Thyroid

Making the patient euthyroid

Mathew John MD, DM, DNB

Consultant Endocrinologist

1866

– “If a surgeon should be so foolhardy as to undertake it [thyroidectomy] … every step of the way will be environed with difficulty, every stroke of his knife will be followed by a torrent of will be followed by a torrent of blood, and lucky will it be for him if his victim lives long enough to enable him to finish his horrid butchery.”

Samuel David Gross

Samuel Gross (standing) in The Gross Clinicby Thomas Eakins

http://en.wikipedia.org/wiki/Samuel_D._Gross

1920

“feat which today can be accomplished by any competent operator without danger of mishap”

Halsted WS: The operative story of goiter. Johns Hopkins Hosp Rep 19:71, 1920

Agenda

• Making a thyrotoxic patient euthyroid before thyroid surgery

• Making a hypothyroid patient euthyroid before surgery

• Post operative management

Thyrotoxic patient Thyrotoxic patient

Euthyroid/hypothyroid

Not in discussion • Preparing patients with hypothyroidism and

hyperthyroidism for non thyroid surgeries • Hypocalcaemia management

Thyroid diseases presenting for surgery

• Euthyroid : Multinodular goiter

Solitary thyroid nodule

• Hyperthyroid : Toxic MNG

: Autonomous functioning thyroid nodule

: Graves’ s disease with large goiter/cold nodule : Graves’ s disease with large goiter/cold nodule

• Thyroid malignancy

• Emergency thyroidectomy : obstructed

: allergic to anti thyroid meds

: Amiadarone induced thyrotoxicosis

: thyroid crisis

Thyroid diseases presenting for surgery

• Euthyroid : Multinodular goiter

Solitary thyroid nodule

• Hyperthyroid : Toxic MNG

: Autonomous functioning thyroid nodule

: Graves’ s disease with large goiter/cold nodule : Graves’ s disease with large goiter/cold nodule

• Thyroid malignancy

• Emergency thyroidectomy : obstructed

: allergic to anti thyroid meds

: Amiadarone induced thyrotoxicosis

: thyroid crisis

Functional status of thyroid

Euthyroid Hypothyroid Hyperthyroid

No preparation Thyroxinesupplementation

•Antithyroid drugs(ATD)•Iodine•Steroids

Graves’ disease vs. AFTN vs. Toxic MNG

Grave’s disease Autonomously

functioning

thyroid nodule

( AFTN)

Toxic MNG

Why should a toxic patient be euthyroid before surgery ?

• Thyrotoxic crisis

• Cardiac arrhythmias and tachycardia

• Worsening of co existent medical conditions: Cardiovascular

Diabetes mellitus Diabetes mellitus

Blood pressure

• Hemodynamic compromise

• Anesthetic drug interactions

Euthyroidism

• Clinically normal: no symptoms, heart rate, tremors, sweating, weight gain, normal appetite

• Normal thyroid function tests ( in steady state )

• Thyroid adequately blocked so that hormones are not released during surgical manipulation

Graves’s disease

• Thyroid hormone production driven by TSH receptor stimulating antibodies

• Choice of ablative therapy: radioactive iodine ablation

• Indications for surgery

1. Large goiter: obstructive 1. Large goiter: obstructive

2. Solitary cold nodule

3. Allergic to ATD

4. Pregnancy (requiring high dose ATD)

TSH: thyroid stimulating hormone ATD: antithyroid drugs

Treatment options

Anti thyroid drugs Iodine Beta blockers

•Carbimazole •PTU

•Lugols iodine•SSKI •Iopanoic acid

•Propranolol •Esmolol

•Iopanoic acid

•Blocks synthesis •Blocks release •Reduces peripheral

conversion

•Blocks uptake of iodine

• Blocks oxidation•Blocks organification•Blocks release • Reduces peripheral

conversion

•Reduces toxic symptoms•Reduces peripheral conversion

Making the patient euthyroid

• Anti thyroid drugs : Carbimazole vs. PTU

• Start Carbimazole 10-30 mg/day based on severity of symptoms and time left for surgery

• Start beta blockers: T. Propranolol 30-120 mg/day

• Call back after 6 weeks and reassess

Beta blockers

• Reduces peripheral symptoms

• Reduces myocardial oxygen consumption, reduces heart rate, improves myocardial efficiency

• Used to prepare patients for surgery

• Used with caution in patients with congestive heart • Used with caution in patients with congestive heart failure, bronchial asthma

• Useful in thyrotoxic crisis

Do we need to use iodine ?

• Given after making the patient euthyroid by ATD

• Benefits:

Involution of the gland

Decreases its vascularity, (decreased rate of intraoperative blood loss)intraoperative blood loss)

• Contraindicated in toxic multinodular goiter and AFTN

Erbil Y,. Effect of lugol solution on thyroid gland blood flow and microvessel density in the patients with Graves' disease. J ClinEndocrinol Metab. 2007 Jun;92(6):2182-9

AFTN : Autonomously functioning thyroid nodule ATD: antithyroid drugs

There was no difference irrespective of treating with iodine in blood loss or other ease of surgery or crisis

Alternate methods of preparation

• Block replacement therapy :

Carbimazole ( PTU) + Thyroxine

• Potassium iodide + beta-blocker

• Iopanoic acid + Propranolol : used for rapid preparation in Amiadarone induced thyrotoxicosis

Feek CM, Stewart J, Sawers A, Irvine WJ, Beckett GJ, Ratcliffe WA, Toft AD: Combination of potassium iodide and propranolol in preparation of patients with Graves' disease for thyroid surgery. N Engl J Med 302:883, 1980

Bogazzi F, Martino E. Preparation with Iopanoic acid rapidly controls thyrotoxicosis in patients with amiodarone-induced thyrotoxicosis before thyroidectomy. Surgery 132:1114-1117, 2002

Toxic MNG/ AFTN

• Less risk of thyroid crisis

• Make patient euthyroid before surgery

• Consider using beta –blocker and small dose anti thyroid drugs before surgery

• Do not use iodine for preparation • Do not use iodine for preparation

Post operative treatment

• Stop antithyroid drugs after surgery

• Beta blockers can be stopped after 2-3 days

Await the histopathology : if benign start Thyroxine • Await the histopathology : if benign start Thyroxine

Calcium metabolism

• Monitor calcium after 12-24 hours or if hypocalcaemia symptoms present

• Hypocalcaemia : hypoparathyroidism

hungry bone syndrome hungry bone syndrome

• If S. Calcium (corrected) < 8.5 mg/dl : supplement calcium with (active) Vitamin D

• Calcium supplements for all operated thyrotoxic patients

Maria

Richsel Maria

Richsel

Kocher T: Uber Kropfextirpation und ihre Folgen. Arch Klin Chir 29:254, 1883.

Hypothyroidism after surgery

• Varying estimates

• Depending on the gland left behind

• Total thyroidectomy : 100 % have hypothyroidism

• Mechanism of hypothyroidism:

reduced thyroid volume reduced thyroid volume

thyroid autoimmunity

reduced vascularity

Subclinical hyperthyroidism

• Normal T4, T3 Suppressed TSH

• Suggests mild overproduction of thyroid hormone

• Less risk of thyroid crisis

• Consider using beta –blocker and small dose anti thyroid drugs before surgery drugs before surgery

Hypothyroidism

Overt hypothyroidism

• Low T4

• Elevated TSH

Subclinical hypothyroidism

• Normal T4

• Mildly elevated TSH

(usually < 10 mIU/ml ) (usually < 10 mIU/ml )

• Does not carry any increased risk

Hypothyroidism

• May be seen in large goitrous Hashimoto’s thyroiditis

• Overt hypothyroidism is unusual in thyroid surgical cases

Risks of untreated hypothyroidism

• Myxedema coma

• Electrolyte imbalance

• Hypoventilation

• Delayed recovery from anesthesia

Hypothermia • Hypothermia

Achieve euthyroidism before surgery

Achieving euthyroidism

• Start Thyroxin 50 -100 mcg/day

• Call back patient after 6 weeks

• Check T4, TSH

• If both are normal, the patient can be taken up for surgery with no additional risk surgery with no additional risk

Message

• Hyperthyroidism and hypothyroidism are common in patients undergoing thyroid surgery

• Making the patient euthyroid improves outcomes

• Hyperthyroidism is treated with 1. Anti thyroid drugs

2. Beta blockers 2. Beta blockers

3. Iodine

• Hypothyroidism is managed with Thyroxine

Thank you

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