Case 7- Thyroid Disease Flashcards
Graves ophthalmology features
Exophthalmos (proptosis)- anterior bulging of the eye out of the orbit
Opthalmoplegia
Conjunctival oedema
Upper eyelid retraction and lag
Inability to close eyelid
Give topical lubricants, steroids
Unique features of Graves’ disease
Diffuse goitre (no nodules)
Graves eye disease
Pretibial myxoedema
Thyroid acropachy (clubbing, soft tissue swelling, periostea new bone formation)
Investigations for Graves disease
Physical thyroid exam
Eye exam if opthalmopathy present
FBC- exclude infection (tachycardia/ sweating), UE, TFT
Thyroid antibodies and calcitonin/thyroglobulin markers- TRAb (exclude medullary, papillary and follicular thyroid cancer)
Thyroid ultrasound with FNA- if TRAbs low?
Radioactive iodine uptake (diffuse, homogenous, increased uptake)
Graves’ disease antibodies
TRAb- specific
Anti TPO- non specific
Anti Tg- non specific
Treatment of a Thyrotoxic storm
BLAH
Beta blocker (propranolol)
Lugols iodine
Anti thyroid drugs/thionamides (PTU)
Hydrocortisone
Hashimoto’s thyroiditis antibodies
Anti TPO
Anti Tg
Difference between Hashimotos and de Quervains
H- autoimmune, rarely hyperthyroid beforehand, and if it is present it is prolonged
DQ- viral infection (also painful/raised ESR), short initial hyperthyroid period
Horner syndrome
Miosis
Partial ptosis
Facial anhidrosis
Sx hyperthyroidism
Heat intolerance, sweating, weight loss, palpitations, tremor, tachycardia, goitre, irritability, onchylosis, oligomenorrhoea, decreased libido, graves specific features
NB- high output cardiac failure in the elderly
Graves differentials
TMG, thyroiditis
Sx hypothyroidism
Tiredness, lethargy, low mood, cold intolerance, increased weight, constipation, menorrhagia, hoarse voice, memory/cognitive impairment, myalgia, cramps, weakness, coarse hair, dry skin, expressionless face, rounded face, reflexes slow to relax, hair loss (lateral edge eyebrows), carpal tunnel syndrome
NB- hyperlipidaemia
Thyroid cancer Sx
Painless, palpable thyroid nodule (no Sx of hyperthyroidism or hypothyroidism)
Advanced symptoms include;
Hoarseness, dyspnoea, dysphagia, cervical lymphadenopathy, tracheal deviation, Horner syndrome
Thyroid nodule investigations
Thyroid exam
FBC UE- see if fit for surgery, exclude infection, Ca (spread to bone)
TFT’s (unchanged in cancer- cold nodules)
Tumour markers or thyroid antibodies- calcitonin (medullary carcinoma) thyroglobulin (follicular/ papillary)
Ultrasound scan (gold standard) and FNA
Thyroid scintigraphy (radioiodine uptake- cold nodules are malignant)
Staging- CXR, HEAD, NECK CT SCAN
NB- remember the markers and cancer types as: MC TFP
Hashimoto’s thyroiditis
Features of hypothyroidism (rarely preceded by a thyrotoxicosis phase where the thyroid hormone is dumped out- causes a diffuse, lumpy painless goitre and hyperthyroidism Sx, but only in rare circumstances and lasts for several months, unlike de Quervain’s hyperthyroid period which only lasts a few weeks)
De Quervains Thyroiditis
AKA- subacute thyroiditis
Triphasic pattern- very short period of hyperthyroidism, then hypothyroidism, then back to euthyroidism
Usually a self limiting viral infection (normally only needs aspirin- steroids in severe cases)
Painful goitre, raised ESR
Thyroid scintigraphy- global reduced uptake of iodine 131
Post partum thyroiditis
First hyperthyroid
Then hypothyroid
Then back to euthyroid (within a year)
Sub clinical disease
Sub clinical hypothyroidism- raised TSH, normal T3/4
Sub clinical hyperthyroidism- low TSH, normal T3/4
Secondary hyperthyroidism
TSH secreting adenoma (different set of results)
Secondary hypothyroidism
Pituitary/ hypothalamic failure
T4 vs T3
Free T4 is better to monitor- more of it (a lot of T3 produced from T4 (peripheral conversion))
BUT- T3 is the active hormone
FNA and cytology of thyroid nodules
Thy1- do again
Thy2- benign
Thy3- intermediate
Thy4- suspicious of malignancy
Thy5- diagnostic of malignant
Radioiodine outcomes
Malignancy- cold nodule
Graves- increased uptake diffusely
TMG- mixed hot and cold nodules (patchy)
Toxic adenoma- 1 hot nodule
Thyroiditis- reduces uptake
Hyperthyroidism treatment regimens
Carbimazole can either be titrated to maintain normal levels (titration block)- more suitable as done over a longer term and suitable in pregnancy (other one isn’t)
Or
The dose blocks all production of thyroid hormone, and then takes levothyroxine until they are euthyroid (block and replace)
Management of Graves’ disease
Graves’ disease patients should be referred to secondary care
Beta blocker
ATD- carbimazole (12-18 months)
Radioiodine treatment (relapse or resistant to ATD therapy)
Thyroidectomy
Management of hypothyroidism
Levothyroxine (cardiotoxicity- cardiac ischaemia/ AF, be careful)
Regular monitoring
Papillary cancer
Most common
Good prognosis, although spreads early
Thyroglobulin
Young women
Follicular carcinoma
Encapsulated
Second most common
Thyroglobulin
Medullary carcinoma
Third most common
Calcitonin often raised
MEN2- family history, symptoms of pheochromocytoma
M for M (MEN and Medullary)
Anaplastic carcinoma
Rare
Old women
Poor prognosis as treatment resistant and frequently invades
Carbimazole MOA
Blocks thyroid peroxidase from coupling and iodinating tyrosine residues on thyroglobulin
Associated with agranulocytosis- sore throat
Contraindications to radio iodine treatment
Pregnancy (avoid 4-6 months following)
Below 16
NB- many will require thyroxine 5 years after treatment
Associations of Hashimoto’s thyroiditis
Autoimmune conditions eg. Coeliac disease, T1DM
MALT lymphoma
Amiodarone and the thyroid gland
Can cause hypothyroidism and hyperthyroidism
continue in hypo, stop in hyper (can use either carbimazole/steroids/potassium perchlorate)
Rare secondary causes of hypothyroidism
Pituitary failure
Down’s syndrome
Rare primary causes of hypothyroidism
Iodine deficiency
Lithium
Side effects of levothyroxine therapy
Hyperthyroidism (over treatment)
Reduced bone mineral density
Worsening of angina
AF
Interacts with iron and calcium carbonate (absorption reduced, so give at least 4 hours apart)
Myxoedema coma
Typically presents with confusion and hypothermia
IV thyroid replacement and fluids
IV corticosteroids
ATD’s in pregnancy
Propylthiouracil in 1st trimester
Carbimazole in 2nd and 3rd
No radioiodine
Hypothyroidism and pregnancy
Thyroxine is safe
Increase thyroxine by 50% as early as 4-6 weeks pregnancy
Sick euthyroid syndrome
Low T3 and T4 (thyroxine)
Normal TSH
No treatment needed
Subclinical hyperthyroidism
Normal T3 and T4
Low TSH
Usually untreated but can offer low dose ATD for 6 months
Subclinical Thyroid Disease
Subclinical Hypothyroidism
TSH raised but T3, T4 normal
-consider offering levothyroxine if the TSH level is > 10 mU/L on 2 separate occasions 3 months apart
-if < 65 years consider offering a 6-month trial of levothyroxine if:
the TSH level is 5.5 - 10mU/L on 2 separate occasions 3 months apart, and there are symptoms of hypothyroidism
in older people (especially those aged over 80 years) follow a ‘watch and wait’ strategy is often used
if asymptomatic people, observe and repeat thyroid function in 6 months
Subclinical Hyperthyroidism
a therapeutic trial of low-dose ant thyroid agents for approximately 6 months in an effort to induce a remission
Most common cause of hypothyroidism
Developed world- Hashimoto’s
Undeveloped world- iodine deficiency
Poor thyroxine compliance biochemistry
High TSH
Normal T4 (TSH lags behind if patient has just taken thyroxine in recent days)
Management of a TMG
Radioiodine therapy
What marker is used to guide treatment success in hypothyroidism?
TSH
Grading Graves ophthalmology
The severity of Grave’s eye disease can be graded using the mnemonic NOSPECS
No signs / symptoms
Only signs (e.g: upper lid retraction)
Signs & symptoms (including soft-tissue involvement)
Proptosis
Extra-ocular muscle involvement
Corneal involvement
Sight loss due to optic nerve involvement
Thyroglossal cyst
Reassure- no surgery