Failure of plasmapheresis, corticosteroids and thionamides to ameliorate a case of protracted amiodarone-induced thyroiditis

The Utility of Intravenous Methylprednisolone as an Adjunct Treatment for Drug-Resistant Amiodarone-Induced Thyrotoxicosis

BACKGROUND

Amiodarone-induced thyrotoxicosis (AIT) may pose treatment challenges. We present a series of patients in which we achieved the normalisation of free T3 (FT3) using intravenous methylprednisolone (ivMP) in AIT refractory to thiamazole and oral prednisone. Namely, in three males (aged 56, 50 and 64, all with a history of AF and/or a low ejection fraction), an addition of ivMP resulted in the normalisation of FT3, which allowed successful thyroidectomy. In another case of a 65-year-old man, we initially succeeded in the normalisation of FT3 using ivMP from FT4 > 7.77 ng/dL (0.93-1.7) to 2.41 ng/dL and in that of FT3 from 14.95 pg/mL (2-4.4) to 2.05 pg/mL), but four weeks after stopping ivMP, despite the continuation of thiamazole and prednisone, there was rebound thyrotoxicosis: FT4 > 7.77 ng/dL and FT3-5.46 pg/mL. Intravenous MP was restated leading to a decline in FT4 to 2.51 ng/dL and in FT3 to 1.92 pg/mL, thus allowing a successful thyroidectomy. Finally, in a 78-year-old man with AF, goitre, and AIT resistant to thiamazole, prednisone and lithium carbonate, we obtained a reduction in FT4 to 1.51 ng/dL and in FT3 to 3.17 pg/mL after seven pulses of ivMP. Oral prednisone was gradually reduced and successfully stopped about six months later. He remained on low-dose thiamazole (5 mg od).

CONCLUSIONS

Pulse ivMP in addition to oral steroids may be a useful adjunct therapy either for the preparation of a thyroidectomy or as a treatment modality in drug-resistant AIT. Though a total cure is possible, there is a danger of a rebound worsening of thyrotoxicosis after premature discontinuation of ivMP.

Severe Hyperthyroidism Complicated by Agranulocytosis Treated with Therapeutic Plasma Exchange: Case Report and Review of the Literature

AIM

To present a case of Graves' disease complicated by methimazole induced agranulocytosis treated with therapeutic plasma exchange (TPE) and review of the literature.

CASE PRESENTATION

A 21-year-old patient with a history of Graves' disease presented to the endocrine clinic. His history was significant for heat intolerance, weight loss, and tremors. Upon examination he had tachycardia, smooth goiter, thyroid bruit, and hyperactive reflexes. He was started on methimazole and metoprolol and thyroidectomy was to be done once his thyroid function tests normalized. On follow-up, the patient symptoms persisted. Complete blood count done showed a white blood cell count of 2100 (4000-11,000 cells/cu mm) with a neutrophil count of 400 cells/cu mm, consistent with neutropenia. He was admitted to the hospital and underwent 3 cycles of TPE and was also given filgrastim. He improved clinically and his thyroxine (T4) levels also came down. Thyroidectomy was done. He was discharged on levothyroxine for postsurgical hypothyroidism.

CONCLUSION

Plasmapheresis may be useful in the treatment of hyperthyroidism. It works by removing protein bound hormones and also possibly inflammatory cytokines. Further studies are needed to clarify the role of various modalities of TPE in the treatment of hyperthyroidism.

Perfect storm: Therapeutic plasma exchange for a patient with thyroid storm

Thyroid storm is a potentially lethal complication of hyperthyroidism with increased thyroid hormones and exaggerated symptoms of thyrotoxicosis. First-line therapy includes methimazole (MMI) or propylthiouracil (PTU) to block production of thyroid hormones as a bridge toward definitive surgical treatment. Untreated thyroid storm has a mortality rate of up to 30%; this is particularly alarming when patients cannot tolerate or fail pharmacotherapy, especially if they cannot undergo thyroidectomy. Therapeutic plasma exchange (TPE) is an ASFA category III indication for thyroid storm, meaning the optimum role of this therapy is not established, and there are a limited number of cases in the literature. Yet TPE can remove T3 and T4 bound to albumin, autoantibodies, catecholamines and cytokines and is likely beneficial for these patients. We report a patient with thyroid storm who could not tolerate PTU, subsequently failed therapy with MMI, and was not appropriate for thyroidectomy. TPE was therefore performed daily for 4 days (1.0 plasma volume with 5% albumin replacement and 2 U of plasma). Over the treatment course, the patient's thyroid hormones normalized and symptoms of thyroid storm largely resolved; his T3 decreased from 2.27 to 0.81 ng/mL (normal 0.8-2.0), T4 decreased from 4.8 to 1.7 ng/mL (0.8-1.8), heart rate normalized, altered mental status improved, and he converted to normal sinus rhythm. He was ultimately discharged in euthyroid state. He experienced no side effects from his TPE procedures. TPE is a safe and effective treatment for thyroid storm when conventional treatments are not successful or appropriate.

Thyrotoxic Storm

Thyrotoxic storm is a syndrome of exaggerated thyrotoxicosis with systemic decompensation seen in 1-2% of hospital admissions for thyrotoxicosis. The diagnosis is based on recognition of typical cardinal manifestations, but even when diagnosed and treated, mortality rates are high. Results of thyroid function tests may be no more abnormal than those seen in uncomplicated thyrotoxicosis. Often, there is a history of partially treated thyrotoxicosis, and/or decompensation related to a precipitating event such as infection, stroke, pulmonary embolism, or radioiodine therapy. Treatment must be aggressive and includes volume repletion with i.v. glucose and saline, and pressor agents may be needed. Patients belong in an intensive care unit, with a cooling blanket for hyperpyrexia. Appropriate cardiac medications are employed to control ventricular rate in those with atrial fibrillation. The thyroid is blocked by large doses of antithyroid agent. In patients unable to swallow, tablets can be crushed and given by nasogastric tube or per rectum. After antithyroid drugs are started, stable iodine as Lugol's solution is given to block further hormone release from the gland. Sodium ipodate can be used instead of iodine and has the advantage of inhibiting conversion of T4 to T3. In severe cases, thyroid hormone may be removed from the circulation by peritoneal dialysis or plasmapheresis, and cholestyramine resin may be used to bind T4 and T3 within the gastrointestinal tract. β-adrenergic antagonists such as propranolol are given, or the very short-acting β-adrenergic blocker, esmolol, has also been used with success. A Swan-Ganz catheter is used to monitor central hemodynamics, especially in patients receiving high-dose propranolol, pressors, digoxin, diuretics, and fluids. Large doses of dexamethasone have been given based on presumed increased glucocorticoid requirements in thyrotoxicosis and because adrenal reserve may be reduced. Therapy must be continued until a normal metabolic state is achieved, at which time iodine is progressively withdrawn and plans made for definitive treatment.

Role of plasma exchange in the thyroid storm

Inadequately treated thyroid storm can lead to death. Therapeutic plasma exchange (TPE) is a suggested treatment when conventional treatments fail, but its indication is not well codified. We report our experience through three explicit cases. Three elderly patients were admitted to our hospital for cardiac or neurologic symptoms due to thyroid storm. After initiation of conventional therapy, TPE was performed with clinical and biological improvement. The speed of symptom resolution varies depending on the severity. This technique must be carried out by experienced medical staff as many complications can occur; nevertheless, in our patients with severe comorbidities, no complications occurred. The action of TPE mainly results from plasma removal of cytokines, putative antibodies, and thyroid hormones and their bound proteins. TPE has a transitory effect and thus should be associated with other thyroid blockers. When there are threatening symptoms, TPE should be done early, without waiting for the efficiency of conventional treatment, since it is the fastest method known for the improvement of the clinical condition. We also suggest starting TPE in case of neurologic symptoms because of very slow and incomplete regression. The Burch and Wartofsky score seems to be a helpful tool in establishing the diagnosis of thyroid storm and for deciding on when to initiate TPE.

Thyroid emergencies

This review presents current knowledge about the thyroid emergencies known as myxedema coma and thyrotoxic storm. Understanding the pathogenesis of these conditions, appropriate recognition of the clinical signs and symptoms, and their prompt and accurate diagnosis and treatment are crucial in optimizing survival.

Amiodarone and thyroid dysfunction

Amiodarone is a potent antiarrhythmic drug associated with thyroid dysfunction. Its high iodine content causes inhibition of 5'-deiodinase activity. Most patients remain euthyroid. Amiodarone-induced thyrotoxicosis (AIT) or amiodarone-induced hypothyroidism (AIH) may occur depending on the iodine status of individuals and prior thyroid disease. AIT is caused by excess iodine-induced thyroid hormone synthesis (type I AIT) or by destructive thyroiditis (type II AIT). If the medical condition allows it, discontinuation of the drug is recommended in type I AIT. Otherwise, large doses of thioamides are required. Type II AIT is treated with corticosteroids. Mixed cases require a combination of both drugs. Potassium perchlorate has been used to treat resistant cases of type I AIT but use is limited by toxicity. Thyroidectomy, plasmapheresis, lithium, and radioiodine are used in select cases of AIT. AIH is successfully treated with levothyroxine. Screening for thyroid disease before starting amiodarone and periodic monitoring of thyroid function tests are advocated.

Total Thyroidectomy for Amiodarone-associated Thyrotoxicosis in Patients with Severe Cardiac Disease

BACKGROUND

Surgical treatment of amiodarone-associated thyrotoxicosis (AAT) is effective although fewer than 100 cases have been reported world wide.

MATERIALS AND METHODS

We reviewed 14 patients treated with total thyroidectomy by a single surgeon from 1998 to 2005.

RESULTS

There were 11 male and 3 female patients who ranged in age from 26 to 82 years (average 50.5). Nine patients refractory to medical management and 5 in whom amiodarone needed to be continued were treated surgically. Ten patients developed thyrotoxicosis while being treated with amiodarone, but 4 became thyrotoxic after ceasing amiodarone 2, 2, 6 and 13 months previously. One patient recently had a cardiac transplant, and 4 were on the active cardiac transplant waiting list. Cardiac ejection fractions ranged from 15% to 50% (average 39%). Four patients had serious complications from medication used to control thyrotoxicosis, including one case of agranulocytosis from carbimazole. Total thyroidectomy was performed under general anaesthesia with no significant intraoperative complications and no deaths. There were no recurrent laryngeal nerve injuries. Two patients required short-term calcium supplementation. All patients had rapid resolution of their symptoms and were euthyroid on thyroxine postoperatively. Two patients had such improvement they were removed from the cardiac transplant list.

CONCLUSIONS

Despite severe cardiac disease, total thyroidectomy can be performed successfully under general anaesthesia. Surgery should be considered early in the treatment plan. Surgery is particularly appropriate where it is considered necessary to continue amiodarone, when there are complications from the medications used to treat thyrotoxicosis and to facilitate fitness for or defer the need for cardiac transplantation.

Amiodarone and the thyroid

Among the drugs affecting the thyroid gland, no drug has puzzled, and at the same time fascinated, endocrinologists more than amiodarone. Amiodarone is a potent class III anti-arrhythmic drug that also possesses beta-blocking properties. It is very rich in iodine, with a 100-mg tablet containing an amount of iodine that is 250 times the recommended daily iodine requirement. Amiodarone produces characteristic alterations in thyroid function tests in euthyroid patients. Understanding these alterations is crucial in avoiding unnecessary investigations and treatment. Amiodarone-induced thyroid dysfunction occurs because of both its iodine content and the direct toxic effects of the compound on thyroid parenchyma. Amiodarone-induced hyperthyroidism is more common in iodine-deficient regions of the world, whereas amiodarone-induced hypothyroidism is usually seen in iodine-sufficient areas. In contrast to amiodarone-induced hypothyroidism, amiodarone-induced thyrotoxicosis is a difficult condition to diagnose and treat. In this review, we discuss the alterations in thyroid function tests seen in euthyroid subjects, the epidemiology and mechanism of amiodarone-induced thyroid dysfunction, treatment options available, and the consequences of amiodarone use in pregnancy and lactation; and finally, we propose a follow-up strategy in patients taking amiodarone.

Perioperative management of the thyrotoxic patient

Preoperative thyrotoxicosis is a potentially life-threatening condition that requires medical intervention before surgery. Most patients are undergoing thyroidectomy for persistent thyrotoxicosis, usually Graves' disease, either having contraindications to or failing medical therapy. Fewer patients are undergoing nonthyroidal surgery that is likely urgent or emergent. The choice of treatment depends on the time available for preoperative preparation, the severity of the thyrotoxicosis, and the impact of any current or previous therapies. Generally treatment is directed at a combination of targets in the thyroid hormone synthetic, secretory, and peripheral pathway with concurrent treatment to correct any decompensation of normal homeostatic mechanisms. Thionamides are the preferred initial treatment unless contraindicated, but do require several weeks to render a patient euthyroid. beta-Blockers should always be used unless absolutely contraindicated because they improve thyrotoxic symptoms especially of the cardiovascular system. Other agents including iodine and steroids can be used if rapid preparation is required or more severe thyrotoxicosis is present. The goal of therapy is to render the patient as close as possible to clinical and biochemical euthyroidism before surgery. Overall, the morbidity and mortality of adequately prepared patients is low.

The effects of amiodarone on the thyroid

Amiodarone is a benzofuranic-derivative iodine-rich drug widely used for the treatment of tachyarrhythmias and, to a lesser extent, of ischemic heart disease. It often causes changes in thyroid function tests (typically an increase in serum T(4) and rT(3), and a decrease in serum T(3), concentrations), mainly related to the inhibition of 5'-deiodinase activity, resulting in a decrease in the generation of T(3) from T(4) and a decrease in the clearance of rT(3). In 14-18% of amiodarone-treated patients, there is overt thyroid dysfunction, either amiodarone-induced thyrotoxicosis (AIT) or amiodarone-induced hypothyroidism (AIH). Both AIT and AIH may develop either in apparently normal thyroid glands or in glands with preexisting, clinically silent abnormalities. Preexisting Hashimoto's thyroiditis is a definite risk factor for the occurrence of AIH. The pathogenesis of iodine-induced AIH is related to a failure to escape from the acute Wolff-Chaikoff effect due to defects in thyroid hormonogenesis, and, in patients with positive thyroid autoantibody tests, to concomitant Hashimoto's thyroiditis. AIT is primarily related to excess iodine-induced thyroid hormone synthesis in an abnormal thyroid gland (type I AIT) or to amiodarone-related destructive thyroiditis (type II AIT), but mixed forms frequently exist. Treatment of AIH consists of L-T(4) replacement while continuing amiodarone therapy; alternatively, if feasible, amiodarone can be discontinued, especially in the absence of thyroid abnormalities, and the natural course toward euthyroidism can be accelerated by a short course of potassium perchlorate treatment. In type I AIT the main medical treatment consists of the simultaneous administration of thionamides and potassium perchlorate, while in type II AIT, glucocorticoids are the most useful therapeutic option. Mixed forms are best treated with a combination of thionamides, potassium perchlorate, and glucocorticoids. Radioiodine therapy is usually not feasible due to the low thyroidal radioiodine uptake, while thyroidectomy can be performed in cases resistant to medical therapy, with a slightly increased surgical risk.

Amiodarone-induced thyroid disorders: a clinical review

Although amiodarone is regarded as a highly effective anti-arrhythmic agent, its use may lead to alterations in thyroid gland function and/or thyroid hormone metabolism, partly because of its rich iodine content. Patients treated with amiodarone may manifest altered thyroid hormone profile without thyroid dysfunction, or they may present with clinically significant amiodarone-induced hypothyroidism or amiodarone-induced thyrotoxicosis. The former results from the inability of the thyroid to escape from the Wolff-Chaikoff effect. It prevails in areas with high dietary iodine intake, and it is readily managed by discontinuation of amiodarone or thyroid hormone replacement. Amiodarone-induced thyrotoxicosis occurs more frequently in areas with low iodine intake; it may arise from iodine-induced excessive thyroid hormone synthesis (type I) or destructive thyroiditis with release of preformed hormones (type II). Type I should be treated with thionamides alone or in combination with potassium perchlorate, whereas type II benefits from treatment with glucocorticoids. Surgery may be a feasible option for patients who require long-term amiodarone treatment.

Antithyroid drugs for the treatment of hyperthyroidism caused by Graves' disease

Therapy for Graves' disease is not straightforward and often involves complex decision making. Long-term antithyroid drug therapy is appealing because it is nonablative, but it is not for everyone. The physician must weigh the advantages and disadvantages of antithyroid drug treatment and help the patient arrive at an individualized therapeutic strategy that is appropriate and cost-effective.

Amiodarone and the thyroid: a practical guide to the management of thyroid dysfunction induced by amiodarone therapy

Amiodarone induces predictable changes in thyroid function tests that are largely explicable in terms of the physiological effects of iodide excess and inhibition of deiodinase activity. Clinically relevant thyroid dysfunction is not uncommon during amiodarone therapy, and requires careful diagnosis and treatment. The diagnosis and management of thyrotoxicosis is probably best supervised by a specialist endocrinologist. Control of hypothyroidism can generally be achieved simply by the addition of T4 to the therapeutic regimen, ideally after an initial assessment by an endocrinologist. The frequency with which amiodarone causes thyroid and other complications serves to emphasize the need for rational prescribing and long-term cardiological follow up.

Amiodarone and the Thyroid

OBJECTIVE

To review the amiodarone-associated alterations in thyroid hormone metabolism and thyroid function and compare them with the effects of inorganic iodide. To clarify the pathophysiologic features and treatment of amiodarone-associated hypothyroidism and thyrotoxicosis.

SUMMARY

Amiodarone, an iodinated benzofuran, is an important antianginal and antiarrhythmic medication. It also alters thyroid hormone metabolism and may precipitate hypothyroidism or hyperthyroidism. Amiodarone-associated hypothyroidism (AAH) is similar to iodine-induced hypothyroidism. Amiodarone-associated thyrotoxicosis (AAT) has a complex pathophysiology. Type I AAT is due to increased thyroid hormone synthesis and release and occurs in patients with multinodular goiter or Graves' disease. Therapeutic interventions may include discontinuation of amiodarone, thionamide therapy, perchlorate, or surgery. In type II AAT, hyperthyroidism is the consequence of a destructive thyroiditis with release of preformed thyroid hormone. Prednisone therapy is the treatment of choice. The distinction between these two entities is of considerable clinical and therapeutic importance.