Figge J, Leinung M, Goodman A D, Izquierdo R, Mydosh T, Gates S, Line B, Lee D W
Department of Medicine, Albany Medical College, NY 12208.
Am J Med. 1994 Mar;96(3):229-34. doi: 10.1016/0002-9343(94)90147-3.
To develop a strategy to identify cases of endogenous subclinical hyperthyroidism and free triiodothyronine (free T3) thyrotoxicosis in otherwise healthy ambulatory patients.
In a retrospective study we reviewed the records of ambulatory patients who had thyroid stimulating hormone (TSH) levels determined between October 1, 1991 and August 31, 1992. Each patient also had a simultaneous free thyroxine (free T4) measurement. Patients were excluded from consideration if they had active, concurrent non-thyroidal illness, psychiatric disease, known hypothalamic/pituitary lesions, were under treatment for hyper- or hypothyroidism, were on drugs known to affect TSH levels, or were pregnant. Patients without exclusions were diagnosed with free T3 toxicosis if they had: (1) a markedly subnormal TSH level (less than or equal to 0.1 mU/L), (2) a normal free T4, (3) a normal total T3, (4) evidence of a primary thyroid abnormality (e.g., autonomous function on a thyroid scan), and (5) an elevated free T3 level by tracer equilibrium dialysis. Patients meeting conditions 1-4, but with normal free T3 levels, were considered to have subclinical hyperthyroidism.
One thousand twenty-five patients had TSH and simultaneous free T4 determinations, and 148 of these had markedly subnormal TSH but normal free T4 levels. Three patients met the criteria for free T3 toxicosis and three had subclinical hyperthyroidism. All six patients had either multinodular glands or a single nodule on thyroid exam. Four patients were treated with radioactive iodine or surgery, resulting in reversal of the TSH suppression in three cases.
Apparently healthy ambulatory patients with subnormal TSH levels should be worked up with measurements of free T4 and total T3. If these are normal, a T3 level (by tracer equilibrium dialysis) be obtained to distinguish subclinical hyperthyroidism from overt free T3 toxicosis. A thyroid scan and radioiodine uptake measurement can be obtained to substantiate the diagnosis. Some patients with these conditions will benefit from treatment.
制定一种策略，以识别健康门诊患者中的内源性亚临床甲状腺功能亢进症和游离三碘甲状腺原氨酸（游离T3）甲状腺毒症病例。
在一项回顾性研究中，我们查阅了1991年10月1日至1992年8月31日期间测定促甲状腺激素（TSH）水平的门诊患者记录。每位患者同时还进行了游离甲状腺素（游离T4）测定。如果患者患有活动性、并发的非甲状腺疾病、精神疾病、已知的下丘脑/垂体病变、正在接受甲状腺功能亢进或减退治疗、正在服用已知会影响TSH水平的药物或怀孕，则将其排除在研究之外。未被排除的患者若具备以下条件则被诊断为游离T3毒症：（1）TSH水平明显低于正常（小于或等于0.1 mU/L）；（2）游离T4正常；（3）总T3正常；（4）有原发性甲状腺异常的证据（例如甲状腺扫描显示自主功能）；（5）通过示踪剂平衡透析显示游离T3水平升高。符合条件1至4但游离T3水平正常的患者被认为患有亚临床甲状腺功能亢进症。
1025例患者进行了TSH和同时的游离T4测定，其中148例TSH明显低于正常但游离T4水平正常。3例患者符合游离T3毒症标准，3例患有亚临床甲状腺功能亢进症。所有6例患者甲状腺检查均发现有多结节腺体或单个结节。4例患者接受了放射性碘或手术治疗，3例患者的TSH抑制得到逆转。
TSH水平低于正常的看似健康的门诊患者应进行游离T4和总T3测定。如果这些指标正常，则应测定T3水平（通过示踪剂平衡透析）以区分亚临床甲状腺功能亢进症和显性游离T3毒症。可进行甲状腺扫描和放射性碘摄取测量以证实诊断。一些患有这些病症的患者将从治疗中获益。
