Hyperthyroidism and Hypothyroidism Flashcards
1
Q
what is the difference between primary and secondary thyroid disease?
A
primary affects thyroid gland itself, secondary is usually from hypothalamus/pituitary gland in brain
2
Q
can you get goitre in secondary thyroid disease?
A
no
3
Q
another word for TSH?
A
thyrotropin
4
Q
where is TSH released and by what?
A
by thyrotroph cells in the anterior pituitary gland
5
Q
what provokes TSH to be released?
A
release of TRH (thyrotropin releasing hormone)
6
Q
what is T4?
A
thyroxine
7
Q
what is T3?
A
lyrothyronine
8
Q
which percentage of thyroid hormone secreted is T4?
A
80%
9
Q
name the plasma proteins that T3 and T4 bind to
A
TBG (thyroid binding globulin)
albumin
pre-albumin
10
Q
where is TRH made?
A
hypothalamus
11
Q
what does TSH do?
A
stimulates thyroid gland to make T3 and T4
12
Q
what do T3 and 4 do?
A
switch off TSH production
13
Q
what does the liver do to T3 and 4?
A
T4 is converted to T3
14
Q
what happens to T3/4 and TSH levels in primary hypothyroidism?
A
free T3/4 = LOW
TSH = HIGH
15
Q
what happens to T3/4 and TSH levels in primary hyperthyroidism?
A
free T3/4 = HIGH
TSH = LOW
16
Q
what happens to T3/4 and TSH levels in secondary hypothyroidism?
A
T3/4wha = low TSH = low
17
Q
what happens to T3/4 and TSH in secondary hyperthyroidism?
A
t3/4 = high tsh = high
18
Q
what is hypothyroidism?
A
insufficient secretion of thyroid hormones from the thyroid gland
19
Q
what is myxoedema?
A
severe hypothyroidism
20
Q
what SHOULD happen to TSH when T3/4 is low?
A
it should increase
21
Q
intake of what chemical is linked to hypothyroidism?
A
iodine
22
Q
goitrous causes of primary hypothyroidism?
A
chronic thyroiditis
iodine deficiency
drug induced
maternally transmitted
23
Q
what drugs can cause hypothyroidism?
A
amiodarone
lithium
24
Q
non goitrous causes of hypothyroidism?
A
atrophic thyroiditis
post ablative or radiotherapy
congenital
25
what is thyroperoxidase?
an enzyme involved in thyroid hormone synthesis
26
most common cause of hypothyroid in western world?
autoimmune hypothyroid eg hashimoto's thyroiditis
27
histological appearance of autoimmune hypothyroid?
t cell infiltrates
| inflammation
28
main pathological process in autoimmune hypothyroid?
antibodies made against thyroperoxidase (TPO)
29
which thyroid related substance is the most highly produced in hypothyroidism?
TSH
30
clinical facial features of hypothyroidism?
```
thin hair
dull, expressionless face
periorbital puffiness
pale, cool skin that is doughy
vitiligo sometimes
hypocarotenaemia
patient is cold all the time
```
31
cardio clinical features of hypothyroidism?
bradycardia, cardiac dilatation, pericardial effusion, worse heart failure
32
GI features of hypothyroid?
constipation
33
metabolic features of hypothyroid?
weight gain
decreased appetite
hyperlipidaemia
34
why should you look at the legs in suspected hypothyroidism?
look for pitting oedema
35
respiratory features of hypothyroidism?
deep hoarse voice
macroglossia
obstructive sleep apnoea
36
neuro features of hypothyroid?
```
confusion
depression
psychosis
muscle stiffness/pain
peripheral neuropathy
bad vision
carpal tunnel
```
37
what effect can hypothyroid have on periods?
can make them longer, not happen at all
38
effect of hypothyroid on MCV?
increase
39
effect of hypothyroid on:
CK
LDL
increase
| increase
40
what electrolyte is particularly lost in hypothyroid?
hyponatraemia
41
what autoantibody is particularly sensitive in autoimmune hypothyroid?
anti-TPO
42
what is the main autoantibody involved in graves disease?
TSH receptors
43
what can rapid restoration of metabolic rate cause?
cardiac arrhythmias
44
treatment for younger patients with hypothyroid?
levothyroxine at 50-100 ug daily
45
hypothyroid treatment for older patients with heart disease?
levothyroxine at 25-50 ug daily
46
what should you do when you change the dose of thyroxine given for hypothyroid?
check TSH 2 months after
47
why is TSH checked in hypothyroid?
can be used as a marker in PRIMARY only to see if treatment is working
48
when should T4 be taken?
before breakfast
49
is T4 or T3 more potent?
T3
50
what drugs interfere with action of thyroxine?
PPIs
| iron tablets
51
how is dose of thyroxine changed in pregnant women with hypothyroid?
increase dose by 25-50%
52
who does myxoedema coma affect?
elderly women with untreated hypothyroidism
53
ECG findings of myxoedema coma?
varying heart block
T wave inversion
QT prolongation
54
clinical presentation of myxoedema coma?
```
type 2 resp failure
adrenal failure
bradycardia
heart block
low body temp
```
55
treatment for myxoedema coma?
rewarm
cardiac monitoring
broad spectrum antibiotics
thyroxine cautiously
56
how is thyrotoxicosis different from hyperthyroidism?
tissues are exposed to excess thyroid hormone, doesnt mean there is a problem with the thyroid gland itself
57
cardiac symptoms of thyrotoxicosis?
palpitations
AF
HF (Rare)
58
sympathetic nervous effects of thyrotoxicosis?
tremor
| sweating
59
CNS effects of thyrotoxicosis?
anxiety
nervousness
irritability
sleep disturbance
60
GI effects of thyrotoxicosis?
frequent, loose bowel movements
61
vision effects of thyrotoxicosis?
lid retraction
double vision
proptosis
62
hair and nail symptoms of thyrotoxicosis?
thin hair
| rapid nail growth
63
do you get weight loss or gain in thyrotoxicosis?
weight loss
64
are you intolerant to cold or heat in thyrotoxicosis?
heat
65
hyperthyroid causes of thyrotoxicosis?
excessive thyroid stimulation eg graves OR thyroid nodules with autonomous function
66
non hyperthyroid causes of thyrotoxicosis?
thyroiditis
exogenous thyroid hormones
ectopic thyroid tissue
67
what forms of thyroiditis can cause thyrotoxicosis?
```
subacute thyroiditis (viral)
post partum thyroiditis
```
68
is graves disease more common in younger or older publications?
younger
69
most common cause of graves disease?
genetic factors plus environmental
70
what would TSH and T3/4 look like in graves disease?
TSH- LOW
| T3/4 = HIGH
71
what does hypercalcaemia + increased ALP indicate?
increased bone turnover
72
what thyroid condition is linked to osteoporosis
graves
73
how low is the TSH levels in graves?
can be almost undetectable
74
what autoantibody should be checked in graves?
TSH receptor antibody
75
clinical signs on examination that suggest graves disease?
pretibial myxoedema
thyroid acropachy
thyroid bruit
graves eye disease
76
when is the only time you would hear a thyroid bruit
graves disease if there was a large goitre
77
lifestyle advice for graves disease?
STOP smoking, makes eyes worse
78
treatment for mild graves eye disease?
topical lubricant
79
treatment for severe graves eye disease?
steroids
radiotherapy
surgery
80
is onset of graves insidious and slow or acute and severe?
acute/severe
81
who gets nodular thyroid tdisease?
older patients
82
how an you differentiate nodular thyroid disease from graves?
slower onset
in older people
thyroid feels nodular but is smooth in graves
goitre can be asymmetrical
83
effect of nodular thyroid disease on T3/4 and TSH?
increases T3/4
| decreases TSH
84
what result will nodular thyroid disease get when checking TSH receptor antibody
negative
85
tests for nodular thyroid disease?
TSH receptor antibody test
thyroid USS
thyroid hormone levels
86
is thyroid storm severe?
yes, do ABC
87
what is thyroid storm?
severe hyperthyroidism
88
clinical features of thyroid storm?
resp and cardio collapse
hyperthermia
exaggerated reflexes
89
most common cause of thyroid sorm?
hyperthyroid patients with an acute infection or recent thyroid surgery
90
treatment for thyroid storm?
```
ugol's iodine
glucocorticoids
beta blockers for tachycardia
fluids
propylthiouracil
```
91
1st line drug for hyperthyroidism?
carbimazole OD
92
1st line drug for 1st trimester of pregnancy in someone who is hyperthyroid?
propylthiouracil BD
93
treatment for graves disease?
dose titration of carbimazole
94
side effects of antithyroid drugs for hyperthyroidism?
allergy
jaundice
increased liver enzymes
agranulocytosis
95
what is agranulocytosis?
absence of neutrophils
96
what should you do if a patient on antithyroid drugs gets agranulocytosis?
take them off them; they cant be used again
97
when is the risk of agranulocytosis highest in hyperthyroid patients?
first 6 weeks of starting antithyroid drugs
98
what beta blocker is of particular use in hyperthyroidism and why?
propranolol, stops T3-T4 conversion in liver
99
1st line treatment for relapsed graves disease?
radioiodine
100
is radioiodine safe in pregnancy?
NO
101
why can't radioiodine be used in active graves disease?
cause hypothyroid
102
what should you do in graves disease when radioiodine is contraindicated?
thyroidectomy
103
surgical risks of thyroidectomy?
recurrent laryngeal nerve palsy
hypothyroidism
hypoparathyroidism
104
clinical symptoms of subacute thyroiditis?
neck tenderness
fever
viral symptoms
105
common cause of subacute thyroiditis?
viral infection
106
what age group is most commonly affected by subacute thyroiditis?
20-50s
107
what do the TFTs look like in patients with inhibited DIO1 receptors?
increased T4
decreased T3
normal TSH
108
which type of thyroid disease occurs in iodine deficient areas?
hyperthyroidism
109
what do you call mild thyroid disease that could progress to hypo/hyperthyroidism?
subclinical thyroid disease
