Methimazole-induced antineutrophil cytoplasmic antibody-associated diffuse alveolar haemorrhage in a Chinese woman with Graves' disease

We report on a case of diffuse alveolar haemorrhage in a Chinese woman due to methimazole-induced antineutrophil cytoplasmic antibodies. A literature search for anti-thyroid drugs associated with antineutrophil cytoplasmic antibody-induced diffuse alveolar haemorrhages is reviewed. Diffuse alveolar haemorrhage is a rare complication of thiourea agents and the treatment often requires corticosteroids or other immunosuppressants, together with withdrawal of the causative agent.

Methimazole-induced agranulocytosis in patients with Graves' disease is more frequent with an initial dose of 30 mg daily than with 15 mg daily

BACKGROUND

Antithyroid drugs (ATDs) are prescribed as the initial therapy for the majority of patients with Graves' disease in many areas of the world. Although, it is well known that agranulocytosis is one of the most serious side effects of ATDs, there has not yet been any conclusive evidence that the prevalence of agranulocytosis induced by ATDs is dose related. This study was performed to determine if the prevalence of agranulocytosis is different depending on the starting dosage of ATDs in patients with Graves' disease.

METHODS

Until 1996, we had typically prescribed 30 mg/d of methimazole (MMI) as the initial dosage for the treatment of Graves' disease at our institution. We changed the initial MMI dosage to 15 mg/d as a general rule in 1997. As a consequence, we acquired two groups of patients with Graves' disease who received different dosages of MMI. We retrospectively compared the prevalence of MMI-induced agranulocytosis in patients who received 15 mg/d of MMI to those who received 30 mg/d of MMI.

RESULTS

There were 2087 subjects treated with 30 mg/d of MMI and 2739 treated with 15 mg/d of MMI. The prevalence of agranulocytosis in the 30 mg/d group was significantly higher than in the 15 mg/d group (0.814% vs. 0.219%, respectively, p < 0.01). The prevalence of agranulocytosis plus neutropenia in the 30 mg/d group was also significantly higher than in the 15 mg/d group (1.581% vs. 0.474%, respectively, p < 0.001).

CONCLUSIONS

It is very likely that MMI-induced agranulocytosis occurs with a larger dosage of MMI and is dose related. Considering both the effectiveness and the risk of serious side effects, we recommend 15 mg/d of MMI as the starting dosage for the treatment of Graves' disease.

[Case report of mucormycosis in a patient with secondary methimazole-induced agranulocytosis]

Agranulocytosis is a rare side effect of antithyroid drugs, it occurs in less than 0.5% of patients, usually during the first few months of treatment. It is considered to be the most serious adverse effect of these medications since it may be complicated by serious, life-threatening infections. Mucormycosis is a severe mycotic infection that usually develops in immunocompromised hosts, such aspatients with diabetes mellitus, hematologic malignancies or immunosuppressive therapy. The association of mucormycosis with methimazole-induced agranulocytosis has not been previously described. The objective of this case presentation is to analyze the case ofa woman with diffuse toxic goiter and methimazole-induced agranulocytosis who developed rhino-palatal mucormycosis.

Drug-induced insulin autoimmune syndrome

Although insulin autoimmune syndrome (IAS) was found to be strongly related with methimazole, rapidly increasing numbers of cases with alpha lipoic acid-induced IAS have been confirmed to be reported since 2003. As alpha lipoic acid has gained popularity as a supplement for dieting and anti-aging, a warning should be issued.

[Drug-induced agranulocytosis--case reports and literature review]

Drug-induced agranulocytosis is believed to be an extremely rare adverse drug reaction. It can be caused by various drugs, but it is mostly described in patients taking antithyroid drugs, antipsychotics and antibiotics. Four cases of patients treated for drug-induced agranulocytosis from January 2006 to March 2007 were described. In two cases agranulocytosis appeared in the course of therapy with methimazole. In one patient agranulocytosis was caused by perazine and by promazine or olanzapine in the last one. In all of the cases the leading symptom was fever, three of our patients had changes of mouth mucosa. All patients were treated with betalactam antibiotics. Granulocyte colony-stimulating factor (G-CSF) was not used in anyone. The recovery of white blood cell count and granulocyte count in all of the patients was detected in the first ten days of hospitalization.

Antithyroid drug-induced aplastic anemia

BACKGROUND

Antithyroid drugs have been used for more than 50 years for the management of hyperthyroidism. Most patients tolerate treatment well but some may develop life threatening side effects such as agranulocytosis and aplastic anemia (AA). We review all cases of antithyroid drug induced AA and describe, as illustrative cases, two women with Graves' disease who developed AA after 8 and 24 weeks of carbimazole (CBM) and methimazole (MMI) treatment respectively.

PATIENT FINDINGS AND SUMMARY

To date, at least 34 cases of aplastic anemia (AA) due to antithyroid drugs [(1 with CMZ, 31 with MMI, and 2 with propylthiouracil (PTU)] have been published, not including the two patients described here. In addition, at least another 14 patients in whom AA developed after treatment with antithyroid drugs (11 with CMZ, and 3 with MMI) have been reported in Yellow Card Scheme data analysis. Patients with AA usually exhibit sudden onset of symptoms after a relative short time of exposure to the drugs, and all have concomitant agranulocytosis. Most have a rapid recovery following discontinuation of the drug and supportive treatment. Although only two antithyroid drug induced AA deaths have been published, the mortality rate was higher in the Yellow Card Scheme data analysis.

CONCLUSIONS

Aplastic anemia associated with antithyroid drug treatment is rarer than antithyroid drug associated agranulocytosis. The prognosis of patients with antithyroid drug induced AA is good overall, but may not be as favorable as that of antithyroid drug induced isolated agranulocytosis.

Long-term follow-up of patients with hyperthyroidism due to Graves' disease treated with methimazole. Comparison of usual treatment schedule with drug discontinuation vs continuous treatment with low methimazole doses: a retrospective study

Antithyroid drugs may be proposed as the firstline therapy for hyperthyroidism due to Graves' disease since some patients undergo prolonged remission after drug withdrawal. On the other hand, some studies, though controversial, indicated that methimazole (MMI) has some immunomodulating activity. We retrospectively analyzed 384 consecutive patients newly diagnosed with Graves' disease in the years 1990-2002 to ascertain whether long-term therapy with low doses of MMI may prevent relapse of thyrotoxicosis. Two hundred and forty-nine patients were included in our study. The date of reduction of MMI dose to 5 mg/day was considered time 0 for survival analysis. In 121 MMI was discontinued in less than 15 months after time 0 (group D), while in the remaining 128 a daily MMI 2.5-5 mg dose was maintained (group M). One hundred and thirty-five patients were excluded for inadequate response to MMI, relapse of thyrotoxicosis that could be related to an improper withdrawal or reduction of MMI, inadequate or too short followup, iodide contamination, steroid or interferon therapy, pregnancy or post-partum. D and M groups did not differ for clinical and hormonal parameters except age, which was lower in D (p=0.019). Age > vs < 35 yr was relevant in survival analysis; therefore patients were divided in 2 groups according to this age cut-off. In younger patients relapse of thyrotoxicosis occurred in 15 patients of group D 2.4-39.6 months (median 19.0) after time 0, and 8 M after 5.9-40.0 (21.3) months, while 14 D and 5 M maintained euthyroidism until the end of the observation after 31.8-95.3 (56.6) months and 30.4-62.1 (46.5) months, respectively. Survival analysis indicated that the risk of relapse was similar in group D and M. In older patients relapse of thyrotoxicosis occurred in 40 patients of group D after 8.2-65.8 (25.4) months and 29 M after 5.8-62.5 (22.4) months, while 52 D and 86 M maintained euthyroidism until the end of the observation, 20.1-168.0 (46.7) months and 24.1-117.4 (53.4) months respectively. Survival analysis indicated that the risk of relapse was increased in group D. Therefore long-term treatment with low doses of MMI seems to prevent relapse in Graves' disease in patients above 35 yr of age. This should be confirmed in a prospective study.

Central nervous system vasculitis after starting methimazole in a woman with Graves' disease

BACKGROUND

Graves' disease (GD), a prototypical autoimmune disorder, is associated with other autoimmune diseases, including vasculitis. Antithyroid drugs, despite their postulated immunosuppressive effects, may cause several autoimmune disorders. Here we describe the first patient with central nervous system (CNS) vasculitis that developed shortly after the start of methimazole (MMI) treatment for GD.

PATIENT FINDINGS

CNS vasculitis was suspected on the basis of the clinical features and neurologic examination, showing a reinforcement of deep reflexes, especially of the left knee and Achilles reflexes. The diagnosis was confirmed by a brain magnetic resonance imaging (MRI), which showed some hyperintensive spots in the subcortical substantia alba and in the parietal area bilaterally, and by a single-photon emission computed tomography (SPECT) imaging, which showed a nonhomogenous distribution of the blood flow in the brain, with a reduced perfusion on the left side of the frontotemporal and parietal regions, and on the right side of the frontotemporal area. MMI was stopped before total thyroidectomy, and symptoms resolved in the next 5 weeks. Six months after MMI was stopped, the brain MRI and SPECT had become normal.

SUMMARY

To our knowledge, this is the first report of CNS vasculitis related to MMI therapy.

[Relationship between methimazole and antineutrophil cytoplasmic antibody-positive vasculitis]

OBJECTIVE

To study the relationship between methimazole (MMI) and antineutrophil cytoplasmic antibody (ANCA)-positive vasculitis.

METHODS

Thirty-three cases with Graves' disease were tested for serum ANCA before and after taking MMI. At the same time, clinicopathological data of two patients with Graves' disease who had antineutrophil cytoplasmic antibody-positive vasculitis during treatment with MMI were analyzed.

RESULTS

Two patients developed antineutrophil cytoplasmic antibody-positive vasculitis during the medication with MMI for 5-6 years; their major clinical manifestations were hematuria and renal failure. Renal biology showed renal vasculitis and vascular necrosis. The disease was relieved after treatment with immunosuppressor. Serum ANCA in the 33 cases was negative before taking MMI. In 3 cases serum ANCA became positive after taking MMI for 2 months, 3 months and 2 years, respectively. The positive rate is 9% (3/33). The major finding was microscopic hematuria. ANCA positive rate was significantly higher after taking MMI than that before taking MMI (chi2) = 5.3, P < 0.05). Microscopic hematuria disappeared after general treatment.

CONCLUSION

There may be a relationship between methimazole and development of antineutrophil cytoplasmic antibody-positive vasculitis. Renal impairment can occur. The signs and symptoms of the vasculitis can disappear after proper treatment.

The prevalence of transient thyrotoxicosis after antithyroid drug therapy in patients with Graves' disease

BACKGROUND

Although transient thyrotoxicosis occurring after antithyroid drug (ATD) withdrawal in patients with Graves' hyperthyroidism has been reported, the prevalence of transient thyrotoxicosis after ATD therapy is as yet unknown. When patients with transient hyperthyroidism are mistakenly regarded as recurrences, they receive unnecessary therapy. The aim of this study was to investigate the prevalence of transient thyrotoxicosis after ATD withdrawal.

METHODS

We selected 110 consecutive patients with Graves' disease whose ATD therapy was stopped from December 2002 to September 2004 prospectively. Patients were observed for more than 1 year after ATD withdrawal, and 12 patients dropped out. Serum levels of free thyroxine (FT(4)), thyrotropin, and thyrotropin-binding inhibitor immunoglobulin were measured at ATD withdrawal, and 3, 6, and 12 months after withdrawal. When the patients showed mild thyrotoxicosis (serum FT(4) level of less than 3.00 ng/dL), we followed them up for 1 month without medication.

RESULTS

The remission rate of the study group was 61.8% (68/110). Twenty-eight patients became euthyroid after transient thyrotoxicosis, equivalent to 41.2% of the remission patients. Eight of 28 patients showed overt thyrotoxicosis, and the rest subclinical thyrotoxicosis. Transient thyrotoxicosis occurred mostly 3-6 months after ATD withdrawal.

CONCLUSIONS

Transient thyrotoxicosis after ATD withdrawal in patients with Graves' disease is not a rare phenomenon. Clinicians should be aware that the recurrence of Graves' disease after the withdrawal of ATD may be transient.

Differential diagnosis and appropriate treatment of four thyrotoxic patients with Graves' disease required to take amiodarone due to life-threatening arrhythmia

We report the treatment of four thyrotoxic patients. Two were cases of type I amiodarone-induced thyrotoxicosis (AIT) treated with methimazole. The third Graves' disease patient, who became hypothyroid 25 years after subtotal thyroidectomy, developed type II AIT. Furthermore, one case with heart failure and ventricular tachycardia, who developed an adverse reaction to antithyroid agents and was prescribed amiodarone, underwent total thyroidectomy. The clinical course was uneventful, and the patient is doing well. Since amiodarone contains a large amount of iodine, it is frequently difficult to make a differential diagnosis. Surgical treatment of Graves' disease patients is recommended when immediate control of hyperthyroidism and heart failure is required.

Aplasia cutis congenita with skull defect in a monozygotic twin after exposure to methimazole in utero

BACKGROUND

Aplasia cutis congenita (ACC) is a condition in which localized or widespread areas of skin are absent at birth. Defective lesions show complete absence of all layers of skin, occasionally extending to skull or dura. ACC is etiologically heterogeneous; many different etiologies including teratogens have been documented.

CASE

We describe the first reported case of a monozygotic twin with ACC after exposure to methimazole in utero. The female patient was born at 36 weeks gestation as the first child of monozygotic twins. The mother received methimazole between the 11th and 17th weeks of pregnancy because of transient hyperthyroidism. The second child did not have ACC. The patient had defects of the scalp, skull, and dura (7 x 5 cm) on the sagittal line of the parieto-occipital region. No other malformations were noted. The scalp defect has been treated daily with sterile physiological saline and petrolatum dressing in addition to intravenous antibiotics. Trafermin, a recombinant human fibroblast growth factor, was sprayed from day 6 to promote epithelialization of the scalp defect. On day 21, she had high fever due to infection of the defect lesion, which was controlled by povidone iodine dressing and intravenous antibiotics. The defect of the scalp was well healed after 6 weeks, but the skull defect remained unclosed.

CONCLUSIONS

We describe a rare case of a monozygotic twin with ACC and skull defect after methimazole exposure in utero. The findings of our case suggest that methimazole is a potential teratogen of ACC.

[Methimazole and propylthiouracil induced acute toxic hepatitis]

Hyperthyroidism is one of the most common endocrinology disorders. Treatment can be either pharmacological, surgical or using radioactive iodine. In Europe methimazole is the antithyroid drug of choice because it can be administered in a single daily dose and has a lower risk of adverse reactions. Around 5% of patients taking thionamides can present any of their side effects, which are usually mild. Liver toxicity due to thionamides is very rare, and severe due to propylthiouracil. We present a clinical case of a cholestatic jaundice and acute toxic hepatitis due to methimazole and a cross-reaction with propylthiouracil. Based on this case a review is presented.

Pharmacologic Management of Feline Hyperthyroidism

Radioiodine is considered the treatment of choice for hyperthyroidism, but in some situations, methimazole therapy is preferred, such as in cats with preexisting renal insufficiency. Unfavorable outcomes from methimazole are usually attributable to side effects, such as gastrointestinal upset, facial excoriation, thrombocytopenia, neutropenia, or liver enzyme elevations. Because restoration of euthyroidism can lead to a drop in glomerular filtration rate, all cats treated with methimazole should be monitored with blood urea nitrogen and creatinine levels in addition to serum thyroxine (T(4)) and a complete blood cell count. Transdermal methimazole is associated with fewer gastrointestinal side effects and can be used in cats with simple vomiting or inappetence from oral methimazole. Hypertension may not resolve immediately when serum T(4) is normalized, and moderate to severe hypertension should be treated concurrently with atenolol, amlodipine, or an angiotensin-converting enzyme inhibitor.

Comparison of methimazole and propylthiouracil in patients with hyperthyroidism caused by Graves' disease

CONTEXT

Although methimazole (MMI) and propylthiouracil (PTU) have long been used to treat hyperthyroidism caused by Graves' disease (GD), there is still no clear conclusion about the choice of drug or appropriate initial doses.

OBJECTIVE

The aim of the study was to compare the MMI 30 mg/d treatment with the PTU 300 mg/d and MMI 15 mg/d treatment in terms of efficacy and adverse reactions.

DESIGN, SETTING, AND PARTICIPANTS

Patients newly diagnosed with GD were randomly assigned to one of the three treatment regimens in a prospective study at four Japanese hospitals.

MAIN OUTCOME MEASURES

Percentages of patients with normal serum free T(4) (FT4) or free T(3) (FT3) and frequency of adverse effects were measured at 4, 8, and 12 wk.

RESULTS

MMI 30 mg/d normalized FT4 in more patients than PTU 300 mg/d and MMI 15 mg/d for the whole group (240 patients) at 12 wk (96.5 vs. 78.3%; P = 0.001; and 86.2%, P = 0.023, respectively). When patients were divided into two groups by initial FT4, in the group of the patients with severe hyperthyroidism (FT4, 7 ng/dl or more, 64 patients) MMI 30 mg/d normalized FT4 more effectively than PTU 300 mg/d at 8 and 12 wk and MMI 15 mg/d at 8 wk, respectively (P < 0.05). No remarkable difference between the treatments was observed in patients with initial FT4 less than 7 ng/dl. Adverse effects, especially mild hepatotoxicity, were higher with PTU and significantly lower with MMI 15 mg/d compared with MMI 30 mg/d.

CONCLUSIONS

MMI 15 mg/d is suitable for mild and moderate GD, whereas MMI 30 mg/d is advisable for severe cases. PTU is not recommended for initial use.

Generalised lymphadenomegaly associated with methimazole treatment in a hyperthyroid cat

A nine-year-old, domestic shorthair cat was diagnosed with hyperthyroidism and treated with methimazole, which resulted in lethargy, inappetence and marked generalised lymphadenomegaly within two weeks of initiation of therapy. Cytology, histopathology and immunohistochemistry were suggestive of atypical lymphoid hyperplasia. Cessation of treatment resulted in resolution of all clinical signs and physical abnormalities within two days. Subsequent treatment with radioactive iodine cured this cat of its hyperthyroidism. The lymphadenomegaly did not return at any stage and the cat is currently asymptomatic. Although methimazole administration for feline hyperthyroidism has been associated with many side effects, lymphadenomegaly has, to the authors' knowledge, not been previously reported.

Methimazole embryopathy: A contribution to defining the phenotype

It has been suggested that children prenatally exposed to methimazole may present some features in common but the phenotype remains to be defined. The reported facial features include upward slanted palpebral fissures, arched flared eyebrows and small nose with a broad bridge. Choanal atresia and other anomalies like esophageal atresia and aplasia cutis were also described with this embryopathy. Additionally, developmental delay was reported in some patients along with one of these major malformation. We present a patient with the mentioned facial features, developmental delay and radio-ulnar synostosis whose mother has been exposed to methimazole during pregnancy and any other ethiological cause could be recognize.

The relation of initial methimazole dose to the incidence of methimazole-induced agranulocytosis in patients with Graves' disease

The relation between the incidence of methimazole (methylmercaptoimidazole; MMI)-induced agranulocytosis and initial MMI dose was evaluated in a group of 514 patients with Graves' disease who were treated between 1995 and 2005. One hundred and forty-six (28.40%) patients had received an initial dose of 30 mg MMI and 277 (53.89%) patients had been treated with 15 mg MMI. Nine patients (1.75%) developed agranulocytosis due to MMI treatment. Six (4.11%) of 146 patients who received an initial dose of 30 mg MMI, two (4.54%) of 44 patients given an initial dose of 20 mg MMI, and one (0.36%) of 277 patients given an initial dose of 15 mg MMI developed agranulocytosis. There was a statistically significant difference in agranulocytosis incidence between patients receiving an initial dose of 30 mg MMI and those who received an initial dose of 15 mg. Although 8 (4.10%) of 195 patients in the high-dose group (20 mg or higher) developed agranulocytosis, only 1 (0.31%) of 319 patients in the low-dose group (15 mg or lower) did. In conclusion, the incidence of agranulocytosis with low-dose MMI therapy was ten times lower than that of the high-dose regimen.

[Drug-induced liver failure caused by thiamazole and methimazole--a case report]

Drug-induced liver injury might be responsible for 1 of 600 to 3500 of all hospital admissions. About 2-3% of all drug adverse effects may be connected with the liver. There could be pure injury of heaptic cells or impairment of hepatocellular bile secretion. In our case there was cholestatic liver injury after the use of thiamazole with the complete regression after the discontinuation of the drug. For two years' the patient was treated with methyltiouracyl without any side effects. After 19 years, because of thyreotoxicosis, the methimazole was used. The acute cholestatic liver injury with the high serum bilirubin level (41.4 mg/dl) was observed. Despite the discontinuation of the drug the patient was deceased.

CONCLUSIONS

There are possible cross reactions among imidazolines in patients who are predispose to develop drug-induced liver failure. The doctors should pay much more attention to possible drug side effects.

[Current problems in the treatment of Graves' disease in pregnancy and in lactation]

In Graves' patients complicated by pregnancy, both maternal and fetal problems related to the disease can be reduced or avoided by controlling hyperthyroidism. However, optimal treatment for mothers may exert detrimental effects on fetuses. Methimazole may cause "methimazole embryopathy". Antithyroid drug doses that maintain mothers in euthyroid status are sometimes excessive fetuses. Furthermore, successful treatment with surgery or radioiodine occasionally may result in fetal hyperthyroidism due to TSH receptor antibody(TRAb). There are approaches to manage these problems. Propylthiouracil is chosen in treating Graves' disease in early pregnancy. In later pregnancy, maternal free thyroxine is maintained near or somewhat above normal. Ablative therapy is not recommended in women whose TRAb levels are extremely high from the standpoint of fetal thyroid state.

[Childhood Graves' disease]

Because of the low frequency of childhood Graves' disease, detailed evidence-based clinical studies have not been reported. Practical clinical work has been performed on the basis of adult clinical references. Therapeutic management includes antithyroid drugs, surgical thyroidectomy and radiologic therapy. Recently in the U.S.A. radiotherapy has become the recommended course of action, even for childhood Graves' disease, whereas in Japan, antithyroid drug therapy is the primary course of action for childhood Graves' disease. In some cases, thyroidectomy is performed following drug therapy. Methimazole (MMI) and propylthiouracil (PTU) have been used, however, MMI is the preferred drug treatment. Compared to PTU, MMI is administered once a day and the frequency of side effects is lower than that of PTU. Evaluation of the TSH receptor antibody value before administration of antithyroid drugs is very useful in estimating the duration of the treatment. No appropriate index has been established guiding when to quit antithyroid drug therapy.

Perinuclear antineutrophil cytoplasmic antibody-associated vasculitis in a patient with Graves' disease treated with methimazole

A 15- year-old Caucasian girl presented with a 1-week history of necrotic ulcers on her bilateral lower extremities, associated with fever and malaise. She had had similar ulcerations on and off over the past 3 years. She had a medical history of Graves' disease, diagnosed in 1999, for which she was taking methimazole (MMI). On physical examination, there were multiple necrotic ulcers with elevated, inflamed borders and an overlying eschar on the bilateral distal extremities (Figure 1). There was one hemorrhagic, flaccid bulla on the lateral aspect of the ankle. Her complete blood count, comprehensive metabolic panel, prothrombin time, and international normalized ratio were within normal limits. Histopathology revealed a neutrophilic vasculitis involving small as well as medium-sized blood vessels. The overlying epidermis and upper dermis showed necrosis (Figure 2). Antinuclear antibody (ANA) was positive at 1:160. Perinuclear (p-) antineutrophil cytoplasmic antibody (ANCA) was positive at 1:320. Cytoplasmic ANCA was negative. The patient did not meet any clinical criteria for a diagnosis of lupus erythematosus. Direct immunofluorescence revealed IgM, complement C3, and fibrin in small- and medium-caliber blood vessels in the dermis, consistent with a leukocytoclastic vasculitis of small- and medium-caliber blood vessels (Figure 3). MMI was stopped and the patient was given prednisone, tapered over 5 days. Her thyroid function remained stable, and she did not develop new necrotic ulcers. One month later, the patient developed urticarial lesions on her lower extremities. Histopathology revealed a lymphocytic vascular reaction. No eosinophils or neutrophils were seen. These newer urticarial lesions resolved. The patient underwent debridement of the thick, necrotic ulcerative eschars. To date, her lesions have resolved (Figure 4). An ANA drawn 5 months after withdrawal of MMI was negative, and p-ANCA was 1:67.

A case of transient central hyperthyroidism

BACKGROUND

Thionamides are the main therapeutic arsenal for treating hyperthyroidism. Perhaps the first case of a patient who developed a transient pituitary hyperthyroidism after discontinuation of a lengthy intake of a thionamide is reported.

CASE REPORT

A 48-year-old woman presented with menstrual irregularities when hypothyroidism with pituitary enlargement was detected. She had been undergoing treatment with methimazole for Graves's hyperthyroidism since the age of 34. Three months after discontinuation of methimazole she presented with clinical and laboratory evidence of thyrotoxicosis, with elevated thyroid-stimulating hormone (TSH) levels and blunted response to thyrotropin releasing hormone (TRH). This secondary hyperthyroidism was self-limited and resolved a few months later.

CONCLUSIONS

Chronic primary hypothyroidism caused by lengthy use of thionamides can result in pituitary hyperplasia and transient thyrotrope dysfunction.

Two-day thionamide withdrawal prior to radioiodine uptake sufficiently increases uptake and does not exacerbate hyperthyroidism compared to 7-day withdrawal in Graves' disease

The appropriate period of antithyroid drug (ATD) discontinuation before radioiodine therapy is the most critical problem in Graves' disease patients under going treatment with ATD. To determine the optimal period that does not alter the outcome of radioiodine therapy or exacerbate hyperthyroidism, we compared serum FT4 levels at radioiodine uptake (RAIU) and therapy outcomes between a 2-day withdrawal group and 7-day withdrawal group. We prospectively recruited 43 patients for the 2-day withdrawal protocol and retrospectively reviewed 49 patients treated with radioiodine following the protocol of 7-day withdrawal. There was no significant difference in RAIU between the 2 groups. The mean serum FT4 level measured on the first day of 24-h RAIU of the 7-day group was significantly higher than that in the 2-day group. There were no significant differences in the outcomes at each point (6 months, 1 year, and 2 years after therapy) between the 2 groups. Our results indicated that withdrawal of ATD for 2 days is superior to 7 days in that 2 days discontinuation did not exacerbate hyperthyroidism. In order to prevent serum thyroid hormone increase after ATD withdrawal and radioiodine therapy, a 2-day ATD withdrawal period before radioiodine therapy may be useful for high-risk patients such as the elderly and patients with cardiac complications. We believe that the 2-day ATD withdrawal method may be useful for patients undergoing treatment with ATD who are to undergo radioiodine therapy.

Allergic reactions to antithyroid drugs are associated with autoimmunity a retrospective case-control study

Thiamazole is the most used antithyroid drug for thyrotoxicosis in Basedow-Graves' (BG) (autoimmune) disease and in toxic multinodular goitre (TMG) (non-autoimmune). This study aims to find whether allergic reactions to thiamazole occur more frequently during the treatment of BG than of TMG.

METHOD

Retrospective study, of 128 patients newly diagnosed and treated for thyrotoxicosis in the first 6 months of 2006, in the Endocrinology Department of "Elias" Hospital, Bucharest. Cases were all patients treated with thiamazole who developed allergic reactions. Controls were all patients treated with thiamazole without allergic reactions. Risk factor was considered to be the presence of BG.

RESULTS

Cases group consisted of 6 patients. All 6 started treatment with thiamazole for BG, and developed allergic reactions after 2-4 weeks of treatment. When thiamazole was withdrawn, allergic symptoms ceased under antihistamines and steroids. In order to control the thyrotoxicosis, antihistamines and oral steroids was administered, together with thiamazole in slow increasing doses. After about 4 weeks under this combination, a tolerance to thiamazole seems to appear. Control group consisted of 122 patients who started thiamazole: 66 for BG and 56 for TMG (without allergic reactions).

CONCLUSION

Allergy to thiamazole was significantly associated with the autoimmune BG, and not with TMG (p = 0.03, OR = 11.04). None of the patients with TMG developed allergic reactions to the drug. Tolerance to this drug may occur.

Cholestasis secondary to hyperthyroidism made worse by methimazole

A 28-year-old man presented with weight loss, jaundice, and pruritus. This was diagnosed to be secondary to Graves disease and the patient was prescribed methimazole. He returned 2 weeks later with worsening of his jaundice. Further investigation, including liver biopsy, indicated that there was superimposed methimazole-induced cholestasis. Discontinuation of methimazole and treatment of hyperthyroidism with lithium followed by radioactive iodine therapy resulted in resolution of his symptoms. This case highlights the fact that worsening cholestasis after therapy for Graves disease should raise the possibility of thionamide-induced exaggeration of liver cholestasis.

[Prevalence of allergy to drugs in a group of asthmatic children and adolescents of northeast of Mexico]

BACKGROUND

Drug adverse reactions are a common cause of morbidity and they constitute an important challenge in medical practice. The allergic reactions represent only a small proportion of all the drug adverse reactions and although their real prevalence is unknown, some estimated numbers have been suggested. It seems that atopia is not a risk factor for the development of this kind of reactions.

PATIENTS AND METHODS

A cross-sectional descriptive study was performed to assess the prevalence of drug allergy in asthmatic children of the northeast of Mexico that attend summer camps. We investigated the history of drug adverse reactions and their clinical features in 90 atopic asthmatic patients from 5 to 15 years old which were evaluated trough a questionnaire that was completed by their parents.

RESULTS

Eight of the 90 evaluated patients (8.8%) had history of adverse reactions to some drug. The drugs involved in that reactions were: penicillin in four patients (50%), aspirin in 2 (25%), trimethoprim and sulfamethoxazole in one (12.5%) and metamizole sodium in one (12.5%). The most common administration route was oral. In all of the cases the diagnosis was made on clinical basis. One of the patients had suffered from anaphylaxis, but in the other seven, urticaria was the unique clinical manifestation of the reaction. In all of the affected patients, the reactions were totally resolved in less than 48 hours.

CONCLUSIONS

The prevalence of drug allergy in this group was similar to that reported in general population. Penicillin was the most common involved drug and urticaria was the most frequent clinical manifestation.

Continuous methimazole therapy and its effect on the cure rate of hyperthyroidism using radioactive iodine: an evaluation by a randomized trial

BACKGROUND

A randomized clinical trial was performed to clarify whether continuous use of methimazole (MTZ) during radioiodine ((131)I) therapy influences the final outcome of this therapy.

DESIGN

Consecutive patients with Graves' disease (n = 30) or a toxic nodular goiter (n = 45) were rendered euthyroid by MTZ and randomized to stop MTZ 8 d before (131)I (-MTZ; n = 36) or to continue MTZ until 4 wk after (131)I (+MTZ; n = 39). Calculation of the (131)I activity included an assessment of the (131)I half-life and the thyroid volume.

RESULTS

The 24-h thyroid (131)I uptake was lower in the +MTZ group than in the -MTZ group (44.8 +/- 15.6% vs. 62.1 +/- 9.9%, respectively; P < 0.001). At 3 wk after therapy, no significant change in serum free T(4) index was observed in the +MTZ group (109 +/- 106 vs. 83 +/- 28 nmol/liter at baseline; P = 0.26), contrasting an increase in the -MTZ group (180 +/- 110 vs. 82 +/- 26 nmol/liter; P < 0.001). The number of cured patients was 17 (44%) and 22 (61%) in the +MTZ and -MTZ groups, respectively (P = 0.17). Cured patients tended to have a lower 24-h thyroid (131)I uptake (50.1 +/- 13.8% vs. 56.4 +/- 17.1%; P = 0.09). By adjusting for a possible interfactorial relationship through a regression analysis (variables: randomization, 24- and 96-h thyroid (131)I uptake, type and duration of disease, age, gender, presence of antithyroid peroxidase antibodies, thyroid volume, dose of MTZ), only the continuous use of MTZ correlated with treatment failure (P = 0.006), whereas a low 24-h thyroid (131)I uptake predicted a better outcome (P = 0.006).

CONCLUSION

Continuous use of MTZ hinders an excessive increase of the thyroid hormones during (131)I therapy of hyperthyroid diseases. However, such a strategy seems to reduce the final cure rate, although this adverse effect paradoxically is attenuated by the concomitant reduction of the thyroid (131)I uptake.

Therapeutic drug monitoring of antithyroid drugs in pregnancy: the knowledge gaps

Despite being a common condition in pregnancy, and despite propylthiouracil (PTU) being perceived as safer than methimazole, there are virtually no epidemiological controlled studies on malformation rate an neurobehavioral outcomes with the former. This knowledge gap must be filled to ensure fetal safety.

Medical management of hyperthyroidism

Radioiodine is considered the treatment of choice for hyperthyroidism, but in some situations, methimazole therapy is preferred, such as in cats with pre-existing renal insufficiency. Methimazole blocks thyroid hormone synthesis, and controls hyperthyroidism in more than 90% of cats that tolerate the drug. Unfavorable outcomes are usually due to side effects such as gastrointestinal (GI) upset, facial excoriation, thrombocytopenia, neutropenia, or liver enzyme elevations; warfarin-like coagulopathy or myasthenia gravis have been reported but are rare. Because restoration of euthyroidism can lead to a drop in glomerular filtration rate, all cats treated with methimazole should be monitored with BUN and creatinine, in addition to serum T4, complete blood count, and liver enzymes. Transdermal methimazole is associated with fewer GI side effects, and can be used in cats with simple vomiting or inappetance from oral methimazole. Hypertension may not resolve immediately when serum T4 is normalized, and moderate to severe hypertension should be treated concurrently with-atenolol, amlodipine, or an ACE inhibitor. Alternatives to methimazole include carbimazole, propylthiouracil, or iodinated contrast agents.

Serum thyrotropin receptor antibodies concentrations in patients with Graves' disease before, at the end of methimazole treatment, and after drug withdrawal: evidence that the activity of thyrotropin receptor antibody and/or thyroid response modify during the observation period

AIM AND METHODS

We performed a quantitative retrospective analysis of serum thyrotropin receptor antibody (TRAb) concentrations measured by a second-generation radioreceptor assay in 58 patients with Graves' disease (GD) at the onset of the disease, at the end of 18 month methimazole (MMI) treatment, and after MMI withdrawal in order to evaluate the correlation between the presence of these antibodies and the relapse of hyperthyroidism. Sixty healthy subjects were enrolled as a control group.

RESULTS

Before MMI treatment the best cutoff TRAb value for identifying patients with GD was 1.45 UI/L (specificity, 100%; sensitivity, 98.3%). At the end of MMI treatment, serum TRAb concentrations were significantly lower (p < 0.001) than those measured at baseline, but they were still significantly higher (p < 0.001) than those found in the control subjects. At the end of MMI treatment, 44 patients (75.9%) had positive TRAb values (>1.45 UI/L). After MMI withdrawal (median, 15 months), 34 patients (58.6%) became hyperthyroid, 4 patients (6.9%) became hypothyroid, and 20 patients (34.5%) remained euthyroid. There was a significant correlation between serum TRAb concentrations at the end of MMI treatment and the percentage of patients who became hyperthyroid (r: 0.56; p < 0.001) and the time of appearance of hyperthyroidism (r: -0.38; p = 0.03). All 4 patients with TRAb values below 0.9 UI/L at the end of MMI treatment remained euthyroid throughout the follow-up period. Among the 27 patients who had serum TRAb values higher than 4.4 UI/L, 23 developed hyperthyroidism and 4 hypothyroidism. The TRAb values between 0.9 and 4.4 UI/L did not discriminate between the 27 patients (46.6%) who remained euthyroid from those who had relapse of hyperthyroidism. Thus a different TRAb end of treatment cutoff was calculated to identify patients who became again hyperthyroid. This TRAb cutoff value was 3.85 UI/L (sensitivity, 85.3%; specificity, 96.5%). All but 1 patient who had serum TRAb values above 3.85 UI/L became hyperthyroid after MMI was withdrawn (positive predictive value, 96.7%). In these patients, relapse of hyperthyroidism was independent of the changes in serum TRAb concentrations (r: 0.27; p = 0.15) and occurred after a median period of 8 weeks (range, 4-48). Hyperthyroidism also developed in 5 of 24 patients who had serum TRAb concentrations lower than 3.85 UI/L at the end of MMI treatment. In these 5 patients the relapse of hyperthyroidism occurred after a median period of 56 weeks (range, 24-120) and was always accompanied by an increase in serum TRAb concentrations.

CONCLUSIONS

TRAb persist in the blood of most patients with GD after 18 months of MMI treatment. Both the frequency and the time of appearance of hyperthyroidism are closely correlated with serum TRAb concentrations at the end of MMI treatment. Our data would suggest that TRAb maintain stimulating activity after a full course of MMI treatment in the large majority of patients with GD. However, it is likely that the potency of these antibodies and/or the thyroid response to them change during treatment, as suggested by the different values measured in euthyroid control subjects and in euthyroid patients after MMI treatment.

Elevation of serum creatine kinase in response to medical treatment of Graves' disease in children

We describe two cases of increases in serum creatine kinase (CK) concentrations in children undergoing treatment of Graves' disease with antithyroid medications. Presenting complaints consisted of myalgias and muscle cramping in both patients, and increases in serum CK levels were noted 1 mo after initiation of antithyroid drugs. Both patients were euthyroid at the time of CK elevation. While the mechanisms for this process are not clear, it is likely that the acute decrease of thyroid hormones in tissues following a state of chronic hyperthyroidism may result in relative hypothyroid states and subsequent alterations in CK concentrations.

CONCLUSION

Although this side effect has been reported in adults, it is a novel finding in children. Clinicians should be aware of the rare potential for elevations in serum CK when initiating treatment for Graves' disease in children.

[Possible teratogenic effects of thiamazole]

A newborn male presented with choanal atresia and minor dysmorphic facial features. At 4 years of age he showed delayed speech and language development. His mother had been treated with thiamazole for pre-existing hyperthyroidism during the first 3 months of pregnancy. It is possible that the maternal use of thiamazole caused the congenital anomalies. Embryopathy caused by maternal thiamazole use during pregnancy has been described several times before and is mainly characterised by choanal atresia, oesophageal atresia, minor dysmorphic facial features, growth retardation and delayed psychomotor development. Because the use of propylthiouracil during pregnancy has not been associated with similar effects, it is the treatment of choice for hyperthyroidism during pregnancy. For pregnant women or women who wish to become pregnant, thiamazole should be prescribed only ifpropylthiouracil cannot be used.

Successful treatment of methimazole-induced severe aplastic anemia with recombinant human granulocyte colony-stimulating factor and high-dosage steroids

The best-known adverse hematologic reaction of methimazole is agranulocytosis. Aplastic anemia is extremely rare. The prognosis within the entity of aplastic anemias is surprisingly good, despite the severe and prolonged course of the disease. The present article reports the case of a 74-yr-old female patient who exhibited aplastic anemia with severe clinical symptoms 8 weeks after the initiation of methimazole administration. The hemorrhagic symptoms were aggravated by a coumarin overdose. Supportive hemotherapy and antibiotic treatment were supplemented with recombinant human granulocyte colony-stimulating factor and high-dosage corticosteroids. The granulocyte count normalized on day 5 of treatment, the platelet count exceeded the critical value on day 11, and on day 25 the patient was discharged in remission.

The safety and efficacy of antithyroid drugs

Thionamides, selective inhibitors of thyroid peroxidase-mediated iodination by tyrosine residues in thyroglobulin, have been effectively used in the treatment of hyperthyroidism. The choices for initial treatment of patients with Graves' disease differ in various countries, and many physicians around the world prefer to administer thionamide drugs as the first choice of treatment for patients with hyperthyroidism. Although some thyroidologists more often consider radioiodine to be the treatment of choice because of its safety and ease of administration, thionamides remain the mainstay of treatment in thyrotoxic children and adolescents and in hyperthyroid women during pregnancy, postpartum period and lactation. A recent study with continuous thionamide treatment for patients with Graves' disease shows its efficacy, safety and cost-benefit properties. Further studies of the effectiveness of continuous thionamide therapy in patients with thyrotoxicosis need to be designed and implemented to determine indications for such therapy in children, adolescents and adults with diffuse toxic goiter, in particular, in those who have had recurrence of hyperthyroidism after discontinuation of one complete course of treatment.

Effects of thyroid function on the course of experimental chronic renal failure in rats

Thyroid hormone has been reported to affect renal function. To investigate the effects of thyroid hormone on the progression of renal deterioration, thyroid hormone (dried thyroid) and an antithyroid drug (thiamazole) were administered to adriamycin (ADR)-induced renal failure rats. The rats were divided into four groups, including 1) ADR-DT, given dried thyroid and thiamazole; 2) ADR-T, given thiamazole; 3) ADR; and 4) control. The survival rate at the end of the study (22 weeks) was 62.5% in ADR-DT group and 100% in ADR-T, ADR, and control groups, respectively. There was a significant difference in the body weight and pulse rate between ADR-DT and ADR-T or ADR groups, except for the pulse rate at week 6 (P<0.05). The creatinine clearance was greater in the ADR-T group than in the ADR or ADR-DT groups at week 22, and was significantly different between the ADR-T and the ADR-DT groups (P<0.05). The fractional kidney weight and tubular changes were significantly greater in the ADR-DT group than in the ADR-T or ADR groups (P<0.05). The interstitial volume was significantly greater in the ADR-DT group than in the ADR-T group (P<0.05). We therefore conclude that a dried thyroid has an aggravative effect in the tubular changes and relative interstitial volume induced by ADR.