Methimazole-induced severe aplastic anemia: unsuccessful treatment with recombinant human granulocyte-monocyte colony-stimulating factor

Clinical characteristics of antithyroid drug-induced aplastic anemia cases over the past 30 years

OBJECTIVE

The authors aimed to investigate the clinical characteristics of antithyroid drug-induced aplastic anemia cases over the past 30 years.

METHODS

The data of patients with antithyroid drug-induced aplastic anemia were retrieved from PubMed and Wanfang Medical Network databases from 1992 to August 2022. The clinical characteristics, such as age distribution, gender tendency, common symptoms, blood cell count, bone marrow features, treatment strategy, and prognosis, were analyzed.

RESULTS

A total of 17 cases (male:female = 1:16) had been retrieved. Patients' age ranged from 16 to 74 years (median 50 years). Among them, 82.3% (14/17) of the patients were administered methimazole (MMI), and 78.6% of them had MMI ≥30 mg/day. In addition, 88.2% (15/17) of the patients had sore throat and fever, and 47.1% (8/17) of the patients had hemorrhagic symptoms. Aplastic anemia occurred within 6 months after initiation of the antithyroid therapy in 94.1% of the patients. Agranulocytosis (94.1%) was the most common and earliest blood cell change, and 47.1% of the patients experienced progressive platelet decline during the treatment process. The treatments include timely withdrawal of antithyroid drugs, broad-spectrum antibiotics, granulocyte colony-stimulating factor (G-CSF)/granulocyte-macrophage colony-stimulating factor (GM-CSF), glucocorticoids and other immunosuppressive agents, and supportive treatments such as erythrocyte transfusion and platelet transfusion. Moreover, 70.6% of the patients had complete or near-complete remission within 8 days to 6 weeks.

CONCLUSION

Aplastic anemia is a rare and serious adverse reaction of antithyroid drugs, which is more common in women. It usually occurs during early treatment with high-dose antithyroid drugs. Most patients have a good prognosis after timely drug ceasing and appropriate treatment.

A comparison of thyroidal protection by iodine and perchlorate against radioiodine exposure in Caucasians and Japanese

Radioactive iodine released in nuclear accidents may accumulate in the thyroid and by irradiation enhances the risk of cancer. Radioiodine uptake into the gland can be inhibited by large doses of stable iodine or perchlorate. Nutritional iodine daily intake may impact thyroid physiology, so that radiological doses absorbed by the thyroid as well as thyroid blocking efficacy may differ in Japanese with a very rich iodine diet compared to Caucasians. Based on established biokinetic-dosimetric models for the thyroid, we derived the parameters for Caucasians and Japanese to quantitatively compare the effects of radioiodine exposure and the protective efficacy of thyroid blocking by stable iodine at the officially recommended dosages (100 mg in Germany, 76 mg in Japan) or perchlorate. The maximum transport capacity for iodine uptake into the thyroid is lower in Japanese compared to Caucasians. For the same radioiodine exposure pattern, the radiological equivalent thyroid dose is substantially lower in Japanese in the absence of thyroid blocking treatments. In the case of acute radioiodine exposure, stable iodine is less potent in Japanese (ED50 = 41.6 mg) than in Caucasians (ED50 = 2.7 mg) and confers less thyroid protection at the recommended dosages because of a delayed responsiveness to iodine saturation of the gland (Wolff-Chaikoff effect). Perchlorate (ED50 = 10 mg in Caucasians) at a dose of 1000 mg has roughly the same thyroid blocking effect as 100 mg iodine in Caucasians, whereas it confers a much better protection than 76 mg iodine in Japanese. For prolonged exposures, a single dose of iodine offer substantially lower protection than after acute radioiodine exposure in both groups. Repetitive daily iodine administrations improve efficacy without reaching levels after acute radioiodine exposure and achieve only slightly better protection in Japanese than in Caucasians. However, in the case of continuous radioiodine exposure, daily doses of 1000 mg perchlorate achieve a high protective efficacy in Caucasians as well as Japanese (> 0.98). In Caucasians, iodine (100 mg) and perchlorate (1000 mg) at the recommended dosages seem alternatives in case of acute radioiodine exposure, whereas perchlorate has a higher protective efficacy in the case of longer lasting radioiodine exposures. In Japanese, considering protective efficacy, preference should be given to perchlorate in acute as well as prolonged radioiodine exposure scenarios.

A Clinical Debate: What Is the Therapeutic Choice for Recurrent Graves' Hyperthyroidism?

Collapse

A comparison of thyroidal protection by stable iodine or perchlorate in the case of acute or prolonged radioiodine exposure

In the case of a nuclear power plant accident, repetitive/prolonged radioiodine release may occur. Radioiodine accumulates in the thyroid and by irradiation enhances the risk of cancer. Large doses of non-radioactive iodine may protect the thyroid by inhibiting radioiodine uptake into the gland (iodine blockade). Protection is based on a competition at the active carrier site in the cellular membrane and the Wolff-Chaikoff effect, the latter being, however, only transient (24-48 h). Perchlorate may alternatively provide protection by a carrier competition mechanism only. Perchlorate has, however, a stronger affinity to the carrier than iodide. Based on an established biokinetic-dosimetric model developed to study iodine blockade, and after its extension to describe perchlorate pharmacokinetics and the inhibition of iodine transport through the carrier, we computed the protective efficacies that can be achieved by stable iodine or perchlorate in the case of an acute or prolonged radioiodine exposure. In the case of acute radioiodine exposure, perchlorate is less potent than stable iodine considering its ED50. A dose of 100 mg stable iodine has roughly the same protective efficacy as 1000 mg perchlorate. For prolonged exposures, single doses of protective agents, whether stable iodine or perchlorate, offer substantially lower protection than after acute radioiodine exposure, and thus repetitive administrations seem necessary. In case of prolonged exposure, the higher affinity of perchlorate for the carrier in combination with the fading Wolff-Chaikoff effect of iodine confers perchlorate a higher protective efficacy compared to stable iodine. Taking into account the frequency and seriousness of adverse effects, iodine and perchlorate at equieffective dosages seem to be alternatives in case of short-term acute radioiodine exposure, whereas preference should be given to perchlorate in view of its higher protective efficacy in the case of longer lasting radioiodine exposures.

Methimazole-Induced Aplastic Anemia with Concomitant Hepatitis in a Young Filipina with Graves' Disease

A 34-year-old female Filipino with Graves' disease on methimazole came in due to fever, sore throat and jaundice. She was initially diagnosed with methimazole-induced agranulocytosis and drug-induced liver injury. She was treated with intravenous broad-spectrum antibiotic and granulocyte colony stimulating factor. On day 4 of admission, she developed pancytopenia and was managed as methimazole-induced aplastic anemia. She was started on steroid therapy and received 1 unit of packed red blood cell. The jaundice also increased, hence, she was given ursodeoxycholic acid. On day 9 of admission, with the consideration of "lineage steal phenomenon," biopsy was done and eltrombopag was started. Patient was discharged stable at 12th hospital day. This case presents 3 rare life-threatening complications of methimazole namely: agranulocytosis, aplastic anemia and hepatitis.

Nuclear medicine imaging and therapy: gender biases in disease

Gender-based medicine is medical research and care conducted with conscious consideration of the sex and gender differences of subjects and patients. This issue of Seminars is focused on diseases for which nuclear medicine is part of routine management and for which the diseases have sex- or gender-based differences that affect incidence or pathophysiology and that thus have differences that can potentially affect the results of the relevant nuclear medicine studies. In this first article, we discuss neurologic diseases, certain gastrointestinal conditions, and thyroid conditions. The discussion is in the context of those sex- or gender-based aspects of these diseases that should be considered in the performance, interpretation, and reporting of the relevant nuclear medicine studies. Cardiovascular diseases, gynecologic diseases, bone conditions such as osteoporosis, pediatric occurrences of some diseases, human immunodeficiency virus-related conditions, and the radiation dose considerations of nuclear medicine studies are discussed in the other articles in this issue.

Successful treatment of methimazole-induced severe aplastic anemia by granulocyte colony-stimulating factor, methylprednisolone, and cyclosporin

A 52-year-old Japanese woman was examined because of general malaise, weight loss and a lump in her left breast. She was diagnosed with cancer of the left breast and Graves' disease, and was administered methimazole (MMI). A left mastectomy was performed for the breast cancer. She presented with a high fever and peripheral blood examination revealed a severe pancytopenia. She was diagnosed with severe aplastic anemia, and administered G-CSF, however, the treatment was unsuccessful. Thus, oral methyprednisolone and cyclosporin were added. There was a remarkable improvement in the peripheral blood count.

[Carbimazole can be the cause of iron deficiency anemia?]

Iron deficiency anemia as a hematologic complication of the antithyroid medication (ATS) that has not been already described in the literature. We report on two exceptional cases: the first case concerns a 24 years old man admitted for an anemic syndrome. He was treated with carbimazole for Graves' disease. The blood count showed a non-regenerative microcytic anemia. Serum ferritin was severely decreased. The etiologic searching for bleeding, hemolysis, malabsorption or iron deficiency was negative. Treatment with iron salts was introduced without any real improvement. Given this situation, and given the negativity of the etiologic investigations, the decision to stop carbimazole was taken. Since that, the clinical and biological evolutions have been favorable. The second observation is much more original and concerns a 35 years old woman. The clinical, laboratory, etiological and treatment data are similar to those of the first observation. The evolution after withdrawal of carbimazole was favorable. The originality of this observation is that a reintroduction test of carbimazole was performed and allowed to reproduce the same haematological effects. These findings led us to hold the diagnosis of anaemia due to carbimazole. In this occasion, and in the light of the data in the literature, we underline the exceptional character of these two cases and we raise the possibility of an etiopathogenic link between administration of ATS and the occurrence of anaemia by iron deficiency.

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.

Pancytopenia in untreated patients with Graves' disease

Severe pancytopenia is a rare but severe complication of thyrotoxicosis. In this report, we describe four patients with Graves' disease who presented with pancytopenia at diagnosis. Methimazole (30-40 mg/d) or propylthiouracil (400 mg/d) restored normal hematopoiesis in three of the patients. The remaining patient evolved to aplastic anemia under therapy with methimazole (60 mg/d), but had an increased peripheral blood count that almost reached normal values after radioiodinetherapy and standard immunosuppressive treatment with antithymocyte globulin (700 mg/d, intravenous infusion for 5 days), oral cyclosporin (400 mg/d), prednisone (30-60 mg/d), and granulocyte colony-stimulating factor (150 microg subcutaneous injection, 3 times per week). We conclude that: (1) a hematologic evaluation of all patients with Graves' disease should be performed before administering antithyroid drugs, (2) antithyroid drugs may be administered to patients with pancytopenia and bone marrow hypercellularity but a reevaluation of the bone marrow must be done if there is no recovery of the peripheral blood cell count when euthyroidism state is achieved, (3) standard immunosuppressive treatment of aplastic anemia caused by antithyroid drugs restores normal hematopoiesis, and (4) a thyroid evaluation of patients with pancytopenia should be done, even though no related symptoms are found.

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.

Methimazole-induced aplastic anemia caused by hypocellular bone marrow with plasmacytosis

Aplastic anemia is a rare but severe complication of methimazole (MMI) treatment for Graves' disease. We present a case of a 53-year-old Japanese female who had been treated with 30 mg/d of MMI for 30 days for Graves' disease and was subsequently admitted to the Japan Self Defense Forces (JSDF) Central Hospital with a mild sore throat and high-grade fever that began the previous day. The patient had a reduced white blood cell count (WBC) count of 0.9 x 10(3) per microliter with severe granulocytopenia and increased lymphocytes, a platelet count of 49 x 10(3) per microliter, and hemoglobin of 10.6 g/dL. Bone marrow (BM) aspirates showed hypocellular bone marrow with plasmacytosis. Because of poor recovery of her peripheral blood values after withdrawal of MMI, she was given transfusions of platelets and erythrocytes thereafter. This is the second report of plasmacytosis in bone marrow of MMI-induced aplastic anemia, and suggests that immunogenic mechanisms may cause this rare complication.

Extrathyroidal actions of antithyroid thionamides

Some compounds having thionamide structure inhibit thyroid functions. Such antithyroid thionamides include mercaptomethylimidazole (methimazole), thiourea and propylthiouracil, of which mercaptomethylimidazole is widely used to treat hyperthyroidism. Undesirable side effects develop from these drugs due to extrathyroidal actions. Antithyroid thionamides inhibit lactoperoxidase which contributes to the antibacterial activities of a number of mammalian exocrine gland secretions that protect a variety of mucosal surfaces. These drugs stimulate both gastric acid and pepsinogen secretions, thereby augmenting the severity of gastric ulcers and preventing wound healing. Increased gastric acid secretion is partially due to the H2 receptor activation, and also through the stimulation of the parietal cell by intracellular generation of H2O2 following inactivation of the gastric peroxidase-catalase system. Severe abnormalities may develop in blood cells and the immune system after thionamide therapy. It causes agranulocytosis, aplastic anemia, and purpura along with immune suppression. Olfactory and auditory systems are also affected by these drugs. Thionamide affects the sense of smell and taste and also causes loss of hearing. It binds to the Bowman's glands in the olfactory mucosa and causes extensive lesion in the olfactory mucosa. Thionamides also affect gene expression and modulate the functions of some cell types. A brief account of the chemistry and metabolism of antithyroid thionamides, along with their biological actions are presented.

Massive plasmocytosis due to methimazole-induced bone marrow toxicity

Pancytopenia is a rare complication of the thionamide therapy reported secondary to aplastic anemia, the bone marrow being invariably hypocellular. We present a case of a 16-year-old female with Graves' disease who presented with massive bone marrow plasmocytosis mimicking multiple myeloma. The patient had already been on methimazole for a month when she was admitted to the Pediatric Unit with the diagnosis of sepsis. CBC revealed pancytopenia. Bone marrow aspirations showed hypocellular-normocellular bone marrow, 98% of plasma cells. At that time, MMI was discontinued and the patient was started on broad-spectrum antibiotics, dexamethasone, and G-CSF. Bone marrow aspiration day +4 still showed hypo-normocellular marrow, with remaining 6% plasma cells. Myeloma screen was negative; ANC >1,000 at day +7, platelets >50,000 at day +24. Twenty-four months after patient's discharge, her clinical condition, CBC, and bone marrow remained normal. To our knowledge this is the first report of pancytopenia due to MMI, where the usual hypoplasia found is replaced by massive plasmocytosis.

Serum levels of adhesion molecules in children and adolescents with immune and non-immune thyroid diseases

Serum levels of sICAM-1, sVCAM-1 and sP-selectin were determined in patients with Graves' disease before and after 8 weeks and 24 months of methimazole therapy, in levothyroxine suppressed patients with non-toxic nodular goiter, and in a group of healthy controls, to elucidate the relationship to circulating antithyroid antibodies and possible role of soluble adhesion molecules as markers of inflammatory activity. sICAM-1, sVCAM-1, and sP-selectin in patients with untreated hyperthyroidism were markedly elevated compared with controls. After 8 weeks of methimazole treatment, the concentrations of these molecules dropped, but were still significantly higher than in healthy children. In patients with clinical and biochemical remission after 24 months of therapy, sICAM-1 values were on the verge of significance, but still higher than in the control group, whereas serum levels of sVCAM-1 and sP-selectin had normalized. Slightly higher serum sICAM-1 values were observed in patients with non-toxic nodular goiter compared with healthy children.

Methimazole-induced aplastic anemia in third exposure: successful treatment with recombinant human granulocyte colony-stimulating factor

The major adverse reactions of antithyroid drugs are hematologic; aplastic anemia (AA) is one of the rarest and most severe complications. Use of recombinant human hemopoietic colony-stimulating factor was reported to be of benefit in patients who developed agranulocytosis, although there is still some doubt regarding the efficacy in AA. We present a case of a 58-year-old female patient with Graves' disease who developed AA in the third exposure to methimazole (MMI). The withdrawal of MMI and early treatment with 5 microg/kg per day recombinant human granulocyte colony-stimulating factor (G-CSF) for 9 days, allowed a favorable recovery of peripheral blood cell count. We conclude that the use of hemopoietic colony stimulating factors might be a suitable means to achieve the correction of severe thionamide-induced hematologic adverse reactions.