Thoracoscopic Thoracic Duct Ligation and Thoracoscopic Pericardectomy for Treatment of Chylothorax in Dogs

Objective— To report the use of thoracoscopic thoracic duct ligation (TDL) and pericardectomy for treatment of chylothorax.
Study Design— Case series.
Animals— Dogs with chylothorax (n=12).
Methods— Dogs with secondary or idiopathic chylothorax had thoracoscopy performed in sternal recumbency through 3 portals in the caudal right hemithorax for TDL and were then repositioned in dorsal recumbency for pericardectomy. Portals were placed in the 5th and 7th intercostal spaces of the right hemithorax with 1 transdiaphragmatic portal in the right paraxiphoid position. Follow-up was performed by recheck examination or telephone interview to determine outcome.
Results— Seven dogs (58%) had idiopathic chylothorax; 6 dogs (85.7%) had complete resolution of their effusion, whereas only 2 of the 5 nonidiopathic dogs (40%) had complete resolution.
Conclusions— Thoracoscopy is minimally invasive, provides excellent observation, and allows for ligation of the thoracic duct in the caudal thorax. Patients with idiopathic chylothorax may have a better prognosis after TDL and pericardectomy than dogs with nonidiopathic chylothorax.
Clinical Relevance— Thoracoscopy for ligation of the thoracic duct and pericardectomy is an acceptable surgical technique for treatment of chylothorax.     

Chylous ascites in three dogs.

Chylous ascites was diagnosed in 3 dogs. Mesenteric lymphangiography was performed in 2 dogs and helped delineate abnormalities of the lymphatic system. The cause of chylous ascites in each dog appeared to be different. In 1 dog, a ruptured mesenteric lymphatic was identified at surgery. Evidence of abdominal lymphatic obstruction was found in another dog. Chylous ascites in the third dog appeared to be a complication of mesenteric lymphangiography for chylothorax.     

Treatment of chronic pleural effusion with pleuroperitoneal shunts in dogs: 14 cases (1985-1999).

OBJECTIVE: To describe complications and outcome associated with chronic nonseptic pleural effusion treated with pleuroperitoneal shunts in dogs. DESIGN: Retrospective study. ANIMALS: 14 dogs. PROCEDURE: Medical records at 4 veterinary schools were examined to identify dogs with chronic nonseptic pleural effusion that were treated by use of a pleuroperitoneal shunt between 1985 and 1999. Signalment, history, physical examination and laboratory findings, cause and type of pleural effusion, medical and surgical treatments, complications, and outcome were reviewed. RESULTS: 10 of 14 dogs had idiopathic chylothorax, and 4 had an identified disease. All but 1 dog with idiopathic chylothorax and 1 dog with chylothorax from a heart base tumor had unsuccessful thoracic duct ligation prior to pump placement. No intraoperative complications developed during shunt placement. Short-term complications developed in 7 of 13 dogs, necessitating shunt removal in 2 dogs and euthanasia in 1. Eight of 11 dogs with long-term follow-up developed complications; the overall mean survival time and the interval in which dogs remained free of clinical signs of pleural effusion were 27 months (range, 1 to 108 months) and 20 months (range, 0.5 to 108 months), respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Pleuroperitoneal shunts can effectively palliate clinical signs associated with intractable pleural effusion in dogs. Numerous short- and long-term complications related to the shunt should be expected. Most complications can be successfully managed, but even when shunts are functional some treatments fail because of severe abdominal distension or massive pleural fluid production that overwhelms the functional capacity of the shunt.     

Hyponatremia and hyperkalemia associated with idiopathic or experimentally induced chylothorax in four dogs

Two dogs with idiopathic chylothorax and 2 dogs with experimentally induced (ie, ligation of the cranial vena cava) chylothorax were treated by intermittent thoracic drainage. Of these 4 dogs, 3 that did not have evidence of renal failure had normal or near-normal serum sodium and potassium concentrations before thoracic drainage began, and all 3 developed repeatedly marked hyponatremia and hyperkalemia during thoracic drainage. Another dog became weak and depressed, ostensibly because of hyperkalemia. Serum sodium and potassium concentrations in 1 dog with spontaneous chylothorax returned to normal after chylothorax resolved and thoracic drainage was stopped. The other 3 dogs died or were euthanatized, and the effect of stopping thoracic drainage could not be evaluated. In 3 dogs in which it was measured, normal-to-high plasma cortisol concentration was observed before and after adrenocorticotropin administration, and 2 dogs also had hyperaldosteronemia. Hyponatremia was hypothesized to be caused by sodium loss via thoracic drainage whereas hyperkalemia may have been multifactorial in origin, but probably was attributable, at least, in part to decreased renal potassium clearance.     

Thoracic duct ligation and pericardectomy for treatment of idiopathic chylothorax

Chylothorax is a devastating disease, and the success rates from either medical or surgical management are less than satisfactory. In some animals with chylothorax, a thickening of the pericardium occurs that is associated with chronic irritation induced by chyle. We hypothesized that pericardial thickening would lead to increased right-sided venous pressures and that abnormal venous pressures would act to impede the drainage of chyle via lymphaticovenous communications after thoracic duct (TD) ligation. We also hypothesized that serosanguineous effusions that occurred after TD ligation could effectively be treated or prevented by pericardectomy in affected animals. TD ligation plus pericardectomy was performed in 17 animals, and pericardectomy alone was performed in an additional 3 animals that presented during a 5.5-year period to the Texas A&M University (College Station, TX). Nineteen animals presented for an evaluation of idiopathic chylothorax (9 dogs and 10 cats), and 1 dog presented for serosanguineous pleural fluid after TD ligation that had been performed elsewhere. Echocardiography was normal in all animals, except for a subjectively thickened pericardium in 7 cats and 6 dogs. Clinical signs of pleural fluid accumulation resolved in 10 of 10 dogs and in 8 of 10 cats after surgery. The overall success rate for the surgical treatment of chylothorax (ie, the resolution of pleural fluid accumulation) in this study was 90% (100% in dogs and 80% in cats). These data suggest that TD ligation in conjunction with pericardectomy has a favorable outcome in animals with idiopathic chylothorax.     

Chylothorax in cats: is there a role for surgery?

Chylothorax is a complex disease with many identified underlying causes including cardiac disease, mediastinal masses, heartworm disease and trauma. Management of this disease should be directed at identifying the cause, if possible, and treating the underlying disorder. In cats with idiopathic chylothorax, medical management is recommended initially because the condition may resolve spontaneously. Owners should be made aware of the potential development of fibrosing pleuritis in affected cats. When medical management is impractical or unsuccessful, surgical intervention should be considered. Surgical options include mesenteric lymphangiography and thoracic duct ligation, pericardiectomy, omentalisation, passive pleuroperitoneal shunting, active pleuroperitoneal or pleurovenous shunting, and pleurodesis. Of these, only thoracic duct ligation and pericardiectomy are preferred by the author because, if successful, the result is complete resolution of the chylothorax, thereby reducing the risk of developing fibrosing pleuritis. Omentalisation may be beneficial in some animals as adjuvant therapy, but this procedure may still allow fibrosing pleuritis to occur. Until the aetiology of the effusion in cats with idiopathic chylothorax is understood, the treatment success rate will be less than ideal. Future research needs to be directed at determining the pathophysiologic mechanisms underlying this disease in cats.     

Lymphangiographic evaluation of experimentally induced chylothorax after ligation of the cranial vena cava in dogs

Ligation of the cranial vena cava (CrVC) distal to the entrance of the azygous vein resulted in chylothorax in 7 of 10 dogs. Of the remaining 3 dogs, 1 developed a serosanguineous effusion that did not become chylous, and 2 dogs did not develop pleural effusion. In 2 of the 7 dogs developing chylothorax, the pleural effusion became serosanguineous within 2.5 weeks after CrVC ligation. Mesenteric lymphangiography was performed 2 to 6 weeks after ligation of the CrVC. Lymphangiectasia was seen in 4 dogs with chylothorax, but was not seen in the 3 dogs with serosanguineous effusions or the 2 dogs that did not develop effusions. One dog with chylothorax died prior to repeat lymphangiography. Less dye entered the thoracic duct, and alternate lymphaticovenous communications to the caudal vena cava were evident in the dogs without chylothorax. Ligation of the thoracic duct at the lymphaticovenous junction was performed in 3 dogs. These dogs did not develop pleural effusion. Lymphangiography was performed immediately after ligation and indicated filling of abdominal lymphatics but not of the thoracic duct. Lymphangiographic findings 6 weeks after ligation also indicated filling of intestinal lymphatics. Results of the present study indicated that ligation of the CrVC causes chylothorax, and that thoracic lymphangiectasia is a consistent finding in animals with experimental chylothorax. Obstruction of the thoracic duct did not induce lymphangiectasia or chylothorax. Impedence of thoracic duct flow into the CrVC may be a cause of clinical chylothorax in the dog.     

Results of thoracic duct ligation in dogs with chylothorax

Thoracic duct lymphangiography and ligation were done on 15 dogs with idiopathic chylothorax. Lymphangiography revealed thoracic lymphangiectasia in all dogs; none had a thoracic duct rupture. Lymphangiography immediately after ligation demonstrated missed branches of the thoracic duct in 4 of the 15 dogs. Eleven of the 15 dogs are alive and doing well. Eight of the 11 had no radiographic or clinical signs of pleural effusion (mean follow-up, 31.5 months; range, 4 to 75 months). The other 3 living dogs had persistent effusion; 2 were successfully managed with a pleuroperitoneal shunt (follow-up, 15 months) or pleurodesis (follow-up, 5 months), respectively, and 1 was not treated because the effusion was mild and the dog did not have clinical signs of disease (follow-up, 14 months). Four of the 15 dogs died or were euthanatized because of persistent effusion (mean follow-up, 11.5 months; range, 3 to 24 months). Considering the lack of treatment alternatives for dogs with idiopathic chylothorax, these results support thoracic duct ligation as a treatment method for dogs.     

Facial neuropathy in dogs and cats: 95 cases (1975-1985)

The medical records of 79 dogs and 16 cats admitted to the New York State College of Veterinary Medicine between January 1975 and October 1985 with facial nerve dysfunction were reviewed. In 31 dogs and 8 cats, facial neuropathy was the only abnormal finding. In 48 dogs and 8 cats, the clinical findings most often noted in the records in addition to facial neuropathy were vestibular signs. Facial neuropathy appeared unassociated with gender or right vs left sides in both dogs and cats, or with hypothyroidism in dogs. Facial neuropathy was associated with increased age, with certain breeds in both dogs and cats, and with otitis media/interna and keratoconjunctivitis sicca in dogs. Causes of facial nerve dysfunction in dogs and cats included surgical and nonsurgical trauma, neoplasia, and otitis media/interna. Facial neuropathy was judged to be idiopathic in 74.7% of dogs and 25% of cats.     

Evaluation of clinicopathologic features, response to treatment, and risk factors associated with idiopathic neutropenia in dogs: 11 cases (1990-2002)

OBJECTIVE: To evaluate the clinicopathologic features, response to treatment, and risk factors associated with idiopathic neutropenia in dogs. DESIGN: Retrospective case series. ANIMALS: 11 dogs. PROCEDURES: Medical records of dogs with idiopathic neutropenia were reviewed. Signalment, history, clinical signs, and response to treatment were recorded and compared with that in dogs with neutropenia attributable to known causes and to dogs without neutropenia (controls). RESULTS: Compared with dogs with neutropenia attributable to known causes, dogs with idiopathic neutropenia had lower neutrophil counts and were younger. When compared with control dogs, age < 4 years was identified as a risk factor for developing idiopathic neutropenia. In all dogs with idiopathic neutropenia, remission of neutropenia occurred within 18 days after administration of prednisone (2 to 4 mg/kg [0.9 to 1.8 mg/lb], PO, daily) and no serious complications or infections developed. CONCLUSIONS AND CLINICAL RELEVANCE: An immune-mediated pathogenesis should be considered for dogs with idiopathic neutropenia in which the cause is not known. Severe neutropenia and young age were significantly associated with idiopathic neutropenia in dogs. Prognosis appeared to be excellent with prednisone treatment.     

Anatomic and volumetric characterization of the cisterna chyli using CT lymphangiography and computer‐assisted design software in dogs with idiopathic chylothorax

The objectives of this retrospective, observational study were to characterize the anatomical features of the cisterna chyli (CC) in a cohort of dogs diagnosed with idiopathic chylothorax that underwent CT lymphangiography (CTLa), and to evaluate the feasibility of computer‐assisted design (CAD) software to quantify volumetric measurements of the CC. Twenty‐three client‐owned dogs with idiopathic chylothorax were included. Additionally, CTLa was performed in three canine cadavers to assess the ability of CAD software to accurately acquire volumetric measurements. Injection sites, attenuation values, anatomic location, dimensions, and aortic diameter to CC ratio (Ao:CC) were recorded. Video records of video‐assisted thoracic surgery (VATS) thoracic duct ligation (TDL) were reviewed in eight out of 23 dogs to compare operative and CTLa findings. The CC was dorsal and right‐sided in 18 out of 23 dogs, located between L1 and L4 in 21 dogs, and extended as far cranially as T11 in two dogs. The median measurements for length, height, and width were 150.0, 5.5, and 13.3 mm, respectively. Median total volume was 1.82 mL. Median volumes to the right and left of the aorta were 1.46 and 0.49 mL, respectively (P = .014). Median total CC volume to body weight ratio (CC:bw) was 0.07 mL/kg. The presence of an intrathoracic CC was observed intraoperatively in six out of eight cases that underwent VATS TDL. Findings supported the use of CTLa and CAD as feasible methods for characterizing the CC in dogs diagnosed with chylothorax. These methods may facilitate interventional planning involving the CC such as embolization.     

Canine neurogenic Keratoconjunctivitis sicca: 11 cases (2006-2010)

Objective To describe the clinical data of dogs with neurogenic Keratoconjunctivitis sicca (KCS) and an ipsilateral dry nose without other neurologic deficits. Procedure The retrospective case study included 11 dogs diagnosed with neurogenic KCS and an ipsilateral dry nose between 2006 and 2010. Medical records were reviewed for breed, age, sex, history, suspected cause of neurogenic KCS, clinical signs, and treatment modalities. Follow‐up information was obtained by re‐examination of patients or completion of a telephone survey with the referring veterinarian or the owners. Results Mean age of the dogs was 6.6 ± 4.5 years. Neurogenic KCS was diagnosed in three females, five spayed females, one male, and two castrated males representing 10 different breeds. Ophthalmic signs of KCS (mean Schirmer tear test [STT] value of 1.9 ± 2.9 mm/min) combined with an ipsilateral dry nose were diagnosed in seven left and four right eyes. The suspected cause of neurogenic KCS was idiopathic in nine and trauma in two cases. Systemic therapy consisted of oral pilocarpine 1–2% eye drops combined with case‐specific topical treatment with cyclosporine 0.2% and tear substitutes. Duration of systemic treatment with pilocarpine until healing was 125 days (range 84–204, median 98 days) for five dogs. One dog was lost to follow‐up, and the remaining five dogs are still under systemic treatment with pilocarpine. Conclusions Neurogenic KCS with an ipsilateral dry nose seems to be a predominantly idiopathic disease of middle‐aged female dogs without breed predisposition, which may be self‐limiting in some cases.     

Chylothorax associated with thrombosis of the cranial vena cava

This study reviewed confirmed cases of concurrent chylothorax and cranial vena caval (CrVC) thrombosis in dogs and cats, and determined predisposing factors for the development of chylothorax associated with CrVC thrombosis. The extent and location of the thrombus, the treatment regime, and the outcome are described. In all 4 cases, implantation of a jugular device was a predisposing factor to thrombosis of the CrVC, and there was extensive thrombosis of the CrVC extending from at least 1 jugular vein to just cranial to the heart. Chylothorax resolved in 3 of the 4 cases after medical and/or surgical intervention. The development of chylothorax concurrently with thrombosis of the CrVC in dogs and cats is likely dependent on the extent and location of the thrombus. Veterinary patients with indwelling jugular devices that develop acute respiratory signs should be assessed for chylothorax associated with thrombosis of the CrVC.     

En bloc ligation of the thoracic duct in twelve dogs with idiopathic chylothorax

Twelve dogs with idiopathic chylothorax were treated by en bloc ligation of the thoracic duct. Six dogs recovered completely. Minimal follow-up in this group was 12 months. Five dogs were euthanized within 5 months of surgery because of persisting liquothorax: two with chylous and three with non-chylous effusions. One dog was euthanized 2 months after surgery because of a recurrence of dyspnoea. It is concluded that the results are comparable with those of a previously described surgical treatment; however, the technique described here is less complicated because it does not require mesenteric lymphangiography.     

Cisterna chyli ablation with thoracic duct ligation for chylothorax: results in eight dogs

OBJECTIVE: To report use of combined cisterna chyli ablation (CCA) and thoracic duct ligation (TDL) for treatment of spontaneously occurring chylothorax in dogs. STUDY DESIGN: Retrospective study. ANIMALS: Eight dogs with chylothorax. METHODS: TDL was performed through a right caudal intercostal thoracotomy and CCA through a left flank paracostal approach or ventral median celiotomy. Long-term outcome (range, 2-48 months; median, 11.5 months) was evaluated by telephone communication with owners. RESULTS: Seven dogs were free of clinical signs related to chylothorax at last follow-up (range, 4-48 months; median, 15.5 months). One dog was euthanatized 2 months after surgery because of lack of improvement. No major complications occurred from CCA. CONCLUSION: CCA and TDL resolved chylothorax in most dogs (88%). CLINICAL RELEVANCE: CCA combined with TDL may improve the outcome of chylothorax in dogs.     

Causes of uveitis in dogs: 102 cases (1989-2000)

Uveitis is one of the most common ocular diseases and one of the most common causes of blindness in dogs. The purpose of this retrospective study was to correlate the signalment, history, clinical signs and ophthalmic findings of dogs with uveitis with the underlying etiology. We conducted a retrospective study of 102 dogs presented to the NCSU-VTH from 1989 to 2000 with clinical signs of uveitis. Medical records of dogs presented for uveitis were reviewed. Dogs were included in the study only if a complete diagnostic work-up database was collected, if sufficient follow-up was documented, and if the uveitis was not secondary to trauma or a hypermature cataract. The mean age +/- SD of all dogs in this study was 6.2 +/- 3.6 years. There were 33 intact and 16 castrated males, and 14 intact and 27 neutered females. Fourteen breeds were represented, with the Golden Retriever (n = 14) most common. Fifty-nine dogs (58%) were diagnosed with idiopathic/immune-mediated uveitis, neoplasia was diagnosed in 25 dogs (24.5%) and 18 dogs (17.6%) were diagnosed with infectious causes of uveitis. Aqueous flare was the most common clinical sign, occurring in 88 dogs (86%). The most common infectious organisms associated with uveitis in the dogs of this study were Ehrlichia canis (n = 7). Lymphosarcoma (n = 17) was the most common neoplasm. In approximately 60% of dogs presenting for uveitis an underlying cause was not found, and a diagnosis of immune-mediated or idiopathic uveitis was made. However, approximately 25% of dogs had ocular and/or systemic neoplasia (with 17% of cases having lymphosarcoma) and 18% with an underlying infectious cause for uveitis. Because of the high percentage of systemic disease associated with uveitis in dogs, extensive diagnostic testing is recommended before instituting symptomatic anti-inflammatory therapy.     

Computed Tomographic Lymphography of the Thoracic Duct by Mesenteric Lymph Node Injection

Objective— To document a novel technique to image the thoracic duct and its tributaries by contrast enhanced computed tomography (CT) lymphography.
Study Design— Clinical report.
Animals— Dogs (n=6) idiopathic chylothorax.
Methods— Ultrasonography was used to guide percutaneous injection of intestinal lymph nodes with nonionic iodinated contrast medium for preoperative CT lymphography of the thoracic duct in 6 dogs with chylothorax. Thoracic CT images were acquired immediately after contrast medium injection. All dogs had subtotal pericardectomy and thoracic duct ligation. Postoperative thoracic duct lymphography was performed in 3 dogs. Superficial cervical lymph node lymphography was performed in 2 dogs to determine cervical lymphatic contribution to thoracic effusions.
Results— Preoperative thoracic duct lymphography using this technique was successful in delineating the cisterna chyli, thoracic duct, and associated lymphatic vessels in all dogs. Immediate postoperative lymphography performed in 2 dogs revealed successful duct ligation in 1 dog and persistent lymphatic leakage in the other. A 1-month postoperative thoracic duct lymphogram performed in 1 dog revealed unsuccessful ligation or recannulation of 1 of 3 redundant vessels seen preoperatively.
Conclusion— Percutaneous CT lymphography results in excellent detection of the thoracic duct and abnormal thoracic duct drainage patterns both pre- and postoperatively. The contribution of superficial cervical lymph node drainage to reoccurrence of effusions can be evaluated.
Clinical Relevance— Percutaneous CT lymphography using ultrasound-guided contrast medium injection should be considered as an alternative to conventional open abdominal approaches to radiographic or CT lymphography.     

Bilateral ventriculocordectomy via ventral laryngotomy for idiopathic laryngeal paralysis in 88 dogs

Bilateral ventriculocordectomy through a ventral median laryngotomy was performed for the treatment of idiopathic laryngeal paralysis in 88 dogs. The purpose of this retrospective analysis was to provide long-term follow-up for a large number of dogs surgically managed with this technique. A combination of medical record and completed client questionnaire information provided short-term (14 days) follow-up for 88 dogs and long-term (>6 mo) follow-up for 42 dogs. Major short-term postoperative complications were identified in 3 of 88 (3.4%) patients. Major long-term complications were identified in 3 of 42 (7.1%) patients. The results of surgery were considered to be very satisfactory in 93% and unsatisfactory in 7%. Three dogs in this series developed aspiration pneumonia. Bilateral ventriculocordectomy through a ventral median laryngotomy is associated with a low incidence of both short- and long-term complications. Due to the ease of this procedure, the minimal surgical trauma to the patient, and the satisfactory results, this surgery should be considered an option for the treatment of idiopathic laryngeal paralysis in the dog.     

Resolution of chylothorax after resection of rib chondroma in a dog

A six-year-old, male dobermann was presented with a history of dyspnoea and bouts of coughing. Radiography and computed tomography of the thorax showed pleural effusion and a well-circumscribed, calcified mass of 10 cm in diameter, appearing to originate from the left first rib. Thoracocentesis revealed that the pleural fluid was chylous in nature. An incisional biopsy was performed, which gave a histological diagnosis of chondroma. Resolution of the chylothorax after en-bloc surgical removal of the tumour suggested that the rib tumour was the initiating cause of the chylothorax. Seventeen months later, rib neoplasia recurred without pleural effusion, and was removed successfully. To the authors' knowledge, rib chondroma, which is an unusual tumour in dogs, has not been previously documented as a cause of chylothorax.     

Horner's syndrome in dogs and cats: 100 cases (1975-1985)

The medical records of 74 dogs and 26 cats with Horner's syndrome (HS) that were admitted to the New York State College of Veterinary Medicine between January 1975 and October 1985 were reviewed. In dogs, but not cats, HS was associated significantly (P less than 0.01) with increasing age. Dogs with hypothyroidism (defined liberally but not rigorously), intracranial neoplasia, or thoracic neoplasia, cats with otitis media/interna (defined liberally), and dogs and cats with brachial plexus root avulsion were at greater risk for developing HS than were animals that were hit by a car. Dogs and cats with otitis externa were at less risk of developing HS than were animals that were hit by a car. The cause of HS could not be determined in 50% of dogs and 42.3% of cats. The results of topical adrenergic drug testing in dogs were inconclusive in localizing lesion site. In dogs and cats, HS appeared to be unassociated with gender, breed, or right vs left side. The important causes of HS in dogs and cats were trauma (hit by car), brachial plexus root avulsion, intracranial and thoracic neoplasia, and otitis media/interna.