بسم اهلل الرحمن الرحيم

Thyrotoxicosis

BY PROF GOUDA ELLABBAN

Definition:

• The term thyrotoxicosis refers to the hypermetabolic clinical syndrome resulting from serum elevations in thyroid hormone levels, specifically free thyroxine (T4), triiodothyronine (T3), or both

• It is common, more common in women than in men

Thyrotoxicosis Vs hyperthyrodism :

• Hyperthyroidism is a type of thyrotoxicosis in which accelerated thyroid hormone biosynthesis and secretion by the thyroid gland produce thyrotoxicosis

• Although many patients have thyrotoxicosis caused by hyperthyroidism, other patients may have thyrotoxicosis caused by inflammation of the thyroid gland, which causes release of stored thyroid hormone but not accelerated synthesis, or thyrotoxicosis, which is caused by ingestion of exogenous thyroid hormone.

Causes:

• -Graves' disease (diffuse toxic goiter) • -toxic multinodular goiter • -solitary toxic nodule • -Thyroiditis • -Subacute Postpartum Silent • -Exogenous iodide (Jod-Basedow phenomenon) • -Neonatal hyperthyroidism • -Pituitary adenoma • -Pituitary resistance to thyroxine and triiodothyronine • -Excess secretion of thyroid stimulating hormone

Graves' disease(diffuse toxic goiter)

• The syndrome is primary thyrotoxicosis • it is an autoimmune disorder • is caused by circulating anti-TSH autoantibodies

which mimic TSH by activating the receptor to stimulate the synthesis and release T3 and T4

• autoantibody production is not linked to the normal pituitary negative feedback loop.

• hypertrophy and hyperplasia of the whole functioning thyroid tissue.

• 50% of patients have a family history of autoimmune endocrine disorder

• usually occurs in younger women and frequently associated with eye signs

Toxic multinodular goiter

• Usually, toxic multinodular goiter (TMNG) is the end result of a slow process that occurs over many years,

• Usually in middle aged or elderly

• TMNG occurs in a patient with multinodular goiter whenever newly generated follicles with some degree of autonomous capability reach sufficient size and functionality to cause thyrotoxicosis. (ie, Plummer disease).

Toxic nodule

• A solitary overactive nodule • May be apart of a generalized

nodularity or a true toxic adenoma • It has been uncoupled from the

normal pituitary-thyroid negative feedback loop

• Clinical Presentation

tiredness

heat intolerance

excessive appetite

weight loss

palpitation

symptoms

signs• signs in the neck: • the thyroid gland is usually enlarged but thyrotoxicosis can be

present withoutany enlargement of the gland. • Signs in the eye: • Lid retraction • Lid lag • Exophthalmos • Ophthalmoplegia • Chemosis • Metabolic signs • The patient looks thin and their face and hands

may be wasted • They look hot and be sweating

signs• Neurological signs: • Irritability • Fine tremor • Agitation • Psychosis • Proximal myopathy • Cardiovascular • Tachycardia, • atrial fibrillation • extrasystole • Cardiac failure • Thyrotoxic cardiomyopathy

Differential diagnosis of thyroid swellings:

• Simple goiter: • Diffuse hyperplastic (physiological, puberty,

pregnancy) • Multinodular goiter. • Toxic: • Diffuse (Graves’ disease) • Multinodular • Toxic adenoma • Neoplastic: • Benign • Malignant

Differential diagnosis of thyroid swellings:

• Inflammatory: • Autoimmune Chronic lymphocytic thyroiditis Hashimoto’s disease • Granulomatous De Quervain’s thyrioditis • Fibrosing Riedel;s throiditis • Infective Acute (bacterial, viral, subacute) Chronic (TB, syphilitic) • Others Amyloid

Investigations

• Serum free T4 and free T3. • TSH level • Thyroid antibodies • Thyroid ultrasound • Fine-needle aspiration • Electrocardiogram

Treatment• Anti-thyroid drugs

• Surgery

• Radioiodine

Anti-thyroid drugs…

• carbimazole • beta-blocker

Advantages - Disadvantages

Surgery

• Advantages - Disadvantages

Radioiodine

• Destroys thyroid cells and reduces the mass of functioning of thyroid tissue

Advantages - Disadvantages

Preoperative preparation

• Make the patient biochemically euthyroid at operation

• Treat the previous symptoms

• Gain specific sign

Surgery for Thyrotoxicosis

Extent of the resection depends on:

• the size of the gland

• the age of the patient

• the experience of the surgeon

• the need to minimize the risk of recurrent toxicity

Surgery for Thyrotoxicosis

All thyroid operation can be assembled from three basic elements

Complications of Thyroidectomy

Hormonal

The complications of any operation, especially:

Damage to related anatomical structures

- Tetany

- Hypothyroidis

m

- Late recurrence of hyperthyroidi

sm

- Haemorrhage

- Sepsis

- Postoperative chest infection

- Hypertrophic scarring (keloid)

- Recurrent laryngeal

nerve

- Injury to trachea

- Pneumothora

x

• Thank You