Thyroiditis
Autoimmune thyroiditis
Subacute thyroiditis
Amiodarone induced thyrotoxicosis
Autoimmune thyroiditis
(T and B Cell pathogenesis)
AKA:
- Hashimoto’s thyroiditis
- Chronic lymphocytic thyroiditis
- painless thyroiditis
- silent thyroiditis
F:M = 10:1
5-8% of all women following pregnancy (postpartum thyroiditis)
Association with other autoimmune disorders
- Type 1 DM + atuoimmne adrenalitis (schmidt syndrome)
- Vitiligo
- Premature Gray Hair
Dx - **Serologic anti TPO / anti thyroglobulin antibodies **
Autoimmune thyroiditis Tx
Supportive
- Low dose bblk for thyrotoxic symptoms
- Low LT4 once a transition to a hypothyroid state
- Will need to monitor for progression
- TSH FT4 Q 3-6 weeks for change
Subacute thyroiditis
AKA :
- Granulomatous thyroiditis / DeQuervain thyroiditis
- Inflammation leading to formation of granulomas consisting of giant cells clustered about foci degenerating thyroid follicles
- US pic attached
Subacute thyroiditis
- Onset non specific viral illness
- Pain localized to the gland / may radiate upwards to the neck and jaw
- maybe slightly enlarged
- Inflammation may spread from one lobe ot the other
Subacute thyroiditis
Low uptake - test of choice
ESR elevated - this is non specific
TFT : elevated FT4/FT3 followed by a hypothyroid 1-3 months after hyperthyroid Phase
Subacute thyroiditis tx
- Pain managemnt and minimizing thyrotoxic sx
- NSAIDs (high dose / may get GI symptoms)
- Prednisone is the mainstay of therapy
- 20-40 mg daily
- 1-3 days after start will decrease pain
- can taper when pain is controlled
- low dose bblk
Amiodarone induced thyrotoxicosis
2 Types:
How to distinguish
1) Type I :
- caused by unregulated production of thyroid hormone
- underline MNG / Autoimmune thyroid dz
- Responds well to antithyroid drugs
- Amiodarone is the source of Iodine / hence increase in production
2) Type II:
- Inflammation with resultant leakage of thyroid hormone
How to distinguish betweent the two.
- Uptake tends to be low in both types
- IL6 may be high in both (not a useful test)
- Thyroid doppler may reveal high blood flow in type I and low blood flow in type II
AIT - most common cases in iodine sufficient regions are:
Tx:
Type II
Tx: Prednisone mainstay of therapy
concurrent tx with MMI or PTU if there is uncertainty
Quick response to prednisone favors TYPE II
AIT - Treatment Type II
- Prednisone - 40 mg daily
- Thyroid hormones start to decease with in 3-7 day sof steriod tx
- Can flare up once wean off steriods
- Some will need to have surgery if have itragenic cushings
*
- Most common effect of amiodarone?
- Amiodarone induced thyrotoxicosis in iodine suffficient regions is?
- Subacute thyroiditis and type 2 AIT respond well to Tx?
- Hypothyroidism
- Type 2 AIT
- Prednisone
Thyroglobulin half life?
1/2 day
- However post surgery Tg levels could stay elevated for more than a week.
- Wait for three weeks
Pertechnetate thyroid scan
- Most useful if patient on MMI / also Iodine not picked up in about 25% thyroid cancers
- Since technetate (VII) can substitute for iodine in the Na/I Symporter (NIS) Channel in follicular cells of the thyroid gland, inhibiting uptake of iodine into the follicular cells, Tc99m-pertechnetate can be used as an alternative to I123 in imaging of the thyroid.
- scintigraphy is performed in conjunction with radioiodine thyroid uptake, the radioiodine
administered activity given for the scan will suffice for the uptake as well. If done separately or in conjunction with a technetium-99m pertechnetate scan, as little as 100 microcuries (3.7 MBq) of iodine-123 or 4 microcuries (0.15 MBq) of iodine-131 may be used. If only a thyroid uptake with iodine-131 is obtained, the administered activity should not exceed 15 microcuries (0.55 MBq).
TKI - Sunitinib specially
Thyroid destruction in a substantial fractio of patients
Increase rate of thyroid hormone inactivation due to increase levels of Type 3 iodothyronine deiodinase - hence need of significantly more (as much as 2X) replacement dose.
Twin pregnancy TSH
TSH will be suppressed due to higher hCG levels.
Hyperthyroidism and pregnancy
Do not aim for normal TSH levels
PTU max of 200 daily / first trimaster due to hepatotoxicity change after first trimaster to MMI
