Lymphocytic-plasmacytic enteritis

This is a chronic inflammatory condition of the small intestine characterized by infiltration of the lamina propria by plasma cells and lymphocytes (). Middle-aged dogs of either sex are most susceptible and it appears more common in the German Shepherd dog although any breed can be affected. Similar infiltrations have been observed in other conditions such as bacterial overgrowth and giardiasis.

In the Basenji a complex disease entity exists, characterized by anorexia, occasional vomiting and chronic diarrhoea. Histological changes to the small intestine resemble lymphocytic—plasmacytic enteritis. The condition is thought to have a hereditary basis and may be precipitated by stress. Hypoalhuminaemia and hypergammaglobulinaemia are other hallmarks of the condition ().

The condition has also been diagnosed in cats which usually only develop a mild form of the condition, and certainly are never as severely affected as the Basenji.

The aetiology of the condition is not understood but may simply reflect a normal intestinal response to antigen such as bacteria, virus or allergen (). This is further substantiated by a resolution of the problem when a hypoallergen diet is fed or where corticosteroids are administered (). Antibodies to many antigens have been sought but so far without success ().

Clinical diagnosis

Three forms of the condition are recognized: (1) dogs presented with chronic vomiting, (2) dogs presented with chronic diarrhoea; and (3) dogs presented with chronic vomiting and diarrhoea.

In addition, evidence of anorexia, halitosis, borborygmi, polydipsia/polyuria and listlessness have been recorded. The signs may be observed to wax and wane and weight-loss occurs especially in advanced cases. Abdominal pain has been observed in some cases manifest as arching of the back or assuming a praying position.

When vomiting occurs it often contains bile, and there is no relationship to feeding, although partially digested food vomited hours after feeding may be observed, indicating disturbed gastric motility. Gastric biopsies are usually normal in such dogs, indicating the need to examine the intestine. It is very important to understand that vomiting may be the only sign associated with inflammatory bowel disease, in some cases, and that there may be no evidence of diarrhoea.

In the diarrhoeic form faeces are often soft or fluid in nature with increased volume, a foul smell and passed with increased frequency. Although the diarrhoea originates from the small intestine it is important to understand that secondary large intestinal involvement may occur.

In advanced cases depression, weight-loss, dull coat, hepatomegaly, splenomegaly and lymphadenopathy may be detected. Ascites and subcutaneous oedema develop when protein-losing enteropathy (PLE) and hypoproteinaemia occur.

In cats the condition has also been recognized, with signs of anorexia, weight-loss and chronic diarrhoea. Vomiting may also be a feature of the condition ().

Laboratory investigation reveals a leucocytosis with lymphocytosis and eosinophilia. Hypoproteinaemia with loss of both albumin and globulin occurs and an associated hypocalcaemia. Xylose and fat absorption are often poor and serum folate and B12 may also be depressed. Exocrine pancreatic insufficiency should be considered in the differential diagnosis, but the trypsin-like immunoreactivity value will be normal. Radiographs are singularly unrewarding.

A definitive diagnosis requires a laparotomy and collection of small intestinal biopsy samples. The condition most often affects the duodenum and jejunum, but may involve the ileum, so samples should be collected from all regions. Histological examination will reveal plasma cell and lymphocyte infiltration of the intestinal wall with some degree of villus atrophy in severe cases ().

Lymphocytic-plasmacytic enteritis: Treatment

As it is considered to be an immune-mediated condition, corticosteroids are frequently used in treatment. Prednisolone is used at 2 to 4mg/kg/day for 2 weeks followed by 1 to 2mg/kg/day for a further 2 weeks, reducing to alternate day therapy if symptoms do not recur. Where PLE is present the doses should be higher and for a longer period of time, up to a year in some cases. Where high doses are poorly tolerated, azathioprine (Imuran; Calmic Medicals) can be included, allowing a reduction of 50% in the prednisolone dose. Use azathioprine at 2mg/kg/day and reduce both drugs as the dog responds to therapy. In cats use 0.3mg/kg of azathioprine on alternate days. Metronidazole (Flagyl; RMB Animal Health) 10mg/kg tid can be used to reduce bacterial overgrowth and to reduce any cell-mediated immune response. The dose may be reduced to twice daily and then once daily after 2 weeks. All three drugs may be used in combination in severe cases. tylosin (Tylan; Blanco Products) has also been shown to be an effective antibiotic in this condition ().

Where vomiting is present, metaclopramidc Timequell; SmithKline Beecham Pharmaceuticals) at 0.5 mg/kg, 30mm before food is often helpful. Where colitis is present then prednisolone may have to be supplemented bv Sala/opyrin (Pharmacia) 20mg/kg, twice daily with or without a/alhioprinc.

The most important features of the diet are that it should be low in fat and non-allcrgenic. Such diets include Hills d/d or Waltham selected protein diet. A good vitamin mineral supplement is essential and if additional energy is required medium chain triglyceride (MCT) such as coconut oil should be used at 1 to 2 ml/kg liveweight.