Evaluation of a child with suspected hyperthyroidism

This algorithm outlines the general approach to children with signs or symptoms of hyperthyroidism/thyrotoxicosis*. By far, the most common cause is Graves disease. For additional details on rare thyroid disorders, refer to UpToDate content on Graves disease in children and its differential diagnosis. The initial laboratory testing is usually performed by the primary care clinician; patients with abnormal results should be referred to a pediatric endocrinologist for further evaluation and management.

TSH: thyroid-stimulating hormone (thyrotropin); fT4: free thyroxine; T3: triidothyroinine; TSHR-Ab: thyrotropin receptor-stimulating antibodies^§; RTH: resistance to thyroid hormone; I-123: iodine-123; TPO-Ab: thyroid peroxidase antibody; Tg-Ab: thyroglobulin antibody; TSI: thyroid-stimulating immunoglobulin; TBII: thyrotropin-binding inhibitor immunoglobulin.

* Hyperthyroidism refers to overproduction of thyroid hormone by the thyroid gland. Thyrotoxicosis is a more general term for the effects of excessive thyroid hormone, which can be due to hyperthyroidism, destructive thyroiditis (with release of preformed thyroid hormone), or exogenous thyroxine.

¶ Stare and lid lag are very common in any form of hyperthyroidism. Ophthalmopathy (exophthalmos, impaired extraocular movements) is specific to Graves disease; it is present in approximately 40% of children with this disorder and usually is mild.

Δ Most children with Graves disease have a diffuse, symmetrical, homogenous goiter. For those with thyroid nodule(s) or asymmetry, refer to UpToDate content on thyroid nodules and cancer in children.

◊ Graves disease is characterized by suppressed TSH, positive TSHR-Ab, and elevated fT4 and/or T3. If fT4 and T3 are normal, patients most likely have subclinical Graves disease.

§ TSHR-Ab can be measured by either a TSI or TBII. In many laboratories, this is now ordered as "TSH receptor antibody" test (TSHR-Ab, or simply TRAb). A positive TSI confirms the presence of a stimulating antibody and a diagnosis of Graves disease. A positive TBII (or TSHR-Ab) confirms that there is an antibody that competes with TSH binding to its receptor but does not provide information about whether it is a stimulating or blocking antibody. A positive TBII (or TSHR-Ab) in a patient with clinical thyrotoxicosis is most likely indicative of Graves disease.

¥ Performing an I-123 uptake and scan in children with hyperthyroidism and negative TSHR-Ab is usually the next diagnostic step, because noninvasive tests generally are not sufficient to distinguish between destructive thyroiditis and causes with increased T4 production (eg, autonomous TSH-secreting nodule).

‡ Graves disease is sometimes difficult to distinguish from Hashitoxicosis. TPO-Ab and Tg-Ab are typically elevated in both disorders but are higher in Hashitoxicosis. For other distinguishing features, refer to UpToDate content on Graves disease in children and adolescents.

† In most cases, the uptake on I-123 scan is clearly increased or decreased. In cases of negative TPO-Ab and Tg-Ab with variable uptake (decreased, normal or increased), other considerations include medications that can suppress TSH (eg, amiodarone, lithium, immune modulators) or early pregnancy, which is associated with transient, usually subclinical hyperthyroidism. Refer to UpToDate content on thyroid disease and pregnancy.

** Factitious thyrotoxicosis due to exogenous thyroxine should be suspected in the setting of hyperthyroidism but absent goiter. It is most commonly seen in adolescents with access to levothyroxine who are trying to lose weight. Serum thyroglobulin is low, in contrast with endogenous hyperthyroidism (eg, Graves disease), in which it is elevated.

Graphic 135058 Version 2.0

خرید پکیج

Evaluation of a child with suspected hyperthyroidism