This document discusses the management of thyrotoxicosis, including investigations and treatment options. Key investigations include thyroid function tests, radioisotope scans, and antibody tests. Treatment options include anti-thyroid drugs, surgery, and radioactive iodine therapy. Anti-thyroid drugs are the first line treatment and help prepare patients for surgery or radioactive iodine therapy. Surgery involves removing parts of the thyroid gland and is indicated when drugs fail or for large goiters. Radioactive iodine therapy uses radiation to destroy the thyroid tissue and is preferred for older patients with no risk of genetic mutations. Long term management may require thyroid hormone replacement therapy.

1. Management of
Thyrotoxicosis
Ahmed Ali Khan
Final year MBBS
2011-12 Batch
JSS Medical College, Mysore

2. Investigations

3. Thyroid Function Tests
• Serum T3 or T4 levels are very high. TSH is very
low or undetectable.
(Normal T3 – 3-9 pmol/L)
(Normal T4 – 8-26 pmol/L)
• If eye signs are present along with the above
values, then other tests are generally not
needed.

4. Radioisotope study
• An 123I or 131I uptake and scan should be
performed.
• An elevated uptake shows ‘hot areas or
nodules’.
• Grave’s disease shows diffuse uniform over-
activity.
• It also helps to differentiate it from other
causes of hyperthyroidism.

7. Antibodies
• Anti-Tg and anti-TPO antibodies are elevated
in up to 75% of patients.
• Elevated TSH-R or thyroid-stimulating
antibodies (TSAb) are diagnostic of Graves'
disease and are increased in about 90% of
patients

8. Other Investigations
• ECG to look for cardiac involvement.
• TRH estimation.
• Total count and neutrophil count are very
essential as anti-thyroid drugs may cause
agranulocytosis.

9. Management

10. • Thyrotoxicosis may be treated by any of 3
treatment modalities —
1. Antithyroid drugs
2. Surgery
3. Radioiodine Therapy 131I

11. Anti Thyroid Drugs
• Indicated in children, pregnant women and
young adults.
• Drugs help maintain euthyroid state for a long
time in hope of spontaneous remission and
prepare the patient for surgery.

12. Anti Thyroid Drugs
• Carbimazole, Propyluracil, Methimazole etc
are some of the commonly used drugs.
• B adrenergic blockers – Ex : Propranolol
• In pregnant women – propylthiouracil is
preferred

13. Anti Thyroid Drugs
• Lugol’s Iodine (5% iodine + 10% potassium
iodide) – decreases the vascularity of the
gland only used as immediate preoperative
measure. 10-30 drops/day for 10 days(makes
the thyroid firm and easier to handle during
surgery)
• Others – Lithium carbonate, Reserpine,
potassium perchlorate

14. Anti Thyroid Drugs
• Pros : no surgery and no use of radioactive
• Cons: prolonged t/t and failure rate about
50%.
• May also cause aplastic anemia,
agranulocytosis, hair loss and liver damage.
• Poor prognosis : large gland size, severity of
disease nad TSH-Rab levels.

15. Surgical Treatment
• Indications
1. Failure of drug therapy
2. Toxic nodular goitre
3. Autonomous toxic nodule
4. Suspected malignancy
5. Grave’s disease in children
6. Very large goitre(substernal/intrathoracic)

16. Surgical Treatment
• Subtotal thyroidectomy – both lobes with
isthmus are removed and tissue equivalent to
pulp of finger is retained at the lower pole of
both the lobes.(5-8 grams)
• Hemithyroidectomy – done for autonomous
nodule. Here, entire lateral lobe with the
isthmus is removed.
• Total Thyroidectomy – Preferred in Grave’s
disease to achieve lowest relapse rate.

18. Surgical Treatment
• Pros – Rapid cure and high cure rate, problems
associated with radioiodine therapy can be
avoided.
• Surgery also provides tissue for biopsy.
• Coexisting parathyroid Ca can be removed if
present.
• Only choice for very large retrosternal toxic
thyroid.
• Cons – Recurrence in 5% cases, Thyroid
insufficiency in (20-45%) and the generally
encountered complications of surgery itself.

19. Radioactive Iodine Therapy (131I)
• Destroys thyroid cells and reduces mass of
thyroid tissue below a critical level by
ablation.
• Indications
1. Primary Thyrotoxicosis after 45 years
2. Autonomous toxic nodule
3. Recurrent Thyrotoxicosis

20. Radioactive Iodine Therapy (131I)
• Usual dosage is 160 microcurie/gm of thyroid
• Patient is first made euthyroid by anti-thyroid
drugs. Then discontinued for 5 days after
which oral radioiodine therapy is initiated.
• Once the preferred dosage is achieved,
radioiodine therapy is stopped. Then anti-
thyroid drugs are started after 7 days and
continued for 8 weeks.

21. Radioactive Iodine Therapy (131I)
• It normally takes about 3 months to get full
response. Additional 1-2 doses of radioiodine
may be required.
• Due to the pre and post radioiodine therapy
dosage of anti-thyroid drugs the patient may
go into a state of hypothyroidism. This can be
tackled by a maintenance dose of L-thyroixine
0.1mg daily.

22. Radioactive Iodine Therapy (131I)
• Pros – No Surgery, No prolonged drug therapy
and a cure rate of about 90%
• Cons – Availabilty of services, necessity of
proper regular follow up and more
importantly, it may cause genetic mutation in
younger individuals and thereby predisposing
them to various malignancies. Hence, only
useful in older adults(>45years).

23. Thank you and have a great day!