Hyprethyrodism

Hyprethyrodism:



is hyperunction of the thyroid whith excess secretion of the thyroid hormone



Etiology:



there are three main types+few rara varieties



A-GRAVES DISEASE (1RYTHROTOXICOSIS=DIFFUSE TOXIC GOITER==EXOPHTHALAMIC GOITER) : ACCOUNTS FOR ABOUT 80% OF PATIENTS OF HYPERTHYROIDISM



causes: 1- mostly its due to thyroid-stimulating antibodies against TSM receptorswhich convert to T3,T4



2-familial etiology and commoner in women than men



3-other thyroid autoantibodis suchas tgyroglobulin,microsomal antibodies may be present



4-it may be asscociated with other autoimmune disorders PA,RA



B-Toxic multinodular goiter (2ry throtoxicosis): accounts for about 10% of patients of hyperthyroidism



occurs at an older age than Graves disease



C-Toxic adenoma: accounts for about 5% of patients of hyperthyroidism



The adenoma is usually solitary



The rest of thyroid is suppressed



D-other rare varieties: accounts for about 5% of patients of hyperthyroidism



Clinical Picture:clinical features of hyperthyroidism due to Graves disease and due to toxic ndular goiter show som differances



Clinical Picture of Graves disease: 1-moderate in size(not palpable),diffuse&smooth unless it arises in aperson with amultinodular goiter



2-abruit may be heard over the goiter in about 50% of cases due to vascularity



3-retrosternal compression : detected by : Dysphagia-Horseness of voice-Horneres syndrome-Dullness over upper sternum



Kocheres sign: striodor onpushing one lobe to the other side



Pembertones sign: cyanosis,engorged external jugular vein during raising the arm



Signs and Symptoms associated with over oroduction of thyroid hormone:



1-METABOLIC;



weight loss,increas heat production whic causes sweating,heat intolerance,increase thirst, lassitude and fatigability, chemical or overt diabetes



2-Skin and Hair



the skin is warm, vevety red, moist&palms of the hand may be erthyematous



pigmentation&pruritus,clubbing,nails grow away from beds



the hair is fine in texture with loss of its curl



pretibial edema



3-Cardiovascular systems:



tachycardia due to direct action of T3,T4&increase effect of catecholamines



palpitation&dyspnea(particularly in the elderly) which lead to AF, HF



increase SBP due to inrease COP



4-Cwnteral nervous systems:



nervousness,hyperexcitability, restlessness&tremers in the uong



chorea occur in children, apathy, psycgosis



5-GIT



sometimes present with diarrhea or vomiting &steatorrhea



6-Musculoskeltal system



proximal muscle weakness in 80% of ptient



bulbar weakness,periodic paralysis&myasthenia gravis rare



7- Eye signs



lid retraction, lid lag, proptosis(exophthalmos), periorbital edema,ophthalmoplegia



Investigations:



A-Hormonal assay



1-total thyroxin&TSH: elevated in most of cases



TSH can be detected by radioimmunoassy, immunoradiometric assay& immunochemiluminometric assy



2- Total T3: in some cases may be present



3-Free T3: it should measured if any abnormality of thyroid-binding globulin



4- thyrotrophin-releasing hormone(TRM) test: it can be carried out if the above results are equivocal



B-THYROID SCANNING: ARE USEFUL FOR IDENTIFYING SOLITARY TOXIC ADENOMAS AND THYROTOXICOSIS



1-99TCM pertechanetate is preferable to I31 since gives amuch lower dose of radiation



2- Iodine is preferable if retrosternal thyroid tissue is suspected



C-Biochemistry:



decrease cholesterol, increase Ca, increase Blood glucose







TREATMENT



1-physical&mental rest



2-sedation: valium tablets2-5mgonce/day before sleep



3-diet: good nutrition&well-balanced diet



4- B-blockers



5-anti-thyroid drugs



6-surgical trearment



7-radio-iodine therapy

from http://www.nmisr.com/vb/showthread.php?t=531417