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Y2 Endocrine > Week 3 > Flashcards

Week 3 Flashcards

1
Q

What is the functional unit of thyroid gland

A

Follicle

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2
Q

Describe the structure of a thyroid follicle

A

Follicular cells arranged into a sphere shape.
Colloid in the centre lumen
Parafollicular cells (C cell) between follicles
Highly vascularised

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3
Q

What is colloid rich of

A

Thyroglobulin

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4
Q

What type of epithelial cells are follicular cells

A

Cuboidal cells

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5
Q

Describe the Hypothalamus-pituitary-thyroid axis

A
  1. Paraventricular nucleus of hypothalamus stimulated, releases TRH into hypophyseal portal system
  2. TRH travels to the anterior pituitary gland which stimulates the release of TSH
  3. TSH travels to thyroid gland through bloodstream and stimulates the synthesis and release of T3 and T4
  4. T3 and T4 hormones exhibit negative feedback which inhibits the release of TRH and TSH
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6
Q

Which part of the thyroid gland is covering the second tracheal ring

A

Isthmus

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7
Q

What structures are visible at the posterior aspect of the thyroid gland

A

Parathyroid glands

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8
Q

What would the TSH/TRH levels be in a hyperactive thyroid gland

A

Low due to high levels of T3 and T4

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9
Q

What substance is required for the synthesis of thyroid hormones

A

Iodine

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10
Q

Describe the movement of the thyroid gland from back of the tongue to its current position in an embryo

A
  1. Begins at 4th week of embryogenesis. Midline thickening at the back of the tongue
  2. Moves downwards, eventually reaching in front of the tracheal rings
  3. becomes in contact with the parathyroid glands which had developed in the area
  4. The residue of the thyroid gland at the back of the tongue becomes foramen caecum
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11
Q

Describe the development of the thyroid gland

A
  1. Endodermal thickening
  2. migrates downwards to form thyroglossal duct
  3. the 2 lobes of thyroid gland and the isthmus develop from the thyroglossal duct
  4. Thyroglossal duct is degraded in most people but not all
  5. the remnant of thyroglossal duct = pyramidal lobe
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12
Q

When will primitive follicles of the thyroid gland become visible and start trapping iodine

A

By 12 weeks

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13
Q

Which condition are people at risk of due to thyroglossal duct not disintegrating

A

Thyroglossal cysts

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14
Q

Where are thyroglossal cysts mostly found

A

Near the hyoid bone

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15
Q

Where to palpate the thyroid gland

A
  1. starting from the chin and moving downwards, palpate the midline
  2. palpate the first hard structure: thyroid cartilage
  3. palpate the second hard structure: cricoid cartilage
  4. move downwards to palpate the first.2 tracheal rings
  5. the isthmus overlies the second tracheal ring
  6. go laterally and medially around and upwards
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16
Q

Nerve supply of the thyroid gland

A

Sympathetic nerve supply: superior, medial, inferior sympathetic trunk

Parasympathetic nerve supply: Vagus nerve

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17
Q

Arterial supply of the thyroid gland

A

Superior and inferior thyroid arteries

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18
Q

Venous drainage of the thyroid gland

A

Superior and middle thyroid veins drain into the internal jugular vein

Inferior thyroid vein drains into the brachiocephalic vein

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19
Q

Which ligament is the primary fixation of the thyroid gland to its surrounding structures

A

Posterior suspensory ligament (Berry ligament)

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20
Q

What nerve is behind the posterior suspensory ligament

A

Recurrent laryngeal nerve

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21
Q

What structures are innervated by the recurrent laryngeal nerve

A

All Intrinsic muscles of the larynx except the cricothyroid muscles

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22
Q

Name the intrinsic muscles of the larynx innervated by the RLN

A

Thyroarytenoid muscle
Posterior cricoarytenoid muscle
Lateral cricoarytenoid muscle
Transverse and oblique cricoarytenoid muscles

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23
Q

Which nerve innervates the cricothyroid muscle

A

Superior laryngeal nerve - a branch of vagus nerve

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24
Q

Function of the cricothyroid muscle

A

Stretches and tenses the vocal cords to make forceful voice
Changes tone of voice

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25
Q

Function of the thyroarytenoid muscle

A

Relax the vocal cords to make softer voice

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26
Q

Function of the posterior cricoarytenoid muscle

A

Sole muscle that abducts the vocal cords hence opening the rima glottidis

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27
Q

Function of the lateral cricoarytenoid muscle

A

Major muscle that adducts the vocal cords hence narrowing the rima glottides

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28
Q

Function of the transverse and oblique cricoarytenoid muscles

A

Adducts the arytenoid cartilage to narrow the laryngeal inlet

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29
Q

Consequence of damage to recurrent laryngeal nerve after thyroidectomy

A

Hoarseness of voice
Loss of voice
Change in pitch
Dyspnea
Dysphagia

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30
Q

Why can dyspnea occur due to RLN damage

A

Because it can cause the paralysis of posterior cricoarytenoid muscle which is the only muscle that can abduct the vocal cords to open the rima glottidis

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31
Q

What is thyroglobulin rich of

A

tyrosine amino acids

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32
Q

Steps of thyroid hormone synthesis

A
  1. Thyroglobulin synthesised by follicular cells
  2. uptake and concentration of iodide into the colloid
  3. Iodide moves into follicular cells
  4. Oxidation of 2 iodide ions into iodine in the follicular cells
  5. Iodine passed into the colloid
  6. iodination of thyroglobulin
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33
Q

Describe the iodination of thyroglobulin to form T3 and T4

A
  1. Peroxidase enzyme in colloid links iodine to tyrosine amino acids in thyroglobulin
  2. Forms 2 intermediaries: tyrosine + 1 iodine and tyrosine + 2 iodine

T3 is formed by those 2 intermediaries joining together
T4 is formed by linkage of 2 tyrosine + 2 iodine

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34
Q

Where is thyroglobulin stored in till it is needed

A

Colloid

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35
Q

Which thyroid hormone is more potent

A

T3

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36
Q

Which drugs are used to treat hyperthyroidism

A

Carbimazole
Propylthiouracil

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37
Q

Mechanism of action of carbimazole

A

Inhibits thyroid peroxidase enzymes which are required for iodination of thyroglobulin

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38
Q

Which thyroid hormone makes up 90% of the thyroid hormones secreted

A

T4

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39
Q

Which thyroid hormone is biologically active

A

T3

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40
Q

Why does T4 need to be converted to T3

A

To become metabolically active

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41
Q

Which organs are responsible for the conversion of T4 into T3

A

Liver and kidney

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42
Q

How are thyroid hormones transported to target cells

A

Bound to serum proteins

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43
Q

What are the serum proteins that thyroid hormones can bind to

A

Thyroxine binding globulin
TTR (transthyretine)
Thyroxine binding pre-albumin
Albumin

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44
Q

Are most thyroid hormones unbound or bound to serum proteins

A

Bound to serum proteins

Only 0.015% of total T4 are free T4
Only 0.33% of total T3 are free T3

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45
Q

Bound / unbound thyroid hormones can enter the cells

A

Unbound

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46
Q

Why does T3 have a more rapid onset and offset of actions

A

Because it is bound less strongly by TBG (thyroxine binding globulin) than T4 and it is not bound significantly by TTR (transthyretin; transports thyroxine and vitamin A aka retinol)

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47
Q

Which, unbound or bound thyroid hormone concentration, correlates more closely to the metabolic state

A

Unbound

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48
Q

Effects of thyroid hormones

A

Increase metabolic rate
Increase in gluconeogenesis and glycogenolysis
Increase in lipolysis
Increase in respiratory rate and heart rate
Growth and development

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49
Q

Why does thyroid hormones cause an increase in gluconeogenesis and glycogenolysis

A

To increase the amount of glucose available for respiration; since increase in metabolic rate = increase in respiration = increase in glucose substrate needed

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50
Q

Why does thyroid hormone cause an increase in respiratory and heart rate

A

To meet the increase in demand of O2 due to the increase in metabolic rate

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51
Q

Thyroid hormones metabolic effects

A

Increases metabolic rate and thermogenesis
Increase blood glucose
Increase lipolysis
Increase FFA oxidation
Increase in protein synthesis

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52
Q

Why do thyroid hormones have effects on growth and development

A

Because the GHRH (growth hormone releasing hormone) and GH requires presence of thyroid hormone for activity

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53
Q

What can occur if a child has hypothyroidism

A

Growth retardation

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54
Q

What happens to the development of CNS in the child if the mother has hypothyroidism

A

The baby can have slower congnitive and intellectual functions

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55
Q

What enzymes are responsible in degrading t3 and T4

A

D1, D2, D3

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56
Q

Where is D3 found

A

Fetal tissue
placenta
Brain except pituitary

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57
Q

Which thyroid degrading enzyme is found in the pituitary

A

D2

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58
Q

Majority of T3 and T4 are degraded by which enzyme

A

D3

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59
Q

Causes of hypothyroidism

A

Primary thyroid gland failure
Secondary to TRH or TSH deficiency
Lack of iodine in diet

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60
Q

What is goitre

A

Enlargement of the thyroid

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61
Q

Symptoms and signs of hypothyroidism

A

Weight gain (due to decrease in BMR)
Slow heart rate
Fatigue
Cold intolerance
Goitre
Constipation
Dry hair
Brittle nails
Vitiligo

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62
Q

Mneumonic for symptoms of hypothyroidism (MOM’S SO TIRED)

A

Memory loss
Obesity (weight gain)
Menorrhagia
Slowness mentally and physically
Skin and hair dryness
Onset is gradual
Tiredness
Intolerance to cold
Raised BP
Enlarged thyroid gland
Depression

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63
Q

What can occur in babies due to hypothyroidism

A

Dwarfism
Intellectual defects
Slow growth and development (reach milestones later or not at all)

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64
Q

What is Grave’s disease

A

Autoimmune disease that causes hyperthyroidism

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65
Q

Symptoms and signs of hyperthyroidism

A

Sweating
Bulging eyes (proptosis)
Goitre
Weight loss
Insomnia
increased nervousness and excessively emotional
Fast heart rate
Heat intolerance

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66
Q

What would the thyroid hormones level be in primary hypothyroidism

A

Low T3/T4
High TSH

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67
Q

What would the thyroid hormones level be in secondary hypothyroidism

A

Low T3/T4
Low/normal TSH

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68
Q

Why is TSH level called “inappropriately normal” in secondary hypothyroidism

A

In secondary hypothyroidism, the low T3/T4 level should cause a high TSH level but because the secondary hypothyroidism is caused by a defect in the pituitary gland, TSH level is low/normal

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69
Q

What will the thyroid hormone level in secondary hyperthyroidism be

A

High T3/T4
High or normal TSH

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70
Q

Hypothyroidism is more common in which type of people

A

Females
White populations
People in areas with high iodine intake

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71
Q

What is secondary hypothyroidism

A

Hypothyroidism not due to thyroid dysfunction

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72
Q

Goitrous causes of primary hypothyroidism

A

Hashimoto’s thyroiditis
iodine deficiency
Amiodarone induced hypothyroidism

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73
Q

Non-goitrous causes of primary hypothyroidism

A

Atrophic thyroiditis
Congenital hypothyroidism
Post partum thyroiditis

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74
Q

What is Hashimoto’s thyroiditis

A

it is an autoimmune destruction of thyroid gland causing reduction in thyroid hormone production

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75
Q

Which group of people are more at risk of Hashimoto’s thyroiditis

A

Family history of autoimmune conditions (e.g. T1 diabetics)
Family history of autoimmune thyroiditis (grave’s / Hashimoto’s)
Turner’s and Down syndrome
Males

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76
Q

What are the secondary causes of hypothyroidism

A

Malignancies
Infections
Trauma
Surgery
Congenital
Radiotherapy

77
Q

What is the most common antibody present in Hashimoto’s thyroiditis

A

Anti- thyroid peroxidase antibodies (anti-TPO)

78
Q

Can you diagnose Hashimoto’s thyroiditis just based on elevated anti-TPO

A

No, because anti-TPO is not specific to Hashimoto’s. It can be present in Grave’s disease (hyperthyroidism) and in healthy people too

79
Q

What test should be done to diagnose hypothyroidism/hyperthyroidism and how do you differentiate whether it is primary or secondary

A

TSH and T3/T4 level
Autoantibodies not required because these are not specific

Primary hypothyroidism: T3/T4 low TSH high
Secondary hypothyroidism: T3/T4 low TSH low/normal

Primary hyperthyroidism: T3/T4 high TSH low
Secondary hyperthyroidism: T3/T4 high TSH high/normal

80
Q

Amiodarone most commonly causes hypothyroidism or hyperthyroidism

A

Hypothyroidism

81
Q

How does amiodarone cause hypothyroidism

A

Wolff Chaikoff effect; Amiodarone contains iodide

Excess iodine blocks the iodination of thyroglobulin causing a reduction in levels of thyroid hormone

82
Q

What is atrophic thyroiditis

A

Non-goitrous cause of primary hypothyroiditis; antibody attack causing the thyroid gland to be severely shrunken

83
Q

What causes congenital hypothyroidism

A

Dyshormonogenesis (defect in synthesis of thyroid hormone)
Abnormal gland development

84
Q

What is postpartum thyroiditis

A

Self limiting inflammation in women after giving birth. Typically progresses from hyperthyroidism into hypothyroidism

85
Q

Who is most at risk of postpartum thyroiditis

A

Pregnant women with T1 diabetes

86
Q

What respiratory symptoms can be seen in hypothyroidism

A

Deep hoarse voice
Macroglossia (abnormally large tongue)
Obstructive sleep apnoea (goitre blocking airway)

87
Q

What gynaecological symptoms can be seen in hypothyroidism

A

Menorrhagia - heavy menstrual bleeding
amenorrhea - absence of periods
oligomenorrhea - infrequent periods

88
Q

Hashimoto’s thyroiditis is Th1/Th2 predominant

A

Th1

89
Q

What cardiac symptoms may occur in hypothyroidism

A

Bradycardia
Cardiac dilatation
Pericardial effusion
Heart failure

90
Q

Management of hypothyroidism

A

Gradual restoration of thyroid hormones using Levothyroxine

91
Q

What is levothyroxine

A

Synthetic version of T4

92
Q

Why is it important to restore the thyroid hormone level gradually instead of rapidly

A

Gradual restoration prevent cardiac arrhythmias

93
Q

Is levothyroxine safe during pregnancy

A

Yes

94
Q

Should you change the dosage of levothyroxine during pregnancy

A

Yes, double the dose during pregnancy

95
Q

What is subclinical hypothyroidism

A

When the patient has elevated TSH but normal T3/T4

96
Q

Do you need to treat subclinical hypothyroidism

A

No unless the patient becomes symptomatic and develop goitre / T3 and T4 level dropped

Otherwise, keep routinely check their TSH and T3/T4 level

97
Q

What is myxoedema

A

Clinical emergency due to severe hypothyroidism

98
Q

Which group of people are at risk of myxoedema

A

Elderly
Long standing, untreated hypothyroidism

99
Q

Signs of myxoedema

A

Bradycardia
Abnormal ECG
Type 2 resp failure
Hypothermia
Adrenal failure

100
Q

What abnormalities on ECG can be seen in myxoedema

A

Heart block
Prolonged QT
T wave inversion

101
Q

Management of myxoedema

A

ABCDE
Passively rewarm the patient
IV levothyroxine
IV hydrocortisone (if there is adrenal failure)

102
Q

What is thyrotoxicosis

A

Clinical state arising when the tissues are exposed to excess thyroid hormones

103
Q

What is hyperthyroidism

A

Overactivity of thyroid gland leading to excess thyroid hormones

104
Q

Is hyperthyroidism the only cause of thyrotoxicosis

A

No, thyrotoxicosis can also be due to e.g. ingestion of excess thyroid hormones

105
Q

Causes of primary hyperthyroidism

A

Grave’s disease
Hashitoxicosis
Toxic multi nodular goitre
Toxic solitary nodule
De Quervain’s thyroiditis

106
Q

What is Grave’s disease

A

Autoimmune condition with TSH receptor antibodies acting like TSH causing excessive stimulation of the thyroid gland

107
Q

What can happen to the thyroid hormone levels of patients with Grave’s disease over time

A

Can switch from hyperthyroidism to hypothyroidism

108
Q

Risk factors of Grave’s disease

A

Young
Family history of autoimmune disease
PMH of autoimmune disease
Smoking

109
Q

What is toxic multi nodular goitre

A

Multiple autonomous nodules develop that are capable of producing and secreting thyroid hormones

110
Q

What is toxic solitary goitre

A

Single autonomous adenoma develop and can produce + release thyroid hormones

111
Q

What is Hashitoxicosis

A

Early stage of Hashimoto’s thyroiditis

In early stage of Hashimoto’s thyroiditis, there can be a period of hyperthyroidism then progresses into hypothyroidism

112
Q

Causes of secondary hyperthyroidism

A

Postpartum thyroiditis
Amiodarone induced thyroiditis
Overtreatment with levothyroxine
Struma ovarii
Pituitary adenoma
Lithium

113
Q

What is De Quervain’s thyroiditis

A

A self limiting condition that causes the thyroid gland to swell rapidly and causes hyperthyroidism

114
Q

What may eventually occur to the thyroid hormone levels in patients with De Quervain’s thyroiditis over time

A

Hyperthyroidism -> hypothyroidism
Due to depletion of colloid and reduction in TSH production

115
Q

What is amiodarone induced thyrotoxicosis type 1

A

Jod Basedow phenomenon which states that excess iodine intake causes excess thyroid hormone synthesis

116
Q

What is amiodarone induced thyrotoxicosis type 2

A

Destructive thyroiditis due to direct toxic effect on follicular cells with resultant release of thyroid hormone

117
Q

Which conditions can lead to both hyperthyroidism and hypothyroidism

A

Hashimoto’s (hashitoxicosis)
Grave’s (progresses into hypothyroridism)
Postpartum thyroiditis
Amiodarone induced
De Quervain’s thyroiditis (progresses into hypothyroiditis)

118
Q

What is struma ovarii

A

Thyroid hormone released from ectopic thyroid tissue related to ovarian teratoma and dermoid tumours

119
Q

Except from thyroid hormone levels, what other labratory test findings can present in Grave’s disease

A

Hypercalcaemia
Increase in alkaline phosphatase
Leucopenia (decrease in WCC)
TSH receptor antibody

120
Q

Why is an elevated level of TSH receptor antibody a good indication for Grave’s disease

A

Because it is present in 90% of patients with Grave’s. Although it is can also be present in Hashimoto’s disease, it is only present in 10-20% of patients

121
Q

Which cardiac arrhythmia can be caused by thyrotoxicosis

A

Atrial fibrillation

122
Q

What are the neurological signs of thyrotoxicosis

A

Anxiety
Nervousness
Sleep disturbance
Tremor
Sweating

123
Q

What symptoms are specific to Grave’s disease

A

Pretibial myxoedema
Thyroid acropachy
Thyroid bruit
Grave’s opthalmopathy

124
Q

What is thyroid bruit

A

Continuous sound heard over thyroid mass, only heard in Grave’s

125
Q

What causes thyroid bruit

A

Enlarged thyroid gland causes proliferation of blood supply and the hypervascularity of thyroid causes the bruit

126
Q

What is thyroid acropachy

A

Periostitis, nail clubbing, swelling of the fingers / toes

127
Q

What is pretibial myxoedema

A

Specific sign of Grave’s disease; thick scaly skin and swelling of the leg due to build up of glycosaminoglycans within the dermis

128
Q

What are the eye abnormalities seen in Grave’s disease

A

Proptosis (bulging of eyes)
Intolerance of bright lights
Excessive dryness
Swelling
Sight loss

129
Q

What are the signs that indicate moderate to severe grave’s ophthamolpathy

A

Diplopia
Significant lid retraction
Significant soft tissue involvement
Exopthalamos > 3mm
Optic neuropathy
Corneal breakdown

130
Q

What is diplopia

A

Double vision

131
Q

Management of mild Grave’s opthalmopathy

A

Topical lubricants
Advise to elevate head when sleeping / wear sunglasses

132
Q

Management of severe Grave’s opthalmopathy

A

Steroids
Surgery
Radiotherapy

133
Q

Management of hyperthyroidism

A
  1. Carbimazole / propylthiouracil

+ Beta blockers for symptomatic relief

  1. Radioiodine therapy
  2. Surgery
134
Q

Which beta blocker is used in hyperthyroidism

A

Propanolol

135
Q

Contraindications for beta blockers

A

Patients with asthma because beta blockers can cause bronchospasm

136
Q

Which drug should be used for hyperthyroidism if beta blockers are contraindicated

A

Calcium channel blocker (dilitiazem)

137
Q

Why are beta blockers used for symptomatic relief in hyperthyroidism

A

Because they can reduce the activity of the sympathetic nervous system hence reduce symptoms caused by it until thioamides take effect

138
Q

Examples of thioamides

A

Carbimezole
Propylthiouracil

139
Q

How do thioamides treat hyperthyroidism

A

By blocking peroxidase to reduce thyroid synthesis

140
Q

Contraindication for carbimazole

A

Pregnant / planning to become pregnant
Deranged LFT

141
Q

Why is carbimazole contraindicated in pregnant women

A

Because it is associated with congenital malformations

142
Q

What tests should be done before giving thioamides

A

FBC and LFT (to check transaminase levels)
Pregnancy test

143
Q

Severe side effect of thioamides

A

Agranulocytosis - absence / reduction of granulocytes especially neutrophils, puts patients at risk of severe infection and sepsis

144
Q

Indications for radioiodine therapy

A

Toxic multi nodular goitre
Toxic solitary goitre

145
Q

Difference between nodular thyroid disease and Grave’s disease

A

Nodular thyroid disease - absent TSH receptor antibodies
Nodular thyroid disease causes asymmetrical goitre whereas Grave’s disease causes smooth goitre
Nodular thyroid disease more common in older patients whereas Grave’s disease more common in younger patients

146
Q

Contraindications for radio iodine therapy

A

Pregnant women / breastfeeding
Those with active thyroid eye disease

147
Q

Side effects of radio iodine therapy

A

Exacerbate thyroid eye disease
Hypothyroidism

148
Q

When is surgery used for hyperthyroidism

A

Other management contraindicated
Recurrent hyperthyroidism
Goitre obstructing other structures

149
Q

Complications of thyroidectomy / hemithyroidectomy

A

RLN damage
Hypothyroidism
Hypocalcaemia

150
Q

How may thyroidectomy lead to hypocalcaemia

A

Damage to parathyroid glands which produce parathyroid hormones

151
Q

Types of thyroid cancer

A

Papillary thyroid cancer
Follicular thyroid cancer
Anaplastic thyroid cancer
Medullary thyroid cancer

152
Q

What is medullary thyroid cancer

A

Thyroid cancer derived from parafollicular C cell
Associated with MEN 2

153
Q

Hormone levels in medullary thyroid cancer

A

Calcitonin raised
Serum Ca2+ reduced (hypocalcaemia)

154
Q

Function of calcitonin

A

Opposes action of PTH, reduces Ca2+ level

155
Q

Which thyroid cancer is the most common

A

Papillary

156
Q

Which thyroid cancer has the worst prognosis

A

Anaplastic, it is the most aggressive form

157
Q

Difference between papillary thyroid cancer and follicular thyroid cancer

A

Papillary cancer is associated with Hashimoto’s thyroiditis whereas follicular cancer is not

Papillary cancer spreads via lymphatics and rarely by blood whereas follicular cancer spreads via blood and rarely lymphatics

Papillary cancer is not related to iodine whereas follicular cancer is related to iodine deficiency

158
Q

Differentiated thyroid cancer is driven by which hormone

A

driven by TSH hormone

159
Q

Risk factors of thyroid cancer

A

Radiation exposure (esp during childhood)
Female
Family history

160
Q

What are the symptoms and signs of thyroid cancer

A

Palpable thyroid nodules
Cervical lymphadenopathy
Stridor
Hoarseness / change in voice

161
Q

What is stridor

A

Harsh, high pitched noise heard on inspiration due to upper airway obstruction

Often described as “barking” sound

162
Q

Because most palpable nodules are benign, what other clinical signs are more suggestive of malignancies

A

Nodule rapidly increasing in size
Vocal cord palsy
Lesion > 4 cm
History of neck or head irradiation
Male (although thyroid cancer is more common in females, males have a worse survival and more aggressive disease)

163
Q

Thyroid cancer is more common in female / male

A

Female

164
Q

Which thyroid cancer is associated with hashimoto’s thyroiditis

A

Papillary

165
Q

What investigations should be done if you suspect thyroid cancer

A

TFT - TSH / T4/ T3
Fine needle aspiration
Fine needle aspiration cytology
Patient specific investigations i.e. if they have certain signs

166
Q

What patient specific investigations can be done if you suspect thyroid cancer

A

Present with vocal palsy - laryngoscopy
Present with suspicious lymph nodes - CT/MRI scan

167
Q

What is AMES

A

pre-operative risk stratification depending on
Age
Metastases
Extent of primary tumour
Size of primary tumour

168
Q

Surgical options for thyroid disease

A

Lobectomy
Hemithyroidectomy
Total thyroidectomy

169
Q

Indications of hemithyroidectomy / total thyroidecomy

A

High AMES risk
Lymph involvement
Distant metastases
Extra-thyroidal invasion

170
Q

Indications of lobectomy

A

Papillary microcarcinoma <1cm diameter
low AMES risk
minimally invasive follicular carcinoma

171
Q

Complications of thyroid surgery

A

RLN damage
hypothyroidism
hypoparathyroidism

172
Q

What happens as a result of hypoparathyroidism

A

Hypocalcaemia

because parathyroid glands produce parathyroid hormone to increase blood calcium levels so damage to those glands can lead to hypocalcaemia

173
Q

What can hypocalcaemia lead to

A

Muscle spasms
Muscle weakness
Seizures
QT prolongation
Predisposition to ventricular arrhythmias

174
Q

Why do you need to monitor calcium levels closely after thyroid surgeries

A

To check for hypocalcaemia due to parathyroid gland damages

175
Q

What should you do if calcium levels are too low after thyroid surgeries

A

Start calcium replacement / IV calcium
Prevent overtreating to prevent hypercalcaemia

176
Q

What ECG changes can happen due to hypercalcaemia

A

shortened QT interval

177
Q

Which hormone acts against parathyroid hormones to decrease blood calcium level

A

calcitonin produced by thyroid gland

178
Q

Post op care for patients after total thyroidectomy / hemi thyroidectomy

A

Surpress TSH level (if papillary / follicular)

Levothyroxine therapy

Whole body iodine scan

Radioiodine ablation (if there are remnants

179
Q

What should be monitored if the patient had surgery due to medullary thyroid cancer

A

Calcitonin and calcium level

180
Q

What should be done before taking the whole body iodine scan

A

Increase TSH level to above 20 by injecting rhTSH

181
Q

Why does TSH level need to be increased before taking whole body iodine scan

A

Because differentiated thyroid cancer (papillary, follicular) is TSH driven hence TSH will stimulate the remaining cancer cells to take up iodine. This allows the cancer cells to light up on the scan

182
Q

What is the use of radio iodine ablation

A

To destroy the remnant thyroid tissue to prevent recurrence of cancer / increase chance of long term remission

183
Q

What safety cautions should the patient be aware of after they receive radio iodine ablation

A

Cannot mother / father a child
Avoid pregnant women / child
Avoid close contact with other people

Till safe

184
Q

Why should TSH level be suppressed after thyroid cancer surgery

A

To prevent recurrence of the cancer

185
Q

How do you suppress TSH level after thyroid cancer surgery

A

Put the patient on levothyroxine to suppress TSH

186
Q

What can happen if the patient overdoses on levothyroxine

A

Heart failure
Atrial fibrillation
Osteoporosis

187
Q

What can be measured to assess for residual tissue / recurrent disease for those that got total thyroidectomy +/- radioiodine ablation

A

Thyroglobulin

188
Q

Mneumonic for symptoms of hypothyroidism (MOM’S SO TIRED)

A

Memory loss
Obesity (weight gain)
Menorrhagia
Slowness mentally and physically
Skin and hair dryness
Onset is gradual
Tiredness
Intolerance to cold
Raised BP
Enlarged thyroid gland
Depression

189
Q

What is sick euthyroid syndrome

A

Hypothyroidism that occurs in any systemic illnesses but tend to not have any symptoms

Y2 Endocrine (6 decks)

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