Enlarged thyroid gland Dr. M. Malek

Enlarged thyroid Diffusely enlarged (goiter) Multinodular (Multinodular goiter) Partially enlarged (single thyroid nodule) جهت معاینه تیروئید از بیمار میخواهیم تا سر خود را به عقب خم کند.(باربارابتز) بیمار نشسته باشد و ما در حالت ایستاده از پشت گردن بیمار را معاینه کنیم.

لمس تیروئید روشهای متعددی برای این معاینه وجود دارد اما بهتر است لمس از خلف انجام شود. از پشت سر انگشتان هر دو دست خود را به گونه ای بر گردن بیمار بگذارید که انگشتان اشاره شما درست زیر کریکوئید قرار گیرد.

گردن بیمار باید راست باشد ولی نه آنقدر که عضلات را کشیده و سفت کند. در صورت لزوم خم شدن گردن بیمار را تعدیل کنید. زمانی که بیمار آب دهانش را قورت میدهد، ایسم تیروئید باید زیر انگشتان شما بالا بیاید. با چرخاندن انگشتان خود به سمت پایین و طرفین، لوبهای طرفی به خصوص کناره های تحتانی آنرا لمس کنید.

Goiter refers to an enlarged thyroid gland Biosynthetic defects Iodine deficiency Autoimmune disease Nodular diseases By different mechanisms

Biosynthesis effect & iodine deficiency→ Reduced efficiency of thyroid hormone synthesis →Increase TSH →Stimulation of thyroid growth (compensatory mechanism)

Enlargement of the thyroid suggests nothing about the function of thyroid. Because can be: Hyper functioning Normal functioning Hypo functioning

Evaluation Is undertaken principally to determine the thyroid function & presence or absence of malignancy.

Thyroiditis Fever, enlarged & tender thyroid Bacterial infection TFTs are usually normal.

Grave, s (diffuse toxic goiter) Is the most common cause of goiter & hyperthyroidism. An autoimmune disease Antibodies act to simulate thyroid function. Exophthalmos, burning, itching, pretibial dermopathy.

Thyroid acropachy:Periosteal proliferation secondary to thyroid disease

Trophoblastic tumors Rarely can simulate goiter & hyperthyroidism. HCG has some biologic cross-activity with TSH.

Jadbasedow phenomenon Hyperthyroidism induced by iodine supplementation.

De quervain,s thyroiditis Subacute granulomatous thyroiditis Painful enlargement Fever, malaise, chills F/M: 3 Unknown cause but usually follows a viral infection by several weeks Neutrophils, lymphocytes & giant cells (granolomata)

Subacute lymphocytic thyroiditis A painless thyroiditis, hyperthyroidism & enlargement Unknown cause probably autoimmune

Hashimoto Chronic lymohocytic thyroiditis Most common thyroid disorders in USA Painless palpable goiter Usually initially euthyroid But ultimately almost always hypothyroid Hyperthyroidism: must be distinguished from Graves

Hashimoto Dx: Antimicrosomal Abs : In approximately 95% Antithyroglobolin Abs : in 50% to 60% Radioactive iodine uptake: may be normal, low or increased Anti TPO antibodyهمان آنتی بادیهای آنتی میکروزومال هستند.

Reidel ,s thyroiditis A rare disorders A firm, enlarged gland Sclerosing fibrous infiltration Hypothyroidism

Endemic goiter In a large fraction of the population. Most commonly a result of iodine deficiency. Now is very rare in the USA owing to iodinization of salt.

Sporadic goiter An enzymatic defect. Leading to low thyroid hormone levels. Elevated level of TSH.

Pituarity adenoma May secret TSH autonomously. Without sensitivity to negative feedback.

TFT Thyroid function tests should be performed in all patients with goiter to exclude thyrotoxicosis or hypothyroidism. Harrison

Thyroid scanning Thyroid scanning is not generally necessary but will reveal increased uptake in iodine deficiency and most cases of dyshormonogenesis. Harrison

Ultrasound Ultrasound is not generally indicated in the evaluation of diffuse goiter unless a nodule is palpable on physical examination. Harrison