Propylthiouracil-induced agranulocytosis: an unusual presentation and a possible mechanism

Therapeutic Plasma Exchange for the Treatment of Hyperthyroidism: Approach to the Patient with Thyrotoxicosis or Antithyroid-Drugs Induced Agranulocytosis

Primary hyperthyroidism is an endocrine disorder characterized by excessive thyroid hormone synthesis and secretion by the thyroid gland. Clinical manifestations of hyperthyroidism can vary from subclinical to overt forms. In rare cases, hyperthyroidism may represent a clinical emergency, requiring admission to an intensive care unit due to an acute and severe exacerbation of thyrotoxicosis, known as a thyroid storm. First-line treatment of hyperthyroidism is almost always based on medical therapy (with thioamides, beta-adrenergic blocking agents, glucocorticoids), radioactive iodine or total thyroidectomy, tailored to the patient’s diagnosis. In cases of failure/intolerance/adverse events or contraindication to these therapies, as well as in life-threatening situations, including a thyroid storm, it is necessary to consider an alternative treatment with extracorporeal systems, such as therapeutic plasma exchange (TPE). This approach can promptly resolve severe conditions by removing circulating thyroid hormones. Here we described two different applications of TPE in clinical practice: the first case is an example of thyrotoxicosis due to amiodarone treatment, while the second one is an example of a severe adverse event to antithyroid drugs (agranulocytosis induced by methimazole).

Can neutrophil/lymphocyte ratio be used as an indicator of inflammation in patients with hyperthyroidism?

Background

In our study, we aimed to evaluate changes in the neutrophil and lymphocyte series and investigate whether the neutrophil/lymphocyte ratio (NLR) is indicative of inflammations in patients with hyperthyroidism.

Methods

A total of 161 patients were enrolled, 121 of which had hyperthyroidism (71 Graves' Disease (GD) and 50 non-Graves hyperthyroidism (NGH) patients) and 40 of which were control group members. Retrospectively, patients' neutrophil and lymphocyte counts were taken, and the NLR was calculated.

Results

While the number of neutrophils was significantly lower in the GD group (p = 0.003), there was no significant difference between the NGH and the control group. In the GD group, NLR values were significantly lower than the other two groups (median 1.39 for GD, median 1.84 for NGH and median 1.83 for the control group, p < 0.001). Only three patients in the GD group had neutropenia. There was also a significant negative correlation between free T3 and neutrophil count and NLR in hyperthyroid patients (r = -0.28, p = 0.001 and r = -0.34, p < 0.001, respectively).

Conclusions

In our study, we found that NLR did not in crease in hyperthyroid patients and that this ratio decreased due to the decrease in neutrophil levels in GD. We thus concluded that NLR is not a suitable indicator of hyperthyroidism.

Use of granulocyte colony-stimulating factor in the treatment of methimazole-induced agranulocytosis: a case report

A comparison of this case to previously published reports suggests that granulocyte colony‐stimulating factor may be associated with improved prognosis in severe antithyroid drug‐induced neutropenia, and that weight‐based doses could be an appropriate strategy.

Concomitant Agranulocytosis and Hepatotoxicity After Treatment with Carbimazole

Objective:

To describe a case of agranulocytosis and severe hepatotoxicity associated with Carbimazole treatment.

Case Summary:

A 37-year-old woman was diagnosed with severe hyperthyroidism resulting from Graves' disease. Treatment with Carbimazole 30 mg/day was initiated. Within 15 days following the start of therapy, both minor (eg, pruritus, rash, urticaria, fever, arthralgias) and potentially life-threatening (eg, agranulocytosis, severe mixed hepatotoxicity with severe cholestatic jaundice) adverse effects developed. The patient's symptoms and laboratory abnormalities resolved following withdrawal of Carbimazole. Treatment with other antithyroid drugs was not attempted, and 131I ablation of the thyroid was successfully performed. Thyroid function was maintained with standard follow-up care. Agranulocytosis, identified following bone marrow biopsy, was treated with granulocyte colony-stimulating factor.

Discussion:

Agranulocytosis and hepatotoxicity are rare adverse effects associated with Carbimazole treatment and are usually dose- and age-related. The likelihood that Carbimazole induced these undesirable events in our patient is rated as probable based on the Naranjo probability scale. We believe this case to be the first to describe minor and major adverse effects related to Carbimazole therapy in a patient with Graves' disease.

Conclusions:

Major adverse effects associated with Carbimazole are infrequent. However, clinicians need to be aware that the effects described here, including severe liver failure and bone marrow toxicity, may occur in patients receiving this drug.

Treatment of hyperthyroidism with antithyroid drugs corrects mild neutropenia in Graves' disease

CONTEXT

Neutropenia secondary to antithyroid drug (ATD) therapy in Graves' disease (GD) is well recognized. However, the effect of hyperthyroidism, prior to and after ATD therapy, on neutrophil counts in patients with GD is unclear.

OBJECTIVE

To study the prevalence of neutropenia in newly diagnosed untreated GD and the effect of ATD on the neutrophil count.

DESIGN

Prospective study from August 2010 to December 2014.

SETTING

Endocrinology outpatient clinic in a single centre.

PATIENTS

Consecutive patients (n = 206) with newly diagnosed GD.

INTERVENTION

ATD therapy.

MAIN OUTCOME MEASURES

Prevalence and factors predicting neutropenia (<2 × 10⁹ /l) and change in neutrophil counts following ATD.

RESULTS

At diagnosis, 29 (14·1%) of GD individuals had neutropenia. Non-Caucasians [odds ratio (95% CI) of 4·06 (1·14-14·45), P = 0·03] and patients with higher serum thyroid hormone levels [OR 1·07 (1·02-1·13), P = 0·002 for serum FT3] were the only independent predictors of neutropenia. All patients with neutropenia had normalized blood neutrophil levels after achieving euthyroidism with ATD therapy. In patients in whom data were available posteuthyroidism (n = 149), change in neutrophil count after achieving euthyroidism was independently related to reduction in thyroid hormone levels (P < 0·01).

CONCLUSIONS

GD is associated with neutropenia in one in seven patients at diagnosis, especially in non-Caucasians and those with higher serum thyroid hormone levels. Neutrophil counts increase with treatment with ATD and are related to reduction in thyroid hormone concentrations. It is therefore important to check neutrophil levels in newly diagnosed patients with GD prior to commencing ATD therapy as otherwise low levels may incorrectly be attributed to ATD therapy.

Characteristics of Korean Patients with Antithyroid Drug-Induced Agranulocytosis: A Multicenter Study in Korea

BACKGROUND

Antithyroid drugs (ATDs) can lead to the development of agranulocytosis, which is the most serious adverse effect. Characteristics of ATD-induced agranulocytosis (AIA) have seldom been reported due to the rarity. In this study, we characterized the clinical features for AIA in Korean patients.

METHODS

We retrospectively reviewed data from patients with AIA diagnosed between 1997 and 2014 at four tertiary hospitals. Agranulocytosis was defined as an absolute neutrophil count (ANC) below 500/mm³.

RESULTS

The mean age of the patients (11 males, 43 females) was 38.2±14.9 years. Forty-eight patients (88.9%) with AIA had fever and sore throat on initial presentation, 20.4% of patients developed AIA during the second course of treatment, and 75.9% of patients suffered AIA within 3 months after initiation of ATD. The patients taking methimazole (n=39) showed lower levels of ANC and more frequent use of granulocyte-macrophage colony-stimulating factor than propylthiouracil (n=15) users. The median duration of agranulocytosis was 5.5 days (range, 1 to 20). No differences were observed between the long (≥6 days) and short recovery time (≤5 days) groups in terms of age, gender, ATDs, duration of ATDs, or initial ANC levels. Four patients (7.4%) who were taking ATDs for less than 2 months died of sepsis on the first or second day of hospitalization.

CONCLUSION

The majority of AIA incidents occur in the early treatment period. Considering the high fatality rate of AIA, an early aggressive therapeutic approach is critical and patients should be well informed regarding the warning symptoms of the disease.

A patient with agranulocytosis following the discontinuation of methimazole treatment for 4 months: A case report

Agranulocytosis is a rare and serious adverse effect of antithyroid drugs (ATD), in particular methimazole (MMI), and usually develops within 3 months following the start of uninterrupted ATD treatment. Agranulocytosis may also develop for the first time following interruption and subsequent resumption of the same ATD treatment. In this case report, a 27-year-old female, who was treated for thyrotoxicosis with MMI, developed agranulocytosis following the discontinuation of MMI treatment for four months. To the best of our knowledge, this is the first study to report this. The aim of this report is to increase the awareness of physicians of the onset of agranulocytosis when MMI is discontinued, and to demonstrate that MMI should be used with caution.

Antithyroid medications and psychosis

INTRODUCTION

Antithyroid drugs (ATDs) are used in the treatment of hyperthyroidism. Very rarely ATDs were reported to trigger acute psychosis in patients with no history of psychiatric disturbances. Our aim is to review the literature on psychosis as a side effect of ATD and to give a personal opinion on this issue.

AREAS COVERED

The cases of acute psychosis elicited by ATD are few and most were reported many years ago, before radioimmunoassay for thyroid-stimulating hormone (TSH) and thyroid hormones was introduced. Most of those cases lack a description of serum thyroid hormone profile before, during and after the appearance of the psychiatric disorder; hence, an abrupt shift from hyperthyroidism to euthyroidism or hypothyroidism cannot be excluded. In addition, patients underwent specific psychiatric therapy, so that it is difficult to attribute the disappearance of the mental disorders to the withdrawal of ATD per se.

EXPERT OPINION

Patients who develop mental disorders while under ATD should be followed by an accurate evaluation of TSH, free triiodothyronine (FT3), and free thyroxine (FT4) levels throughout the course of the psychiatric disease. The use of new imaging techniques could be helpful in ruling out the encephalopathy associated with autoimmune thyroid diseases and other cerebral pathologies that might be possible causes of these mental disorders.

Reactive metabolites and agranulocytosis

Central to most hypotheses of the mechanism of idiosyncratic drug-induced blood dyscrasias is the involvement of reactive metabolites. In view of the reactive nature of the majority of such metabolites, it is likely that they are formed by, or in close proximity to the blood cells affected. The major oxidative system of neutrophils generates hypochlorous acid. We have demonstrated that the drugs associated with the highest incidence of agranulocytosis are oxidized to reactive metabolites by hypochlorous acid and/or activated neutrophils. There are many mechanisms by which such reactive metabolites could induce agranulocytosis. In the case of aminopyrine-induced agranulocytosis, most cases appear to involve drug-dependent anti-neutrophil antibodies, and these are likely to be induced by cell membrane antigens modified by the reactive metabolite of aminopyrine. The target of agranulocytosis associated with many other drugs is usually neutrophil precursors and may involve cytotoxicity or a cell-mediated immune reaction induced by a reactive metabolite. In the case of aplastic anaemia, there is evidence in some cases for involvement of cytotoxic T cells, which could either be induced by metabolites generated by neutrophils, or more likely, by reactive metabolites generated by stem cells.

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.

Management of a pregnant patient with Graves' disease complicated by propylthiouracil induced agranulocytosis

Relapse and exacerbation of Graves' disease during pregnancy is rare, and thionamide induced agranulocytosis is an uncommon side effect. We report a case of a pregnant woman in her 24th week of gestation that experienced a relapse of Graves' disease that was complicated by propylthiouracil induced agranulocytosis. Following the discontinuation of propylthiouracil and administration of a broad-spectrum of antibiotics, agranulocytosis subsided within 10 days. A total thyroidectomy to avoid any future relapse was planned and a short course of a beta-adrenergic blocker and Lugol solution were prescribed before the operation. At the 28th week of gestation, a total thyroidectomy was performed without complications and thyroxine replacement therapy was commenced. At the 40th week of gestation, labor was induced and a 3,370 g healthy male infant was born without clinical features of thyrotoxicosis. We report herein on the patient and the treatment options for this rare and complicated case.

Therapeutic plasmapheresis in patients with severe hyperthyroidism in whom antithyroid drugs are contraindicated

Four patients with Graves' disease in whom antithyroid drugs could not be used were treated by plasmapheresis preoperatively. On admission all patients had severe hyperthyroidism. All patients were treated by beta blockers, cholestyramine and inorganic iodine before plasmapheresis. Plasmapheresis course consisted of three sessions. Removed plasma was replaced by a synthetic colloid solution and human albumin other than fresh-frozen plasma. Plasmapheresis led to decreases in serum T3 concentrations >78-40% and free T4 concentrations >69%. Near-total thyroidectomy could be performed in all patients. Although screening coagulation tests were within normal limits, patients 1 and 4 experienced more blood loss than usual during the operative procedure. Plasmapheresis could be used as an alternative therapeutic option in the preoperative management of severe hyperthyroid patients with contraindications to antithyroid drugs. However, this is an invasive procedure and patients should be followed carefully for prolonged clinic/subclinic coagulopathy due to plasma exchange.

Drug-associated agranulocytosis: 20 years of reporting in The Netherlands (1974-1994)

In this descriptive study, all 425 reports were included concerning drug-associated agranulocytosis as registered between 1974 and 1994 in the files of the Drug Safety Unit of the Dutch Inspectorate for Health Care. All reports were analysed as to the probability of agranulocytosis or neutropenia according to previously defined criteria. Subsequently, the causal relationship between exposure and outcome was assessed. It concerned 149 men and 271 women. One hundred and twelve reports were unclassifiable because age, gender, or total number of leukocytes at the time of reaction were unknown. In 100 reports agranulocytosis was probable, in 78 possible, in 8 reports neutropenia was probable, in 20 reports neutropenia was possible, and in 107 reports agranulocytosis or neutropenia were unlikely. In the 13 reports of probable agranulocytosis or neutropenia with a certain causal relationship, causative drugs were cimetidine, dipyrone, sulphasalazine, methyldopa, spironolactone, propylthiouracil (2), thiamazole, sulphamethoxazole with trimethoprim, gentamicin, a combination preparation containing aminophenazone, benzylpenicillin and indomethacin. The individual drugs most often reported to cause agranulocytosis or neutropenia were: dipyrone (19), mianserin (15), sulphasalazine (13), sulphamethoxazole with trimethoprim (11), the group of penicillins (9), cimetidine (8), the thiouracil derivatives (8), phenylbutazone (8), and penicillamine (8). Agranulocytosis is a serious and fairly frequently reported adverse reaction. The reporting system of the Drug Safety Unit can be used very well for signal generation concerning adverse reactions to drugs.

Methimazole-induced agranulocytosis treated with recombinant human granulocyte colony-stimulating factor (G-CSF)

A 35-year-old female hematology technician with Graves' disease developed agranulocytosis a few days after starting therapy with Tapazole (methimazole). Because of a recent report of use of recombinant human granulocyte colony-stimulating factor (G-CSF) in patients with propylthiouracil-induced agranulocytosis, 5 micrograms/kg/day G-CSF was administered and her granulocyte count returned to normal after three doses, on the sixth day after the last dose of methimazole. We conclude that in patients with drug-induced agranulocytosis, the use of G-CSF, in addition to discontinuation of the offending drug, hastens recovery and reduces morbidity.

Propylthiouracil (PTU)-induced agranulocytosis treated with recombinant human granulocyte colony-stimulating factor (G-CSF)

Two premenopausal female patients with Graves' hyperthyroidism and propylthiouracil (PTU)-induced agranulocytosis are presented. The first patient, age 47, received 300 mg of PTU per day and developed agranulocytosis within 6 weeks of the commencement of therapy. There were no granulocytes in the peripheral smear and a bone marrow biopsy demonstrated an absence of the entire myeloid cell line as well as the presence of many granulomas. The second patient, age 39, received PTU 1600 mg per day for two and half weeks and then 2 days of methimazole, 200 mg per day. She developed complete agranulocytosis on peripheral smear within 3 weeks of the initiation of therapy. Her bone marrow biopsy demonstrated maturation arrest of the granulocytic cell line at the myelocyte stage. In addition to discontinuing their antithyroid drugs, both patients were treated with G-CSF subcutaneously. The first patient received 300 micrograms of G-CSF on days 2 and 4 after discontinuing PTU with the appearance of 4.7 x 10(9)/L granulocytes and granulocyte precursors on day 4. The second patient received 575 micrograms of G-CSF for 2 days and 300 micrograms for 1 additional day beginning on the third day after discontinuing antithyroid drugs. On the second treatment day there were 5.8 x 10(9)/L granulocytes and granulocyte precursors on the peripheral smear. A comparison to previously published cases on antithyroid drug induced agranulocytosis suggests that the use of G-CSF decreased the amount of time required for marrow recovery after the cessation of the offending drug.

The role of leukocyte-generated reactive metabolites in the pathogenesis of idiosyncratic drug reactions

Evidence strongly suggests that many adverse drug reactions, including idiosyncratic drug reactions, involve reactive metabolites. Furthermore, certain functional groups, which are readily oxidized to reactive metabolites, are associated with a high incidence of adverse reactions. Most drugs can probably form reactive metabolites, but a simple comparison of covalent binding in vitro is unlikely to provide an accurate indication of the relative risk of a drug causing an idiosyncratic reaction because it does not provide an indication of how efficiently the metabolite is detoxified in vivo. In addition, the incidence and nature of adverse reactions associated with a given drug is probably determined in large measure by the location of reactive metabolite formation, as well as the chemical reactivity of the reactive metabolite. Such factors will determine which macromolecules the metabolites will bind to, and it is known that covalent binding to some proteins, such as those in the leukocyte membrane, is much more likely to lead to an immune-mediated reaction or other type of toxicity. Some reactive metabolites, such as acyl glucuronides, circulate freely and could lead to adverse reactions in almost any organ; however, most reactive metabolites have a short biological half-life, and although small amounts may escape the organ where they are formed, these metabolites are unlikely to reach sufficient concentrations to cause toxicity in other organs. Many idiosyncratic drug reactions involve leukocytes, especially agranulocytosis and drug-induced lupus. We and others have demonstrated that drugs can be metabolized by activated neutrophils and monocytes to reactive metabolites. The major reaction appears to be reaction with leukocyte-generated hypochlorous acid. Hypochlorous acid is quite reactive, and therefore it is likely that many other drugs will be found that are metabolized by activated leukocytes. Some neutrophil precursors contain myeloperoxidase and the NADPH oxidase system, and it is likely that these cells can also oxidize drugs. Therefore, although there is no direct evidence, it is reasonable to speculate that reactive metabolites generated by activated leukocytes, or neutrophil precursors in the bone marrow, could be responsible for drug-induced agranulocytosis and aplastic anemia. This could involve direct toxicity or an immune-mediated reaction. These mechanisms are not mutually exclusive, and it may be that both mechanisms contribute to the toxicity, even in the same patient. In the case of drug-induced lupus, a prevalent hypothesis for lupus involves modification of class II MHC antigens.(ABSTRACT TRUNCATED AT 400 WORDS)

Aplastic anemia associated with antithyroid drugs

Prognosis in aplastic anemia is usually linked to the degree of hypoplasia in the bone marrow and pancytopenia in the blood. The authors were, therefore, intrigued when a patient with methimazole-associated aplastic anemia who satisfied criteria for severe disease recovered rapidly and completely once her drug was withdrawn. Review of the English language literature revealed ten fully documented cases of aplastic anemia associated with use of the antithyroid drugs methimazole, carbimazole, and propylthiouracil. Analysis of the ten and of an eleventh case presented here indicated that the disorder is typically characterized by severe pancytopenia and profound marrow hypoplasia, yet surprisingly good prognosis, ie, minimum survival of more than 70% with partial or complete recovery from symptoms and cytopenias in survivors within 2-5 weeks. The only deaths, both in the 1950s, were from brain hemorrhage in patients who were not transfused with platelets. The discrepancy between the clinical and laboratory severity of antithyroid drug-associated aplasia, on the one hand, and its relatively good prognosis and short term course, on the other, should be kept in mind when considering these patients for bone marrow transplantation or for therapy with antithymocyte globulin.

Drug metabolism by leukocytes and its role in drug-induced lupus and other idiosyncratic drug reactions

This review presents a unifying hypothesis that provides a connection between several types of hypersensitivity reactions associated with several types of drugs and explains some of the therapeutic effects (antiinflammatory activity and antithyroid effects) of these same drugs. This hypothesis centers on the oxidation of these drugs to chemically reactive metabolites by peroxidases. The drugs of interest have functional groups that are easily oxidized. The major peroxidase involved in this hypothesis is MPO because of its critical location in leukocytes which play a key role in the function of the immune system. However, thyroid peroxidase can probably also oxidize many of the same drugs to reactive metabolites, and this may be responsible for the thyroid autoimmunity observed in connection with some hypersensitivity reactions. Peroxidases have also been described in the skin and in platelets, and their presence may be responsible for the high incidence of skin reactions in the hypersensitivity response and the occurrence of immune-mediated thrombocytopenia, respectively. Involvement of other peroxidases, such as prostaglandin peroxidase, may also be important for antiinflammatory effects of drugs. In addition, leukocytes contain prostaglandin synthetase, and the activation of leukocytes leads to the release of arachidonic acid and the production of prostaglandins. This process may also lead to the metabolism of drugs to reactive metabolites. In studies of the metabolism of procainamide and dapsone, aspirin and indomethacin did not inhibit the formation of the hydroxylamine by neutrophils and mononuclear leukocytes. This is evidence against the involvement of prostaglandin synthetase in these oxidation; however, preliminary studies with other drugs suggest that prostaglandin synthetase may contribute to the metabolism of some drugs by leukocytes. Furthermore, the metabolism of phenylbutazone, phenytoin, and tenoxicam, as well as our preliminary work with other drugs such as carbamazepine, suggests that the range of drugs that are metabolized to reactive metabolites by peroxidases may be broader than initially suspected. There are several other drugs that do not fit into the functional group classes covered in this review but have similar properties. A good example is alpha-methyldopa, which is associated with drug-induced lupus, immune-mediated hemolytic anemia, and other hypersensitivity reactions. Such drugs may also be metabolized to reactive metabolites by peroxidases. Another aspect of the hypothesis is that an infection, or other inflammatory condition, may be an important risk factor for a hypersensitivity reaction because such a stimulus leads to activation of leukocytes which can lead to formation of reactive metabolites from certain drugs.(ABSTRACT TRUNCATED AT 400 WORDS)