Diagnosis of hyperthyroidism

Diagnosis of hyperthyroidismAuthorDouglas S Ross, MDSection EditorDavid S Cooper, MDDeputy EditorJean E Mulder, MDDisclosuresAll topics are updated as new evidence becomes available and our peer review process is complete.Literature review current through: Oct 2012. | This topic last updated: May 4, 2012. INTRODUCTIONThe diagnosis of hyperthyroidism is usually evident in patients with unequivocal clinical and biochemical manifestations of the disease. Other patients have fewer and less obvious clinical signs, but definite biochemical hyperthyroidism. Still others have little or no clinical hyperthyroidism and their only biochemical abnormality is a low serum thyrotropin (TSH) concentration, a disorder called subclinical hyperthyroidism.Following a brief discussion of the clinical manifestations of hyperthyroidism, the diagnosis and evaluation of patients with hyperthyroidism will be presented here. An overview of the clinical manifestations of hyperthyroidism, disorders that cause hyperthyroidism, the diagnosis of hyperthyroidism during pregnancy, and subclinical hyperthyroidism are discussed in detail separately. (See "Overview of the clinical manifestations of hyperthyroidism in adults"and "Disorders that cause hyperthyroidism"and "Hyperthyroidism during pregnancy: Clinical manifestations, diagnosis, and causes"and "Subclinical hyperthyroidism".)CLINICAL MANIFESTATIONSSymptomsOvert hyperthyroidismMost patients with overt hyperthyroidism have a dramatic constellation of symptoms. These symptoms characteristically include anxiety, emotional lability, weakness, tremor, palpitations, heat intolerance, increased perspiration, and weight loss despite a normal or increased appetite [1,2].While the combination of weight loss and increased appetite is a characteristic finding, some patients gain weight, in particular younger patients, due to excessive appetite stimulation [1]. Other symptoms that may be present include hyperdefecation (not diarrhea), urinary frequency, oligomenorrhea or amenorrhea in women, and gynecomastia and erectile dysfunction in men [3,4]. (See "Overview of the clinical manifestations of hyperthyroidism in adults".)Milder symptomsPatients with mild hyperthyroidism and older patients often have symptoms that are referable to one or only a few organ systems [5]. Isolated symptoms and signs that should lead to evaluation for hyperthyroidism in patients of any age include unexplained weight loss, new onset atrial fibrillation, myopathy, menstrual disorders, and gynecomastia.Other conditions that should suggest the possibility of hyperthyroidism include osteoporosis, hypercalcemia, heart failure, premature atrial contractions, shortness of breath, and a deterioration in glycemic control in patients with previously diagnosed diabetes. (See "Overview of the clinical manifestations of hyperthyroidism in adults".)Older patientsIn older patients, cardiopulmonary symptoms such as tachycardia (or atrial fibrillation), dyspnea on exertion, and edema may predominate [1,6-8]. They also tend to have more weight loss and less of an increase in appetite [1]. The most dramatic example of this phenomenon is "apathetic thyrotoxicosis," in which elderly patients have no symptoms except for weakness and asthenia. (See "Overview of the clinical manifestations of hyperthyroidism in adults", section on 'Geriatric hyperthyroidism'.)Subclinical hyperthyroidism, defined as normal serum levels of free T4 and T3 with a suppressed TSH level, is associated with a threefold increase in the risk of atrial fibrillation in older persons (figure 1). (See "Epidemiology of and risk factors for atrial fibrillation"and "Subclinical hyperthyroidism", section on 'Atrial fibrillation'.)Physical examinationThe physical examination may be notable for hyperactivity and rapid speech. Many patients have stare (lid retraction) and lid lag, representing sympathetic hyperactivity. The skin is typically warm and moist, and the hair may be thin and fine. Tachycardia is common, the pulse is irregularly irregular in patients with atrial fibrillation, systolic hypertension may be present, and the precordium is often hyperdynamic [6]. Tremor, proximal muscle weakness, and hyperreflexia are other frequent findings.Exophthalmos, periorbital and conjunctival edema, limitation of eye movement, and infiltrative dermopathy (pretibial myxedema) occur only in patients with Graves' disease. (See "Pathogenesis and clinical features of Graves' ophthalmopathy (orbitopathy)"and "Pretibial myxedema in autoimmune thyroid disease".)Thyroid sizeThe presence and size of a goiter depends upon the cause of the hyperthyroidism. (See "Disorders that cause hyperthyroidism".) Thyroid enlargement ranges from minimal to massive in patients with Graves' disease or toxic multinodular goiter. A nonpalpable thyroid occurs commonly in elderly patients with Graves' disease. (See "Disorders that cause hyperthyroidism", section on 'Toxic adenoma and toxic multinodular goiter'and "Overview of the clinical manifestations of hyperthyroidism in adults", section on 'Geriatric hyperthyroidism'.) Patients with painless (silent or lymphocytic) thyroiditis may have no, minimal, or modest thyroid enlargement. The absence of any thyroid enlargement should also suggest exogenous hyperthyroidism or struma ovarii. (See "Exogenous hyperthyroidism"and "Struma ovarii".) A single palpable nodule raises the possibility of an autonomously functioning thyroid adenoma. (See "Disorders that cause hyperthyroidism", section on 'Toxic adenoma and toxic multinodular goiter'.) The thyroid is painful and tender in subacute (granulomatous) thyroiditis. (See "Subacute thyroiditis".)Laboratory tests