Chylothorax in pets - Causes, diagnosis and treatment

Chylothorax is a condition in which chyle (lymphatic fluid rich in fats) accumulates in the chest cavity. This puts pressure on the lungs and can lead to breathing difficulties and reduced stamina. The condition occurs in both dogs and cats and can have various causes.

In this article, we discuss the causes, symptoms, diagnosis, treatment options, and prognosis of chylothorax in pets.

What is chylothorax?

In chylothorax, chyle leaks from the lymphatic vessels into the chest cavity. Chyle is produced in the intestines during fat digestion and contains fat-rich particles (chylomicrons) and lymphocytes. Normally, it flows through the thoracic duct into the bloodstream. When this large lymphatic vessel is damaged or obstructed, the fluid leaks into the chest cavity.

The causes are diverse:

• Heart disease
• Tumors in the chest cavity
• Trauma with damage to the thoracic duct
• Thrombus or increased venous pressure
• Idiopathic: with no identifiable cause
• ...

Symptoms of chylothorax

The symptoms arise from fluid buildup in the chest cavity and lung compression:

• Breathing difficulty and rapid breathing
• Exercise intolerance
• Coughing
• Cyanosis (bluish discoloration of the mucous membranes due to severe oxygen deficiency)
• Weight loss and lethargy in chronic cases

Diagnosis of chylothorax

The diagnosis is made based on:

• Physical examination: dullness on auscultation
• X-rays: fluid in the chest cavity
• Ultrasound: confirmation of fluid accumulation
• Thoracocentesis (fluid aspiration): milky fluid with a high triglyceride content
• Additional tests: cardiac ultrasound, CT scan, or thoracoscopy to identify any underlying cause

Treatment of chylothorax

Conservative treatment

• Regular thoracocentesis to remove fluid and relieve breathing distress
• Low-fat diet and medication therapy

Nevertheless, conservative treatment offers little chance of a cure.

Surgical treatment

Surgical treatment is always recommended and offers the best chance of success. This treatment is now always performed through a combination of thoracic duct ligation, pericardectomy, and cisterna chyli ablation.

Recovery and prognosis

The prognosis largely depends on any underlying cause. With the latest surgical techniques (using special staining and minimally invasive surgery), the success rate for idiopathic chylothorax in dogs is approximately 85-95%. In cats, the disease remains more difficult to control and the prognosis is highly variable.

Early diagnosis can make surgery easier and lead to a better prognosis.

Want to know more?

Read more about our services in surgery, thoracic surgery, and internal medicine. Our specialized veterinarians at Nesto have extensive experience in diagnosing and treating chylothorax and work with modern techniques.

Frequently asked questions (FAQ)

What is chylothorax?

A condition in which lymphatic fluid (chyle) accumulates in the chest cavity, causing breathing problems.

Which animals most often develop chylothorax?

Both dogs and cats.

How is chylothorax diagnosed?

Through X-rays, ultrasound, and analysis of the fluid via thoracocentesis.

How is chylothorax treated?

By removing fluid, dietary management, medication, and surgery.

What is the prognosis?

That depends on the cause. Surgery always gives better results, but success rates vary.