L4 - Thyroid Disease COPY

Question 1

EXAMINING THE THYROID

i) what should be felt then moving down and laterally to locate the thyroid gland?
ii) what may a bruit represent on ausculatation?
iii) what does dullness when percussing over the sternum indicate?
iv) what could this further cause?

Answer 1

i) feel the thyroid cartilage then move down and lateral
ii) bruit can represent overactivity of the thyroid (increased blood flow)
iii) dull percussion over the sterum may indicate retrosternal extension
iv) retrosternal extension can cause tracheal deviation

Question 2

THYROID FUNCTION TESTS

i) which three hormones are principally checked?
ii) which is deemed to be the best biomarker of thyroid status?
iii) what are the two main thyroid autoantibodies?

Answer 2

i) TSH, free T4 and free T3
ii) TSH

iii) thyroid peroxidase auto-antibody (Anti-TPO) and
TSH receptor autoantibody (TRAB)

Question 3

TSH

i) how quickly does it respond to change in thyroid status? what does this mean for its use clinically?
ii) what does using TSH levels to look at thyroid function assume?
iii) when may it not be a valid indicator of disease

Answer 3

i) slow to respond to change in thyroid status (6wks)
- means its not very useful in an acute setting

ii) using TSH levels assumes that the PG has normal function
iii) may not be a valid indicator in pituitary disease

Question 4

THYROID AUTOANTIBODIES

i) does presence of autoantibods mean the patient will develop autoimmune disease?
ii) what may auto-antibods be a marker of?
iii) where are many auto-antibods found?
iv) what are the two main types of auto-antibod? give an example of each

Answer 4

i) no (negative result doesnt exclude autoimm disesae but prescence helps confirm dx)
ii) AAs can be a marker of risk
iii) many AAs are sequestered or found intracellularly

iv) two main types are destructive (target thyroid hormone for destruc) eg anti TPO
or stimulatory - stim TSH receptor eg TRAB

Question 5

SYMPTOMS/SIGNS OF HYPOTHYROIDISM

i) name four main symptoms
ii) how does it affect cold tolerance?
iii) name four signs of severe disease
iv) what can it lead to if left untreated
v) what is myxoedema? when is it seen?

Answer 5

i) lethargy, mild weight gain, facial puffiness, dry skin, hair loss, constipation, hoarseness
ii) less tolerant of cold
iii) severe disease - change in appearance of face, periorbital oedema, bradycardia, carpal tunnel
iv) stupor or coma

v) myxoedema is a coma due to the accumulation of glycosaminoglycans in the interstitial space of tissues - puffy appearance
- only seen in very severe hypothyroidism

Question 6

CAUSES OF HYPOTHYROIDISM

i) what is seen in relation to TSH, T3 and T4 levels in primary hypothyroidism? explain
ii) what is the most common cause of primary
iii) name five other causes of primary
iv) what causes secondary hypothyroidism?
v) what is seen in relation to TSH, T3 and T4 in secondary?

Answer 6

i) high TSH and low T3 and T4 - HT and PG dont have negative feedback on them as the thyroid isnt producing lots of T3 and T4
ii) autoimmune is the most common cause
iii) other causes are iatrogenic (hypo after treatment for hyper), thyroiditis, congenital, drugs (lithium and amiodarone), iodine deficiency
iv) secondary caused by problems of HT or PG
v) secondary = low TSH, T3 and T4

Question 7

INVESTIGATIONS FOR HYPOTHYROIDISM

i) what would be the expected TSH and FT4 findings for autoimmune hypothyroidism?
ii) when would thyroid auto-antibodies be checked?
iii) is imaging necesary?

Answer 7

i) high TSH and low FT4
ii) only if history is suggestive
iii) no

Question 8

TREATMENT FOR HYPOTHYROIDISM

i) what drug is the patient usually started on? what dose is initially given?
ii) which two parameters would mean starting the patient on a lower dose with increments 4-6 weekly?
iii) what is a sign of overtreatment?
iv) is there evidence to support T3/T4 combination therapy?

Answer 8

i) start on thyroxine - initially give a significant dose eg 100ug daily
ii) start on a lower dose and slowly increase if >65yrs or ischaemic heart disease
iii) overtreatment = TSH suppression
iv) no evidence to support T3/T4 combination therapy

Question 9

SYMPTOMS AND SIGNS OF HYPERTHYROIDISM

i) what is another name of hyperthyroidism?
ii) name five symptoms
iii) how are periods affected?
iv) name five signs seen on examination

Answer 9

i) thyrotoxicosis

ii) weight loss associated with increased appetite
initially energised then lack of energy
heat intolerance
itchy skin
increased sweating

ii) sparse menstrual periods
iv) tremor, warm skin, tachycardia, brisk reflexes, eye signs, thyroid bruit, AF

Question 10

THYROID EYE DISEASE

i) what condition is it associated with? what % of these patients does TED occur in?
ii) what confers increased risk?
iii) what mediates it?
iv) there is inflammation of all orbital tissues except for where?
v) which imaging modality may be helpful?
vi) give two mild symptoms
vii) give four worrisome symptoms

Answer 10

i) associated with Graves Disease (autoimmune hyperthyroidism)
- 20% of graves patients will have TED

ii) smoking confers increased risk
iii) autoantibody mediated
iv) inflammation of fat, muscles, eyelid, conjunctiva but not the eye
v) CT scan

vi) mild symp - itchy/dry eyes
- prominent eyes/change in appearance

vii) worrisome symp - diplopia/loss of sight
loss of colour vision,
swollen conjunctiva,
cant close eyes
ache behind eye

Question 11

SIGNS ASSOC WITH THYROTOXICOSIS

what is seen in the

i) hands (2)
ii) pulse (2)
iii) neck (3)
iv) eyes (3)
v) what type of thyrotoxicosis is a bruit exclusively associated with?

Answer 11

i) fine tremor and warm hands
ii) sinus tachycardia and possible AF
iii) goitre, smoothness, bruit
iv) lid retraction, proptosis (eyes pushed forward) opthalmoplegia (eye movement probs causing double vision)
v) graves disease/autoimmune

Question 12

CAUSES OF THYROTOXICOSIS

i) what is the most common cause? what % of cases does this account for?
ii) what is the mech of the most common cause?
iii) what age/gender does it mostly affect?
iv) name four other causes
v) which drug may cause it? why?
vi) name four things that make the dx likely to be graves disease

Answer 12

i) autoimmune hyperthyroidism aka graves disease
- accounts for 75% of cases

ii) mechanism of autoimmune - autoantibody (TRAB) stimulates the TSH receptor
- causes excess thyroid hormone production and thyroid growth (goitre)

iii) women 30-50yrs

iv) 1) toxic multinodular goitre (enlarged thyroid)
2) toxic adenoma
3) thyroiditis
4) drugs

v) amiodarone - has lots of iodine in it therefore causes thyroid dysfunction
vi) personal/fam hx of autoimmune/thyroid/endocrine conditions, goitre with a bruit, thyroid eye disease, + TRAB

Question 13

what three causes of thyrotoxicosis are seen in A,B,C?

Answer 13

A = graves disease (autoimmune)

B = toxic adenoma (one nodule)

C = toxic multinodular goitre

Question 14

GESTATIONAL THYROTOXICOSIS

i) why does this occur?
ii) which two things make it more likely to occur?
iii) when does it tend to settle? why?

Answer 14

i) placental B HcG is structurally similar to TSH and has TSH like action on the thyroid
ii) more likely to occur in twin pregnancy and if the mother has hyperemesis
iii) settles after the first trimester because HCG levels fall

Question 15

THYROID FUNC TESTS FOR HYPERTHYROIDISM

i) what are the expected findings of TSH, T3, T4?
ii) what two things can be ‘thyroid’ driving factors?
iii) what further test can be conducted?
iv) what type of scan may be useful to look at areas of increased activity and differentiate between different causes?

Answer 15

i) high T3 and T4/low TSH

ii) autonomous thyroid function (not PG or HT)
or TRAB mediated (autoimmune/Graves)

iii) thyroid autoantibody test
iv) thyroid uptake isotope scan can show uptake and differentiate between between different causes

Question 16

GRAVES DISEASE TREATMENT OPTIONS

i) what are the three main treatment options?
ii) what drug can be given for symptom control? when is this contraindicated?
iii) give three risks of no treatment

Answer 16

i) medical, radioiodine and surgery

ii) beta blockers for symptom control
- dont give if asthmatic

iii) risk of no tx
- worsensing of symptoms, atrial fibrillation/stroke and osteoporosis

Question 17

MEDICAL THERAPY FOR GRAVES DISEASE

i) which two drugs are principally used?
ii) how long is the course? why?
iii) what two methods can be used to give these drugs?
iv) name a rare side effect
v) what proportion of patients recieving medical therapy will have long term cure?
vi) when is the most common time to relapse? can this be predicted?

Answer 17

i) carbimazole and propylthiouracil

ii) long course = 18mnth-2yrs
- takes 6-8 weeks to control thyroid hormones then keep up the doses to avoid relapse

iii) titration (start high dose then decrease)
block replace (start with one drug then as levels settle add in thyroxine)

iv) agranulocytosis
v) 1/3 have long term cure and 2/3 relapse
v) most likely to relapse in first year and this cant be predicted in advance

Question 18

RADIOIODINE TREATMENT FOR GRAVES DISEASE

i) what is it? how does it work?
ii) what state must the patient be in for this to start?
iii) what happens to 40% of patients post RI tx?
iv) give three scenarios where this would not be suitable
v) how long must men and women wait before trying to concieve post tx?

Answer 18

i) tablet of iodine made RA
- given orally and RI is conc in the thyroid and the radiation kills the thyroid cells

ii) patient must have had medical tx and be euthyroid
iii) 40% of patients will be hypothyroid post tx and put on lifelong thyroxine
iv) not suitable for pregnant, breastfeeding or if have thyroid eye disease
v) men wait 4 months and women wait 6 months

Question 19

SURGERY FOR GRAVES DISEASE

i) what procedure is carried out?
ii) what state must the patient be in before surgery? how is this achieved?
iii) name five risks of surgery
iv) which two treatments may need to be given lifelong post sx? why?
v) what is the initial and subsequent treatment for toxic adenoma/multinodular goitre?

Answer 19

i) sub total thyroidectomy
ii) patient must be euthyroid so have medical treatment first
iii) anaethetic, neck scar, hypothyroidism, hypoparathyroidism, vocal cord palsy due to recurrent laryngeal nerve damage

iv) thyroxine - if hypothyroid
calcium and vitamin D - if hypoparathyroid

v) initial tx is short term medical therapyto control thyroid hormones then subsequent RI curative treatment

Question 20

AGREEING EXPECTATIONS OF TX

i) why may it take the patient a while to feel normal again? what occurs during this period?
ii) do thyroid treatments help thyroid eye disease?
iii) what are the risks of tx in relation to weight?

Answer 20

i) there is a lag phase of a few months aka metabolic rollercoaster
ii) no
iii) weight gain

Question 21

TX OPTIONS FOR THYROID EYE DISEASE

i) name two ‘active’ treatments
ii) name two types of drugs that may be given
iii) is RT suitable?
iv) what is burn out? how can this be rectified? (2)

Answer 21

i) smoking cessation and steroids such as IV methylprednisolone or oral prednisolone
ii) steroids eg prednisolone or immunosupressive/steroid sparing agents
iii) yes

iv) burn out is when the eye is no longer inflammed but there are still problems eg diplopia
- may be left with disfigurement

• fix with orbital decompression or eyelid surgery

Question 22

THYROID STORM - CAUSES

i) what is it usually secondary to?
ii) what can cause it?
iii) name three things that can be a trigger

Answer 22

i) secondary to Graves disease
ii) can be cause by start stop of medication eg erratic compliance, sx or RI without medical treatment first
iii) triggered by sx, childbirth or acute severe illness

Question 23

THYROID STORM

i) what is it?
ii) name four symptoms
iii) is there a high mortality rate?
iv) where does the patient need to be cared for?

Answer 23

i) under or untreated hyperthyroidism
ii) Graves symptoms (goitre, thyroid eye), adgitation, tachycardia, HF, N&V, hepatocell dysfunc
iii) yes
iv) need ITU care

Question 24

THYROIDITIS

i) what is it?
ii) what is the first transient phase? how long does it take for this to resolve?
iii) what drug can be given in the transient phase?
iv) how would an isotope scan look?
v) would anti-thyroids work?
vi) which phase can last 4-6 months? what % of these patients will be normal in one year?
vii) what treatment and surveilance is carried out?

Answer 24

i) thyroid becomes inflammed and spits out thyroid hormone which is already there (there is no overproduction)
ii) firstly get transient mild thyrotoxicosis which usually resolves in 1-2 months
iii) can give beta blockers
iv) isotope scan would be cold
v) no antithyroids would not work
vi) longer hypothyroid phase may last 4-6 months and 80% recover in 1 year
vii) may need thyroxine treatment when hypo and have annual thyroid func tests

Question 25

WHEN TO CONSIDER THYROIDITIS

i) give five instances when thyroiditis should be considered
ii) what type of diseases place a patient at increased risk of thyroidisits?
iii) taking which drugs may be associated with a patient developing thyroiditis?

Answer 25

i) 1) patient is pregnant or 1 year postnatal (espec if T1DM, smoker)
2) patient has a tender thyroid (and raised inflammatory markers)
3) clinical thyroid status doesn’t fit lab results (rapidly changing thyroid func tests)
4) no Dx features of Graves disease

ii) autoimmune diseases
iii) if patient is taking immunomodulatory medication

Question 26

DISEASES ASSOCIATED WITH THYROID DISEASE

i) name five autoimmune diseases that may be associated
ii) name two syndromes that may be associated
iii) name two drugs associated with thyroid disease - what is the effect of each
iv) how often are thyroid tests reccomended in these situations?

Answer 26

i) T1Dm, pernicious anaemia, coeliac, addisons, premat ovarian failure
ii) turner syndrome and downs syndrome
iii) lithium - inhibits thyroid synth and secretion (causes hypo) amiodarone - iodine rich and can cause both hypo and hyper
iv) test these patient annually

Question 27

GOITRE/THYROID NODULES IN EUTHYROID PATIENTS

i) in which situation may there be swelling but normal thyroid function?
ii) which may be multinodular and is more common in iodine deficient areas?
iii) which present as assymetrical nodule in euthyroid patients
iv) which malignancy must be excluded? which imaging modality is helpful

Answer 27

i) goitre
ii) goitre
iii) thyroid nodule

iv) thyroid cancer
- use US or FNA for cytology