LA CONSULTA SEMANAL

JUNIO 2000

CONSULTA:

Arch Intern Med 2000 Apr 24;160(8):1067-71 

Update on the management of hyperthyroidism and hypothyroidism. 

Woeber KA 

Department of Medicine, University of California, San Francisco, Mount Zion Medical Center, 94143-1640, USA. 

Clinical aspects, laboratory investigation, and treatment of hyperthyroidism and hypothyroidism are reviewed in light of recent information. Special circumstances, such as hyperthyroidism during pregnancy, Graves ophthalmopathy, iodine-induced hyperthyroidism, and subclinical hypothyroidism, are also 
considered. 

Publication Types: 

Review 

Review, tutorial 

Medicina (B Aires) 1999;59(6):698-704 

Management of overt and subclinical hypothyroidism. Factors influencing L-thyroxine dosage. 

Rezzonico JN, Pusiol E, Saravi FD, Rezzonico M, Bossa N 

Hospital Italiano, Mendoza, Argentina. 

With the aim of establishing optimal dosage schedules, 171 women with either overt (OH, n = 80) or subclinical (SCH, n = 91) hypothyroidism were assessed before and 6 months after starting L-thyroxine (LT4) replacement therapy. Each group was further classified into four subgroups according to post-therapy serum TSH level, as follows: A) complete suppression; B) partial suppression; C) normal range and D) above normal range (insufficient response). In all subgroups, LT4 doses were higher for OH than for SCH, whether expressed as total daily dose (micrograms) or as a function of either actual or ideal body weight (micrograms/kg BW). In OH, LT4 dose was higher for subgroups A or B as compared with either C or D. In SCH, subgroup A received a larger dose than the other subgroups. Post-treatment serum thyroxine levels showed the same pattern for both OH and SCH. Mean LT4 dose was similar in patients with high and normal antithyroid antibodies and in patients with goiter and in those without it. In goitrous patients thyroid volume decreased in subgroup B, particularly in those patients that had elevated antithyroid antibodies, but not in subgroup C. In OH patients a significant negative correlation was found between daily LT4 dose per kg actual BW and actual BW, especially in subgroup C for patients with a body mass index > 27 kg/cm2 (r = -0.90, p < 0.001). In subgroup C of the SCH group, a negative correlation between LT4 dose and age was noticed. Both in OH and in SCH, LT4 dose per kg actual BW required to obtain a serum TSH within the normal range was lower in women with a body mass index (BMI) > 27 kg/m2 than in those with a BMI < or = 27 kg/m2. LT4 doses for subgroup C did not differ from those needed in hypothyroid patients with previous Graves' disease, in either OH or SCH patients. 

Postgrad Med 2000 Jan;107(1):143-6, 149-52 [Texto completo] 

Disclosing subclinical thyroid disease. An approach to mild laboratory abnormalities and vague or absent symptoms. 

Smallridge RC 

Mayo Medical School, Jacksonville, Florida, USA. smallridge.robert@mayo.edu 

Patients with subclinical thyroid disease often have no apparent symptoms or only nonspecific complaints. However, increasing evidence that early disease is associated with behavioral, psychiatric, biochemical, and organ-specific abnormalities has led several specialty organizations to publish or modify position papers. Serum TSH testing is the most sensitive method of identifying early thyroid dysfunction. It should be considered in patients who have risk factors for mild thyroid failure, have symptoms that could be related to thyroid disease, or are taking exogenous thyroid hormone. T4 therapy should be strongly considered in patients with a TSH level of 10 mIU/L or more. If observation is elected in asymptomatic patients with lesser TSH elevation, periodic measurements are advised. In patients with TSH suppression who are taking thyroid hormone, the dose should be lowered. If the TSH level is decreased because of endogenous suppression and free-T4 and T3 levels are normal, options include observation and treatment with an antithyroid drug or thyroid ablation. Early therapy should be considered in older patients and those with heart disease or nodular thyroid disease. The goal of all treatment methods should be to keep the TSH level in the normal range. 

Rev Med Interne 1999;20 Suppl 1:16S-18S 

[Subclinical thyroid disorders: strategies]. 

[Article in French] 

Duprey J 

Unite d'endocrinologie-nutrition, Hopital Ambroise-Pare, Boulogne, France. 

Thyroid 1998 Sep;8(9):803-13 

Subclinical thyroid disease in the elderly. 

Samuels MH 

Division of Endocrinology, Diabetes, and Clinical Nutrition, Oregon Health  Sciences University, Portland 97201, USA. 

The development of sensitive assays for thyrotropin (TSH) has led to the discovery that many older patients have abnormal TSH levels without other alterations in serum thyroid hormone levels, conditions termed subclinical hypothyroidism (isolated elevation of TSH levels) and subclinical hyperthyroidism (isolated suppression of TSH levels). Subclinical hypothyroidism occurs in 5% to 10% of elderly subjects, and is especially prevalent in elderly women. Subclinical hyperthyroidism is less common, affecting less than 2% of the elderly population. The causes of subclinical thyroid disease in the elderly are similar to those of thyroid disease in the general population, although medications and iodine-containing compounds may play an increased role. Potential risks of subclinical hypothyroidism in the elderly include progression to overt hypothyroidism, cardiovascular effects, hyperlipidemia, and neurological and neuropsychiatric effects. Potential risks of subclinical hyperthyroidism in the elderly include progression to overt hyperthyroidism, cardiovascular effects (especially atrial fibrillation), and osteoporosis. Decisions to treat elderly subjects with subclinical thyroid disease should be based on a careful assessment of these risks in the individual patient. 

Publication Types: 

Review 

Review, tutorial 

Geriatrics 1998 Apr;53(4):32-8, 41 

Thyroid dysfunction: how to manage overt and subclinical disease in older patients. 

Wallace K, Hofmann MT 

Department of Medicine, Allegheny University Hospitals, Philadelphia, USA. 

Thyroid dysfunction is relatively common in older patients, but its clinical presentation varies. It may be obvious from the classic presenting symptoms, or it may be asymptomatic and discovered incidentally during routine testing. The clinical diagnosis of hypothyroidism and hyperthyroidism can be difficult in older patients, because many of the usual symptoms may be mistaken for the effects of aging or other medical conditions. Even so, these diseases in their overt forms are always significant and require treatment. On the other hand, subclinical hypo- and hyperthyroidism are often incidental biochemical abnormalities that may or may not require intervention. 

Publication Types: 

Review 

Review, tutorial 

Am Fam Physician 1998 Feb 15;57(4):776-80 [Texto completo] 

Subclinical hypothyroidism: deciding when to treat. 

Adlin V 

Temple University School of Medicine, Philadelphia, Pennsylvania, USA. 

While screening patients for thyroid disease, physicians often find increased thyrotropin-stimulating hormone (TSH) levels in patients whose free thyroxine (T4) levels are not below normal. This state, termed "subclinical hypothyroidism," is most commonly an early stage of hypothyroidism. Although the condition may resolve or remain unchanged, within a few years in some patients, overt hypothyroidism develops, with low free T4 levels as well as a raised TSH level. The likelihood that this will happen increases with greater TSH elevations and detectable antithyroid antibodies. Because patients with subclinical hypothyroidism sometimes have subtle hypothyroid symptoms and may have mild abnormalities of serum lipoproteins and cardiac function, patients with definite and persistent TSH elevation should be considered for thyroid treatment. Levothyroxine, in a dosage that maintains serum TSH levels within the normal range, is the preferred therapy in these patients. 

Publication Types: 

Review 

Review, tutorial 

Arch Intern Med 1997 May 26;157(10):1065-8 

Subclinical thyroid dysfunction. 

Woeber KA 

Department of Medicine, University of California, San Francisco-Mount Zion Medical Center, USA. 

Subclinical thyroid dysfunction may be defined as an abnormal serum thyrotropin concentration in an asymptomatic patient with a normal serum free thyroxine concentration. This article addresses the prevalence, natural history, and potential pathophysiological consequences of subclinical hypothyroidism and subclinical thyrotoxicosis. Subclinical hypothyroidism, which occurs in more than 10% of women older than 60 years, may be accompanied by an unfavorable serum lipid profile and may lower the threshold for the development of major depressive disorder. Subclinical thyrotoxicosis, which is most commonly due to thyrotropin-suppressive levothyroxine sodium therapy, may be associated with reduced bone mineral density in postmenopausal women and confers a 3-fold relative risk for the development of atrial fibrillation. While there are no outcome data to support therapeutic intervention in subclinical thyroid 
dysfunction, some screening and management recommendations are offered. 

Publication Types: 

Review 

Review, tutorial 

BMJ 1997 Apr 19;314(7088):1175-8 [Texto completo] 

Hypothyroidism: screening and subclinical disease. 

Weetman AP 

Department of Medicine, University of Sheffield Clinical Sciences Centre, Northern General Hospital. 

Publication Types: 

Review 

Review, tutorial 

Comments: 

Comment in: BMJ 1997 Aug 23;315(7106):491 

Postgrad Med J 1996 Mar;72(845):141-6 

Subclinical thyroid disease. 

Elte JW, Mudde AH, Nieuwenhuijzen Kruseman AC 

Department of Internal Medicine, Sint Franciscus Gasthuis, Rotterdam, Netherlands. 

Thyroid disease can roughly be divided into functional and anatomical disorders. Subclinical disease is by definition not accompanied by symptoms or signs and usually goes unrecognized for the bearer (and the observer). In this communication an overview will be given of existing literature and some own results concerning subclinical hypothyroidism, subclinical thyrotoxicosis and thyroid incidentalomas. Apart from definitions, data on prevalence, clinical effects, prognostic significance and the need for and response to therapy will be discussed. 

Publication Types: 

Review 

Review, tutorial