Giant Cell and Granulomatous Myocarditis

An Update on Myocarditis in Forensic Pathology

In forensic medicine, myocarditis is a complicated topic in the context of sudden death and medical malpractice. A good knowledge of the etiopathology, histopathology, and available literature are both indispensable and essential for the correct management and evaluation of the causal link. Some agents, which are rarely lethal for humans, are not necessarily related to death from myocarditis, even if an infection in other organs such as the gastrointestinal tract is documented. The diagnosis of the causes of death is often difficult and confusing. In some cases, the hypothetical diagnosis of myocarditis as the cause of death is formulated by deduction, causing error and misleading the correct temporal evaluation of pathological events. We reviewed the literature realizing that histomorphological data are scarce and often poorly documented. Only after COVID-19 have the histomorphological aspects of myocarditis been better documented. This is due to poor autopsy practice and poor accuracy in identifying the specific histotype of myocarditis with identification of the responsible agent. We believe that four points are essential for a better understanding and complete diagnosis of the disease: (1) clinical classification of myocarditis; (2) etiological classification of myocarditis; (3) pathophysiology of viral and bacterial infections with host response; and (4) histopathological diagnosis with precise identification of the histotype and pathogen. In the review we provide histological images from authoritative scientific references with the aim of providing useful information and food for thought to readers.

Myocarditis and inflammatory bowel diseases: A single-center experience and a systematic literature review

BACKGROUND

Myocarditis and inflammatory bowel diseases (IBD) are rare conditions, but may coexist. Myocarditis in IBD may be infective, immune-mediated, or due to mesalamine toxicity. A gap of knowledge exists on the clinical features of patients that present myocarditis in association with IBD, especially for endomyocardial biopsy-proven cases. Our aims are: 1) to describe the clinical characteristics of patients with an associated diagnosis of myocarditis and IBD in a single-center hospital, 2) to perform a systematic review of the literature of analogous cases.

METHODS

We retrospectively analyzed data of patients followed up at the outpatient Cardio-immunology and Gastroenterology Clinic of Padua University Hospital, to identify those with an associated diagnosis of myocarditis and IBD. In addition, a systematic review of the literature was conducted. We performed a qualitative analysis of the overall study population.

RESULTS

The study included 104 patients (21 from our single center cohort, 83 from the literature review). Myocarditis in IBD more frequently affects young (median age 31 years) males (72%), predominantly with infarct-like presentation (58%), within an acute phase of the IBD (67%) and with an overall benign clinical course (87%). Nevertheless, a not negligible quote of patients may present giant cell myocarditis, deserve immunosuppression and have a chronic, or even fatal course. Histological evidence of mesalamine hypersensitivity is scarce and its incidence may be overestimated.

CONCLUSIONS

Our study shows that myocarditis in association with IBD, if correctly managed, may have a spontaneous benign course, but predictors of worse prognosis must be promptly recognized.

Myocarditis associated with COVID-19 and its vaccines - a systematic review

Since the beginning of the COVID-19 (Coronavirus Disease of 2019) pandemic, myocarditis has received much attention and controversy as one of the more worrisome cardiovascular complications. After the availability of highly effective COVID-19 mRNA vaccines in late 2020, myocarditis was also appreciated as an important vaccine-related adverse event. Though the overall frequency of clinically evident viral myocarditis is rare in the general population, young males show a higher predilection for COVID vaccine-induced myocarditis. The severity of COVID-19 viral myocarditis is variable, ranging from very mild to severe, while vaccine-induced myocarditis is usually mild, and rarely a severe or fatal disease. The diagnosis of either COVID-19 or vaccine-induced myocarditis is based on typical clinical features, laboratory investigations, and imaging, preferably with cardiac magnetic resonance. The management of COVID-19 myocarditis is supportive care for mild or moderate disease. For the rare patient who develops severe disease, advanced heart failure therapies such as mechanical circulatory support devices may have to be employed and can be lifesaving. Avoidance of strenuous exercise during the bout of myocarditis and its recovery phase is important. Despite the small but finite risk of vaccine-induced myocarditis, the benefits of protection against COVID-19 disease and its attendant complications far outweigh the risks.

Parvovirus B19-Associated Myocarditis: A Literature Review of Pediatric Cases

Parvovirus B19 (B19V) infection may lead to myocarditis, a life-threatening condition in pediatric patients. In this review, we aim to present published pediatric cases of B19V-associated myocarditis in order to understand the deep complex connections and draw useful conclusions. We performed a comprehensive search of MEDLINE, Science Direct, and Google Scholar electronic databases. A total of 32 cases were included in our study. The most common presenting symptom was tachycardia in 22/32 patients (68.7%), followed by tachypnoea (21/32, 65.6%), fever, and rash (12/32, 37.5% for both of them). Cardiac arrest, loss of consciousness, and systemic infection were associated with the worst prognosis, with statistically significant differences (p-value 0.001, 0.02, 0.001. respectively). A percentage as high as 90.4% of patients with left ventricular (LV) dysfunction and reduced ejection fraction (EF) were discharged. Twelve patients required ventilatory support, five required extracorporeal membrane oxygenation (ECMO), and three underwent heart surgery. Treatment with immunosuppressive agents and immunoglobulin was found to be beneficial for patients (p-value 0.006 and 0.004, respectively). In conclusion, B19V myocarditis has high mortality rates in children. There is no specific antiviral treatment for B19V infection and therapeutic strategies for myocarditis aim to delay the worsening of heart failure and to preserve the LV function. Inotropic drugs, diuresis, ventilatory support, Intravenous immunoglobulin (IVIG), and immunosuppressive therapy seem to help the recovery of the myocardium in children with LV dilation, dysfunction, and reduced EF. Children with cardiac arrest, arrhythmias, and loss of consciousness have the worst prognosis.

Pathological and clinical effects of interleukin-6 on human myocarditis

BACKGROUND

Numerous basic studies have shown a relationship between interleukin-6 (IL-6) and the development or severity of myocarditis. However, there has been no study in which the effect of IL-6 levels in patients with myocarditis was evaluated.

METHODS

We enrolled control patients (n = 12) and consecutive patients with acute myocarditis (n = 13), including lymphocytic, eosinophilic, and giant cell myocarditis, and investigated the pathological and clinical effects of IL-6 on human myocarditis.

RESULTS

The serum IL-6 level in patients with myocarditis (16.7 [9.9, 103.8] pg/mL) was significantly higher than that in the control patients (1.4 [1.0, 1.9] pg/mL) (P<0.001). Immunohistochemical analysis showed that IL-6 was expressed in infiltrating inflammatory cells of endomyocardial biopsy samples from all patients with myocarditis. Moreover, the log-transformed value of serum IL-6 level showed significant positive correlations with serum creatine kinase (CK) level, CK-MB level, peak CK level, peak CK-MB level and C-reactive protein level (all P ≤ 0.005) and a negative correlation with the left ventricular (LV) ejection fraction (p = 0.014). We divided the patients with myocarditis into a low IL-6 group (9.9 [4.5, 14.2] pg/dL, n = 7) and a high IL-6 group (108.9 [51.1, 130.9] pg/dL, n = 6). The degree of infiltration of IL-6-expressing inflammatory cells in myocardial samples obtained from patients in the high IL-6 group was significantly more severe than that in samples obtained from patients in the low IL-6 group. Furthermore, patients in the high IL-6 group significantly more frequently received catecholamine therapy (P = 0.005), venoarterial extracorporeal membrane oxygenation (P = 0.029), and artificial respirator support (P = 0.021) in the acute phase of myocarditis.

CONCLUSION

The results suggest that there is a strong impact of IL-6 on cardiac injury and dysfunction in patients with myocarditis.

[Inflammatory cardiomyopathies: Diagnosis, correlations with imaging, interest of myocardial biopsy and place of molecular biology]

Inflammatory cardiomyopathies, also known as "myocarditis" are inflammatory pathologies affecting the myocardium and characterized by vast etiological and clinical heterogeneity. They can be asymptomatic, particularly in viral forms, or be responsible for sudden death, particularly in subjects under 35 years olds. Due to insufficient sensitivity and specificity of imaging and biology, the gold standard is histopathological and is performed on an endomyocardial biopsy or on explanted heart samples in a transplant context. Their classification has considerably evolved and is now based on the identification of a predominant cell pattern such as lymphocytic, neutrophilic or eosinophilic polynuclear, giant cell or granulomatous myocarditis. These different patterns will guide the etiological diagnosis, prognosis and the therapies to be implemented. Due to the importance of viral etiologies, this morphological analysis must be complemented by a virological analysis based on PCR with viral load quantification. In addition, some authors have been able to demonstrate the occurrence of myocarditis in patients with arrhythmogenic cardiomyopathy of genetic origin. The aim of this chapter is to review the current state of knowledge on inflammatory cardiomyopathies and their management.

Viral Myocarditis-Incidence, Diagnosis and Management

Viral myocarditis has an incidence rate of 10 to 22 per 100,000 individuals. The presentation pattern of viral myocarditis can range from nonspecific symptoms of fatigue and shortness of breath to more aggressive symptoms that mimic acute coronary syndrome. After the initial acute phase presentation of viral myocarditis, the virus may be cleared, resulting in full clinical recovery; the viral infection may persist; or the viral infection may lead to a persistent autoimmune-mediated inflammatory process with continuing symptoms of heart failure. As a result of these 3 possibilities, the diagnosis, prognosis, and treatment of viral myocarditis can be extremely unpredictable and challenging for the clinician. Herein, the incidence, etiology, definition and classification, clinical manifestation, diagnosis, pathogenesis, prognosis, and treatment of viral myocarditis are reviewed, and how acute clinical care teams might differentiate between viral myocarditis and other acute cardiac conditions is discussed.

Clinicopathological manifestations of myocarditis in a heart failure population

Myocarditis continues to present challenges in diagnosis and management. The goal of this study is to determine the occurrence and manifestations of myocarditis in a heart failure (HF) population. The analyzed patients had acute or persistent HF and were referred over a 6-year period to a quaternary HF center for advanced HF therapies including mechanical circulatory support, left ventricular assist device (LVAD) implantation, and/or heart transplantation. The histopathological diagnosis of myocarditis was made based on the presence of an inflammatory infiltrate of the myocardium, typically with associated cardiomyocyte (CMC) damage, combined as indicated with immunohistochemical and molecular biology characterization. The pathological findings were correlated with a panel of clinical parameters and clinical course of the patients. Myocarditis was identified in 36 patients, with initial diagnoses made in 10 (40%) of 25 by endomyocardial biopsy (EMB), 1 by atrial biopsy (maze procedure), 7 (2.1%) of 331 at LVAD implantation, and 18 (7.8%) of 229 in the explanted heart. There were 20 cases of lymphocytic myocarditis, 4 cases of giant cell myocarditis, 3 cases of eosinophilic myocarditis, and 9 cases of lymphohistocytic with granulomas myocarditis - cardiac sarcoidosis. EMB was performed in 25 patients and was positive in 10 (40%) of cases. Myocarditis was found in 23 explanted hearts including 18 cases de novo and 5 cases with a previously positive specimen. Of the 23 explanted hearts, 21 were nonischemic cardiomyopathy and 2 were ischemic cardiomyopathy. Our findings show that, in patients presenting to a quaternary medical center, myocarditis can be manifest as acute HF as well as a complicating factor in chronic HF.

A case of a giant cell myocarditis that developed massive left ventricular thrombus during percutaneous cardiopulmonary support

Background

Giant cell myocarditis, characterized by infiltration of multinucleated giant cells in the myocardium, is a rare type of myocarditis. It often progresses rapidly into fulminant heart failure and indicates a poor prognosis. When a patient with giant cell myocarditis develops into severe myocarditis presenting with a cardiogenic shock, we should use a percutaneous cardiopulmonary support (PCPS), which could occur complications. We experienced a patient with giant cell myocarditis, who developed left ventricular thrombus formations during the circulation support therapy with PCPS for cardiogenic shock.

Case presentation

A 60-year-old man who developed a cardiogenic shock was transferred to our hospital. After the admission, inotropic agents were increased and an intra-aortic balloon pumping was started. But these therapies did not improve his hemodynamic status. He was placed PCPS. Then, he underwent endomyocardial biopsy and was diagnosed with giant cell myocarditis. On the next morning, he developed complete atrioventricular block, and subsequently, thrombus formations occurred in his left ventricular outlet tract and Valsalva sinus despite an anticoagulant therapy. Thereafter, we intensified the anticoagulant therapy to prevent further thrombus formation, but he developed an intracranial hemorrhage. He did not recover from heart failure and died 16 days after the admission.

Conclusions

We present a patient with giant cell myocarditis who developed widespread thrombosis in the left ventricle during the circulatory support with PCPS, despite anticoagulant therapy. In this case, decreased left myocardial contractility caused by giant cell myocarditis and increased left ventricular afterload by the retrograde perfusion from the PCPS induced the thrombotic tendency and congestion in the left ventricle. In addition, he developed complete atrioventricular block, which reduced the left ventricular ejection and enhanced the thrombus formation. Because patients with giant cell myocarditis have a low probability of spontaneous recovery, heart transplantation or ventricular assist device implantation may be required for circulatory support. We should establish mechanical circulatory support rapidly to improve the prognosis of patients with giant cell myocarditis. Moreover, a ventricular assist device, which can prevent both ventricular congestion and retrograde blood flow, might be suitable to prevent complications as this case.

Diagnosis of myocarditis: Current state and future perspectives

Myocarditis, i.e. inflammation of the myocardium, is one of the leading causes of sudden cardiac death (SCD) and dilated cardiomyopathy (DCM) in young adults, and is an important cause of symptoms such as chest pain, dyspnea and palpitations. The pathophysiological process of disease progression leading to DCM involves an ongoing inflammation as a result of a viral-induced auto-immune response or a persisting viral infection. It is therefore crucial to detect the disease early in its course and prevent persisting inflammation that may lead to DCM and end-stage heart failure. Because of the highly variable clinical presentation, ranging from mild symptoms to severe heart failure, and the limited available diagnostic tools, the evaluation of patients with suspected myocarditis represents an important clinical dilemma in cardiology. New approaches for the diagnosis of myocarditis are needed in order to improve recognition, to help unravel its pathophysiology, and to develop new therapeutic strategies to treat the disease. In this review, we give a comprehensive overview of the current diagnostic strategies for patients with suspected myocarditis, and demonstrate several new techniques that may help to improve the diagnostic work-up.

Acute mechanical circulatory support for fulminant myocarditis complicated by cardiogenic shock

In fulminant myocarditis complicated by cardiogenic shock, early mechanical circulatory support (MCS) may prevent cardiomyopathy and death. We sought to examine the outcomes of patients with fulminant myocarditis supported with MCS. A retrospective review of patients with acute cardiogenic shock treated with MCS from 2007 to 2013 was conducted, and patients with a diagnosis of fulminant myocarditis were included in this series. At our center, 260 patients received MCS for acute cardiogenic shock, and 11 were implanted for fulminant myocarditis. Eight received the Centrimag biventricular assist device (BIVAD), and three received veno-arterial extracorporeal membrane oxygenator (VA ECMO), though 1 VA ECMO-supported patient was transitioned to BIVAD due to refractory shock. The mean acute support time was 14.7 ± 4.4 days. Two patients required long-term left ventricular assist devices and were further supported for 55 and 112 days. Eight patients recovered with a mean ejection fraction of 54 ± 7 %, and one was successfully transplanted. Eight patients survived to discharge (73 %) with mean follow-up: 292.6 ± 306.8 days. All three deaths were due to neurologic complications. MCS should be considered in patients with fulminant myocarditis complicated by shock. With aggressive medical therapy, early utilization of MCS carries promising outcomes.

Update on myocarditis

Myocarditis is an inflammatory disease of the heart frequently resulting from viral infections and/or post-viral immune-mediated responses. It is one of the important causes of dilated cardiomyopathy worldwide. The diagnosis is presumed on clinical presentation and noninvasive diagnostic methods such as cardiovascular magnetic resonance imaging. Endomyocardial biopsy remains the gold standard for in vivo diagnosis of myocarditis. The therapeutic and prognostic benefits of endomyocardial biopsy results have recently been demonstrated in several clinical trials. Although remarkable advances in diagnosis, understanding of pathophysiological mechanisms, and treatment of acute myocarditis were gained during the last years, no standard treatment strategies could be defined as yet, apart from standard heart failure therapy and physical rest. In severe cases, mechanical support or heart transplantation may become necessary. There is some evidence that immunosuppressive and immunomodulating therapy are effective for chronic, virus-negative inflammatory cardiomyopathy. Further investigations by controlled, randomized studies are needed to definitively determine their role in the treatment of myocarditis.

Myocarditis

Myocarditis is an underdiagnosed cause of acute heart failure, sudden death, and chronic dilated cardiomyopathy. In developed countries, viral infections commonly cause myocarditis; however, in the developing world, rheumatic carditis, Trypanosoma cruzi, and bacterial infections such as diphtheria still contribute to the global burden of the disease. The short-term prognosis of acute myocarditis is usually good, but varies widely by cause. Those patients who initially recover might develop recurrent dilated cardiomyopathy and heart failure, sometimes years later. Because myocarditis presents with non-specific symptoms including chest pain, dyspnoea, and palpitations, it often mimics more common disorders such as coronary artery disease. In some patients, cardiac MRI and endomyocardial biopsy can help identify myocarditis, predict risk of cardiovascular events, and guide treatment. Finding effective therapies has been challenging because the pathogenesis of chronic dilated cardiomyopathy after viral myocarditis is complex and determined by host and viral genetics as well as environmental factors. Findings from recent clinical trials suggest that some patients with chronic inflammatory cardiomyopathy have a progressive clinical course despite standard medical care and might improve with a short course of immunosuppression.

Influenza myocarditis and myositis: case presentation and review of the literature

Myocarditis, a general inflammatory condition of the heart muscle, can result from a variety of etiologies, the most common being viral. Despite common pathogens, concomitant myocarditis and myositis remains a rare event. Although a common cause of respiratory illness, extrapulmonary infections with influenza are infrequent. We describe the case of a patient who presented to our centre with concomitant "seasonal" H1N1 influenza A myocarditis further complicated by pan-myositis. The patient's condition rapidly declined, eventually requiring biventricular mechanical support, in addition to multilimb fasciotomies. The cardiac support required was progressive, from a percutaneous left ventricular assist device, to extracorporeal membrane oxygenation, to eventual biventricular assist device support for bridge-to-transplantation. This case motivated a detailed review of the literature (a total of 29 cases were identified), in which we found that patients with influenza myocarditis/myositis were predominantly female (63%) and young (mean age 33.2 years) and continue to have a high incidence of morbidity and mortality (27%). As a result of its atypical pattern, the 2009 H1N1 pandemic strain has gained attention. From our review, we found 7 patients with of 2009 H1N1 pandemic influenza myocarditis. Serial serum cytokine analysis did not demonstrate a "cytokine storm," which has been associated with other virulent influenza strains. The PB1-F2 marker in particular has been associated with a vigorous cytokine response. The 2009 H1N1 and "seasonal" influenza strains lack this marker. In those patients with community-acquired influenza, interleukin-6 has been shown to correlate with symptoms. For patients with myocarditis resulting in shock, mechanical circulatory support has gained acceptance as a means to recovery or transplantation.

Rare causes of calcitriol-mediated hypercalcemia: a case report and literature review

CONTEXT

Calcitriol-mediated hypercalcemia resulting from elevated extrarenal 25-hydroxyvitamin D-1alpha-hydroxylase (1alpha-hydroxylase) activity has not previously been described in giant cell polymyositis.

CASE

We report an unusual case of hypercalcemia due to disseminated granulomatous disease in a 62-yr-old woman with profound proximal muscle weakness and weight loss. She was initially diagnosed with vitamin D deficiency myopathy with a low serum 25-hydroxyvitamin D; serum calcium at this time was low-normal. Vitamin D(3) 3000 IU daily was prescribed. One month later, blood work showed new hypercalcemia and hypercalciuria with normalized 25-hydroxyvitamin D. 1,25-dihydroxyvitamin D was high-normal, despite a suppressed PTH, undetectable PTHrP, and essentially normal renal function. Her hypercalcemia resolved, and her strength improved only after prednisone was added to bisphosphonate therapy. Two weeks later, she died from acute congestive heart failure.

METHODS AND RESULTS

Autopsy revealed a disseminated giant cell myositis affecting skeletal, cardiac, and gastrointestinal smooth muscle. Immunohistochemistry localized 1alpha-hydroxylase to the inflammatory infiltrates in skeletal and cardiac muscle.

EVIDENCE

A review of English publications in Medline and Embase, including a reference search of retrieved articles, revealed that calcitriol-mediated hypercalcemia has been described in over 30 conditions, most of which are granulomatous in nature, ranging from inflammatory conditions and foreign body exposures to infections and neoplasms.

CONCLUSIONS

Hypercalcemia resulting from autonomous 1alpha-hydroxylase activity may be unmasked by low-dose vitamin D supplementation and should not be excluded from the differential diagnosis of nonparathyroid causes if the serum calcitriol is inappropriately normal, rather than frankly elevated.

Comparison of necropsy findings in patients with sarcoidosis dying suddenly from cardiac sarcoidosis versus dying suddenly from other causes

The clinical diagnosis of cardiac sarcoidosis can be difficult and is largely dependent on newer imaging modalities. A retrospective search of sudden cardiac deaths was performed from a reference laboratory and statewide medical examiner system for a 12-year period. Planimetry was performed on gross photographs of transverse short-axis sections, and the phase of the lesion and the portion of myocardium extent was estimated histologically. Lesions were classified histologically as early (primarily lymphocytic), intermediate (primarily granulomatous), and late (primarily scar). A total of 41 cases were found, including 25 in which the death was ascribed to sarcoidosis of the heart (group 1) and 16 in which sudden death was due to other findings (group 2). No significant differences were found in age or activity at death, although gross scars and epicardial nodules were more frequent in group 1 (p <0.0001). In the hearts with gross scars, the ventricular septum had the largest percentage of involvement (32%) followed by the posterior wall (25%). Histologically, the intermediate phase predominated in group 1, and the late phase predominated in group 2. Approximately 50% of the cases in group 1 had involvement in the right ventricular apex and septum, suggesting a positive yield by biopsy. In conclusion, cardiac sarcoidosis causing sudden death is characterized by extensive active granulomas with a predilection for the subepicardium and ventricular septum.

Cardiac sarcoidosis

Cardiac sarcoidosis (CS) is a rare but potentially fatal condition that may present with a wide range of clinical manifestations including congestive heart failure, conduction abnormalities, and most notably, sudden death. Recent advances in imaging technology allow easier detection of CS, but the diagnostic guidelines with inclusion of these techniques have yet to be written. It has become clear that minimally symptomatic or asymptomatic cardiac involvement is far more prevalent than previously thought. Because of the potential life-threatening complications and potential benefit of treatment, all patients diagnosed with sarcoidosis should be screened for cardiac involvement. Patients with CS and symptoms such as syncope need an aggressive workup for a potentially life-threatening etiology, and often require implantable cardioverter-defibrillator therapy. CS patients without arrhythmic symptoms are still at risk for sudden death and may warrant an implantable cardioverter-defibrillator for primary prevention reasons. Although corticosteroids are regarded as the first-line drug of choice, therapy for CS is not yet standardized, and it is unclear at this point whether asymptomatic patients require therapy. Randomized clinical trials are clearly warranted to answer these very important patient care questions, and are endorsed fully by the authors.

Fulminant myocarditis

Fulminant myocarditis is an inflammatory process that occurs in the myocardium and causes acute-onset heart failure. If patients with fulminant myocarditis are aggressively supported in a timely manner, nearly all can have an excellent recovery. In this Review, we discuss the clinical and histological distinguishing features of fulminant myocarditis and contrast this disease entity with nonfulminant myocarditis. The epidemiology, pathophysiology, clinical presentation, methods of diagnosis, management options and prognosis of fulminant myocarditis are reviewed in detail.