Thyroid Disease Flashcards
Graves Disease
Antibodies against TSH receptor
2.5% of women and .25% of men
Increased with family history, recent iodine exposure and postpartum
Diagnosis = Thyroid scan or TSH receptor antibodies
Management of Graves disease
Control symptoms = Beta blockers
Control hyperthyroidism =
- Thionamides - Carbimazole or propylthiouracil
- Iodine 131
- Surgery
PTU vs Carbimazole
PTU =
- Shorter half life
- Blocks conversion from T4 to T3
- Safer in pregnancy
- Associated with fulminant inflammatory hepatitis
Carbimazole =
- Daily dose
- No effect on deiodinase
S/Es: Rash, Raised LFTs, neutropenia, pANCA vasculitis
Approach to thionamide therapy
Titrate to effect
12-18 months of treatment
50% of long term remission
Most relapses in six months
Graves ophthalmopathy
Can be independent of thyrotoxicosis
Can be asymmetrical
SMOKING +++
Iodine therapy
Management = steroids and surgical debulking
Periodic paralysis associated with graves disease?
Transient severe hyperkalaemia following high carbohydrate meal or severe exercise
Asian people
Only during thyrotoxic phase
Control by controlling thyrotoxicosis
Toxic MNG
Increased with poor iodine intake
Usual presentation of thyrotoxicosis
Can be isolated T3 increase
Treat with Iodine 131
Monitor for malignancy
Thyroiditis
Thryotoxicosis without TSHR and with poor uptake on thyroid scan
Causes:
- De Quervians
- Post pregnancy
- Hashimotos
- Amiodarone
Treat wit NSAIDS and pred for pain and beta blockers for symptoms
Amiodarone induced thyroid disease
Hypothyroidism:
- Due to interference of T4 synthesis
- Withdraw amiodarone and commence thyroxine
Hyperthyroidism:
- Type 1 = iodine load
- Type 2 = thyroiditis = Free T4»_space;»T3
Treatment = stop amiodarone and commence steroids and PTU/CBZ
Lithium and thyroid?
Hypothyroidism due to inhibition if T4 production and secretion
Thyroiditis
Immunotherapy and the thyroid?
Anti CTLA-4 and PD-1 inhibitors –> thyroiditis and central hypothyroidism
Anti-CD52 - alemtuzumab = graves disease and thyroiditis
Interferon Alpha –> hypothyroidism
TKIs –> hypothyroidism
RXR agonist –> decreased TSH –> hypothyroidism
When to treat subclinical hypothyroidism
Definitely:
- TSH >10
- Symptoms of hypothyroidism
- Preconception or early pregnancy
Consider:
- HF
- Antibody positive
- High cholesterol
When to treat subclinical hyperthyroidism
TSH <0.1
Symptoms of thyroxicosis
Co-existing AF or OP
Types of thyroid cancer
Follicular:
- Follicular carcinoma
- Papillary carcinoma
- Poorly differentiated carcinoma
Medullary cancer
- MEN 2 and MTC - RET mutations
- LETHAL
Genetic drivers of papillary carcinoma
BRAF V600E = 60%
RTK fusions = 15%
RAS = 13%
Assessing nodules ? cancer
Should be >1cm
? TSH normal - if normal more likely cancer
FNA - if malignant = surgery
FNA = normal = monitor for growth
Treatment of follicular derived thyroid cancers
Thyroidectomy and LN dissection
Papillary >1cm or follicular = post op iodine 131 ablation AND if high risk TSH suppression
Allows follow up with iodine 131 scan and thyroglobulin antibodies
Survival benefit only if local invasion or mets at Dx
Papillary <1cm and no mets = nil abalation or suppression
Systemic treatments for follicular derived thyroid cancers
Use to increase differentiation prior to further Iodine 131 therapy
Multitargeted TKIs:
- Sorafenib
- Vemurafenib - Targets BRAK 600E mutation
Treatment of medullary thyroid carcinoma
Thyroidectomy
RET oncogene sequencing
Monitor with calcitonin levels
Thyroid and pregnancy
BHcG can stimulate TSH receptor –> low TSH
Associated with hyperemesis of pregnancy
Must increase dose of T4 in pregnancy x 1.3 in 1st 20 weeks if possible
Treat subclinical hypothyroidism
Diagnosing factitious hyperthyroidism?
Psych history/body image/treated hypthyroidism
No goitre/ nodules/ exophthalmos
High T4/T3 ratio (if thyroxine ingestion)
If acute TSH incompletely suppressed despite very high fT4
No aTPO* or aTSHR antibodies
Low/ suppressed thyroglobulin
