non-neoplastic lymphoid disease

• Chyle is a mixture of lymph and chylomicrons. Chylomicrons are lipids absorbed from intestine that are transported via lymphatics (causing the mix). Chylous effusions may result from rupture (e.g. trauma) or obstruction (e.g. neoplasia) of thoracic duct or other major lymphatic vessel. This is often idiopathic as the site of leak is not always determined.
• Chyle effusions (thoracic, abdominal) are rare. Chylothorax is usually a bilateral pleural effusion

  • Chylous effusion = chyle
  • Previously classified as modified transudate (progressing to exudate as inflammatory cells react to its presence) - OLD TEXTBOOKS
  • Lipid will interfere with refractometry which makes classification harder

  Thoracocentesis can be therapeutic and diagnostic, treatment may also involve the ligation of the thoracic duct (referral job and hence doesn’t need ligation of the specific leak site)
• Lymphangiectasia (lacteal dilation)
• With lymphangiectasia, the intestinal lymphatics dilate and lose chyle into the lumen causing a protein-losing enteropathy. Most cases are idiopathic (remain unknown) but they can be…

  • Congenital (inherited)
  • Acquired obstruction (e.g. neoplasia)

  The disease is thought to be common in dogs but rare in cats and can be managed with low-fat diet, +/- immunosuppressives (e.g. prednisolone). The work up is the same as any other PLE.
• a dog with lymphangiectasia will have a hx of GI signs e.g., weight loss, D+ and V+ and can present with a poor BCS and, if severe, ascites. Biochem will show parameters indicating a PLE e.g., hypoalbuminaemia but also hypercholesterolemia (a component of chyle). Ultrasound can identify the hyperechoic (dilated) lacteals) but biopsy is the only way to get a definitive diagnosis.

  • Consider endoscopic vs. surgical - low albumin can reduce healing ability and hence may lead to peritonitis as the wound is leaky and leaving intestinal contents into the abdomen
• label the image

  A) mesenteric

  B) lipids

  C) thoracic