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