3. THIOAMIDES
•They bind to the thyroid peroxidase and prevent oxidation of
iodide/iodotyrosyl residues.
•If given in excess can cause reduction in feedback inhibition, this
causes increased TSH secretion from pituitary and may cause goitre.
•These drugs are quickly absorbed orally and are widely distributed in
the body, they are metabolized in liver and excreted by kidney.
4. USES –
• As definitive therapy – remission may occur upto half of the patients
with graves after 1-2 years of treatment
Remissions are rare in case of MNG.
•Preoperatively – Patients with hyperthyroidism are rendered euthyroid
before performing surgery to prevent thyroid crisis.
•Along with I131 – Initial control with ATD – 1-2 weeks gap –
radioactive dose – resume ATD after 5-7 days and gradually withdraw
over 3 months as response to I131 develops. This approach is prefered
in older patients.
5. ADVANTAGES –
• No surgical risk, scar or chances of injury to parathyroid glands or
RLN
• Hypothyroidism if induced is reversible
• Can be used even in children and young adults
DISADVANTAGES –
• Prolonged treatment is required as relapse rate is high
• Not practical in uncooperative patient
• Drug toxicity
6. IONIC INHIBITORS
• They inhibit iodide trapping
• They are toxic and are not clinically used nowadays.
• Thiocyanates can cause liver, kidney, bone marrow, and brain
toxicity.
• Perchlorates can cause rashes, fever, aplastic anaemia,
agranulocytosis
7. IODINE AND IODIDES
• Iodine is the fastest acting thyroid inhibitor.
• In graves disease, if given, the gland becomes less vascular and firm.
• With daily administration peak effects are seen in 10-15 days after
which thyroid escape occurs and thyrotoxicosis may occur.
• All facets of thyroid function seems to be effected but most
importantly is the inhibition of hormone release – Thyroid
constipation
8. USES –
• Preop preparation – for thyroidectomy, iodine is given 10 days before
surgery to make the gland firm, less vascular and easy to operate on.
• Thyroid storm – Lugol’s iodine(6-10 drops) is used to stop any
further release of T4,T3 from the thyroid and to decrease T4 to T3
conversion.
• Prophylaxis of endemic goiter
•Antiseptic – Tincture iodine, povidone iodine
9. ADVERSE EFFECTS –
• Acute reaction – swelling of lips, angioedema larynx, fever, joint
pain, petechial hemorrhages, thrombocytopenia etc, further exposure
to iodine should be stopped immediately.
• Chronic overdose( Iodism ) – Inflammation of mucous membranes,
salivation, rhinorrhoea, sneezing, lacrimation, swelling of eyelids,
headache, rashes. These symptoms regress on stopping iodine.
•Thyrotoxicosis maybe aggravates in MNG.
10. RADIOACTIVE IODINE
• Stable isotope of iodine is I127.
• I131 emits γ rays and also β rays.
• It gets concentrated by thyroid, gets incorporated in colloid and
emits radiation from within.
• The thyroid follicular cells undergo pyknosis and necrosis followed
by fibrosis.
• It is administered as sodium salt of I131 dissolved in water and taken
orally.
• Diagnostic – 25-100 mc curie is given
• Therapeutic – in hyperthyroidism due to grave’s or MNG, the dose is
m curie.
• Response starts after 2 weeks and reaches peak at 3 months.
11. ADVANTAGES –
• Treatment with I131 is simple, op basis and inexpensive.
• No surgical risk, injury to parathyroid glands, RLN
• Permanent cure
DISADVANTAGES –
• Hypothyroidism
• Long latent period of response
• Contraindicated during pregnancy
• Not suitable for young adults as they are most likely to develop
hypothyroidism
• Patients must be quarantined and avoid physical contact with
children/ pregnant women.
12. BETA BLOCKERS
• They are used to rapidly alleviate manifestations of thyrotoxicosis
that are due to sympathetic overactivity such as palpitations,
nervousness, tremors, sweating.
• They are used in following situations
while awaiting response to carbimazole/ PTU/ I131
Along with iodide for preoperative preparation.
In thyroid storm
13. THYROID STORM
• Non selective beta blockers – they offer symptomatic relief and also
prevent peripheral conversion of T4 to T3. Propranolol 1-2 mg slow
IV followed by 40-80 mg orally for every 6 hrs.
• PTU – 200-300 mg orally 6 hrly
• IOPANIC ACID – iodine containing radiocontrast media, they are
potent inhibitors of hormone release.
• Corticosteriods – Hydrocortisone 100 mg 8 hrly followed by oral
prednisolone.
• Diltiazem - 60-120 mg may be added if tachycardia is not controlled
• Rehydration, anti anxiolytics, external cooling and antibiotics
14. SURGERY
• Hemithyroidectomy
• Total thyroidectomy
• Indications –
Hyperthyroidism for which medical management has failed or not
preferred
Goiters with/ without compressive symptoms
Thyroid nodules
15. ADVANTAGES –
• Cure is rapid and cure rate is high.
DISADVANTAGES –
• Recurrence of thyrotoxicosis may occur in 5% of subtotal
thyroidectomy
• Risk of permanent hypoparathyroidism/ Nerve injury
COMPLICATIONS –
• Hemorrhage
• RLN paralysis and voice change
• Thyroid insufficiency
• Parathyroid insufficiency
• Thyroid crisis
• Wound infection
16. GRAVE’S OPHTHALMOPATHY
• It is an auto immune disorder caused by the activation of orbital
fibroblasts by antibodies directed against thyroid receptors.
• It is characterized by enlargement of extraocular muscles, fat and
connective tissue.
• Risk factors include genetic, environment and immune factors,
among the environmental factors, smoking being the most
consistently linked risk factor.
•The patients usually complain of gritty sensation in eye, photophobia,
lacrimation, dry eye, discomfort, and forward protrusion of the eye. In
more advanced cases, patient may complain eye socket (orbital) pain,
double vision, or blurred vision.
17. •Eyelid retraction (Dalrymple's sign) is the most common presenting
sign of thyroid eye disease, present in upto 90% of patients.
