Thyroid Storm-induced Severe Dilated Cardiomyopathy and Ventricular Tachycardia

Focus on Autoimmune Myocarditis in Graves' Disease: A Case-Based Review

The manifestations of hyperthyroidism-related myocardial damage are multitudinous, including arrhythmia, dilated cardiomyopathy, valvular diseases, and even cardiogenic shock. Acute myocarditis induced by thyrotoxicosis had been reported in a few studies. However, attention on its prevalence and underlying mechanisms is sorely lacking. Its long-term harm is often ignored, and it may eventually develop into dilated cardiomyopathy and heart failure. We report a case of Graves' disease with a progressive elevation of hypersensitive cardiac troponin-I at several days after discontinuation of the patient's anti-thyroid drugs. Cardiac magnetic resonance imaging (CMRI) showed inflammatory edema of some cardiomyocytes (stranded enhanced signals under T2 mapping), myocardial necrosis (scattered enhanced signals under T1 late gadolinium enhancement) in the medial and inferior epicardial wall, with a decreased left ventricular systolic function (48%), which implied a possibility of acute myocarditis induced by thyrotoxicosis. The patient was then given a transient glucocorticoid (GC) treatment and achieved a good curative effect. Inspired by this case, we aim to systematically elaborate the pathogenesis, diagnosis, and treatment of hyperthyroidism-induced autoimmune myocarditis. Additionally, we emphasize the importance of CMRI and GC therapy in the diagnosis and treatment of hyperthyroidism-related myocarditis.

Cardiovascular Events in Patients with Thyroid Storm

CONTEXT

Thyroid storm can present as a multitude of symptoms, the most significant being cardiovascular (CV). It is associated with various manifestations such as cardiac arrhythmia, heart failure, and ischemia. However, the frequencies of events and characteristics associated with patients that experience these events are not known.

METHODS

Study cohort was derived from the National Inpatient Sample database from January 2012 to September 2015. Total hospitalizations of thyroid storm were identified using appropriate ICD-9 diagnostic codes. The analysis was performed using SAS.

OBJECTIVE

To better understand the frequency and characteristics CV occurrences associated with thyroid storm, through a retrospective analysis of thyroid storm hospital admissions.

DESIGN

The study cohort was derived from the National Inpatient Sample database from January 2012 to September 2015.

SETTING

Total hospitalizations of thyroid storm were identified using International Classification of Diseases (ICD)-9 diagnostic codes. The analysis was performed using Statistical Analysis System (SAS).

RESULTS

A total of 6380 adult hospitalizations were included in the final analysis, which includes 3895 hospitalizations with CV events (CEs). Most frequently associated CEs were arrhythmia (N = 3770) followed by acute heart failure (N = 555) and ischemic events (N = 150). Inpatient mortality was significantly higher in patients with CEs compared with those without CEs (3.5% vs 0.2%, P < 0.005). The median length of stay was also higher in patients with CEs compared with those without CEs (4 days vs 3 days, P < 0.0005). Atrial fibrillation was the most common arrhythmia type, followed by nonspecified tachycardia.

CONCLUSIONS

In patients who were hospitalized due to thyroid storm and associated CEs significantly increased in-hospital mortality, length of stay, and cost. Patients with obesity, alcohol abuse, chronic liver disease, and COPD were more likely to have CEs. Patients with CV complications were at higher risk for mortality. In-hospital mortality increased with ischemic events and acute heart failure. Further evaluation is needed to further classify the type of arrhythmias and associated mortality.

Case report: a patient with thyroid storm, refractory cardiogenic shock, and cardiac arrest treated with Lugol's iodine solution and veno-arterial extra corporal membrane oxygenation support

Background

Thyroid storm is a life-threatening condition. Refractory cardiogenic shock and cardiac arrest are rare complications of thyroid storm and the treatment options are limited.

Case summary

A 35-year- old woman treated for Grave’s disease was admitted with thyrotoxicosis complicated by infection and neutropenia caused by thionamide treatment. After treatment including beta-blockers, steroids, and Lugol’s iodine solution, she went into cardiac arrest. Echocardiography after resuscitation demonstrated severe biventricular heart failure. The patient was in refractory cardiogenic shock with recurrent cardiac arrest and mechanical circulatory support with a veno-arterial extra corporal membrane oxygenation (V-A ECMO) circuit was established. After 2 days on V-A ECMO and supportive treatment with iodine solution, glucocorticosteroids, and levosimendan, her myocardial function recovered and thyroid hormone levels were normalized. Veno-arterial extra corporal membrane oxygenation was discontinued, and the patient was treated with early total thyroidectomy. The patient made a full recovery with no neurological/cognitive impairment, as assessed after 4 weeks.

Discussion

Adverse reactions to standard treatment of hyperthyroidism contributed to this patient’s development of thyroid storm and the following refractory cardiogenic shock. When she was critically unstable, levosimendan improved myocardial function while inotropic support with dobutamine was ineffective, likely due to prolonged beta-antagonist administration. Temporary support with V-A ECMO, until effective lowering of thyroid hormone levels and improvement in myocardial function were obtained, was life-saving in this young patient and may be considered in refractory cardiogenic shock caused by thyroid storm.

Cardiogenic Shock Induced by Anterior Pituitary Hypofunction and Thyrotoxicosis

Cardiogenic shock occurs when the heart is unable to pump enough blood for the needs of the body. Hypopituitarism is a condition in which the pituitary gland does not produce enough of one or more hormones, and it rarely occurs with thyrotoxicosis. We report a rare case of cardiogenic shock induced by anterior pituitary hypofunction and thyrotoxicosis. A 47-year-old woman was admitted twice to the hospital due to generalized worsening muscle pain for 13 days, and accompanied by a transient loss of consciousness. Cardiogenic shock developed during hospitalization, which improved with active resuscitative measures. Laboratory tests showed thyrotoxicosis. Pituitary magnetic resonance imaging (MRI) and relevant hormone tests confirmed anterior pituitary hypofunction. The patient was given hormone replacement therapy, which stabilized her condition. We believe cardiogenic shock may be a serious complication of hypopituitarism. We recommend establishing an expert system (ES) to facilitate the early diagnosis and treatment of cardiogenic shock, improve the professional skills of primary care physicians, and optimize treatment plans.

Apathetic Thyroid Storm with Cardiorespiratory Failure, Pulmonary Embolism, and Coagulopathy in a Young Male with Graves' Disease and Myopathy

A 38-year-old gentleman presented with thyroid storm with multiorgan involvement in the form of heart failure (thyrotoxic cardiomyopathy), respiratory failure (respiratory muscle fatigue), hepatic dysfunction, fast atrial fibrillation, pulmonary embolism, and disseminated intravascular coagulation (DIC). His Graves' disease (GD) remained undiagnosed for nearly 8 months because apart from weight loss, he has not had any other symptoms of thyrotoxicosis. The presentation of thyroid storm was atypical (apathetic thyroid storm) with features of depression and extreme lethargy without any fever, anxiety, agitation, or seizure. There were no identifiable triggers for the thyroid storm. Apart from mechanical ventilation and continuous veno-venous renal replacement therapy in the intensive care unit, he received propylthiouracil (PTU), esmolol, and corticosteroids, which were later switched to carbimazole and propranolol with steroids being tapered down. He was diagnosed with thyrotoxic myopathy which, like GD, remained undiagnosed for long (fatigability). A high index of suspicion and a multidisciplinary care are essential for good outcome in these patients.