August issue.indd

N.G. Mahon L. Nölke H. McCann D. Sugrue J. Hurley
Departments of Cardiothoracic Surgery and Clinical Cardiology, Mater Misericordiae Hospital, Eccles St., Dublin, Ireland

Correspondence to: Mr Lars Nôlke, Department of Cardiothoracic Surgery, Mater Misericordiae Hospital,, Eccles Street, Dublin, Ireland

Case report

Discussion

References

Keywords: Chylopericardium
Surg J R Coll Surg Edinb Irel., 1 August 2003, 236-238

A 25-year-old male was discovered to have an asymptomatic pericardial effusion during routine preemployment medical evaluation. During pericardiocentesis 1200 ml of milky-white fluid was obtained; subsequent biochemical evaluation confirmed the chylous nature of this fluid. Following thorough evaluation a diagnosis of isolated chylopericardium was made. Following several recurrences he underwent thoracotomy with ligation of the thoracic duct and creation of a pericardial window. There are relatively few published reports of true isolated chylopericardium and the aetiology and pathogenesis remain unknown. A primary abnormality of the thoracic lymphatic valve system is postulated. The most effective treatment is surgical with ligation of the thoracic duct above the diaphragm and creation of a pericardial window

CASE REPORT
A 25 year male was found at a routine preemployment medical assessment to have cardiomegaly on a chest radiograph. He was referred for echocardiography, which demonstrated a pericardial effusion without echocardiographic evidence of tamponade. The patient was asymptomatic. There was no history of cardiac disease, chest trauma, chest pain or recent viral infection. Physical examination was unremarkable.

Routine laboratory tests demonstrated a normal blood count, electrolytes and urea, calcium level, liver function tests, lactate dehydrogenase and normal lipid profile.

He was admitted for a diagnostic and therapeutic pericardiocentesis at which 1200cc of milky white fluid was aspirated. Biochemical analysis of this confirmed the presence of chylomicrons-triglyceride content of 27mmol/l, cholesterol level of 0.6mmol/l, lactate dehydrogenase (LDH) of 359mmol/l and protein content of 42mg/dl. Cytology revealed predominantly lymphocytes with no evidence of malignant cells. Ziel Nielsen staining was negative. Subsequent investigations included normal computerised tomography (CT) of the thorax, and abdomen and a normal pelvic ultrasound and lymph-scintiscan. A diagnosis of isolated chylopericardium was made. The patient was discharged and readmitted six weeks later with recurrence of the effusion necessitating repeat pericardiocentesis. Following further recurrence he underwent balloon pericardiotomy. This failed to prevent reaccumulation of pericardial fluid and he ultimately underwent anterior thoracotomy with thoracic duct ligation and creation of a pericardial window. This was uncomplicated and he has had no recurrence at 18 months follow-up.

DISCUSSION
Chylopericardium is most commonly seen as a consequence of thoracic and cardiac surgery and in association with congenital lymphangiomatosis.^1-2 It may also occur as a result of chest trauma, mediastinal neoplasms, following mediastinal radiotherapy and thrombosis of the subclavian vein in Behcets syndrome or following catheterisation of the subclavian vein.^3-5 It has also been reported in association with Jaffe-Campanacci syndrome, characterised by café au lait spots and nonossifying fibromata of the bones and following pericardiocentesis for acute idiopathic pericardial effusion.^6-7

Primary or isolated pericardial effusion is rare. It was first reported in 1886 by Hasebrock (1888) who described the aspiration of 22.6cc of chylous fluid at autopsy in a patient who died following aspiration secondary to tracheal obstruction and ulceration.8 In 1935, Yater reviewed 100 cases of chylothorax and noted three cases of associated chylopericardium.⁹ The term primary pericardium was first employed by Groves and Effler (1954) who described a case of isolated accumulation of chyle in the pericardium with no obvious cause.¹⁰ In a review of the literature, 57 cases of true (no obstructive lesions or history of previous cardiac surgery) isolated chylopericardium have been documented.

Age at presentation ranges from infancy to 79 years, with the majority of cases presenting in children or young adults. It occurs with equal frequency in males and females. Up to 40% of cases are asymptomatic and tamponade is rare (6%).Diagnosis is confirmed by the creamy white appearance of the pericardial fluid, the presence of fat droplets microscopically and the confirmation of the presence of chylomicrons on electrophoresis. The biochemical make-up varies with diet. Cholesterol levels range from 1.7mmol/l to 4.6mmol/l and protein from 3.15 to 7.6g/dl. Cytology generally reveals a predominance of lymphocytes. Lymphangiography is usually normal. Occasionally, pooling of contrast in the pericardial sac is demonstrated. Other findings include lymphangiectasis and previously unidentified lymphangioma.

The aetiology of chyloperdicardium remains unclear. Fatty acids absorbed in the gastro-intestinal tract are converted into triglycerides and incorporated into chylomicrons, which are transported by lymphatics ultimately to the thoracic duct, which empties into the left subclavian vein. A macroscopic communication between the thoracic duct and the pericardial sac is demonstrated in a minority of cases.¹¹ Connections between the pericardium and the lymphatic system have been inferred from experiments in which pericardial fluid has been examined for the presence of ingested Sudan III or I131triolein.¹² The thoracic duct is connected indirectly with the pericardial space via mediastinal lymph nodes. Because of the presence of valves within the lymphatics, reflux cannot occur into the pericardium unless the pressure exceeds 15cm of water. This may occur in the presence of thoracic duct obstruction and accounts for the occurrence of secondary chylopericardium as outlined above. However, animal ligation experiments have demonstrated that even if there is obstruction of the thoracic duct, chylopericardium does not necessarily occur since the duct can drain via collaterals to the azygous venous system. Also, lymphatic return may occur via the right thoracic duct. Elevated pressures may also occur in the presence of lymphangiectasis.¹³

Medical treatment has consisted of dietary restriction of fat intake to medium chain fatty acids or total parenteral nutrition. Medium chain fatty acids are not converted to triglycerides but are absorbed directly by the portal system and do not contribute to lymph formation. While permanent resolution of chylopericardium has been reported following thoracocentesis and dietary treatment, predominantly in children, this approach has mostly been of limited success.¹⁴ One case, associated with allergic extrinsic alveolitis responded to steroid therapy.¹⁵

Treatment with intravenous octeotride a somatostatin analogue may be beneficial, although its role has only been shown in chylothorax, to date.¹⁶ The majority of cases require surgical treatment, most commonly creation of a pericardial window alone or in combination with ligation of the thoracic duct. Creation of a pericardial window alone is associated with recurrence of chylopericardium in approximately 50% of cases, whereas recurrence is rare following additional ligation of the thoracic duct.^13,17 Recurrence following this procedure has been attributed to duplication of the thoracic duct.¹⁸

Other treatments, described for secondary chylopericardium, include creation of a pericardial-peritoneal fistula, and the creation of a pericardial-peritoneal shunt using the Denver shunts.^19,20 The procedure has been described in four paediatric cases; in one of these the device was subsequently removed without re-accumulation of chyle.

In summary, we describe a case of isolated chylopericardium, which ultimately responded to ligation of the thoracic duct and creation of a pericardial window. This is a rare condition, the aetiology and pathogenesis of which remain obscure. Based on existing reports the optimal definitive treatment in adults is surgical.

REFERENCES
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8. Hasebrock K. Analyse einer chylosen pericardierlen Flussigkeit (chylopericardium). Ztschr Physiol Chemie 1888;12:289
9. Yater WM. Non-traumatic chylothorax and chylopericardium;review and report of a case due to carcinomatous thromboangiitis obliterans of the thoracic duct and upper great veins. Ann Intern Med 1935;9:600
10. Groves LK, Effler DB. Primary chylopericardium. N Engl J Med 1954;250:520
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14. Kosloske AM, Martin LW, Schubert WK. Management of chylothorax in children by thoracentesis and medium-chain triglyceride feedings. Journal of Pediatric Surgery 1974;9: 365-371.
15. Bewick DJ, Johnstone DE, Landrigan PL. Primary chylopericardium associated with allergic alveolitis. Canadian Medical Association Journal 1984;130:1577-1579.
16. Mikroulis D, Didilis V, Bitzikas G, Bougioukas G. Octreotide in the treatment of chylothorax. Chest 2002;121: 2079-2080.
17. Akamatsu H, Amano J, Sakamoto T, Suzuki A. Primary chylopericardium]. Annals of Thoracic Surgery 1994;58: 262-266.
18. Kannagi T et al. Primary chylopericardium. Chest 1982;81: 105-108.
19. Bakay CWTS. Treatment of cardiac tamponade due to isolated chylopericardium following open heart surgery. Journal of Cardiovascular Surgery 84 A.D.;25:249-251.
20. Chan BB, Murphy MC, Rodgers BM. Management of chylopericardium. Journal of Pediatric Surgery 1990;25: 1185-1189.

The Royal College of Surgeons of Edinburgh

• Non-Surgical Intervention - Dr J P McDonald (Consultant Orthodontist), Fife Health Board

• Surgical Intervention in Children - Dr A Kerr (Consultant in Otolaryngology, Royal Infirmary, Edinburgh)

• Childhood Diseases - Dr T Marshall (Consultant Physician, Royal Hospital for Sick Children, Edinburgh)

• Aspects of Surgery in Relation to Adults and Children - Mr G W McGarry (Consultant in ENT, Glasgow Royal Infirmary)

• Adult Sleep Apnoea/Hypopnoea Syndrome - Dr Heather Engleman (Edinburgh University), Sleep Studies Centre

• Surgical Intervention - Mr Ian McClure (Consultant in Oral and Maxillofacial Surgery), Perth Royal Infirmary

Miss Donna Watters
Dental Secretary
The Faculty of Dental Surgery
Royal College of Surgeons of Edinburgh
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