亚临床甲状腺功能减退对心血管系统的影响

亚临床甲状腺功能减退症（亚甲减）诊断主要依赖于实验室的生化结果,是指以临床无症状或症状轻微、患者血清中促甲状腺激素（TSH）水平升高而游离甲状腺素（FT4）水平正常为基本特征的临床状态。我国人口普查显示[1],随着血清促甲状腺激素放射免疫测定TSH技术的不断改进,亚临床甲减的检出率随年龄增加呈现明显上升趋势,一般在1%～6%,老年人与女性多见。     

亚临床甲状腺功能减退与冠心病及其危险因素之间关系的研究进展

亚临床甲状腺功能减退症（subclinical hypothyroidism）是指血清促甲状腺激素（thyroid-stimulating hormone,TSH）水平升高,血清游离甲状腺素（free thyroxine,FT4）和游离三碘甲腺原氨酸（free triiodothyronine,FT3）水平正常,患者没有或几乎没有甲状腺功能减退的相应症状和体征的甲状腺疾病,简称亚临床甲减[1],好发于老年及女性[2,3],临床症状不典型或缺乏,诊断有赖于实验室检查.     

亚临床甲状腺功能减退症

亚临床甲状腺功能减退症（简称亚临床甲减，subclinical hypothyroidism），以往也称轻度甲状腺功能减退症或临床前甲状腺功能减退症。一般是指血清游离甲状腺素（FT4）在正常范围，而血清促甲状腺激素（thyroid—stimulating hormone，TSH）水平升高，患者没有明显的甲状腺功能减退（甲减）的临床症状和体征，是甲状腺功能减退症的早期阶段，诊断必须依靠血清学检查。国内外对亚临床甲减的治疗和处理尚无统一的意见和观点，本文就有关亚临床甲减研究的现状进行复习，以供临床诊疗参考。     

轻微甲状腺功能减退

轻微甲状腺功能减退（甲减）的特点是促甲状腺素（TSH）升高，游离甲状腺素（FT4）正常，诊断轻微甲减需要排除其他引起TSH升高的疾患和药物，多数临床观察提示，对轻微甲减进行替代治疗能够降低血脂，缓解躯体和神经精神症状，还可以预防明显甲减的出现。     

妊娠期甲状腺功能减退症的诊治进展

妊娠期甲状腺功能减退(简称甲减)包括临床甲减(overt hypothyroidism)和亚临床甲减(subclinical hypothyroidism,SCH)。因其对妊娠妇女及新生儿的影响而日益受到临床重视。1妊娠期甲状腺功能减退的流行病学和诊断1.1妊娠期甲状腺功能减退的诊断妊娠期甲减要依据妊娠期特异性的促甲状腺激素(TSH)、游离甲状腺素(FT4)或总甲状腺素(TT4)参考范围确定诊断[1-2]。上述诊断标准精准,但是受到可行性的限制。2017年美国甲状腺学会(ATA)修订的妊娠和产后甲状腺疾病诊治指南推荐,如果得不到妊娠期特异性TSH参考范围,4.0 mU/L可以作为妊娠期诊断甲减的TSH切点值[1]。     

亚临床甲状腺功能减退症的治疗

亚临床甲状腺功能减退症(亚甲减)以基线促甲状腺激素(TSH)水平升高和血清游离甲状腺素水平正常为特征,亚临床或隐匿性甲减常常反映甲状腺激素分泌的缺陷。甲状腺破坏性治疗(甲状腺次全切除术或放射碘治疗)或颈部广泛放射治疗后的亚临床甲减应开始使用左甲状腺素(L-T4)治疗;妊娠和哺乳期的亚甲减也应使用L-T4治疗。其他早期使用甲状腺激素替代治疗的指征包括TSH水平升高以及抗甲状腺过氧化物酶(TPO)抗体阳性,因为这些患者的亚甲减很可能进展为临床甲减。提示存在甲状腺激素相对缺乏的临床体征和症状的所有患者都应该试用L-T4替代治疗,这些患者包括亚临床甲减并发不孕、抑郁症或其他神经心理异常。单纯血清TSH水平升高或高胆固醇血症不是L-T4治疗的适应症,除非患者有甲状腺疾病史以及提示甲状腺激素缺乏的临床症状。     

亚临床甲状腺功能减退症的治疗

亚临床甲状腺功能减退症(亚甲减)以基线促甲状腺激素(TSH)水平升高和血清游离甲状腺素水平正常为特征，亚临床或隐匿性甲减常常反映甲状腺激素分泌的缺陷。甲状腺破坏性治疗(甲状腺次全切除术或放射碘治疗)或颈部广泛放射治疗后的亚临床甲减应开始使用左甲状腺素(L-T4)治疗；妊娠和哺乳期的亚甲减也应使用L-T4治疗。其他早期使用甲状腺激素替代治疗的指征包括TSH水平升高以及抗甲状腺过氧化物酶(TPO)抗体阳性，因为这些患者的亚甲减很可能进展为临床甲减。提示存在甲状腺激素相对缺乏的I临床体征和症状的所有患者都应该试用L-T4替代治疗，这些患者包括亚临床甲减并发不孕、抑郁症或其他神经心理异常。单纯血清TSH水平升高或高胆固醇血症不是L-T4治疗的适应症，除非患者有甲状腺疾病史以及提示甲状腺激素缺乏的临床症状。     

亚临床甲状腺功能减退与动脉粥样硬化

亚临床甲状腺功能减退(SCH)又称轻度甲状腺功能衰竭,主要诊断依据是血清促甲状腺激素(TSH)增高,而血清游离甲状腺素(FT4)正常,同时应排除以下引起TSH增高的情况:甲状腺功能减低患者左旋甲状腺素(L-T4)替代剂量不足,严重疾患恢复期患者暂时TSH升高,破坏性甲状腺炎恢复期,未经治疗的原发肾上腺皮质功能不全,注射TSH的患者.     

轻微甲状腺功能减退

轻微甲状腺功能减退(甲减)的特点是促甲状腺素(TSH)升高,游离甲状腺素(FT4)正常。诊断轻微甲减需要排除其他引起TSH升高的疾患和药物。多数临床观察提示,对轻微甲减进行替代治疗能够降低血脂、缓解躯体和神经精神症状,还可以预防明显甲减的出现。     

老年亚临床甲状腺功能减退症的诊治特点

亚临床甲状腺功能减退症(甲减)是老年人群常见的疾病.诊断标准为血清促甲状腺激素(TSH)水平升高伴游离甲状腺素(FT4)水平正常.TSH正常值上限随年龄增长而升高,但临床上尚缺乏根据年龄调整的TSH正常值范围.老年亚临床甲减与老龄化症状极为相似,易于被忽视.持续性亚临床甲减可对老年人心血管、认知、肌肉骨骼等方面带来负面影响,而TSH小于10 mIU/L的轻度亚临床甲减可能与75岁以上老人长寿相关.老年亚临床甲减的治疗应该强调个体化,TSH大于10 mIU/L或存在其他危险因素时,应给予左旋甲状腺素(L-T4)治疗.初始剂量推荐25～75μg/d,每4～6周根据TSH水平和临床表现调整剂量,至维持剂量后每6～12个月监测甲状腺功能.     

Hypothyreose

An autoimmune thyroiditis represents the main reason of hypothyroidism, defined as a lack of thyroid hormone. This autoimmune process results in destruction of functioning thyroid follicles. While subclinical or latent hypothyroidism is defined on the basis of laboratory values (an elevation of TSH with normal peripheral hormone levels), the typical signs and symptoms are associated with hypothyroidism. In about 80% of cases antibodies against thyroid peroxidase can be measured, but only in about 40–50% of cases antibodies against thyroglobulin are detectable. If hypothyrodism has been diagnosed, substitution with levothyroxine should be initiated, with the therapeutic goal to decrease TSH level to the lower normal range. In cases of subclinical hypothyroidism, levothyroxine medication should be started in patients with a high TSH value, positive antibodies and/or the typical ultrasound of autoimmune thyroiditis. However, substitution with levothyroxine in any case of elevated TSH values should be avoided.     

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??Abstract??Hypothyroidism often results in the elevation of serum total cholesterol??low-density lipoprotein cholesterol and triglyceride??and is one of common causes for secondary dyslipidemia.This association is mainly attributed to the reduction of circulating thyroid hormones.Recently??results from epidemiological studies showed that subclinical hypothyroidism??defined as a serum thyroid stimulating hormone (TSH) concentration above the normal range with normal serum FT??4 and FT??3 concentration??was closely associated with dyslipidemia.Experimental studies confirmed the role of TSH per se in lipid metabolism.For overt hypothyroidism??replacement therapy with thyroid hormones can correct dyslipidemia.However??the beneficial effects of replacement therapy on dyslipidemia in subclinical hypothyroidism were not established by clinical trials??which warrants further intervention studies to answer it.     

Hypothyroidism in patients with autoimmune pancreatitis

AIM To examine thyroid function and clinical features of hypothyroidism in autoimmune pancreatitis(AIP) patients.METHODS We examined thyroid function in 77 patients with type 1 AIP(50 males, 27 females; median age 68 years, range 33-85) diagnosed according to the Japanese diagnostic criteria for AIP 2011. We compared clinical and serological findings between patients with and without various categories of hypothyroidism. The change in hypothyroidism after steroid therapy was also examined. RESULTS Eight patients(10%) had hypothyroidism of 6 patients had subclinical hypothyroidism with a normal serum free thyroxine(FT4) and high thyroid stimulating hormone(TSH) level, and 2 patients had central hypothyroidism with low serum free triiodothyronine(FT3), FT4 and TSH levels. A significant goiter of the thyroid was not observed in any patient. There were no significant differences in age; male to female ratio; serum concentrations of IgG and IgG 4-related disease(IgG4-RD); presence of antithyroglobulin antibody, antinuclear antigen or rheumatoid factor; or presence of extrapancreatic lesions between the 6 patients with subclinical hypothyroidism and patients with euthyroidism. After steroid therapy, both subclinical and central hypothyroidism improved with improvement of the AIP.CONCLUSION Hypothyroidism was observed in 8(10%) of 77 AIP patients and was subclinical in 6 patients and central in 2 patients. Further studies are necessary to clarify whether this subclinical hypothyroidism is another manifestation of IgG4-RD.     

左旋甲状腺素治疗妊娠期亚临床甲减妇女对后代神经智力发育影响的前瞻性研究

目的 通过前瞻性观察妊娠期亚临床甲状腺功能减退(甲减)妇女左旋甲状腺素(L-T4)治疗后甲状腺功能指标的动态变化和后代神经智力的发育情况,探讨L-T4对妊娠期亚临床甲减妇女后代神经智力发育的影响.方法17例亚临床甲减孕妇未接受治疗(SCH组),23例亚临床甲减孕妇接受L-T4治疗(SCH+LT4组),24例正常孕妇(C组)作为对照组.3组孕妇分别在妊娠12周(G12)、16周(G16)、20周(G20)、24周(G24)、28周(G28)、32周(G32)和(或)36周(G36)接受随访检查,检测血清TSH、TT4、FT4、TT3、FT3、甲状腺过氧化物酶抗体(TPOAb)和甲状腺球蛋白抗体(TgAb).应用Bayley量表对所有孕妇的后代在14～30月龄检测智力和运动评分.结果SCH组、SCH+LT4组和C组孕妇后代的智力发育指数(MDI)分别为115.12分、118.56分和117.63分;运动发育指数(PDI)分别为115.47分、120.65分和117.50分.与其他两组比较,SCH+LT4组MDI和PDI评分均较高,SCH组MDI和PDI评分均较低,但3组间比较没有统计学差异.SCH组孕妇的血清TSH在妊娠过程中始终保持在2.0 mIU/L以上,各时点都明显高于C组(均P＜0.05);血清TT4和FT4水平除G28和G32外其他时点均略低于同时点C组水平.SCH+LT4组孕妇基础血清TSH水平明显高于其他两组(均P＜0.01),血清TT4和FT4水平则低于其他两组;在接受L-T4治疗后血清TSH水平明显下降,自G12至孕末期始终与C组水平相当,且低于同时点SCH组孕妇的水平;血清TT4和FT4水平则明显升高至与对照组相当的水平.结论L-T4的及时治疗能够维持妊娠早期亚临床甲减患者妊娠全程血清TSH在正常水平,这很可能会避免后代智力和运动能力发育水平的下降.     

亚临床甲状腺功能减退症患者及甲状腺功能正常者甲状腺功能与血糖水平的关系

目的研究亚临床甲状腺功能减退症患者及甲状腺功能正常者甲状腺功能与血糖的关系。方法采用整群抽样法于2007年至2010年从沈阳市城市成年居民中招募2751名研究对象,行问卷调查,测量血压、身高、体重、腰围、促甲状腺激素、游离三碘甲状腺原氨酸、游离甲状腺素、空腹血糖、口服葡萄糖耐量试验2h血糖、甘油三酯、总胆固醇和高密度脂蛋白胆固醇。将受试者分为亚临床甲状腺功能减退症组（n=193）及甲状腺功能正常组（n=2146）,甲状腺功能正常组又进一步分为促甲状腺激素低水平组（n=352,促甲状腺激素／〉0．3-〈1．0mU／L）、促甲状腺激素中水平组（n=916,促甲状腺激素≥1．0-≤1．9mU／L）、促甲状腺激素高水平组（n=944,促甲状腺激素1．9〈-≤4．8mU／L）。受试者根据血糖水平进一步分为糖耐量正常组、糖调节异常组、糖尿病组,分析甲状腺功能指标与血糖的关系。采用t检验及方差分析进行数据统计。结果亚临床甲状腺功能减退症组口服葡萄糖耐量试验2h血糖明显高于甲状腺功能正常组[（8．34-4．4）vs（7．74-4．2）mmol／L,t=一2．163,P〈0．05],2组糖调节异常及糖尿病的患病率差异无统计学意义。糖尿病组游离甲状腺素水平高于糖调节异常组和糖耐量正常组[分别为（16．8±2．1）、（16．3±2．1）、（16．2±1．9μmol／L,F=10．515,P〈0．01],女性中糖尿病组[15．3％（26／188）]及糖调节异常组[15．0％（34／227）]亚临床甲状腺功能减退症的患病率明显高于糖耐量正常组[9．5％（86／903）]（）（2值分别为7．165、5．685,均P〈0．05）,女性亚临床甲状腺功能减退症的患病率明显高于男性[11．1％（146／1318）VS4．6％（47／1027）,x2=31．852,P〈0．01]。多元线性回归分析显示,校正体质指数、腰围、血压、血脂后,总体受试者空腹血糖与游离甲状腺素呈正相关（β=2．748,P〈0．01）,男性受试者空腹血糖与游离甲状腺素亦呈正相关（口=2．346,P〈0．01）,女性受试者口服葡萄糖耐量试验2h血糖与游离甲状腺素呈正相关（／3=2．748,P〈0．01）。在正常范围内,游离甲状腺素水平越高,糖尿病的患病危险越大[总体：比值比（OR）=1．142,95％可信区间（cl）1．064-1．225,P〈0．01;女性：OR=1．147,95％C11．024-1．284,P〈0．05：男性：OR：1．142,95％C11．035-1．261,P〈0．01]。促甲状腺激素及游离三碘甲状腺原氨酸与糖尿病无关。结论女性糖调节异常和糖尿病患者亚临床甲状腺功能减退症的患病率增高;游离甲状腺素与血糖水平呈正相关,游离甲状腺素越高,糖尿病的患病风险越大。     

The incidence of thyroid function abnormalities in patients attending an outpatient lipid clinic.

Thyroid disorders are known to influence lipoprotein metabolism. In the current study we examined the incidence of thyroid function abnormalities in patients attending our outpatient lipid clinic. During the last 2 years, 248 patients were admitted to our lipid clinic for the diagnosis and management of dyslipidemia. In all cases, a detailed medical history was obtained and a thorough physical examination was performed with emphasis on the presence of symptoms/signs indicative of underlying thyroid diseases. In addition to lipid parameters, thyrotropin (TSH) and free thyroxine (FT4) levels were measured in a fasting blood sample. Seven female asymptomatic patients (2.8%) had frank biochemical hypothyroidism, and 11 patients (9 female, 2 male) (4.4%) had subclinical hypothyroidism with TSH levels between 5.8-19 mU/L. After restoration of a euthyroid state with levothyroxine therapy, no significant changes in serum lipid parameters were observed in the whole group of patients with subclinical hypothyroidism. However, in 4 patients with TSH levels >12 mU/L relatively small doses of levothyroxine (75 microg/day) were followed by a significant improvement of serum lipid profile. Interestingly, 3 patients exhibited clinical or subclinical hyperthyroidism that influenced serum lipid parameters as well as the effectiveness of hypolipidemic treatment. It is concluded that thyroid function abnormalities are relatively common in dyslipidemic patients attending a lipid clinic and could significantly affect the patients' lipid profile as well as the patients' management.     

Prevalence of thyroid dysfunction in Thai HIV-infected patients

Increasing prevalence of thyroid function abnormality has been reported in HIV-infected patients. We aim to evaluate the prevalence and assess risk factors of thyroid dysfunction in Thai HIV-infected patients. A cross-sectional study was conducted. Serum thyroid hormone concentrations (FT4, FT3, and TSH) and thyroid autoantibodies (TgAb and TPOAb) were measured by electrochemiluminescence immunoassay. A total of 200 HIV-infected outpatients were included. Ninety-seven patients (48.5%) were men (mean age of 36.3 +/- 8.3 years). Duration of HIV infection was 49.6 +/- 35.1 months and 53% had previous opportunistic infections (OI). Mean CD4 cell count was 340.6 +/- 173.1 cells/mm(3). Of these, 167 patients (83.5%) received antiretroviral therapy (ARV). Abnormal thyroid function test was detected in 32 patients (16%). Twenty-seven patients (13.5%) had decreased thyroid function (primary hypothyroidism 3, subclinical hypothyroidism 12, and low FT4 with low or normal TSH 12) whereas 5 patients had increased thyroid function (overt hyperthyroidism 1, subclinical hyperthyroidism 1, and isolated high FT3 3). None had clinical features of thyroid hormone dysfunction. Thirteen patients (6.5%) had thyroid antibody positive. Patients who received ARV had higher mean FT3 levels than those who were na?ve to ARV (p = 0.017). History of previous OI was found to be an independently significant risk factor for decreased thyroid function with the odds ratio of 3.28 (95% CI =1.183-9.099; p = 0.022). Hypothyroidism was common among Thai HIV-infected patients, especially in those who had history of previous OI. It is therefore suggested that screening and/or monitoring of thyroid hormone in HIV-infected patients should be considered.     

High prevalence of thyroid abnormalities in a Chilean psychiatric outpatient population

The aim of the present study was to establish the prevalence of thyroid disturbances in patients consulting for panic and mood disorders. These data may be relevant because thyroid functional alterations affect the success of treatment in these pathologies. We studied prospectively 268 psychiatric outpatients (204 females and 64 males) diagnosed by DSM-IV criteria. We excluded patients with addictive disorders and major medical disease. We measured TSH, Free T4 (FT4) and antimicrosomal antibodies (AMA). We diagnosed classical hypothyroidism when the TSH value was >10 microUI/ml (NV=0.25-4.3) and subclinical hypothyroidism when the TSH value was between 5-10 microUI/ml. Hyperthyroidism was diagnosed when FT4 >1.4 (NV=0.8-1.4), the TSH suppressed and the radioiodine uptake >20% (NV=5-15). Positive antimicrosomal antibodies (AMA) titres were >1:100 dilution. Hypothyroidism was diagnosed in 26/268 patients (9.7%); 10 cases corresponded to the classical form (38.5%) and 16 cases to the subclinical form (61.5%). Hyperthyroidism was found in 6/268 patients (2.2%). Normal thyroid function with positive AMA was found in 28/268 patients (10.4%). Hypothyroidism was more common in patients with mood disorders, and hyperthyroidism in patients with panic disorders. Patients with panic disorder had significant higher levels of FT4. The prevalence of positive AMA, hypothyroidism and hyperthyroidism was higher in women than men. We found a high frequency of thyroid abnormalities in a psychiatric outpatient population. These data suggests that routine evaluation of thyroid function should be considered in patients consulting for mood and panic disorders.     

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??Abstract??Subclinical hypothyroidism is a common endocrine and metabolic disease??which characterized by elevated level of thyroid-stimulating hormone (TSH) with normal free thyroxine (FT??4) level.The incidence rate is 4% to 10% of the world’s population??and It is more common in women.The causes of subclinical hypothyroidism are much complicated.They could generally be divided into two categories??abnormal structure and/or dysfunction of thyroid gland itself or non-thyroid organs.Serum TSH is the most important mark to screen and diagnose the disease.80% patients are with positive anti-thyroid antibodies.Since subclinical hypothyroidism has certain clinical harm??it is recommended a screening in high-risk groups and a replacement therapy to patients with serum TSH>10 mU/L.Treatments should follow a principle of stratification and individuation.     

Serum TSH concentration as an aid to monitoring compliance with thyroid hormone therapy in hypothyroidism

To monitor the compliance of patients taking levothyroxine as replacement therapy for primary hypothyroidism, the authors measured serum thyroid-stimulating hormone (TSH), free thyroxine index (FT4I), and free triiodothyronine index (FT3I) in patients attending the endocrine clinic. During a 6-month period, there were 159 visits by 132 patients with treated hypothyroidism. Five of the 132 patients had TSH levels greater than 12 microU/ml (normal, 0.3-5.7 microU/ml), with FT3I greater than 85 (normal, 70-160) and FT4I greater than 7 (normal, 4.2-11). Four others had TSH greater than 6 microU/ml with normal FT3I and normal FT4I. These nine patients had normal thyroid tests documented on replacement therapy in the past. Five of the nine admitted to discontinuing their medicine for more than 1 week or taking it erratically. Two untreated hypothyroid patients had daily thyroid function tests after they were started on full replacement doses of levothyroxine. Both achieved FT4I greater than 4.2 by day 8 and FT3I greater than or equal to 70 by day 18, but serum TSH concentration did not fall consistently below 20 microU/ml until day 23 in one patient and day 21 in the other and did not fall to the normal range by discharge at day 37 in one patient or day 42 in the other. Thus, although treatment with levothyroxine will normalize serum T4 and T3 concentrations within 3 weeks, normalization of serum TSH may take several more weeks. This prospective study in a large out-patient clinic shows that 4% of patients with treated primary hypothyroidism may have elevation of serum TSH to more than twice the upper limit of normal, while serum T4 and T3 are clearly normal.(ABSTRACT TRUNCATED AT 250 WORDS)