Successful treatment of massive acute thyroid hormone poisoning with iopanoic acid

Review of oral cholecystographic agents for the management of hyperthyroidism

OBJECTIVE

Although the use of oral cholecystographic agents (OCAs) had declined due to limited availability, there is literature to suggest it is an effective medication for thyrotoxicosis in appropriate clinical situations.

METHODS

The authors performed a PubMed search and systematically reviewed all the English written case reports, original studies and reviews from 1953 to 2012. Additional information was supplemented from available online pharmacologic databases.

RESULTS

The off-label use of OCAs was reviewed for the management of neonatal and adult Graves' disease, subacute thyroiditis, amiodarone-induced thyroiditis (AIT), exogenous hyperthyroidism, toxic multinodular goiter (TMNG), thyrotropinoma, thyrotoxicosis during pregnancy, rapid pre-operative control of hyperthyroidism, and thyroid storm. Adverse effects were also reviewed.

CONCLUSION

OCAs generally are effective agents in treating thyrotoxicosis in the etiologies reviewed. OCAs are clinically relevant in patients who require rapid control, such as in the pre-operative state or patient who cannot tolerate a thyrotoxicosis state. OCA may also be beneficial in situations where other anti-thyroidal medication would be hazardous or ineffective, such as thionamide allergy or exogenous thyrotoxicosis. Given concern for long-term relapse, OCAs should be considered a short-term bridge to definitive therapy. OCAs are limited in TMNG and should be second line after glucocorticoids in AIT II. OCAs do not preclude the use of radioactive iodine, which can be performed one week after OCA therapy.

Drug-induced hyperthermic syndromes: part I. Hyperthermia in overdose

Drugs and natural compounds that affect the thermoregulatory system can induce or contribute to hyperthermia when used in excess. Hyperthermia associated with drug overdose is dangerous and potentially lethal. This article reviews the body's process of maintaining thermodynamic equilibrium, and describes the mechanisms by which it is influenced by sympathomimetic and anticholinergic drugs, salicylates, and thyroid replacement medications. Appropriate treatment strategies such as cooling and the administration of counteractive medications are discussed.

Thyroid medications during pregnancy

Euthyroid women experience dramatic changes in their thyroid physiology in order to accommodate the presence of placental and fetal tissues. These adaptations to the pregnant state make it crucial to develop reliable trimester-specific intervals for thyroid parameters. Use of non-pregnant reference intervals could lead to erroneous assessment of thyroid status in this rapidly changing hormonal environment. Only with a full appreciation of physiologic changes in thyroid parameters during a euthyroid pregnancy, can thyroid dysfunction be appropriately diagnosed and managed. Iodine sufficiency during pregnancy can be achieved with supplementation using a multivitamin. Both hypothyroidism and hyperthyroidism should be diagnosed using the appropriate reference intervals for pregnancy. Hypothyroid women are best treated with a specific brand of levothyroxine. Hypothyroidism should ideally be treated prior to conception. If newly recognized during pregnancy, it should be fully treated as early as possible. Frequent monitoring of thyroid status is essential as many women demonstrate an increased requirement for thyroid hormone during the first trimester. Although mild hyperthyroidism may be well tolerated during pregnancy, overt hyperthyroidism requires treatment. Thionamides are the mainstay of therapy. Following their initiation, close monitoring is required to avoid maternal and fetal hypothyroidism. There are occasional circumstances when other medical therapy or surgical therapy may be employed for hyperthyroidism. Thyroidectomy is generally safe in the second trimester in an appropriately prepared woman. There is limited data about the role and safety of oral contrast agents, iodine, amiodarone, and perchlorate. Radioiodine therapy is contradicted during pregnancy.

The use of oral radiographic contrast agents in the management of hyperthyroidism

Oral iodinated radiographic contrast agents such as ipodate and iopanoic acid form an important part of the armamentarium used to treat hyperthyroidism. They rapidly and dramatically reduce serum triiodothyronine (T3) levels by inhibiting conversion of thyroxine (T4) to T3 in the periphery and by blocking secretion from the thyroid. Potential risks from the large iodine load resulting from their use limit their widespread applicability. In addition, they are ineffective when used alone on a long-term basis. However, these agents may be especially useful in treating thyrotoxic patients preoperatively, in neonatal Graves' disease, in massive levothyroxine ingestion, and when other conventional antithyroid drugs are unsuccessful or contraindicated.