Effective Preoperative Plasmapheresis Treatment of Severe Hyperthyroidism in a Patient with Giant Toxic Nodular Goiter and Methimazole-Induced Agranulocytosis

Fighting thyrotoxicosis with therapeutic plasma exchange: A case report

Thyrotoxicosis is the clinical condition resulting from an excess of thyroid hormones for any reason. The main causes are Graves-Basedow disease, toxic multinodular goitre and toxic adenoma. The medical treatment to control thyroid function includes antithyroid drugs, beta blockers, iodine solutions, corticosteroids and cholestyramine. Although therapeutic plasma exchange is not generally part of the therapy, it is an alternative as a preliminary stage before the definitive treatment. This procedure makes it possible to eliminate T4, T3, TSI, cytokines and amiodarone. In most cases, more than one cycle is necessary, either daily or every three days, until clinical improvement is observed. The effect on thyrotoxicosis is temporary, with an approximate duration of 24-48h. This approach has been proposed as a safe and effective alternative when the medical treatment is contraindicated or not effective, and when there is multiple organ failure or emergency surgery is required.

Clinical characteristics of neutropenic patients under antithyroid drug: Twelve-year experience in a medical center

BACKGROUND

Thionamide-induced agranulocytosis (TiA) is a rare adverse event with a reported incidence of approximately 0.1% to 1.75%. Prompt recognition of TiA is critical to reduce the mortality rate. However, the differential diagnosis between cases of TiA and non-TiA neutropenia can be challenging due to the potential simultaneous involvement of other causes of neutropenia, such as concomitant chemotherapy, liver dysfunction, or infection. The aim of the present study was to investigate the possible factors associated with the development of TiA.

METHODS

This was a retrospective cohort study of patients treated with antithyroid drugs (ATDs) in Taipei Veterans General Hospital, Taipei, Taiwan, from 2006 to 2018. Patients who developed a neutropenic event during treatment with ATDs were identified from their medical records. The diagnosis of TiA was based on the following: (1) development of neutropenia during treatment or within 7 days after previous exposure to the same ATDs; (2) complete resolution of neutropenia within 1 month after discontinuation of the culprit drug with an absolute neutrophil count (ANC) >1500/μL; and (3) exclusion of other causes of neutropenia. The incidence and risk factors of TiA were analyzed and compared with those of non-TiA neutropenia.

RESULTS

Among 6644 patients treated with ATDs, 66 (mean age: 53 ± 15 years; 16.2% men) developed a neutropenic event and 20 were diagnosed with TiA (incidence: 0.3%). In the univariate analysis, compared with non-TiA neutropenia, TiA was associated with a lower Charlson Comorbidity Index, shorter treatment duration, lower cumulative ATD dosage, higher ATD dosage, higher ANC, and higher levels of free T4 at the time of the neutropenic event. In the multivariate logistic regression analysis, after adjusting for age, gender and the time to neutropenia, the cumulative ATD dose to neutropenia and ATD dosage at the time of the neutropenic event, Charlson Comorbidity Index, free T4 levels (odds ratio [OR], 4.44; 95% CI, 1.48-13.25), and ANC (OR, 1.00; 95% CI, 1.00-1.01) remained independently associated with TiA.

CONCLUSION

Patients with TiA were more likely to have higher levels of free T4 and ANC at the time of the neutropenic event vs those with non-TiA neutropenia.

Preoperative preparation for Graves' disease

Thyroidectomy is always regarded as the crucial treatment for Graves' disease, especially in cases of poor efficacy or excessive side effects of antithyroid- drugs and 131I radioiodine therapy. To decrease the incidence of hemorrhage, thyroid storms and other severe complications during the perioperative period, surgeons explore different therapies to prepare for thyroidectomy. We performed a review of preoperative preparation with a focus on the Graves' disease population. Most of the previous schemes are effective, which contributes to the smooth operation of patients, but there is no unified standard for preoperative preparation. This review aims to summarize the preoperative preparation of Graves' disease and the latest developments. Prospective studies with longer follow up-up periods are required to select appropriate preoperative regimens based on personal thyroid statements and to identify target populations of benefit.

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).

Generalized gingival necrosis in a patient under methimazole use

Hyperthyroidism is a common disease, with a prevalence between 0.2% and 0.5%, characterized by an increase in the synthesis and release of thyroid hormones. Management of this condition requires medical intervention to correct the hormonal imbalance and control its clinical manifestations. Methimazole is a thionamide derivative considered among the first-choice treatment options for hyperthyroidism. However, it may cause serious side effects such as neutropenia or agranulocytosis, which, although rare, can lead to death. The clinical manifestations of this complication range from fever, ulcerations in the oral and pharyngeal mucosa, tonsillitis, and lymphadenopathy to hemorrhagic necrosis and septicemia. This report describes the case of a patient with generalized gingival necrosis that was related to the use of methimazole for the treatment of hyperthyroidism.

Preoperative plasmapheresis in patients with Graves' disease intolerant to antithyroid drugs

Antithyroid drugs (ATDs) are the mainstay of treatment for Graves' disease with possible detrimental adverse effects. Surgery or radioactive iodine (RAI) ablation is the second choice among the treatment options in cases of non-remission. Normalization of serum thyroid hormone levels as much as possible is required before surgery or RAI to prevent thyrotoxic crisis in patients with uncontrolled Graves' disease. In recent decades, therapeutic plasma exchange (TPE) has been used in the treatment of thyroid storm, drug-induced hepatotoxicity and agranulocytosis, or patients with hyperthyroidism scheduled for emergency surgery. TPE is an effective method to reduce serum FT3, FT4, and TRAB levels in severe hyperthyroid conditions. Although TPE-related complications are rare, the risk of bleeding needs to be taken into consideration in patients who were scheduled for surgery within 24 h after TPE. In terms of reducing intraoperative bleeding, patients can be referred to surgery 24-48 h after TPE, or fresh frozen plasma transfusion can be the preferred treatment for emergency cases.

Unraveling diverse action of triton X-100 and methimazole on lysozyme fibrillation/aggregation: Physicochemical insights

Identification of functionalities responsible for prevention of fibrillation in proteins is important to design effective drugs in addressing neurodegenerative diseases. We have used nonionic surfactant triton X-100 (TX-100) and antithyroid drug methimazole (MMI) to understand mechanistic aspects of action of these molecules having different functionalities on hen egg-white lysozyme at different stages of fibrillation. After establishing the nucleation, elongation and maturation stages of fibrillation of protein at 57 °C, energetics of interactions with these molecules have been determined by using isothermal titration calorimetry. Differential scanning calorimetry has permitted assessment of thermal stability of the protein at these stages, with or without these molecular entities. The enthalpies of interaction of TX-100 and MMI with protein fibrils suggest importance of hydrogen bonding and polar interactions in their effectiveness towards prevention of fibrils. TX-100, in spite of several polar centres, is unable to prevent fibrillation, rather it promotes. MMI is able to establish polar interactions with interacting strands of the protein and disintegrate fibrils. A rigorous comparison with inhibitors reported in literature highlights importance -OH and >CO functionalities in fibrillation prevention. Even though MMI has hydrogen bonding centres, its efficiency as inhibitor falls after the inhibited lysozyme fibrils further interact and form amorphous aggregates.