Chylothorax in a Scottish Terrier: A Case Study (copy)

Introduction

• Presentation of a case study: Tyke Ziegler, a Scottish Terrier with chylothorax.

• Owner Kyle Ziegler's interest in presenting the case to undergraduate students at the University of Florida.

• Overview of the presentation: evaluation, diagnosis, and treatment of chylothorax.

About the Presenter

• Originally from California.

• Former music major.

• Veterinary education:

  • University of California, Davis (DVM).

  • Texas A&M (internship).

  • Colorado State University (surgical residency).

  • Surgery faculty at the University of Florida.

Case Presentation: Tyke

• Patient: Tyke, a white Scottish Terrier.

• Signalment: 7 years old, male intact.

• Presentation: approximately a one-month history of dyspnea, lethargy, and anorexia.

• Initial evaluation by general practice veterinarian revealed a chest issue.

• Referred to a specialty practice for further evaluation.

Physical Exam Findings

• Depressed and dull mentation (obtunded).

• Inspiratory dyspnea (difficulty breathing on inspiration).

Breathing Patterns

Obstructive Pattern

• Slow, deep, prolonged breaths.

• Typical of upper airway obstruction (e.g., laryngeal paralysis).

• Common in older labs.

Restrictive Pattern

• Rapid, shallow breaths.

• Indicates lungs cannot fully expand.

• Chest moves in small, rapid excursions.

• Tyke exhibited a restrictive breathing pattern.

• Absent lung sounds (no broncho vesicular sounds).

Oxygen Dissociation Curve

• Important concept for veterinary students.

• X-axis: partial pressure of oxygen.

• Y-axis: saturation of hemoglobin with oxygen.

• Steep logarithmic curve: small changes in partial pressure of oxygen can cause significant changes in hemoglobin saturation.

• Dogs can decompensate rapidly and become hypoxemic.

• Tyke was hypoxemic on presentation.

Differential Diagnoses

• Need to stabilize the patient before further diagnostics.

Pleural Space Disease:

Air Accumulation

• Pneumothorax: air in the pleural space due to trauma or external puncture.

• Eliminates negative pressure gradient, inhibiting lung expansion.

Masses

• Tumors from chest wall, lung, or mediastinum.

• Can restrict lung expansion.

Fluid

• Various types: blood, pus, chyle.

• Blood (hemothorax): from trauma, hemorrhage into the thoracic cavity.

• Pus (pyothorax): infection in the thorax.

• Chyle (chylothorax)

Pulmonary Disease:

Parenchymal Disease

• Examples: pulmonary fibrosis, pneumonia, atelectasis, tumors.

Diagnostic Approach

• After stabilization, determine the cause of dyspnea.

• Fluid analysis is crucial; red top tube indicates fluid collection.

• Chyle appearance: milky white.

Chest Radiographs

• Performed on Tyke due to relative stability, with supplemental oxygen and sedation.

• Revealed increased soft tissue density consistent with fluid.

• Unstable patients may require immediate thoracocentesis before radiographs.

Thoracocentesis

• Diagnostic and therapeutic procedure.

• Involves inserting a needle into the chest wall to remove fluid or air.

• Can stabilize the patient.

Fluid Analysis

• Color: red (hemorrhagic), clear (serous), white (chylous), yellow (urine).

• Protein content: helps classify fluids.

Fluid Classification

Transudate

• Very low cell count (less than 1,000).

Modified Transudate

• Cell count between 1,000 and 5,000.

• Chyle is classified as a modified transudate.

Exudate

• High white blood cell count (over 5,000).

• Triglyceride levels:

  • Diagnostic for chylothorax.

  • Chyle triglyceride levels are typically three times greater than serum levels.

• In Tyke's case, chyle triglyceride level was five or six times greater than serum level, confirming chylothorax.

Video and Radiographic Examples

• Comparison of pneumothorax and pleural effusion.

Pneumothorax

Radiographic Findings

• Black (air) surrounding white (soft tissue) structures.

• Heart elevated off the sternum.

• Lung lobe retraction due to air compressing the lung.

Video

• Bleb: rupture in the lung lobe causing air leakage.

• Collapsed lung lobe that does not inflate.

Pleural Effusion

Radiographic Findings

• Increased white (fluid/soft tissue) in the pleural space.

Thoracoscopic Image

• Fluid accumulation preventing lung inflation.

• Similar to Tyke's condition, but with milky fluid.

Emergency Treatment

• Stabilization is the priority: IV catheter, IV fluids, oxygen, sedation, analgesia.

Therapeutic Thoracocentesis

Sterile Technique

• Essential to prevent pyothorax.

  • Clip fur with a #40 blade.

  • Scrub with 0.05% chlorhexidine and alcohol.

  • Use sterile gloves, needles, and syringes.

Gravity and Fluid Pockets

• Fluid tends to accumulate ventrally.

• Use gentle negative pressure to avoid lung damage.

Ultrasound Guidance

• Preferred technique to locate fluid pockets between ribs.

• Fluid appears as a black circle.

Chylothorax Etiology

• Often unknown (idiopathic) in approximately 80% of cases.

Mechanisms

Increased Hydrostatic Pressure

• Increased pressure against lymphatic walls.

Causes

• Cranial vena cava thrombosis: clot in the cranial vena cava, obstructing chyle flow.

  • Cisterna chyli and thoracic duct: major lymphatic pathways.

  • Blockage leads to increased pressure and chyle leakage.

• Cardiomyopathy (dilated cardiomyopathy): heart muscle dilation increases pressure.

• Pericardial effusion: fluid around the heart increases pressure.

Disruption of Lymphatics

Causes

• Trauma (gunshot wounds, dog bites).

• Lymphangiectasia: loss of lymphatic integrity, causing chyle leakage. Poorly understood.

Idiopathic Chylothorax

• No identifiable cause.

• Most common category (80% of cases).

• Tyke's case was idiopathic.

Treatment Options

Medical Management

• Typically unrewarding.

• Palliative care rather than addressing the underlying cause.

Dietary Fat Reduction

• Reduce fat intake to decrease chyle production.

Rutin (benzopyran)

• Reported to increase macrophage activity in clearing chyle.

• May decrease chyle production and have anti-inflammatory effects.

Steroids

• Used if initial medical management fails.

• Aim to decrease lymphocyte infiltration into the chest.

• Questionable efficacy.

Success Rate

• Less than 20% with medical management alone.

• Typically trialed for 3-4 weeks before considering surgery.

Surgical Management

• Considered after medical management failure.

• Aims to stop chyle flow through the thoracic duct.

Techniques

• Cisterna chyli ligation.

• Thoracic duct ligation (TDL): most common procedure.

• Pericardectomy: removal of pericardium to reduce hydrostatic pressure.

• Combined TDL and pericardectomy: preferred method.

Omentalization

• Physiologic drain technique using omentum to absorb residual chyle.

Success Rate

• Variable (65-100%), likely around 70-80%.

Tyke's Surgery

• Thoracotomy: incision into the chest through the tenth intercostal space on the right side.

  • In dogs, the thoracic duct is on the right side.

• Methylene blue injection into a lymph node to visualize the thoracic duct (did not work well in Tyke's case).

• Finischeto rib spreaders used to retract ribs.

• DeBenke thumb forceps used to identify the thoracic duct.

• Ligation of the thoracic duct with silk ligature and hemoclips.

• Azygos vein used as a landmark for thoracic duct location.

• Pericardectomy was performed.

Post-operative Care and Prognosis

• Tyke is doing very well with no recurrence of fluid.

• Immediate post-operative concerns: blood, chyle, or air accumulation, pain management, and hypoxemia.

• Close monitoring of blood gases and lung function.

• Long-term success rate: 75-85% after six weeks of healing.

• Lifetime concern for recurrence.

• Tyke will be examined by his regular veterinarian bi-annually.

Conclusion

• Successful surgical intervention in Tyke's case.

• Rewarding experience to see patients recover and improve quality of life.

• Gratitude to Kyle Ziegler, his family, and Dr. Larkin for the opportunity to present the case.

• Offer to answer questions via email.

SIMPLIFIED

Introduction

• Case study: Tyke Ziegler, a Scottish Terrier with chylothorax.

• Owner Kyle Ziegler's interest in presenting the case to students.

• Overview: evaluation, diagnosis, and treatment of chylothorax.

About the Presenter

• From California.

• Former music major.

• Veterinary education:

  • University of California, Davis (DVM).

  • Texas A&M (internship).

  • Colorado State University (surgical residency).

  • Surgery faculty at UF.

Case Presentation: Tyke

• Patient: Tyke, white Scottish Terrier.

• Signalment: 7 years old, male intact.

• Presentation: one-month history of dyspnea, lethargy, and anorexia.

• Initial evaluation: chest issue.

• Referral to specialty practice.

Physical Exam Findings

• Obtunded.

• Inspiratory dyspnea.

Breathing Patterns

Obstructive Pattern

• Slow, deep, prolonged breaths.

• Upper airway obstruction (e.g., laryngeal paralysis).

• Common in older labs.

Restrictive Pattern

• Rapid, shallow breaths.

• Lungs cannot fully expand.

• Chest moves in small, rapid excursions.

• Tyke: restrictive breathing pattern.

• Absent lung sounds.

Oxygen Dissociation Curve

• X-axis: partial pressure of oxygen.

• Y-axis: saturation of hemoglobin with oxygen.

• Steep curve: small changes in partial pressure cause significant changes in hemoglobin saturation.

• Dogs decompensate rapidly and become hypoxemic.

• Tyke was hypoxemic.

Differential Diagnoses

• Stabilize patient before diagnostics.

Pleural Space Disease:

Air Accumulation

• Pneumothorax: air in pleural space.

• Inhibits lung expansion.

Masses

• Tumors from chest wall, lung, or mediastinum.

• Restrict lung expansion.

Fluid

• Blood, pus, chyle.

• Blood (hemothorax): trauma, hemorrhage.

• Pus (pyothorax): infection.

• Chyle (chylothorax).

Pulmonary Disease:

Parenchymal Disease

• Examples: pulmonary fibrosis, pneumonia, atelectasis, tumors.

Diagnostic Approach

• Determine cause of dyspnea after stabilization.

• Fluid analysis is crucial.

• Chyle appearance: milky white.

Chest Radiographs

• Performed on Tyke with supplemental oxygen and sedation.

• Increased soft tissue density (fluid).

• Unstable patients: immediate thoracocentesis before radiographs.

Thoracocentesis

• Diagnostic and therapeutic.

• Needle into chest wall to remove fluid/air.

• Can stabilize the patient.

Fluid Analysis

• Color: red, clear, white, yellow.

• Protein content: classifies fluids.

Fluid Classification

Transudate

• Very low cell count (less than 1,000).

Modified Transudate

• Cell count: 1,000-5,000.

• Chyle is a modified transudate.

Exudate

• High white blood cell count (over 5,000).

• Triglyceride levels:

  • Diagnostic for chylothorax.

  • Chyle triglycerides: three times greater than serum levels.

• Tyke: chyle triglycerides five to six times greater than serum.

Video and Radiographic Examples

• Pneumothorax vs. Pleural Effusion.

Pneumothorax

Radiographic Findings

• Black (air) surrounding white (soft tissue).

• Heart elevated off the sternum.

• Lung lobe retraction.

Video

• Bleb: rupture causing air leakage.

• Collapsed lung lobe.

Pleural Effusion

Radiographic Findings

• Increased white (fluid/soft tissue) in pleural space.

Thoracoscopic Image

• Fluid preventing lung inflation.

• Similar to Tyke's, with milky fluid.

Emergency Treatment

• Stabilization: IV catheter, IV fluids, oxygen, sedation, analgesia.

Therapeutic Thoracocentesis

Sterile Technique

• Clip fur.

  • Scrub with chlorhexidine and alcohol.

  • Use sterile gloves, needles, and syringes.

Gravity and Fluid Pockets

• Fluid accumulates ventrally.

• Use gentle negative pressure.

Ultrasound Guidance

• Locate fluid pockets between ribs.

• Fluid appears as a black circle.

Chylothorax Etiology

• Idiopathic in 80% of cases.

Mechanisms

Increased Hydrostatic Pressure

• Increased pressure against lymphatic walls.

Causes

• Cranial vena cava thrombosis: clot obstructing chyle flow.

  • Cisterna chyli and thoracic duct: lymphatic pathways.

• Cardiomyopathy: heart muscle dilation increases pressure.

• Pericardial effusion: fluid around the heart increases pressure.

Disruption of Lymphatics

Causes

• Trauma (gunshot wounds, dog bites).

• Lymphangiectasia: loss of lymphatic integrity.

Idiopathic Chylothorax

• No identifiable cause.

• Most common (80% of cases).

• Tyke's case was idiopathic.

Treatment Options

Medical Management

• Typically unrewarding.

• Palliative care.

Dietary Fat Reduction

• Reduce fat intake.

Rutin (benzopyran)

• Increases macrophage activity in clearing chyle.

Steroids

• Decrease lymphocyte infiltration.

• Questionable efficacy.

Success Rate

• Less than 20% with medical management alone.

• Trialed for 3-4 weeks before surgery.

Surgical Management

• After medical management failure.

• Stops chyle flow.

Techniques

• Cisterna chyli ligation.

• Thoracic duct ligation (TDL): most common.

• Pericardectomy: removal of pericardium.

• Combined TDL and pericardectomy: preferred.

Omentalization

• Physiologic drain technique.

Success Rate

• Variable (65-100%), likely around 70-80%.

Tyke's Surgery

• Thoracotomy: incision into the chest.

• Tenth intercostal space on the right side.

• Thoracic duct is on the right side in dogs.

• Methylene blue injection (did not work well).

• Finischeto rib spreaders to retract ribs.

• DeBenke thumb forceps to identify the thoracic duct.

• Ligation of the thoracic duct with silk ligature and hemoclips.

• Azygos vein used as a landmark.

• Pericardectomy was performed.

Post-operative Care and Prognosis

• Tyke is doing well, no recurrence of fluid.

• Immediate post-operative concerns: blood, chyle, or air accumulation, pain management, and hypoxemia.

• Close monitoring of blood gases and lung function.

• Long-term success rate: 75-85% after six weeks of healing.

• Lifetime concern for recurrence.

• Tyke will be examined bi-annually.

Conclusion

• Successful surgical intervention in Tyke's case.

• Gratitude to Kyle Ziegler, his family, and Dr. Larkin.

• Offer to answer questions via email.