Salvage Cisterna Chyli and Thoracic Duct Glue Embolization in 2 Dogs with Recurrent Idiopathic Chylothorax

A 4-year-old male castrated English Mastiff weighing 72 kg (158 lb) was evaluated for acute dyspnea after a 1-week history of restlessness, episodes of increased respiratory effort, and inappetance. The dog was otherwise healthy and received seasonal heartworm preventative medication and routine vaccinations. On initial examination, the dog was bright, alert, responsive, and had a body condition score of 5/9. The body temperature was 101.8°F (38.7°C), and the heart rate was 150 beats/min. There was an increased respiratory effort during both inspiration and expiration with an abdominal component. Thoracic auscultation revealed decreased lung sounds in the ventral lung fields. Heart sounds were of normal rhythm, but muffled. Femoral pulses were bilaterally symmetric, and pulse quality was strong and synchronous with the heartbeat. A complete blood count, serum biochemistry profile, and coagulation screen were all within normal limits. Occult heartworm test and titers for Ehrlichia canis and Borrelia burgdorferi were negative. Thoracocentesis yielded 0.575 L of a milky, turbid fluid from the right hemithorax and 1.5 L of similar fluid from the left hemithorax. Analysis of the pleural fluid (using a hematology analyzer) revealed a composition of 87% lymphocytes, 9% macrophages, and 4% neutrophils, with fluid triglyceride concentration of 498 mg/dL. The sample was too lipemic to obtain an accurate total protein concentration. No microorganisms or atypical cells were identified. Comparison of the fluid triglyceride concentration with the serum triglyceride concentration (57 mg/dL; reference interval 50–150 mg/dL), combined with cytologic findings, was consistent with chylous effusion. Thoracic radiography revealed a small hyperlucent region in the caudodorsal thorax, suggesting mild pneumothorax presumably secondary to recent thoracocentesis. No evidence of valvular or myocardial disease was observed during echocardiogram evaluation. The presumptive diagnosis was idiopathic chylothorax. The owners decided to pursue conservative medical management with Rutin administration at 48 mg/kg (105.6 mg/lb) PO q8h. No change in diet was made at that time. The dog returned with chylothorax 2 weeks later, and the owners decided to pursue surgical treatment by pericardectomy and thoracic omentalization via a median sternotomy. During surgery, 6 L of chylous pleural effusion was removed. All lung lobes were examined and appeared normal. The pericardium appeared grossly normal, but was partially resected and submitted for histopathology. The omentum was mobilized through the diaphragm and sutured within the thoracic cavity. Thoracostomy tubes were placed bilaterally to enable evacuation of fluid, air, or both after the procedure. Recovery from anesthesia was uneventful. Pleural fluid production decreased dramatically within the next 4 days, and the dog was discharged with Rutin treatment at 48 mg/kg (105.6 mg/lb) PO q8h. The dog was healthy and breathing normally at reexamination 1 week later. Histopathology of the pericardium revealed severe mesothelial cell proliferation with lymphoid infiltration of the pleural surface. Continued treatment with Rutin was recommended for an additional 4 weeks until reexamination. The dog was readmitted 1 year later with a decreased appetite, weight loss of 3.3 kg (7.3 lb; 4.6% of body weight), tachycardia, tachypnea, and recurrence of pleural effusion identified on referral thoracic radiographs. Because of return of the previous clinical From the Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA (Clendaniel, Weisse, Culp, Berent); and the Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA (Solomon); Present addresses: Mid-Atlantic Veterinary Specialists, Malvern, PA (Clendaniel); Animal Medical Center in New York City, NY (Weisse, Berent); Department of Veterinary Surgical and Radiological Sciences, University of California-Davis, School of Veterinary Medicine (Culp). This work was performed at the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania located in Philadelphia, PA. This manuscript was presented in abstract form at the 2010 ACVIM Forum, Anaheim, California. Corresponding author: Dr William Culp, University of California-Davis, School of Veterinary Medicine, One Garrod Drive, Davis, CA 95616; e-mail: [email protected]. Submitted July 28, 2013; Revised September 13, 2013; Accepted October 22, 2013. Copyright © 2014 by the American College of Veterinary Internal Medicine 10.1111/jvim.12257 Abbreviations: