12 甲状腺功能亢进症与甲状腺功能减退症1

null Hypothyroidism (甲状腺功能减退症) Hypothyroidism (甲状腺功能减退症) Guo Qinglian Department of Clinical Laboratory Science WuHan University , School of Medicine A patient before and after successful treatment of primary hypothyroidism. A patient before and after successful treatment of primary hypothyroidism. NEW WORDSNEW WORDSHypothyroidism 甲减 Lethargy 昏睡，无力 Coarsen 使粗糙 Hoarseness 嘶哑 Tendon reflexes 腱反射 Anaemia 贫血 Dementia 痴呆 Constipation 便秘 NEW WORDSNEW WORDSBradycardia 心搏缓慢 Carpal tunnel syndrome 腕管综合征 Subfertility 低生育力 Galactorrhoea 乳溢 Lithium carbonate 碳酸锂 Panhypopituitarism 全垂体功能减退症 Hypothalamic-pituitary-thyroid axis 下丘脑－垂体－甲状腺轴NEW WORDSNEW WORDSAdequacy 充分，恰当 Profoundly 极度地，深深地 Cretinism 呆小症 Neonatal 初生儿的 Diurnal 每日的，白天的 Nadir 最低点，最坏时 Transthyretin 转甲状腺素 Pancreatitis 胰腺炎HYPOTHYROIDISMHYPOTHYROIDISMCLINICAL FEATURES CAUSES DIAGNOSIS TREATMENT SCREENING FOR NEONATAL HYPOTHYROIDISM NON-THYROIDAL ILLNESS CLINICAL FEATURES（1）CLINICAL FEATURES（1） Lethargy and tiredness: be liable to be tired Cold intolerance: slow rate of metabolism Weight gain: mucous dropsy (粘液性水肿) Dryness and coarsening of skin and hair：endocrinal disorders(内分泌紊乱) Hoarseness: pressed recurrent laryngeal（喉返神经） Slow relaxation of muscles and tendon reflexes: 肌肉舒张和腱反射迟缓// muscle constriction relaxation period prolongs clench one’s fist (握拳) CLINICAL FEATURES（2）CLINICAL FEATURES（2）Anaemia: decreased amounts of RBC and Hb Dementia(痴呆): mental and nervous system,dull witted Constipation: damage of digestion system, less movement of large intestine Bradycardia(心搏缓慢): cardiovascular system, thyroxine maintains the normal heartbeat Muscle stiffness（肌肉僵硬） Carpal tunnel syndrome（腕管综合征）: anatomic construction (解剖学构造)，median nerve(正中神经) mucous dropsy Subfertility and galactorrhoea: endocrine systemCOMMON CAUSESCOMMON CAUSESOver 90% of cases of hypothyroidism occur as a consequence of: Autoimmune destruction of the thyroid gland（primary hypothyroidism ） Excessive radioiodine or surgical treatment of hyperthyroidism ( secondary hypothyroidism) RARER CAUSESRARER CAUSES Transient (短暂的)hypothyroidism due to treatment with drugs such as lithium carbonate TSH deficiency which may be a component of panhypopituitarism（全垂体功能减退症） Congenital defects such as blocks in the biosynthesis of T4 and T3,or end-organ resistance to their action Severe iodine deficiency DIAGNOSISDIAGNOSISDeficiency of thyroid hormones Primary hypothyroidism :TSH concentration elevates Secondary hypothyroidism:less common 1 hypothalamic damage (下丘脑损伤) 2 pituitary damage（垂体损伤） Investigation of pituitary function and TRH test：other clinical features except those of hypothyroidism nullThe damage location of hypothyroidismFunction of TRHFunction of TRHTRH can promptly stimulate the pituitary to synthesize and secrete the stored TSH in pituitary.Damaged location of hypothyroidismDamaged location of hypothyroidismPrimary: thyroid /TRH test :+ Secondary: pituitary/TRH test :- Secondary: hypothalamic /TRH test :delayed +Strategy for the biochemical investigation of suspected hypothyroidismStrategy for the biochemical investigation of suspected hypothyroidismTREATMENTTREATMENTReplacement therapy with T4 Monitor TSH concentration Figure 3 shows the need for careful monitoring of treatment.Biochemical monitoring of a patient during treatment for thyroid disease.(1)Biochemical monitoring of a patient during treatment for thyroid disease.(1)Biochemical monitoring of a patient during treatment for thyroid disease.(2)Biochemical monitoring of a patient during treatment for thyroid disease.(2)131I therapyThyroxine treatmentCompliance?Biochemical monitoring of a patient during treatment for thyroid disease.(1)Biochemical monitoring of a patient during treatment for thyroid disease.(1) 131I therapyThyroxine treatmentCompliance?SCREENING FOR NEONATAL HYPOGHYROIDISMSCREENING FOR NEONATAL HYPOGHYROIDISMCongenital hypothyroid disorders Replacement thyroid hormone should be given and normal development can occur. Cretinism TSH screening test: elevated TSH,primary neonatal hypothyroidismNON-THYROIDAL ILLNESSNON-THYROIDAL ILLNESSHypothalamic-pituitary-thyroid axis Diurnal rhythm In systemic illness Normal regulation is disturbed. T4,rT3 T4,T3 TSHA typical non-thyroidal illness patternA typical non-thyroidal illness patternT4 (nmol/l) 44 T3(nmol/l) 0.6 TSH(mU/l) 5.1When should thyroid function tests be performed?When should thyroid function tests be performed?Until after the acute phase has passed. Not during an acute illness unless there are good clinical grounds. SUMMARY1 : HypothyroidismSUMMARY1 : HypothyroidismHypothyroidism is common and is most often due to the destruction of the thyroid gland by autoimmune disease,surgery or radioiodine therapy. Primary hypothyroidism is confirmed by an elevated TSH in a serum specimen. A TRH test is used to investigate secondary hypothyroidism due to pituitary or hypothalamic causes. SUMMARY 2: Hypothyroidism SUMMARY 2: HypothyroidismHypothyroidism is managed by thyroxine replacement,and therapy is monitored by measuring the serum TSH concentration. Patients with severe non-thyroidal illness may show apparent abnormalities in thyroidal hormone results,known as the ‘low T3 syndrome ’ or non-thyroidal illness pattern of results. CLINICAL NOTECLINICAL NOTEPatients with severe hypothyroidism should be initially treated with very small doses of thyroxine –25 micrograms daily.At higher doses,patients are at an increased risk of developing angina or suffering a myocardial infarction. The dose should be slowly increased over a number of months until the patient is rendered euthyroid.CASE HISTORY34CASE HISTORY34Investigation of a 63-year-old woman with effort angina revealed a serum TSH of 96 mU/l and a srrum T4 of 23 nmol/l .an ECG showed some evidence of ischaemia but was not diagnostic of myocardial infarction. Further biochemical investigation revealed: Cholesterol(mmol/l) 9.3 Creatine kinase(U/l) 290 AST(U/l) 35 Explanation for case history 34Explanation for case history 34As the TSH is approximately 20 times the upper limit of the reference range and the serum T4 is significantly decreased,this woman has severe hypothyroidism.skeletal and cardiac muslces are involved in the hypothyroid process,causing the release of creatine kinase into the circulation.this,combined with a decrease in the catabolic rate of creatine kinase,will be sufficient to cause the creatine kinase to increase to the levels observed in this case . nullThe aspartate aminotransferase is at the upper end of the reference range and this will fall along with the creatine kinase and cholesterol after a few weeks treatment with thyroxine.in view of the evidence of myocardial ischaemia it is prudent to proceed cautiously in this case with a low dose of thyroxine and gradually increase it in a step-wise manner.