Hyperthyroidism BỆNH CƯỜNG GIÁP Ở CÂY LÚA

Control of thyroid functionThe synthesis and release of thyroid hormones is regulated by negative feedback mechanism involve: -The pituitary hormone TSH thyroid stimulating hormone -Th

« GROUP 1 »

1 Thyroid Gland Anatomy – Physiology

1 Thyroid Gland Anatomy – Physiology

Control of thyroid function

The synthesis and release of thyroid hormones is

regulated by negative

feedback

mechanism involve:

-The pituitary hormone TSH

(thyroid stimulating hormone) -The TRH

(thyrotropin releasing

hormone)

The normal thyroid gland produces about 80% T4 and about 20% T3, however, T3 possesses about four times the hormone "strength" as T4.

T4 is involved in controlling the rate of metabolic

processes in the body and influencing physical

development

1 Thyroid Gland Anatomy – Physiology

· Increased expression of Na/K ATPase;

· increased sarcolemmal calcium uptake

· increased beta adrenergic receptor levels in myocardium;

· increased hepatic production of sex steroid binding globulin;

· Bone: (cartilage ossification, maturation of epiphyses, chondrocyte maturation; - thyroid hormone has a direct effect on bone, and indirect effects through growth hormone release and IGF-1 action);

· neuronal: cortical growth, axonal and dendritic growth, myelination; T3 is vital for normal brain

development, and fetal TSH secretion starts by about 11-12 weeks The auditory and visual sensory

systems appear particularly dependent on T3

· renal: increased renal plasma flow and GFR, Tm in tubules

Tissue effects of T3 include:

1 Thyroid Gland Anatomy – Physiology

2 Pathology

Hyperthyroidism’s Causes

Grave Disease (Basedow )

2 Pathology

Toxic Multinodular Goiter

2 Pathology

Hyperthyroidism is the overproduction of thyroid hormones by an overactive thyroid.

3 Definition

4 : 1

Age: 20 - 40

3 Epidemiology

-Toxic Adenoma -Thyroiditis

6.1 Clinic

• Weigh loss

• Fatigue

• an enlarged thyroid gland (bruit)

• Warm moist skin

• Light or absent menstrual periods

• Increased bowel movements

• Staring gaze, “lid lag”

6.1 Clinic

6.1 Subclinic

The thyroid scan is used to determine the size, shape and position of the thyroid gland.

6.1 Subclinic

Common Forms (85-90% of cases) Radioactive iodine uptake over neck

Diffuse toxic goiter (Graves disease) Increased Toxic multinodular goiter (Plummer disease) Increased Thyrotoxic phase of subacute thyroiditis Decreased Toxic adenoma Increased

Less Common Forms

Iodide-induced thyrotoxicosis Variable Thyrotoxicosis factitia Decreased

Uncommon Forms

Pituitary tumors producing thyroid-stimulating hormone Increased

Excess human chorionic gonadotropin (molar pregnancy/choriocarcinoma) IncreasedPituitary resistance to thyroid hormone Increased Metastatic thyroid carcinoma Decreased Struma ovarii with thyrotoxicosis Decreased

The thyroid uptake

(RAIU) is performed

to evaluate the

function of the gland

6.1 Subclinic

(A) Normal

(B) Graves disease : diffuse increased uptake in both thyroid lobes.

(C) Toxic multinodular goiter (TMNG):

“hot” and “cold” areas of uneven uptake.

(D) Toxic adenoma : increased uptake in

a single nodule with suppression of the surrounding thyroid.

(E) Thyroiditis : decreased or absent uptake.

6.1 Subclinic

6.3 Treatment

• Grave’s disease: diffuse goiter

• Toxic multinodular goiter

& thyroid adenoma: autonomous goiter

Regulatory

• Wolff-Chaikoff effect: Reduction in thyroid

hormone levels caused by ingestion of a large amount of iodine

• Antithyroid drug

• Radioactive iodine

• Thyroidectomy

Antithyroid drug - Thionamide

• Propylthiouracil

• Methimazole

Propylthiouracil

Radioactive iodine

• http://www.youtube.com/watch?v=Evdkh5yv6gA&feature=related

Thyroidectomy

ATA/AACE Guideline 2011

– Coexistent cardiovascular disease

• Alternative: Calcium channel blockers

Radioactive iodine

• Khả năng tái phát thấp

• Thời gian hết bệnh: 4-8 tuần

• Nguy cơ cho phụ nữ có thai

• Làm tăng nguy cơ ung thư

• Nguy cơ nhược giáp cao

• Lack of access to a high-volume thyroid surgeon

• Contraindications to ATD use.

• Relatively higher value

– Definitive control of hyperthy-roidism

– Avoidance of surgery

– Avoidance potential side effects of antithyroid medications

• Relatively lower value

– Lifelong thyroid hormone replacement

– Rapid resolution

– Potential worsening or development of GO

• Symptomatic management

• Pretreatment with methimazole prior to radioac-tive iodine therapy

Antithyroid drugs

• Tác dụng phụ của thuốc

• Nguy cơ tái phát cao

• Previous known major adverse reactions to ATDs

• Patients with high likelihood of remission (patients, especially females, with mild disease, small goiters, and negative or low- titer TRAb)

• The elderly or others with comorbidities or with limited life expectancy

• Limited longevity and are unable to

• follow radiation safety regulations

• Previously operated or irradiated necks

• Lack of access to a high-volume thyroid surgeon

• Moderate to severe active

• GO.

– Avoidance of ATD side effects

– The need for continued monitoring

– The possibility of disease recurrence.

• Symptomatic compression or large goiters (≥80 g)

• Relatively low uptake of radioactive

• Iodine

• Thyroid malignancy is documented or suspected

• large nonfunctioning, photopenic, or hypofunctioning nodule

• Coexisting hyperparathyroidism requiring surgery

• Pregnancy in <4–6 months

• TRAb levels are particularly high

• Moderate to severe active GO.

– Potential surgical risks

– Lifelong thyroid hormone replacement.

• Rendered euthyroid with Methimazole

• Potassium iodide should be given in the immediate preoperative period

Toxic multinodular goiter & Thyroid

Hyperthyroidism can lead to a number of complications:

•Heart problems Some of the most serious complications of hyperthyroidism involve the heart

These include a rapid heart rate, a heart rhythm disorder called atrial fibrillation and congestive heart failure — a condition in which your heart can't circulate enough blood to meet your body's needs These complications are generally reversible with appropriate treatment.

•Brittle bones Untreated hyperthyroidism can also lead to weak, brittle bones (osteoporosis) The

strength of your bones depends, in part, on the amount of calcium and other minerals they

contain Too much thyroid hormone interferes with your body's ability to incorporate calcium into your bones.

•Eye problems People with Graves' ophthalmopathy develop eye problems, including bulging, red

or swollen eyes, sensitivity to light, and blurring or double vision.

•Red, swollen skin In rare cases, people with Graves' disease develop Graves' dermopathy, which

affects the skin, causing redness and swelling, often on the shins and feet.

6.4 Complication & Sequela

Thyroid storm

complication of hyperthyroidism, which may

occur when a thyrotoxic patient becomes very

sick or physically stressed.

Its symptoms can include: an increase in

body temperature to over 40 degrees Celsius,

tachycardia, arrhythmia, vomiting, diarrhea,

dehydration, coma, and death.

Earlier in this century, the mortality of thyroid

storm approached 100% However, now, with

the use of aggressive therapy as described

above, the death rate from thyroid storm is less

than 20%.

6.4 Complication & Sequela

thryroiditis can eventually lead to hypothyroidism (a

lack of thyroid hormone)., as the thyroid gland is

damaged.

Also, radioodine treatment of Grave’s disease

often eventually leads to hypothyroidism

Such hypothyroidism may be avoided by regular

thyroid hormone testing and oral thyroid hormone

supplementation.

6.4 Complication & Sequela

http://emedicine.medscape.com/article/121865-overview#a0104

http://www.radiologyinfo.org/en/info.cfm?pg=thyroiduptake

http://www.endocrineweb.com/conditions/hyperthyroidism/hype rthyroidism-overactivity-thyroid-gland-0

http://www.dalanphim.com/ykhoathuongthuc/binhcuonggiaptra ng.html

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