Endocrinology - The Thyroid Flashcards
What is a goitre
Painless enlargement of the thyroid gland
DDx diffuse goitre - physiological
Puberty
Pregnancy
DDx diffuse goitre - autoimmune
Grave’s
Hashimoto’s
DDx diffuse goitre - thyroiditis
De Quervains
Rediel’s thyroiditis
DDx diffuse goitre - drugs (4)
Antithyroid Dx
Lithium
Iodine excess
Amiodarone
Multinodular goitre DDx
Toxic multinodular goitre
Subacute thyroiditis
Solitary nodule goitre DDx (5)
Follicular adenoma Benign nodule Thyroid malignancy Lymphoma Metastasis
Infiltration nodular goitre cause
TB
Sarcoid
Ix thyroid swelling (7)
FBC (anaemia) ESR TFT Thyroid autoantibodies CT neck/thorax USS FNAC
When would treatment be required on a euthyroid pt with a goitre? (3)
Cosmesis
Possibility of malignancy
If causing pressure Sx
M:F Thyrotoxicosis
1:5 M:F
Causes thyrotoxicosis (7)
Graves Toxic multinodular goitre Solitary toxic adenoma Thyroiditis Dx induced XS iodine intake Hashitotoxicosis
Who gets toxic multinodular goitre
Older women
What is Plummers disease
Toxic multinodular goitre
Drugs that induce thyrotoxicosis (2)
amiodarone
XS levothyroxine
Rare 2’ causes thyrotoxicosis (2)
TSH secreting pit adenoma
Resistance to thyroid hormone
Sx hyperthyroidism (7)
Weight loss Increased appetite Irritability Restlessness Tremor Heat intolerance Palpitations
Signs hyperthyroidism (9)
Tremor Hyperkinesis TachyC/AF Full pulse Warm vasodilated peripheries Exophthalmos Lid lag/stare Goitre/bruit Thyroid acropachy
Grave’s ophthalmology (4)
Lagophthalmos
Exophthalmos
Ophthalmoplegia
Periorbital oedema
Mortality rate thyroid storm
10%
What causes thyroid storm? (5)
Period of stress Infection Surgery Childbirth Untx/uncontrolled hyperthyroidism
Sx thyroid storm (6)
Hyperpyrexia Severe tachyC Extreme restlessness Profuse sweating Confusion/psychosis Liver dysfunction
Tx thyroid storm (5)
Propylthiouricale Propranolol K iodide High dose steroids Supportive measures
Ix hyperthyroidism (5)
TSH Free T3/4 TRAb Technetium uptake scan CT/MRI orbit
Technetium uptake scan pattern - graves
diffuse pattern
Technetium uptake scan pattern - Toxic nodular goitre
One or more ‘hot’ nodules
Technetium uptake scan pattern - thyroiditis
Reduced/absent uptake
Mx hyperthyroidism - 1’ care:
20-40mg propranolol tds
Consider starting carbimazole if not controlled
What are the 2 types of antithyroid therapy for hyperthyroidism
Titration
Block and replace
Titration regime antithyroid drugs
Start at high dose
Titrate down until patient is euthyroid
block and replace titration regime
high dose
Then levothyroxine added back once T3/4 levels controlled
1st line antthyroid drug
Carbimazole
2nd line antithyroid drug
Propylthyrouracil
Why is PTU 2nd line antithyroid drug
B/c risk severe liver injury 1/10,000
How do both antithyroid drugs work
Preffered substrate for TPO
Risk carbimazole (3)
Skin rashes
Agranulocytosis
Cholestatic jaundice
If a patient is on carbimazole, when should you advise them to see the GP?
If the develop any mouth ulcers, sore throats or fever
What is 1st line Tx hyperthryoidism in non-graves pt
Radioactive iodine therapy
How does radioactive iodine therapy work?
131I = taken up by thyroid cells
–> Induces DNA damage + cell death
What must be done 1 week before starting radioiodine therapy?
Discontinue anti-thyroid drugs
C/I Radio active iodine (3)
Pregnancy
Brest feeding
Active Grave’s ophthalmology
What should patients avoid after radio active iodine/
Avoid contact w/ children 3 w
Do not try to concieve 6 months
what is the small increase risk of in patients who have radio active iodine therapy?
Thyroid cancer
Types of surgical Mx hyperthyroidism (2)
Total
or sub-total thyroidectomy
Post-op complications thyroidectomy (4)
Haematoma –> asphyxia
Hypothyroidism
Hypocalcaemia
VC paresis b/c dmaage to rec laryngeal nn
Mx haematoma post thyroidectomy
ER removal of sutures
Prevelance hypothyroidism
1-2%
F:M hypothyroidism
10:1
common causes hypothyroidism (3)
Hashimoto’s thyroiditis
Atrophic thyroiditis (autoimmune)
Prev Tx for hyperthyroidism
What is Hashimoto’s thyroiditis
T cell destruction of gland
+ B cell secretion of inhibitory TSH receptor ab
Appearance goitre Hashimoto’s thyroiditis
Symmetrical, bosselated goitre
Appearance goitre atrophic thyroiditis
NOT associated with goitre ;)
Less common causes hypothyroidism (5)
Drugs Iodine deficiency Thyroiditis 2' causes e.g.: Hypothalamic disorders Pituitary disorders
Drugs causing hypothyroidism (3)
Amiodarone
Iodine XS
Lithium
Sx hypothyroidism (7)
Tiredess W gain Cold intolerance Goitre Depression Myalgia Constipation
Signs hypothyroidism
Mental slowness Dry thin hair Dry skin Slow relaxing reflexes bradycardia myxoedema
What is myxoedema
The accumulation of mucopolysaccarides in SC tissue
Ix hypothyroidism
FBC TFTs TPO antibodies Cholesterol CK
Why do we check Cholesterol + CK when investigation for hypothyroidism
Cholesterol -raised in hepatic hypothyroidism
CK - raised in mm hypothyroidism
TFT values hypothyroidism (1’ vs 2’)
1’ raised TSH, reduced T4
2’ - low TSH + T4
Mx hypothyroidism
Levothyroxine for life
Low starting dose
reassess ev 4-6w until TSH in lower 1/2 norm
What does acute thyroiditis follow
URTI
PS acute thyroiditis (4)
Fever
Malaise
Thyroid swelling + tenderness
Appearance acute thyroiditis Tc scan
Low/no take up
Tx acute thyroiditis
propranolol + simple analgesia
Most common type of thyroid cancer
Papillary carcinoma
Who gets: papillary carcinoma
40-50y/o
Spread: papillary carcinoma
Local mostly
Rarely –> lung/bone
Prognosis: papillary carcinoma
Good
RF papillary carcinoma
Previous neck irradiation
Tx papillary carcinoma
Surgical resection
Freq - follicular carcinoma
20%
Which sex gets more follicular carcinoma
Females
Spread: follicular carcinoma
Blood –> bone
Prognosis follicular carcinoma
Good if resectable
Tx follicular carcinoma
Surgical resection
% medullary cell carcinoma
5%
Who gets medullary cell carcinoma
Familial
Edlerly or
Children w/ MEN IIa/IIb
What cells do medullary cell carcinomas arise from
Parafollicular C cells
Spread medullary cell carcinoma
Local nodes + mets
Slow growing
Prognosis medullary cell carcinoma
Poor
% anaplastic cell carcioma
<5%
Who gets anaplastic cell carcinoma
Elderly
Spread anaplastic cell carcinoma
Rapid, aggressive
Locally invasive –> tracheal/SVC obstruction
Prognosis anaplastic cell carcinoma
Poor
Mx anaplastic cell carcinoma
External radiotherapy as palliation
PS thyroid cancer
Mostly asymp
May be hoarseness/dysphagia
usually euthyroid