Amiodarone induced thyrotoxicosis: Difference between revisions
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{{Infobox medical condition | |||
| name = Amiodarone-induced thyrotoxicosis | |||
| image = [[File:Amiodarone_structure.svg|200px]] | |||
File:Amiodarone_structure.svg| | | caption = Chemical structure of [[Amiodarone]] | ||
| field = [[Endocrinology]] | |||
== Amiodarone | | synonyms = AIT | ||
| symptoms = [[Hyperthyroidism]], [[weight loss]], [[palpitations]], [[tremor]], [[anxiety]], [[heat intolerance]] | |||
| complications = [[Thyroid storm]], [[heart failure]], [[atrial fibrillation]] | |||
| onset = Variable, often months after starting amiodarone | |||
| duration = Can be prolonged, depending on treatment | |||
| causes = [[Amiodarone]] use | |||
| risks = Pre-existing [[thyroid disease]], high [[iodine]] intake | |||
| diagnosis = [[Thyroid function tests]], [[ultrasound]], [[radioiodine uptake test]] | |||
| differential = [[Graves' disease]], [[toxic multinodular goiter]] | |||
| prevention = Monitoring thyroid function before and during amiodarone therapy | |||
| treatment = [[Antithyroid drugs]], [[corticosteroids]], [[thyroidectomy]] | |||
| medication = [[Methimazole]], [[propylthiouracil]], [[prednisone]] | |||
| frequency = 10-20% of patients on amiodarone | |||
| deaths = Rare, but can occur if untreated | |||
}} | |||
'''Amiodarone induced thyrotoxicosis''' (AIT) is a form of [[thyrotoxicosis]] that occurs as a result of treatment with the antiarrhythmic medication [[amiodarone]]. Amiodarone is commonly used to treat and prevent a variety of cardiac arrhythmias, but it can have significant effects on the [[thyroid gland]] due to its high iodine content and direct toxic effects on thyroid cells. | '''Amiodarone induced thyrotoxicosis''' (AIT) is a form of [[thyrotoxicosis]] that occurs as a result of treatment with the antiarrhythmic medication [[amiodarone]]. Amiodarone is commonly used to treat and prevent a variety of cardiac arrhythmias, but it can have significant effects on the [[thyroid gland]] due to its high iodine content and direct toxic effects on thyroid cells. | ||
== Pathophysiology == | == Pathophysiology == | ||
Amiodarone contains a large amount of iodine, approximately 37% by weight, which can lead to alterations in thyroid function. The drug can cause both [[hypothyroidism]] and thyrotoxicosis. AIT is classified into two main types: | Amiodarone contains a large amount of iodine, approximately 37% by weight, which can lead to alterations in thyroid function. The drug can cause both [[hypothyroidism]] and thyrotoxicosis. AIT is classified into two main types: | ||
* '''Type 1 AIT''': This type occurs in patients with pre-existing thyroid abnormalities, such as [[nodular goiter]] or latent [[Graves' disease]]. The excess iodine from amiodarone leads to increased synthesis of thyroid hormones. | * '''Type 1 AIT''': This type occurs in patients with pre-existing thyroid abnormalities, such as [[nodular goiter]] or latent [[Graves' disease]]. The excess iodine from amiodarone leads to increased synthesis of thyroid hormones. | ||
* '''Type 2 AIT''': This type is a destructive thyroiditis, where amiodarone causes direct damage to thyroid follicular cells, leading to the release of preformed thyroid hormones into the circulation. | * '''Type 2 AIT''': This type is a destructive thyroiditis, where amiodarone causes direct damage to thyroid follicular cells, leading to the release of preformed thyroid hormones into the circulation. | ||
== Clinical Features == | == Clinical Features == | ||
Patients with AIT may present with symptoms of thyrotoxicosis, which can include: | Patients with AIT may present with symptoms of thyrotoxicosis, which can include: | ||
* [[Tachycardia]] | * [[Tachycardia]] | ||
* [[Weight loss]] | * [[Weight loss]] | ||
| Line 27: | Line 33: | ||
* [[Anxiety]] | * [[Anxiety]] | ||
* [[Palpitations]] | * [[Palpitations]] | ||
The clinical presentation can vary depending on the type of AIT and the underlying cardiac condition being treated with amiodarone. | The clinical presentation can vary depending on the type of AIT and the underlying cardiac condition being treated with amiodarone. | ||
== Diagnosis == | == Diagnosis == | ||
The diagnosis of AIT is based on clinical suspicion, laboratory tests, and imaging studies. Key diagnostic steps include: | The diagnosis of AIT is based on clinical suspicion, laboratory tests, and imaging studies. Key diagnostic steps include: | ||
* Measurement of serum [[thyroid-stimulating hormone]] (TSH), [[free thyroxine]] (FT4), and [[free triiodothyronine]] (FT3) levels. | * Measurement of serum [[thyroid-stimulating hormone]] (TSH), [[free thyroxine]] (FT4), and [[free triiodothyronine]] (FT3) levels. | ||
* [[Thyroid ultrasound]] to assess the gland's structure and identify nodules or goiter. | * [[Thyroid ultrasound]] to assess the gland's structure and identify nodules or goiter. | ||
* [[Radioiodine uptake test]] to differentiate between Type 1 and Type 2 AIT, although this test is often limited by the iodine load from amiodarone. | * [[Radioiodine uptake test]] to differentiate between Type 1 and Type 2 AIT, although this test is often limited by the iodine load from amiodarone. | ||
== Management == | == Management == | ||
The management of AIT depends on the type and severity of the condition: | The management of AIT depends on the type and severity of the condition: | ||
* '''Type 1 AIT''': Treatment may involve the use of thionamides such as [[methimazole]] or [[propylthiouracil]] to reduce thyroid hormone synthesis. Potassium perchlorate may also be used to block iodine uptake. | * '''Type 1 AIT''': Treatment may involve the use of thionamides such as [[methimazole]] or [[propylthiouracil]] to reduce thyroid hormone synthesis. Potassium perchlorate may also be used to block iodine uptake. | ||
* '''Type 2 AIT''': Treatment typically involves the use of glucocorticoids, such as [[prednisone]], to reduce inflammation and hormone release. | * '''Type 2 AIT''': Treatment typically involves the use of glucocorticoids, such as [[prednisone]], to reduce inflammation and hormone release. | ||
In some cases, discontinuation of amiodarone may be necessary, although this must be balanced against the risk of exacerbating the underlying cardiac condition. | In some cases, discontinuation of amiodarone may be necessary, although this must be balanced against the risk of exacerbating the underlying cardiac condition. | ||
== Prognosis == | == Prognosis == | ||
The prognosis of AIT varies depending on the type and the patient's response to treatment. Type 2 AIT often resolves more quickly with appropriate therapy, while Type 1 AIT may require prolonged treatment and monitoring. | The prognosis of AIT varies depending on the type and the patient's response to treatment. Type 2 AIT often resolves more quickly with appropriate therapy, while Type 1 AIT may require prolonged treatment and monitoring. | ||
== See Also == | |||
== | |||
* [[Thyrotoxicosis]] | * [[Thyrotoxicosis]] | ||
* [[Amiodarone]] | * [[Amiodarone]] | ||
| Line 59: | Line 52: | ||
* [[Hypothyroidism]] | * [[Hypothyroidism]] | ||
* [[Graves' disease]] | * [[Graves' disease]] | ||
{{Endocrinology}} | {{Endocrinology}} | ||
{{Thyroid diseases}} | {{Thyroid diseases}} | ||
[[Category:Thyroid diseases]] | [[Category:Thyroid diseases]] | ||
[[Category:Endocrinology]] | [[Category:Endocrinology]] | ||
Latest revision as of 22:37, 5 April 2025
Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD medical weight loss NYC and sleep center NYC
| Amiodarone-induced thyrotoxicosis | |
|---|---|
| |
| Synonyms | AIT |
| Pronounce | N/A |
| Specialty | N/A |
| Symptoms | Hyperthyroidism, weight loss, palpitations, tremor, anxiety, heat intolerance |
| Complications | Thyroid storm, heart failure, atrial fibrillation |
| Onset | Variable, often months after starting amiodarone |
| Duration | Can be prolonged, depending on treatment |
| Types | N/A |
| Causes | Amiodarone use |
| Risks | Pre-existing thyroid disease, high iodine intake |
| Diagnosis | Thyroid function tests, ultrasound, radioiodine uptake test |
| Differential diagnosis | Graves' disease, toxic multinodular goiter |
| Prevention | Monitoring thyroid function before and during amiodarone therapy |
| Treatment | Antithyroid drugs, corticosteroids, thyroidectomy |
| Medication | Methimazole, propylthiouracil, prednisone |
| Prognosis | N/A |
| Frequency | 10-20% of patients on amiodarone |
| Deaths | Rare, but can occur if untreated |
Amiodarone induced thyrotoxicosis (AIT) is a form of thyrotoxicosis that occurs as a result of treatment with the antiarrhythmic medication amiodarone. Amiodarone is commonly used to treat and prevent a variety of cardiac arrhythmias, but it can have significant effects on the thyroid gland due to its high iodine content and direct toxic effects on thyroid cells.
Pathophysiology[edit]
Amiodarone contains a large amount of iodine, approximately 37% by weight, which can lead to alterations in thyroid function. The drug can cause both hypothyroidism and thyrotoxicosis. AIT is classified into two main types:
- Type 1 AIT: This type occurs in patients with pre-existing thyroid abnormalities, such as nodular goiter or latent Graves' disease. The excess iodine from amiodarone leads to increased synthesis of thyroid hormones.
- Type 2 AIT: This type is a destructive thyroiditis, where amiodarone causes direct damage to thyroid follicular cells, leading to the release of preformed thyroid hormones into the circulation.
Clinical Features[edit]
Patients with AIT may present with symptoms of thyrotoxicosis, which can include:
The clinical presentation can vary depending on the type of AIT and the underlying cardiac condition being treated with amiodarone.
Diagnosis[edit]
The diagnosis of AIT is based on clinical suspicion, laboratory tests, and imaging studies. Key diagnostic steps include:
- Measurement of serum thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) levels.
- Thyroid ultrasound to assess the gland's structure and identify nodules or goiter.
- Radioiodine uptake test to differentiate between Type 1 and Type 2 AIT, although this test is often limited by the iodine load from amiodarone.
Management[edit]
The management of AIT depends on the type and severity of the condition:
- Type 1 AIT: Treatment may involve the use of thionamides such as methimazole or propylthiouracil to reduce thyroid hormone synthesis. Potassium perchlorate may also be used to block iodine uptake.
- Type 2 AIT: Treatment typically involves the use of glucocorticoids, such as prednisone, to reduce inflammation and hormone release.
In some cases, discontinuation of amiodarone may be necessary, although this must be balanced against the risk of exacerbating the underlying cardiac condition.
Prognosis[edit]
The prognosis of AIT varies depending on the type and the patient's response to treatment. Type 2 AIT often resolves more quickly with appropriate therapy, while Type 1 AIT may require prolonged treatment and monitoring.
See Also[edit]
| Physiology of the endocrine system | ||||||||
|---|---|---|---|---|---|---|---|---|
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