Lymphangiectasia

Signalment

Breed predisposition:
- Yorkshire Terrier
- Lundehund
- Rottweiler
- Soft Coated Wheaten Terriers

Description

Lymphangiectasia is characterised by dilation and dysfunction of the lymphatic vessels of the intestines. Consequently, protein rich lymph leaks into the intestinal lumen, causing a protein-losing enteropathy and severe lipid malabsorption. It is relatively common in dogs but rare in cats.

Lymphangiectasia can be classified as primary or secondary. Primary lymphangiectasia may form part of of a localised or a more widespread lymphatic abnormality. Secondary lymphangiectasia is the result of lymphatic obstruction. The obstruction may be caused by:

inflammation, neoplastic infiltration o fibrosis
thoracic duct obstruction
right sided cardiac failure
caval obstruction
hepatic disease

Lymphagiectasia often accompanies a lipogranulomatous inflammation, but it is not clear which is the primary event. Lymphangitis can cause lymphatic obstruction but the leakage of lymph can cause a granuloma to form.

Diagnosis

Clinical Signs

Weight loss
Chronic diarrhoea, steatorrhoea
Ascites, oedema or chylothorax may result if there is severe hypoproteinaemia or lymphatic obstruction
Increased appetite
Vomiting, lethargy and anorexia (less common)

Laboratory Tests

Haematology

Panhypoproteinaemia
Lymphopaenia

Biochemistry

Hypocholesterolaemia
Hypocalcaemia due to hypoproteinaemia, vitamin D and calcium malabsorption
Hypomagnesaemia

Other Tests

Faeacal α1-proteinase inhibitor concentrations or chromium 51-labelled albumin may be used to confirm protein-losing enteropathy.

Diagnostic Imaging

Ultrasound

Abdominal ultrasonography may reveal pleural fluid or ascites as well as help to narrow down other differential diagnoses. Mucosa of intestinal loops may appear thickened due to oedema.

Endoscopy

Grossly, multiple white lipid droplets with prominent mucosal blebs can be seen.

Histopathology

Preferably, a full thickness biopsy is needed for a definitive diagnosis.

Refer to Lymphangiectasia for pathology

It is essential to distinguish a true lymphangiectasia from a secondary lacteal dilation due to Inflammatory Bowel Disease (IBD). In the case of IBD, inflammtory infiltrate will be seen in the lamina propria, but the degree of infiltration may be underestimated if oedema is present.

Treatment

Identify and treat the underlying cause if it is caused by secondary lymphangiectasia
Supplementation of fat soluble vitamins
Anecdotal report of glutamine supplementation
Prednisolone at 0.5-1.0 mg/kg PO BID
- Anti-inflammatory and immunosuppressive effect may be beneficial
- This is particularly true if there is associated lymphangitis, lipogranulomas and a lymphocytic-plasmacytic infiltration of the lamina propria.
Antimicrobials such as metronidazole or tylosin
- This may be beneficial due to their potential immunomodulatory effect and modulation of enteric flora
Diuretics, preferably combinations, such as frusemide and spironolactone are used to treat effusions.
Short term treatment with plasma or colloids can be given for plasma expandsion.

Prognosis

Guarded. The response to treatment is generally poor although some dogs may do well. Dogs in may be in remission for several years but the disease eventually progress to fulminant hypoproteinaemia.

References

Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company.
Hall, E.J, Simpson, J.W. and Williams, D.A. (2005) BSAVA Manual of Canine and Feline Gastroenterology (2nd Edition) BSAVA
Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier.