Diorders of thyroid

40 %
60 %
Information about Diorders of thyroid
Health & Medicine

Published on March 27, 2014

Author: mprasadnaidu

Source: slideshare.net


Disorders of Thyroid and parathyroid glands

M.Prasad Naidu MSc Medical Biochemistry, Ph.D.Research Scholar

 1. Hyperthyroidism  2. Thyroid Adenoma  3. Grave’s disease

 Causes:  Due to the presence of TSH like substances – proved by RIA studies  The conc of TSH was found to be 0/less in plasma of Hyperthyroidism patients  The TSH like substances are Abs which bind with same membrane receptors of TSH  These substances activate c-AMP system ↑T4  These Abs act for long time (12hrs) (TSH-1hr)  The ↑ of high T4 caused by Abs suppresses TSH production  Usually these Abs are developed b/cos autoimmunity

 Some times – localised tumor develops in Thyroid tissue called Thyroidadenoma  TA secretes large quantities of T4&T3  It is not associated with autoimmunity  As far as this adenoma remains active, the other parts of Thyroid gland will not secrete the hormone.  This is b/cos the hormone from Adenoma ↓ depresses the production of TSH

 Autoimmune disease  Normally TSH combines with surface receptors of thyroid cells  syn of T4  But in GD , the TSH autoAbs (B-TSAB) produced by B-lymphocytes (Plasma cells) activate the TSH-receptors & ↑ secretion of T4

 Intolerance to heat ( due to ↑ BMR)  ↑ sweating ( due to vasodialation)  ↓ body wt ( Fat metabolism)  ↑ motility of GIT  diarrhoea  Muscular weakness  ↑protein catabolism  Nervousness, extreme fatigue, inability to sleep, mild tremor in the hands, psychoneurotic symptoms such as extreme anxiety/worry (stimulation of CNS)  Enlargement of Thyroid gland i.e, Toxic goiter  Exophthalmos: Autoimmune  some degree of protrusion of eye balls – if severe blindness develops due to  i)protrusion of eye ball stretches the optic nerve  Ii) eye lids cannot be closed  dry  infection

 ↓ secretion of Thyroid hormones  Autoimmune disease which causes destruction of Gland  In most patients it starts as the glandular inflammation called – Thyroiditis  Thyroiditis  fibrosis of the gland  Hypothyroiditis Myxedema (adults) Cretinism (Children)

 Due to hypothyroidism in adults  Causes: occurs in severe conditions – complete lack of thyroid hormones  Signs & symptoms:  Swelling of the face  Bagginess under the eyes  Non-pitting type of edema:- when pressed it does not make pits and the edema is hard (accumulation of Pro+cho.SO4 which form hard tissue with ↑ accumulation of fluid)  Atherosclerosis: ↑ cholesterol – blood ↑ bp

 Other general symptoms:  Fatigue & muscular sluggishness  Extreme somnolence ( 14-16 hrs/day)  Menorrhagia & polymenorrhea  ↓ Cordiovascular functions such as ↓heart rate, ↓ force of contraction of heart ↓ crodiac out put , ↓ blood volume  ↑Body wt  Constipation  Mental sluggishness  ↓ hair growth  Scaliness of the skin  Frog like husky voice

 Children  Causes: congenital absence of thyroid gland (genetic disorder or lack of I2 in diet)  Features:  The newborn baby may appear normal at birth (due to supply of T4 from mother)  But after few weeks – starts developing sluggish movements croacking sound while crying  mentally retarded  Skeletal growth is more affected than soft tissues  Tongue becomes so big – affects swallowing & breathing  Stunted growth

CRETINISM DWARFISM Mental retardation Development of Nervous system is normal Diff parts of the body are disaapropriate Proportionate Reproduction system is affected normal

 Enlargement of thyroid gland  Occurs both in hypothyroidism & Hyperthyroidism  Goiter in Hyperthyroidism  Toxic Goiter  Due to tumor of the gland – Size ↑ - ↑ number of hormones secreting cells ↑ hormone level – Toxic Goiter  Goiter in hypothyroidism –non toxic Goiter  Only enlargement of gland – hormone secretion is ↓

 Based on the cause, Non-toxic Goiter is of 2 types  i) Endemic Colloid Goiter:-  Due to lack of I2 – I2 intake <50µg/day  Therefore no formation of hormones  By feed back mechanism, hypothalamus and anterior pituitary are stimulated  This ↑ secretion of TRH and TSH  secretion of TGb Follicles  As there are no hormones to be cleaved, ↑ accumulation in the follicles  Therefore ↑ size of the gland  In Swiss, Alps, Andes, Great region of US and in India – Kashmir Valley Soil does not I2↓  Therefore Food stuffs lack I2 – very common before the introduction of iodized salts

 Enlargement of Thyroid gland occurs even without I2 deficiency  Exact cause not known  These patients are first affected by Thyroiditis which reduce synthesis of Thyroid hormones  Therefore secretion of TSH ↑  ↑ Size of the gland  In some persons the abnormal enzyme system leads to Goiter(due to deficiency of enzymes like peroxidase, iodinase and deiodinase which are required synthesis of T3&T4)

 Goitrogenic Substances: ( Goitrogens)  Eg: Goitrin  Contains antithyroid substances like propylthiouracil  Therefore TSH secretion ↑ enlargement of Thyroid gland  Goitrogens  in turnips, cabbage, soyabeans  The goitrogens become active only during low I2 intake

 Treatment for Hyperthyroidism:-  1. Surgical removal: Thyroidectomy  2. Antithyroid substances: Thiocyanate, thiourylenes, high conc of inorganic iodides  Treatment of hypothyroidism:  Only treatment is administration of Thyroid extract/ ingestion of pure thyroxine ( tablet)

 Drugs which supress the secretion of T3&T4  1. Thiocyanate: the same active pump which transports I- into Thyroid cells, transports thiocyanate also  So thiocyanate competitively inhibits I2 transport  I2 transport is inhibited  ↓ synthesis of Thyroxine

 Thiourea related substances  Eg: Propylthiouracil and methimazole prevent the formation of T4 from iodides and Tyr  This is achieved by blocking peroxidase activity and partly by blocking coupling of MIT & DIT  During the use of these two antithyroid agents even though the synthesis of Thyroid hormone is inhibited , the formation of TGb is not stopped  The deficiency of the hor ↑ TSH secretion ↑ Size Thyroid gland with more secretion of TGb  TGb accumation in gland  enlargement  non- toxic G

 All phases of Thy.activity ↓  ↓ release of Thyroxine  ↓ Size  ↓ blood supply  Therefore iodides are frequently administrated to hyperthyroid patients

 The most accurate diagnostic test is Direct measurement of conc of Free thyroid hormones in the plasma (T3&T4)  Measurement of BMR:-  In Hyperthyroidism, ↑ 30-60%  In hypothyroidism, ↓ 20-40%  The measurement of TRH and TSH:-  In Hyperthyroidism total absence of TRH & TSH (due to –ve feed back mechanism by the ↑level of Thyroid hormones)

Add a comment

Related presentations

Related pages

Thyroid Problems, Disease - Symptoms, Causes, and Diagnosis

Learn more from WebMD about the causes of different types of thyroid problems.
Read more

Thyroid disease - Wikipedia, the free encyclopedia

A thyroid disease is a medical condition impairing the function of the thyroid. Different thyroid diseases include Hashimoto's thyroiditis, hyperthyroidism ...
Read more

Thyroid Disorders: Learn About Symptoms and Treatment

There are a variety of thyroid disorders, that can cause a variety of symptoms such as dry skin, constipation, depression, nervousness, fatigue ...
Read more

Thyroid Diseases: MedlinePlus - National Library of ...

The thyroid is a gland in the neck. The thyroid gland creates hormones that affect metabolism. Learn about thyroid diseases, such as hypothyroidism.
Read more

Thyroid - Wikipedia, the free encyclopedia

The human thyroid as viewed from the front, with arteries visible. Note the superior thyroid artery, which supplies the thyroid with much of its blood.
Read more

Thyroid disorders Symptoms, Diagnosis, Treatments and ...

Thyroid disorders information including symptoms, diagnosis, misdiagnosis, treatment, causes, patient stories, videos, forums, prevention, and prognosis.
Read more

4 Common Thyroid Disorders - Medical Information & Trusted ...

Four common thyroid disorders include Hashimoto's disease, Graves' disease, goiter, and thyroid disorders. Learn about their symptoms, diagnosis, and ...
Read more

Thyroid Gland Diseases: Hormones, Cancer, Doctors, Drugs ...

Learn the basics of thyroid disease, including hypothyroidism, hyperthyroidism, thyroid cancer, and goiters. Article also explains thyroid hormones and ...
Read more

Symptoms of Thyroid disorders - RightDiagnosis.com

Symptoms of Thyroid disorders including 33 medical symptoms and signs of Thyroid disorders, alternative diagnoses, misdiagnosis, and correct diagnosis for ...
Read more

Information on Thyroid Disorders | Hormone Health Network

Find questions, answers and patient guidance to thyroid problems, including underactive and overactive thyroid, by visiting Hormone.org.
Read more