A case of constrictive pericarditis with a milk of calcium pericardial effusion undergoing surgical treatment

Abstract

Milk of calcium (MOC) pericardial effusion (PE) is extremely rare and has rarely been reported. A 78-year-old man was referred to our institution because of breathlessness and bilateral leg edema. Echocardiography revealed mild PE. In addition, abrupt posterior motion of the ventricular septum in early diastole was observed. A non-contrast chest computed tomography revealed a hyperdense PE, with Hounsfield units of 130, suggestive of MOC PE. Right heart catheterization (RHC) revealed that the right ventricular pressure had a dip and plateau pattern. We diagnosed the patient with constrictive pericarditis (CP) with MOC PE. As the right heart failure secondary to CP was refractory to medical therapy, we decided to perform surgical treatment. During pericardiectomy, a highly viscous PE, of which the color was pale and reddish brown, was aspirated. Chemical analysis of the PE revealed a very high calcium content of 39.2 mmol/L. The clinical symptoms secondary to CP improved. RHC performed postoperatively confirmed the disappearance of a dip and plateau pattern in the right ventricular pressure. In conclusion, we experienced a of CP with MOC PE and surgical treatment contributed to the improvement of the clinical symptoms and pericardial constriction secondary to CP.

Learning objective

Because constrictive pericarditis (CP) with milk of calcium (MOC) pericardial effusion (PE) can cause severe morbidity and even mortality, the early diagnosis of CP is important in patients suspected of having MOC PE. MOC PE has hyperdensity on computed tomography, so its findings could be helpful in the diagnosis of MOC PE. Pericardiectomy for CP with MOC PE may contribute to the improvement of the clinical symptoms and pericardial constriction secondary to CP.

Introduction

Milk of calcium (MOC) is a relatively rare colloidal suspension of calcium crystals and has been found primarily in the gallbladder and kidney [1]. MOC pericardial effusion (PE) is extremely rare and has rarely been reported. To date, there are only three cases describing MOC PE [[2], [3], [4]]. One of these was a post-mortem case in a patient who developed MOC PE and died of heart failure secondary to constrictive pericarditis (CP) [2]. Since CP could have coexisting MOC PE, it is important to evaluate the presence of CP in patients suspected of having MOC PE. However, the accumulation of data on the investigation of MOC PE is insufficient. In addition, the effective therapy for CP with MOC PE is not fully described. Herein, we report a case of CP complicated by MOC PE in a patient who underwent surgical treatment, which contributed to the improvement of clinical symptoms and pericardial constriction.

Case report

A 78-year-old man was referred to our institution because of dyspnea and bilateral leg edema that lasted about a month. He was diagnosed with prostate cancer three years prior, and he had undergone chemotherapy for two years. On presentation, his vital signs were unremarkable. His cardiac examination exhibited a normal S1 and S2, no murmur, and no friction rub. A chest examination revealed no crackles. The result of his physical examination was significant for distension of the jugular veins and edema of the bilateral legs. There was no pulsus paradoxus or Kussmaul sign.

The laboratory results were unremarkable except for an elevated brain natriuretic peptide level (177.3 pg/mL) and C-reactive protein level (1.5 mg/dL). The chest X-rays revealed bilateral pleural effusions. Echocardiography revealed a mild PE with pericardial thickening (Fig. 1a). In addition, abrupt posterior motion of the ventricular septum in early diastole (septal shudder and bounce) (Fig. 1b) was noted. The mitral media annulus velocity (e') by tissue Doppler was normal (8.19 cm/s), and the hepatic vein diastolic expiration/inspiration was normal (0.52). Non-contrast chest computed tomography (CT) showed a hyperdense pericardial effusion (PE) [Hounsfield units (HU) – 130] with circumferential calcifications along the pericardium and thin calcifications of the epicardial surface of the right atrium and right ventricle (Fig. 1c). A right heart catheterization (RHC) was performed four days after admission. It showed an increase in the mean right atrial pressure (mRAP) of 19 mmHg and right ventricular end-diastolic pressure (RVEDP) of 25 mmHg with a dip and plateau pattern and findings of an equalization of the end-diastolic pressures and simultaneous right and left ventricular pressure tracings (Fig. 1d). A coronary angiogram revealed normal coronaries. Cardiac magnetic resonance imaging (CMR) showed circumferential pericardial thickening. ¹⁸F- fluorodeoxyglucose-positron emission tomography (FDG-PET) did not show any intense uptake in the heart, and 67Ga-citrate scintigraphy showed no abnormally high tracer accumulation in the heart. A diagnosis of CP with MOC was made based on the association of the signs and symptoms of right heart failure and findings on the imaging modalities including echocardiography, CT, CMR, and RHC.

Fig. 1.

Echocardiographic findings before the heart surgery, preoperative chest computed tomography (CT), and right heart catheterization (RHC) findings.

(a) Two-dimensional echocardiography, in the apical long-axis view, showing a pericardial effusion (PE) (red arrow).

(b) Echocardiography showing early diastolic bulging of the interventricular septum towards the left ventricle (“septal bounce”) (yellow arrow).

(c) A chest CT showing a hyperdense PE with increased Hounsfield units of 130 (yellow star), circumferential calcification along the pericardium with circumferential calcifications along the pericardium (orange arrows) and thin calcifications of the epicardial surface of the right atrium and right ventricle (red arrow).

(d) RHC showing the dip-and-plateau pattern of the right ventricular pressure and equalization of the end-diastolic pressures during a simultaneous recording of the right and left ventricular pressures (red arrows).

Although we started medical therapy including diuretics, the clinical symptoms and echocardiographic findings secondary to CP did not improve. As the right heart failure secondary to CP was refractory to medical therapy, we decided to perform open-heart surgery.

On-pump beating open heart surgery was performed via a median approach to dissect the pericardium with calcification. During the pericardiectomy, a highly viscous PE with a pale and reddish-brown color was found (Fig. 2a). After the pericardiectomy (Fig. 2b), because the epicardium of the right atrium and right ventricle was thickened tissue with thin calcification on its surface, an epicardial waffle procedure was performed (Fig. 2c). Chemical analysis of the PE revealed a high calcium content of 39.2 mmol/L and a pH of 7.6, indicating alkalinity. Toxicological screening of the MOC PE was negative. No pathological malignant pattern of the MOC PE was observed.

Fig. 2.

Findings during open-heart surgery.

(a) A large amount of viscous pale-colored fluid (blue arrows) was drained.

(b) The pericardium with calcifications was dissected and removed.

(c) The thick epicardium of the right atrium and right ventricle with calcification on its surface was sharply dissected into small fragments (waffle procedure) (white arrows).

The clinical symptoms secondary to the CP improved. An RHC performed 10 days postoperatively showed a decrease in both the mRAP (from 19 to 10 mmHg) and RVEDP (from 25 to 14 mmHg) and the disappearance of a dip and plateau pattern in the right ventricular pressure (Fig. 3a). A chest CT performed 1 month postoperatively confirmed that the MOC PE was removed and the calcification around the pericardium was reduced (Fig. 3b). Six months postoperatively, the patient was doing well with no further right heart failure.

Fig. 3.

Postoperative right heart catheterization (RHC) and chest computed tomography (CT) findings.

(a) Postoperative RHC showing the normal right ventricular waveform (light blue arrow), indicating the disappearance of the dip-and-plateau pattern of right ventricular pressure.

(b) Postoperative chest CT showing that the MOC PE was removed and the calcification around the pericardium was reduced.

Discussion

We experienced a case who was diagnosed with CP with an MOC PE, and surgical treatment including a pericardiectomy and epicardial waffle procedure contributed to the improvement in the clinical symptoms and pericardial constriction secondary to the CP.

The etiology of the MOC PE is still unclear. Sarosi et al. first reported an MOC PE in a patient with a history of radiotherapy for Hodgkin's disease [3]. A PE is the most common pericardial complication associated with radiotherapy. MOC could develop in the body, such as in the gallbladder and renal cysts [1], but the pericardial sac may be an ideal site for the development of an MOC PE due to the presence of an effusion, inflammation, and stasis.

A case was described by Ninomiya et al. that presented with autopsy findings in a patient who had developed an MOC PE and died of heart failure secondary to CP [2]. CP with an MOC PE could cause severe morbidity and even mortality. Therefore, it is important to evaluate the presence of a CP in patients suspected of having an MOC PE. In our case, a chemical analysis of the MOC PE showed a high calcium level of 39.2 mmol/L. Looi et al. also described a case of an MOC PE in which the chemical analysis of the MOC PE showed a very high calcium level of 830 mmol/L [4]. Regarding the CT values, the MOC PE had a high density on CT, ranging from 130 to 150 HU [2,4]. That finding was consistent with the results of the present case. The CT findings could be helpful in the diagnosis of an MOC PE. CP could present with variable and non-specific clinical symptoms and signs resulting from right heart failure. Therefore, an early diagnosis of CP is difficult and often made late [5]. In our case, the patient could be diagnosed with CP by the presence of an MOC PE, which contributed to the early decision for surgical treatment.

In the present case, no common cause of the CP was identified, including a viral infection, post-cardiac surgery, radiotherapy, connective tissue disease, malignancy, or tuberculosis. It was assumed that some kind of cause would have caused the CP to develop and subsequently induce the MOC PE, but we were unable to identify it. The 18F-FDG PET imaging, 67Ga citrate scintigraphy, and pathologic evaluation of the MOC PE showed no abnormal findings, indicating that at least no malignancy or inflammation appeared to be involved in the development of the CP and MOC PE.

The effective treatment for CP with an MOC PE and its prognosis is still unknown. A pericardiectomy is considered the mainstay of the treatment for CP [6,7]. Two cases of CP with an MOC PE reported by Sarosi et al. and Looi et al. underwent a pericardiectomy [3,4], but its therapeutic effect was not fully described. We confirmed that the preoperative right ventricular pressure waveform with a dip-and-plateau pattern improved to a normal right ventricular waveform postoperatively. Considering the finding that surgical treatment contributed to the improvement in the clinical symptoms and pericardial constriction secondary to the CP, it seems to be an effective treatment option even for CP associated with an MOC PE. However, a pericardiectomy could cause high morbidity and mortality rates, especially in cases with a delayed diagnosis and treatment [8]. Further research is needed to assess the risk-benefit ratio of a surgical treatment for CP associated with an MOC PE.

Funding sources

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of competing interest

The authors have no conflicts of interest to declare.