hyperthyroidism and thyrotoxicosis Flashcards
What two conditions are associated with both hypo and hyperthyroidism?
Pernicious anaemia
Thymoma
What neuromuscular condition is often ass with thymoma?
Myasthenia Gravis
Symptoms of hyperthyroidsim
Heat intolerance
Amenorrhea
Tremor, sweat
Pretibial myxoedema
Exophthalmus
Causes of hyperthyroidism
Solitary toxic adenoma
Toxic nodular goitre
De Quervans
Treatment for Graves Disease
Carbimazole, propothyrorizide
Radioactive iodine
How can you visualise the metabolic activity of the thyroid?
Thyroid isotope scna (isotopes taken up by metabolically active tissues)
Ultrasound biopsy how done
Fine needle aspiration
What are the target tissue of T3/T4?
Heart
liver
Bone
CNS
Which form is more active and which from is more abundant of T3/4?
T3 - more active
T4 = more abundant
Metabolised in lvier
If lower T3/4 what happens to TSH, TRH?
Increases - negative feedback system
What does low TSH, high T3 and T4 mean?
Hyperthyroidism
Investigations for hyperthyroidism
Thyroid uotake scan
Thyroid antibodies
CNS symptoms hyperthyroidism
Agitation
Anxiety
Delirium
Psychosis
Stupor
Coma
General symptoms hyperthyroidism
CNS - anxiety, agitation etc
CVS - tacht, arrhytmia etc
Exophthalmos
Lid retraction
Thyroid acropathy
CVS symptoms hyperthyroidism
Tachycardia >140/min
Arrhytmia
Congestive cardiac failure
CV collapse
TfT levels in hyperthyroidism
Low TSH
High FT4 + FT3
Eye symtpoms of hyperthyroidism
Exophthalmos
Lid retraction
What does hyperthyroidism increase the risk of?
Diabetes
Dangerous complication of hyperthyroidism
Thyroid storm
Management of thyroid storm
Beta blocker/digocin, propanolol 60mg QDS
Thionamide - antithyroid medication PTU 200mg every 4 hours
Iodine solution - Loqols soluteion drops QDS
Steroids and bile acid eg hydrocortisone 100mg QDS + cholerstyramine 4mg QDS
What does thionamide do?
Blocks T3/T4 synthesis
What does iodiine solution do?
Blocks release of T3/T4
When treat subclincial hyperthyrodisim
Evidence for adverse effects on skeleton + the heart only in patinets with serum TSH levels < 0.1mU/L
Treatment be considered in patients TSH <0.1mU/L
Serum TSH 0.1-0.45 mU/L
What is Graves disease?
Anti-TSH receptor agonist antibodies bind to receptors stimulates excess T3/T4 production due to hyperplasia and unregulated production
What type of anitbodies are in Graves disease?
IgG
Which two opposite diseases do you find anti-TPO in?
Graves (80%) and hashimotos (95%)
What antibodies are linked to Hashimotos?
Thyroid Peroxidase Antibody (TPO Ab) - anti- TPO
Thyroglobulin TgAb
Can hashimotos cause hyperthyrodisim?
Yes. It mainly causes hypothyrodisim but can cuase hyper.
Which antibodies are ass with Graves disease?
TSH-R anitbodies
(Anti-TPO + 80% of the time)
ACTIVATES thyroid gland
What is thyrotoxicosis?
Clincial manifestation of excess circulating thyroid hormones due to any cause including hyperthyroidism
Risk factors for hyperthyroidism
Female
Family history
Smoking - Graves
Autoimmune disease
What type of hyperthyroidism is smoking specifically a reisk factor for?
graves
causes of Graves disease
Graves disease
Toxic multinodular goitre
Toxic thyroid nodule (adenoma)
TSH - secreting pituitary adenoma
Pituitary thyroid hormone resistance syndrome
High conc of human chorionic gonadotrophin - hcG
Iodine
Struma ovarii
Functional thyroid cancer mets
Complciations of hyperthyroidism
Graves orbitopathy
Thyrotioxic crisis - thyrpid storm
Compression symptoms - large goitre
Thyrotioxic periodic paralysis
A fib
HF
Reduced bone mineral density and osteoporosis
Mood disorders - psychosis
Pregnancy complications
Mortality
Peak incidence Graves disease/risk factors
30-50 years
Women
FH autoimmune
T1DM
Peak incidence Graves disease/risk factors
30-50 years
Women
FH autoimmune
T1DM
What is toxic nodular goitre?
Benign follicular adenomas
Functioning thyroid nodules that secrete excess hormone
What is toxic thyroid nodule?
Nodule that secretes enough hormone to suppress the secretion TSH from pituitary with consequent suppression of contralateral thyroid lobe
Multiple nodules -> toxic nodular goitre
What is pituitary thyroid hormone resistance syndrome?
Rare genetic condition - mutations in TH receptor beta gene
When do high conc of hcG occur?
Gestational thyrotoxicosis - 1st trimester, transient, no treemtnet needed
Hyperemesis gravidum - dehydration, ketonuria, 5% weigh tloss
Chorionic gonadotrophin secreting tumours (hcG stimulates TSH receptors)
What drug can induce thyrotoxicodis?
Amiodarone - high iodine content
Delayed presenation - long half life
Anti-retrovirals
Cancer immunotherapy drugs - interferon alpha
Amiodarone two mechanisms of causing hyperthyroidism
1 - due to high iodine content
2 - destructive thyroiditis - direct toxic effect amiodarone on thyroid cells
What can graves orbitopathy lead to?
Sight threatening complications - dysthyroid neuropathy, severe corneal exposure and ulceration or corneal breakdonw
QOL + psychosocial wellbeing
What triggers a thyroid storm?
Acute infection, trauma, pregnancy, surgery, stroke
Prev undiagnosed or abruptly stopped antithyroid meds
Features of a thyroid stomr
Systemic decompensation -
Fever
Tachycardia
Agitation
Hyperthermia
HOTN
AF
HF
Jaundice
Delirium
Coma
What is thyrotoxic periodic paralysis?
Rare complciation characterised by muscle paralysis, hypokalemia
Higher prevalence in asian people with hyperthryoidsim
What is thyrotoxic periodic paralysis?
Rare complciation characterised by muscle paralysis, hypokalemia
Higher prevalence in asian people with hyperthryoidsim
Exam for hyperthyroifism
Enlarged thyroid - goitre
Signs of graves disease
Other autpimmune conditions eg vitiligo
Pulse, BO, temp, weight, signs fluid oveload and HF
Why prescribe a beta blocker for hyperthyroidism initially?
Adrenergic symptoms
eg palpitiations, tremor, tahcycardia, anxiety
What drugs perscribe for hyperthyroidism?
Beta blockers - adernergic symptoms
Carbimazole +propylthiouracil
Who offer carbimaxole to?
Troublesome symptoms despite beta blocker or if cant tolerate or use them
At risk of complication
Taking drug treatment eg lithium or amiodarone
What i first line treatment for Graces and toxic nodular goitre?
Radioactive iodine treatment
How do carbimazole/propylthiouracil work?
Decrease thyeoid hormone synthesis acting as a preferred substrate for iodination by thyroid peroxidase(key enxyme in the hormone production)
Why is propylthiouracil not first line?
Small risk of severe liver injury
Used in preganacy or thyrotoxic crisis
Hwo are antithyroid drugs used>
In prep for surgery or radioactive treatment
Mid term - 12-18 months
Become euthyroid in 4-8 weeks
Long term if more complex treatment eg surgery declined or contraindicated
Remission in 50% from meds
Whne is radioactive treatment contraindicated?
Active or severe orbitopathy in Graces disease -> de novo development
Pregnancy or women planning pregnancy in next 6 months, men in next 4 months
WHen is surgery indicated for hyeprthyroidism?
Prevent recurrence
Compression symptoms from large goitre
Co-exisitng potnetually malignant thyroid nodule
Havn’e tolerated antithyroid drug treatment or its ineffective or contraindicated
What reduces risk of thyrotoxicosis after surgery?
Achieveing euthyroidism pre srugery with antithryoid drugs
Post thyroid op complications
Hypotnyroidism
Hypocalcemia
Hypoparathyroidism
Vocal cord paresis = recurrent laryngeal nerve damage
Side effects of carbimaxole or propylthiouracil
Agranulocytosis
Neutropenia
Carbimazole - acute pancreatitis
Polythiouracil - severe liver disease
What do you check before starting anitthyroid drugs?
FBC, LFTs
How do antithyroid drugs work?
Act as a preferred substrate for thyroid peroxidase iodination - key enzyme
How does radioactive iodine treatment work?
Damages DNA leading to death of thyroid cells
Symptoms of neutropenia or agranulocytosis to safety net for when on antithyroid drugs
Fever, sore throa, mouth ulcers, febrile or non specific illness, brusing, malaise
Stop medication immediately and arrange urgent test for WCC
How often do you test TSH level when starting antithryoid drugs?
Every 6 weeks until TSH in reference range, then every 3 months
What monitor after stop antithyroid drugs?
TSH within 8 weeks of stopping, then every 3 months for a year then annually
How often monitor with radioactive iodine treatment>
Every 6 weeks for first 6 months or until TSH in range
Continue to monitor after euthyroid
What medication lifelong do you give to patients after total thyroidectomy?
LT4 replacement theraoy
Measure TSH annually if hemi
What are the contraindications for propylthiouracil?
Severe hepatic impairement
Galactose intolerance
Adverse effects of propylthiouracil
Cutaneous vasculitis
Leuco,thrombocyto,pancytopenua
Aplastic anaemia - not enough RBC produced
Agranulocytosis
Hypothrombinaemia
Acute glomerulonephritis
SLE
Vommitting
Hypersensitivity reactions
Hepatic disorders
What drugs interact with propylthiouracil?
Drugs that also increase the risk of myelosuppression (bone marow suppression, reduced production of blood cells) eg Azathioprine, ethosuximide, leflonimide, methotrexate, trimethoprin
Pathology of thrombocytopenia?
Low platelet count
What is agranulocytosis?
What is a potentially fatal complication of anticancer treatment (often chemotherapy) and carbimazole
Neutropenic sepsis
What are common causes of agranulocytosis?
Radio/chemotherapy
Antipsychotic meds
Antithyroid meds
Leukaemia
HIV/hepatitis
Rheumatoid arthritis
What is agranulocytosis?
Severe neutropenia - WCC <0.5
Contraindiciations for carbimazole
Severe blood disorders
Severe hepatic impariment
Acute pancreatitis
Women childbearing potnetial unless on effective contraception
Adverse effects of carbimazole
Nausea, taste disturbacne, headache, fever, malaise
Myelosuppression, myopathy, alopecua, jaundice
Acute pancreatitis
Drug drug interactions with carbimazole
Other drugs that cause myelosupression - azathioprine, methotrexate, trimethoprin
Digoxin - affects conc
Coumarins eg warfarin - enhances anticoagulation efefct - monitor INR
contraindications fpor beta blockers
Asthma.
Uncontrolled heart failure.
Prinzmetal’s angina.
Marked bradycardia.
Hypotension.
Sick sinus syndrome.
Second- or third-degree atrio-ventricular (AV) block.
Cardiogenic shock.
Metabolic acidosis.
Severe peripheral arterial disease.
Phaeochromocytoma.
What is seen in nuclear scintigraphy with toxic multinodular goitre?
Patchy uptake
When is diffuse and increased activity with a decreased backgorund seen on nuclear scintigraphy?
Graves disease
What indicated thyroiditis on nuvelar scintigraphy?
Trace or absent uptake -> inflammation or destruction of thyroid tissue
Treatemnt 1st line for toxic multinodular goitre?
Radioiodine therapy
Benigin causes of thyroid nodules
Multinodular goitre
Thyroid adenoma
Hashimotos thyroiditis
Cysts - colloid, simple, haemorrhagic
Malignant causes of thyroid nodules
Papillary carcinoma - most common
#Follicular, medullary or anaplastic carcinoma
Lmyphoma
Imaging of choice for thyroid nodule
Ultrasnongraophy
Urgent 2 week wait referral for thyroid lump when:
Unexplained thyroid lump
Mass with hoarseness or voice change
Lymphadnopathy ass
Sudden onset rapidly expanding painless mass increasing in size
Sus thyroid nodule malignany
Compressive symptoms eg SOB, dysphagia
Red flags for malignancy in thyroid nodule
> 3cm lymph node
Persistent or reapidly growing >6 weeks
Neck malignancy red flags
dysphagia or pain on swallowing (odynophagia); cough; persistent voice change or hoarseness; ipsilateral otalgia, nasal obstruction, or epistaxis; sore throat, loose or misaligned teeth; haemoptysis;
Haemotological cancer red flags ass with thyroid lump
persistent fatigue, night sweats, unexplained fever, weight loss; unexplained bruising, bleeding, or petechiae; unexplained persistent or recurrent infections, bone pain, and alcohol-induced lymph node pain.
Risk factors for thyroid malignancy
such as smoking, excess alcohol intake, betel nut use; previous history of head and neck cancer or irradiation; history of Hashimoto’s thyroiditis (increased risk of lymphoma).
Causes of thyrotoxicosis
Graves’ disease
toxic nodular goitre
acute phase of subacute (de Quervain’s) thyroiditis
acute phase of post-partum thyroiditis
acute phase of Hashimoto’s thyroiditis (later results in hypothyroidism)
amiodarone therapy
Contrast
Who shouldnt receive iodinated contrast
Exisitng thyrotoxicosis
More risky in elderly patient with pre-existing thyroiddisease
Investigations for thyrotoxicosis
TSH down, T4 and T3 up
thyroid autoantibodies
other investigations are not routinely done but includes isotope scanning
Features of thryotoxicosis
Weight loss
‘Manic’, restlessness
Heat intolerance
CARDIAC features of thryotxicosis
palpitations, tachycardia
high-output cardiac failure may occur in elderly patients, a reversible cardiomyopathy can rarely develop
Skin features thyrotoxicosis
Increased sweating
Pretibial myxoedema: erythematous, oedematous lesions above the lateral malleoli
Thyroid acropachy: clubbing
GI, genae and neuro in thyrotoxicosis
Diarrhoea Oligomenorhea
Anxiety, tremor
What is postpartum thyroiditis
Postpartum thyroiditis presents with a transient acute phase of thyrotoxicosis, followed by a period of hypothyroidism. This can occur 2 – 6 months following birth or miscarriage
Typical symptoms of thyrotoxicosis
Recent unintended weight loss
Increased appetite
Diarrhoea
Heat intolerance (patients may appear underdressed for the weather)
Over-activity and restlessness
Tremor
Palpitations
Irritability
Muscle weakness
Loss of libido
Oligomenorrhoea
Important areas of history in thyrotoxicosis
AI donditions eg Graves or recent viral infection - de Quercans thyroiditis
FH graves disease
Use of amiodarone levothyroxine recent contrast use
Obs history
Clinical features of thyrotoxicosis
Thin and brittle hair
Warm and moist skin
Irregular or fast heart rate
Fine tremor
Brisk reflexes
Palmar erythema
Lid lag and lid retraction
Goitre (enlargement of the neck due to an enlarged thyroid gland)
Graves orbitopathy/opthalmopatyh symptoms
Change in the appearance of the eyes (usually staring or bulging eyes)
A feeling of grittiness in the eyes or excessive dryness in the eyes
Watery eyes
Intolerance of bright lights
Swelling or feeling of fullness in upper or lower eyelids
New bags under the eyes
Redness of the lids and eyes
Blurred or double vision
Pain in or behind the eye, especially when looking up, down or sideways
Difficulty moving the eyes
Differentiating TED from other eye conditions
Symptoms may occur in the wrong season for hayfever
Allergies usually cause itchy eyes, whereas TED does not
Conjunctivitis usually causes sticky eyes, whereas TED usually does not
TED often is associated with an ache or pain in or behind the eye, especially when trying to look up or sideways, whereas the other conditions mentioned are not
TED is sometimes associated with double vision, whereas the other causes of eye symptoms are not
Management of thyroid eye disease
Smoking cessation
Elevate head in bed to avoid monring lid swelling
Avoid fluctuating thyroid levels
Avoid radioidine treatment
Selenium suppplements
Artificial tear drops, gel, ointments
Steroids if sigificatnt inflammation
Add immunosupression/readiotherapy to prevent relapse
Surgery for thyroid eye disease after inflmmation settled
Decmompression surgery when oressure on nerve or protrusion
Eye muscle surgery, eyekid surgery
Prisms attached to glasses
Complications of orbiopathy
Dysthyroid optic neuropathy
Globe subluxation
Corneal ulceration
What is dysthyroid optic neuropathy
Deteriorating visual acuity or decreased colour discriminatuon
Features of graves orbitopathy
Eye irritation, photophobia, or excessive watering of the eyes.
Redness of the eyes or eyelids and/or lid swelling.
Change in the appearance of the eye or eyelids:
Eyelid retraction (sclera is visible above the superior corneal limbus).
Lid lag (delay in moving the eyelid as the eye moves downward).
Proptosis (exophthalmos, eyeball protrusion, an inability to fully close the eyes as the upper and lower lids do not fully appose).
Persistent double vision in any direction of gaze (typically when looking upwards and outwards).
Unexplained deterioration in visual acuity; change in the intensity or quality of colour vision in one or both eyes; orbital aching or restricted eye movements — suggests dysthyroid optic neuropathy.
History of globe subluxation — one or both eyes suddenly ‘popping out’; typically lasts more than a few seconds, is painful, and the lids could not be closed.
What can subclinical hyperthyroidism cause
AF, osteoporosis ‘
Increased dementia risl
-> 6 month trial low dose antithyroidn
