Diltiazem-Associated Cardiogenic Shock in Thyrotoxic Crisis

Unusual Presentations of Thyrotoxic Tricuspid and Mitral Regurgitations in 62 Adults: A Systematic Review of Case Reports with In-depth Pathophysiological Review

Background

Thyrotoxicosis is related to cardiovascular mortality. This can be caused by several clinical manifestations involving the rare provocation of tricuspid regurgitation (TR) and mitral regurgitation (MR). However, there are still no clear data on thyrotoxic TR and/or MR. This study examines the progression of TR, MR, heart failure (HF) and pulmonary hypertension (PH) in response to the thyrotoxic heart manifestations, clinical characteristics and treatment approaches.

Methods

A PRISMA-based systematic search was conducted using PubMed and other databases up to 17 June 2023. The outcomes of this study were TR, MR, HF and PH with their progression on follow-up, clinical characteristics and treatment approaches.

Results

A total of 57 case reports involving 62 patients (45.77 ± 13.41 years) were included in this study. They were predominantly women (n=50; 80.65%) and diagnosed with Graves' disease (n=41; 75.81%). All patients were diagnosed with thyrotoxicosis, and this included 23 (37.10%) cases of thyroid storm. From echocardiographic studies, several patients improved clinically within the first 6 months of follow-up, including 20 TR patients (83.33%) in 6 months, nine MR patients (69.23%) in 3 months, eight HF patients (66.67%) in 2 months and 16 PH patients (76.19%) in 6 months.

Conclusion

Several mechanisms are involved in thyrotoxic TR and/or MR, including the direct thyroid hormone effect and the indirect effect of other hyperthyroidism-associated factors. Patients with thyrotoxic TR and/or MR, including those with HF and PH, can experience clinical and structural improvements following hyperthyroidism treatment in the first 6 months.

Data Analysis and Systematic Scoping Review on the Pathogenesis and Modalities of Treatment of Thyroid Storm Complicated with Myocardial Involvement and Shock

Thyroid storm (TS) is a rare and fatal endocrine emergency that occurs due to undiagnosed and inadequately treated hyperthyroidism after stressful conditions in patients with thyroid disorders. The objective of this systematic scoping review was to better understand the pathophysiology of TS and its complications, in terms of myocardial affection, tachyarrhythmia, and cardiogenic shock. In addition, we explored the pharmacological, mechanical, and surgical treatments for TS. We also evaluated the outcomes of TS according to sex and cardiac involvement. Additionally, analytical analysis was performed on the selected data. A literature review of peer-reviewed journals was carried out thoroughly using medical terms, MeSH on PubMed, Google Scholar, and combinations such as thyrotoxicosis-induced cardiomyopathy, thyroid storm, cardiogenic shock, myocardial infarction, endocrine emergency, Burch-Wartofsky score, extracorporeal circulatory support, and thyroidectomy. A total of 231 papers were eligible (2 retrospective studies, 5 case series, and 224 case reports) with a total of 256 TS patients with cardiac involvement between April 2003 and August 2023. All age groups, sexes, patients with TS-induced cardiomyopathy, non-atherosclerotic myocardial infarction, tachyarrhythmia, heart failure, shock, and different forms of treatment were discussed. Non-English language articles, cases without cardiac involvement, and cases in which treatment modalities were not specified were excluded. Female sex was predominant, with 154 female and 102 male patients. Approximately 82% of patients received beta-blockers (BBs), 16.3% were placed on extracorporeal membrane oxygenation (ECMO) support, 16.3% received therapeutic plasma exchange (TPE), and 13.8% underwent continuous renal replacement therapy (CRRT), continuous venovenous hemofiltration (CVVHD), or dialysis. Overall, 18 females and 16 males died. BB-induced circulatory collapse, acute renal failure, CRRT, and ventricular fibrillation were significantly associated with mortality. Awareness of TS and not only thyrotoxicosis is vital for timely and appropriate treatment. The early diagnosis and management of TS in cardiac settings, including pharmacological, mechanical, and surgical modalities, can save high-risk patients. Sex matters in the presentation, treatment, and mortality of this population. However, further large-scale, and well-designed studies are required.

N-Acetylcysteine, an ROS Inhibitor, Alleviates the Pathophysiology of Hyperthyroidism-Induced Cardiomyopathy via the ROS/Ca2+ Pathway

Hyperthyroidism is common and can induce cardiomyopathy, but there is no effective therapeutic strategy. The purpose of this study was to investigate the molecular mechanism of hyperthyroidism-induced cardiomyopathy (HTC) and the effect of N-acetylcysteine (NAC), an ROS inhibitor, on the pathophysiology of HTC in vivo and in vitro. Compared with those in the control groups in vivo and in vitro, TT3 and TT4 were significantly increased, the structure of myocardial cells was enlarged and disordered, and interstitial fibrosis and the apoptosis of myocardial cells were markedly increased in the L-Thy group. The ROS and inflammatory response were increased in the hyperthyroidism group. In the NAC group, the contents of TT3 and TT4 were decreased, the myocardial cell structure was slightly disturbed, fibrosis and apoptosis were significantly reduced, and the ROS level and inflammatory response were significantly reduced. Interestingly, L-Thy decreased the viability of fibroblasts and H9c2 cells, suggesting that L-Thy-induced fibrosis was not caused by the proliferation of fibroblasts. The molecular mechanism of HTC could be explained by the fact that L-Thy could cause cardiac hypertrophy, inflammation, and fibrosis by regulating the Ca2+/calpain/Rcan1-dependent signalling pathway, the Ca2+/Rcan1/NF-κB/p65-dependent signalling pathway, and the Ca2+/ROS/Bcl-2/caspase-3-dependent signalling pathway. In conclusion, NAC can alleviate the pathophysiology of hyperthyroidism-induced cardiomyopathy, probably by regulating the ROS/Ca2+-dependent pathway.

Diltiazem-Induced Reversible Cardiogenic Shock in Thyroid Storm

Early recognition of underlying thyroid disease in patients presenting with new-onset tachyarrhythmia is central to management, as usual rate-control strategies can result in significant mortality and morbidity. Hyperthyroidism-induced cardiomyopathy complicated by cardiogenic shock is a life-threatening condition. Thyroid storm can lead to irreversible cardiovascular collapse and death if proper treatment is not initiated as soon as possible. In this case, we report a 44-year-old female who presented to the emergency department (ED) with the chief complaints of anxiety and palpitations. Her past medical history was significant for anxiety, but she was otherwise healthy. An electrocardiogram (ECG) in the ED demonstrated atrial fibrillation (A. fib) with rapid ventricular response (RVR) felt to be secondary to thyroid storm based on the Burch-Wartofsky point scale (BWPS), which is a quantitative diagnostic tool that uses clinical manifestation in diagnosing thyroid storm. The patient was initially managed with a continuous infusion of diltiazem to achieve rate control with a goal heart rate <115 beats per minute (bpm). Shortly after initiating the infusion, the patient developed signs and symptoms consistent with cardiogenic shock. Bedside echocardiogram revealed an estimated ejection fraction (EF) <10% with concomitant pulmonary edema. Repeat echocardiogram within 72 hours after stopping diltiazem and starting appropriate treatment for thyroid storm showed improvement of EF to 35%. 

Management of Cardiogenic Shock due to Thyrotoxicosis: A Systematic Literature Review

Background

A grave complication of thyrotoxicosis, or thyroid storm, is the development of heart failure and cardiomyopathy. Recognizing this condition is imperative in preventing further left ventricular dysfunction and cardiogenic shock. This manuscript aims to review the literature on cardiogenic shock associated with thyrotoxicosis and present management recommendations on this rare condition.

Methods

A literature search was performed in December of 2018, using the PubMed medical search engine. A systematic search was carried out using the keywords Thyroid Storm AND Cardiogenic Shock and Thyrotoxicosis AND Shock.

Management

Decrease of thyroid hormone levels using therapeutic plasma exchange LV Unloading and ventilation by Impella and Extracorporeal Mechanical Ventilation (ECMO).

Conclusion

Patients presenting with thyroid storm-induced shock may not be suitable candidates for traditional management with β-adrenergic blockers (β-blockers). The use of β-blockers could exasperate their condition. Through extensive literature review on this rare condition, the most effective management was found to be therapeutic plasma exchange in order to decrease thyroid hormone levels, which have direct toxic effect on the heart. Furthermore, the use of ECMO and Impella is advised to reduce pressure on the heart and ensure the patient’s organs are well oxygenated and perfused while the left ventricle is recovering.