DISORDERS

OF THE THYROID

GLANDHYPOTHYROIDISM

& THYROTOXICOSIS

PHYSIOLOGY

• NORMAL DAILY INTAKE FOR IODINE150 – 200 μg

• Incorporation of iodide into tyrosine1 m. J → 3-monoiodotyrosine – MIT2 m. J → 3,5-diiodotyrosine – DIT

• Coupling reactions: MIT + DIT = T3

DIT + DIT = T4

• T3 and T4 are binded to thyroglobulin (Tg)

• In bloodstream T3 and T4 are also binded to albumins (1:1000), active are only free forms fT3 i fT4

• Regulation by TSH and TRF

HYPOTHYROIDISMHYPOTHYREOSIS

•

THYREOGENIC (PRIMARY)

the most frequent

PITUARY (SECONDARY)

consequence of insufficiency of pituary gland

• Prevalence –inborn1:5000 of newborns

• Etiology : lack of the gland, dysplasia of the

gland, defect of synthesis or secretion

HYPOTHYREOSISsymptoms in adults

• Reduced energy level, tiredness, weakness, apathy,

• Cold intolerance

• Dry skin, brittle hair, loss of hair, nonpitting odema of the skin

• Deeping of the voice

• Inotropic and chronotropic effect on heart

• Accerelation of development of atherosclerosis (CAD) - hypercholesterolemia

• In elder patients – symptoms are milder

LABORATORY DIAGNOSTICS

• ↑ TSH > 4 m.U./ l

• ↓T4

• antibodies against thyreoglobulins – in

autommune thyroiditis

• scyntygraphy – reduced uptake of

radioisotope by thyroid gland

Myxedema

Examination

of thyroid gland

TREATMENT

• Substitution L-T4

• Gradually: increase of the dose for 25 μg

every 1 – 2 weeks

• TSH – regular control during the treatment

THYROTOXICOSIS

HYPERTHYREOSIS

-autoimmune disorder: thyroid gland stimulating factors (immunoglobulins) Graves’ Disease

-single functionating nodule(s) is/are autonomous Plummer’s Disease

-Hashimoto’s thyroiditis

-iatrogenic

HYPERTHYREOSIS – signs & symptoms

• goiter (90%pts)

• Ophtalmopathy

• Increased contractility of heart, rapid HR, AF

• Nervousness, irritability, problems with concentration

• Sleeplessness

• Tremor

• Weight loss & increased apetite

• Soft, smooth, atrophic, warm skin

• Sweating, hypertermia

• Loose stools / mild diarrhoe

HYPERTHYREOSIS

– diagnostics

• fT3 ↑↑↑ (~100%)

• fT4 ↑↑↑ (~90%)

• TSH ↓

• Ultrasonography

• Scintigraphy

Thyroid gland in sonographyA-normo-B-hyper- & hypo-C-hypo-D-hypo-echogenic areaswith calcifications

Scintygraphy of thyroid gland

HYPERTHYREOSIS – treatment

• Pharmacological: methimazole,

propylotiouracyl Side effects: agranulocytosis,

cholestasis

• Surgical

• Radioactive iodine