A case of neonatal fulminant myocarditis with dystrophic calcification: Usefulness of two-dimensional speckle-tracking echocardiography

Abstract

Dystrophic calcification is a rare but fatal complication associated with severe myocarditis. Detecting calcified lesions and evaluating ventricular function are essential for the management of myocarditis. We report a case of neonatal acute myocarditis with dystrophic calcification successfully assessed by two-dimensional speckle-tracking echocardiography. The calcification spontaneously resolved, and the recovery of myocardial function was evaluated by speckle-tracking echocardiography. Speckle-tracking echocardiography could be a useful method to evaluate regional ventricular dysfunction corresponding to dystrophic calcification as well as that caused by myocarditis and the follow-up because of its repeatability.

Learning objective

1) Dystrophic calcification can occur as a rare complication associated with severe myocarditis. 2) Dystrophic calcification can spontaneously resolve with the recovery of myocardial function. 3) Speckle-tracking echocardiography is a useful tool for the evaluation of the extent of and myocardial function in dystrophic calcification and the follow-up.

Introduction

Acute myocarditis is an inflammatory disease of the myocardium with a variety of pathogeneses and clinical manifestations [1]. In severe myocarditis, some cases of a rare complication of myocardial dystrophic calcification are associated with severe myocardial injury [[2], [3], [4], [5], [6]]. Since dystrophic calcification is related to poor prognosis, detecting calcified lesions and evaluating ventricular function are essential for the management of myocarditis. Speckle-tracking echocardiography (STE) is a useful tool for evaluating subclinical and regional ventricular dysfunction in patients with myocarditis [7]. Therefore, this modality may be valuable for evaluating regional ventricular dysfunction within the area of myocardial calcification.

Here, we report a case of neonatal acute myocarditis complicated by dystrophic calcification. The changes over time in the clinical course of cardiac function and dystrophic calcified lesions can be evaluated using two-dimensional STE (2D-STE).

Case report

A boy was born at 38 weeks of gestation by vaginal delivery without neonatal asphyxia, although his mother had a fever of unknown etiology 4 days prior to delivery, which she spontaneously recovered from without treatment. The patient's birth weight was 2324 g. He visited a doctor with the complaint of poor feeding and activity at nine days of age. Echocardiography revealed deterioration of cardiac contraction, and he was transferred to our pediatric intensive care unit for further evaluation and treatment. On admission, his vital signs showed a heart rate of 145 beats/min, respiratory rate of 60 beats/min, blood pressure of 76/54 mmHg, and oxygen saturation of 93 % under room air conditions. Physical examination revealed a facial pallor and peripheral coldness. No heart murmur or hepatomegaly was detected. Chest radiography revealed cardiac enlargement and pulmonary congestion (Fig. 1A). Electrocardiography revealed mild ST depression in V4 and V5. A left bundle-branch block was also observed (Fig. 1B). Echocardiography showed a decrease in the left ventricular ejection fraction of 32 % without any structural abnormalities or abnormal origins of the coronary arteries. There was no significant atrioventricular regurgitation or evidence of pulmonary hypertension. Pericardial effusion was also observed (Fig. 1C). Moreover, the myocardium at the base of the left ventricular septum showed higher echogenicity than other parts in the four-chamber view (Fig. 1D). Laboratory test results showed an elevation of creatine kinase (369 U/l), troponin T (5.35 ng/ml), and brain natriuretic peptide level (732.4 pg/ml). Thus, the patient was diagnosed with acute neonatal myocarditis. However, no significant increase in viral antibody levels was observed when testing for the suspected cause of myocarditis.

Fig. 1.

Chest radiograph, electrocardiogram, and echocardiography at admission.

A) Chest radiograph shows cardiomegaly and pulmonary congestion.

B) Electrocardiogram shows mild depression in V4 and V5 and left bundle branch block.

C) Echocardiography shows pericardial effusion circumferentially (arrow).

D) Echocardiography showing high echogenicity of the myocardium at the base of the left ventricular septum (arrow).

He was treated with inotropic agents and diuretics in addition to intravenous immunoglobulin therapy. However, his cardiac function deteriorated over time and he required extracorporeal membrane oxygenation (ECMO) support on the day after admission. On the 6th day of hospitalization, a calcified lesion with an acoustic shadow appeared at the base of the septum in the four-chamber view. In the 2D-STE analysis from apical two-, three-, and four-chamber view, myocardial contraction was poor, except for the lateral and posterior walls (Fig. 2A). On the 10th day of hospitalization, myocardial contraction gradually recovered. However, the calcified lesion at the base of the septum became thin and showed poor contraction (Fig. 2B, D, E). On the 12th day of hospitalization, the patient was weaned off ECMO support. On the 47th day of hospitalization, computed tomography (CT) revealed a calcified lesion in the ventricular septum (Fig. 3). Therefore, we diagnosed this condition as a complication of dystrophic calcification. The patient was discharged on the 51st day. Five months after the onset of myocarditis, the dystrophic calcification at the base of the septum gradually disappeared, and the myocardial contraction evaluated by 2D-STE also recovered (Fig. 2C).

Fig. 2.

Changes in echocardiographic findings and 2D-STE analysis.

A) On hospital day 6, the four-chamber image on echocardiography showed a calcified lesion at the base of the septum (arrow, upper panel). 2D-STE analysis revealed globally poor myocardial contraction, except in the posterolateral wall (lower panel).

B) On hospital day 10, the four-chamber image on echocardiography revealed a distinct calcified lesion (arrow, upper panel). 2D-STE analysis revealed regionally poor contraction consistent with the calcified lesion (lower panel).

C) Five months after the onset of myocarditis, the four-chamber image on echocardiography showed that the calcified lesion had disappeared (arrow). 2D-STE analysis reveals recovered myocardial contraction of the septum.

D) On hospital day 10, the left ventricular short-axis image on echocardiography revealed a distinct calcified lesion (arrow).

E) On hospital day 10, the left ventricular long-axis image on echocardiography revealed a distinct calcified lesion (arrow).

2D-STE, two-dimensional speckle tracking echocardiography.

Fig. 3.

Computed tomography scan on the 47th day of hospitalization. It shows a calcified lesion at the ventricular septum (arrow).

Discussion

This is the first case of neonatal acute myocarditis complicated by dystrophic calcification, in which the clinical course was evaluated using 2D-STE. 2D-STE was able to evaluate the regional ventricular dysfunction caused by massive inflammation in the acute phase and residual dysfunction at the area of dystrophic calcification in the recovery phase.

Dystrophic calcification is a rare but fatal complication associated with severe myocarditis [[2], [3], [4], [5], [6]]. The diagnosis of myocardial calcification is often diagnosed by histopathological review of autopsy specimens [4,5]. Conversely, there have been some reports of the resolution of calcified lesions over time in survivors [2]. In our case, the myocardial calcification disappeared spontaneously, and the corresponding regional ventricular dysfunction recovered over time. Although the mechanism of recovery in this patient is unclear, the surviving myocardium may recover after the disappearance of calcification if the extent of the calcification is small and localized. Therefore, an accurate evaluation of its extent and corresponding ventricular function is important for risk stratification and management of myocarditis. To detect myocardial calcification, echocardiography, CT, and magnetic resonance imaging can be useful. Cardiac magnetic resonance (CMR) imaging is now a confirmed modality for diagnosing myocarditis. CMR can globally evaluate not only ventricular function but also histological findings, such as myocardial inflammation, edema, and necrosis [1]. However, CMR is not always a readily and safely available modality, especially for patients with severe myocarditis and life-threatening conditions. In addition, it is often difficult to adequately assess a small neonatal heart due to the limited spatial resolution of CMR. CT imaging can better assess the area of calcification with higher sensitivity compared with echocardiography; however, CT can only evaluate the static status of the myocardium with calcification, and checking CT scans repeatedly is challenging due to risks associated with increased radiation exposure. Echocardiography can also detect calcification [5], even though it might not be sufficiently sensitive to evaluate the extent of calcification accurately. In addition, through combining STE, it is capable of assessing the dynamic status of the myocardium.

In our case, 2D-STE was used to evaluate both the regional ventricular dysfunction due to myocarditis and the remaining dysfunction at the area of dystrophic calcification. Moreover, it successfully highlighted functional recovery during follow-up. Previous studies have reported that STE, as well as CMR, is a useful method for the evaluation of subclinical and regional myocardial dysfunction caused by myocarditis [[8], [9], [10]]. Similarly, STE may have the potential to accurately evaluate the functional deterioration of the myocardium corresponding to dystrophic calcification. However, 2D-STE is incapable of assessing histopathological changes, unlike CMR. CT, in addition to standard echocardiography, may be necessary to assess the extent of calcification. Indeed, myocardial calcification in our case was initially detected by standard echocardiography and then confirmed using CT. Therefore, composite assessment using standard echocardiography, STE, and CT may be valuable for evaluating severe myocarditis with dystrophic calcification. Moreover, STE was also helpful for patient follow-up at the outpatient clinic because of its repeatability.

Conclusion

Dystrophic calcification is a rare but fatal complication associated with severe myocarditis. STE is a useful method for evaluating regional ventricular dysfunction corresponding to dystrophic calcification. Furthermore, STE is helpful for functional post-discharge follow-up in the area of calcification.

Financial support

This research received no specific grant from any funding agency, commercial, or not-for-profit sectors.

Consent statement

Written informed consent was obtained from the patient's family for publication of this case report, including accompanying images.

Declaration of competing interest

The authors declare that there is no conflict of interest.