop?
- 4th week of embryogenesis
43
Where does the thyroid gland originate?
- thickening of the back of tongue
| - foramen caecum
44
Where does the thyroid gland descend down?
- thyroglossal duct
45
Remnant of the thyroglossal due can be called?
- pyramidal lobe
46
What spinal level does the thyroid gland sit?
- C5-T1
47
What is the arterial supply to the thyroid gland
- superior and inferior thyroid artery
48
Explain the steps in thyroid hormone synthesis
- thyroglobulin synthesis
- uptake and concentration of iodide
- oxidation of iodide to iodine
- iodination of thyroglobulin
- formation of MIT and DIT
- T3 and T4
49
What is the most abundant thyroid hormone?
- T4
50
What is the most potent thyroid hormone?
- T3
| - 4 times more potent than T4
51
What transports the thyroid hormones?
- Thyroxine binding globulin
| - TBG
52
What is the role of de-iodinases?
- derogates T3 and T4
| - Mainly D3 and D1 involved
53
Where would the de-iodinases enzyme D3 be found?
- fetal tissue
- placenta
- brain (except pituitary)
54
What investigations should be performed for a solitary thyroid nodule?
- TSH
| - USS fine needle aspiration
55
What is the treatment for a low risk differentiated thyroid cancer?
- lobectomy
56
What is the treatment for a high risk differentiated thyroid cancer?
- total thyroidectomy
| - also consider radioactive iodine
57
What tumour cell marker can be used for follow up patients with previous thyroid cancers?
- thyroglobulin (Tg)
58
What is the frequency of TSH measurements for patients with previous thyroid cancer?
- TSH every 6 months for 5 years
| - TSH every year for a further 5 years
59
What puts an increased risk of thyroid lymphoma?
- hashimoto's thyroditis
60
What is the diagnostic tool for thyroid lymphoma?
- core biopsy
61
Treatment of thyroid lymphoma?
- steriods
- r-chop chemo
- radiotherapy
62
What cells are involved in medullary thyroid carcinoma?
- c-cell
63
What investigations are done for multinodular goitre?
- TSH
| - CT scan
64
Treatment for a multinodular goitre?
- leave alone?
- radioactive iodine
- surgery
65
Describe primary thyroid disease
- disease affecting the thyroid gland itself
66
Describe secondary thyroid disease?
- hypothalamic or pituitary disease
| - no thyroid pathology
67
What thyroid hormones are measured?
- TSH
- Free T3
- Free T4
68
What does TSH levels reflect?
- reflects tissue thyroid hormone action
69
Where is T4 deionised to T3?
- liver
70
Explain the blood results you would expect with primary hyperthyroidism?
Free T3/4 = high
| TSH = low
71
Explain the blood results you would expect with secondary hyperthyroidism?
Free T3/4 = high
| TSH = high or normal
72
Explain the blood results you would expect with primary hypothyroidism?
Free T3/4 = low
| TSH = High
73
Explain the blood results you would expect with secondary hypothyroidism?
Free T3/4 = low
| TSH = normal or low
74
Define myxoedema
- severe hypothyroidism
| - medical emergency
75
Explain pretibial myxoedema?
- rare clinical sign of Grave's disease
76
What are some primary causes of hypothyroidism
- Hashimotos
- iodine deficiency
- post-radiotherapy
77
What are some secondary causes of hypothyroidism?
- infection
- malignancy
- trauma
78
Clinical features of hypothyroidism?
- weight gain
- decreased appetite
- constipation
- depression
- reduced heart rate
79
Treatment of hypothyroidism?
young pt - levothyroxine 50-100ug daily
| elderly pt - levothyroxine 25-50ug daily
80
Once commencing levothyroxine when should you check TSH levels?
- after 2 months
81
In secondary hypothyroidism what blood result is unreliable?
- TSH
| - use free t4/3
82
Hashimoto's thyroiditis is associated with what autoantibody?
- TPO antibodies
83
Symptoms of a myxoedema coma?
- bradycardia
- heart block
- type 2 resp failure
84
Treatment of myxoedema coma
- rewarm
- antibiotics
- thyroxine
85
Define thyrotoxicosis?
- cels exposed to excess thyroid hormones
86
Symptoms of thyrotoxicosis
- palpitations, AF
- Tremor
- sweating
- heat intolerance
- weight loss
87
Causes of thyrotoxicosis which are not associated with hyperthyroidism?
- de quervains
- postpartum thyroditis
- over treatment of levothyroxine
88
What autoantibody is associated with Grave's disease
- TSH receptor antibody (TRAb)
89
Symptoms of Grave's disease
- pretibial myxoedema
- thyroid acropachy
- thyroid bruit
- eye disease
90
Symptoms of thyroid storm?
- resp and cardiac collapse
| - exaggerated reflexes
91
What antithyroid drug should be used in the 1st trimester of pregnancy?
- propylthiouracil
92
What is a side effect of anti-thyroid drugs?
- agranulocytosis
93
Explain agranulocytosis?
- low WCC
- side effect of anti-thyroid drugs
- warn patient if fever, oral ulcer or oropharyngeal infection STOP DRUG
94
What is the beta-blocker of choice in hyperthyroidism?
- propranolol
95
When might radio iodine be used?
- relapse of Grave's disease
96
What is radioactive iodine contraindicated in?
- pregnancy
97
Risk during thyroidectomy?
- recurrent laryngeal nerve palsy
- hypothyrodism
- hypoparathyroidism
98
Explain subacute thyroiditis?
- may be triggered by viral infection
| - self-limiting
99
What is the affect of amiodarone on the thyroid?
- abnormal TFTs
- high free T4
- low free t3
- normal TSH
100
Explain subclinical thyroid disease?
- abnormal TSH
| - normal T4/3
101
Indication of a high risk subclinical hypothyroidism?
- TPO antibody postitive
102
Post operative checks after thyroidectomy?
- calcium levels
| - whole body iodine scanning
