Feline Lymphocytic-Plasmacytic Enterocolitis (LPE)

1. Definition

Feline Lymphocytic-Plasmacytic Enterocolitis (LPE) is a chronic idiopathic inflammatory bowel disease characterized by infiltration of the intestinal mucosa with lymphocytes and plasma cells. It is the most common form of inflammatory bowel disease (IBD) in cats, leading to malabsorption and chronic gastrointestinal signs.

2. Species Commonly Affected

Domestic cats, particularly middle-aged to older individuals.
No specific breed predilection, though some studies suggest a higher incidence in purebred cats.

3. Etiology

Idiopathic: The exact cause remains unknown.
Proposed Factors:
- Genetic predisposition.
- Abnormal immune response to dietary antigens or intestinal microbiota.
- Disruption of the mucosal barrier leading to increased intestinal permeability.

4. Detailed Pathophysiology

LPE involves an inappropriate immune response within the gastrointestinal tract:

Immune Dysregulation: An imbalance between regulatory and effector T-cells leads to chronic inflammation.
Mucosal Barrier Dysfunction: Increased intestinal permeability allows luminal antigens to penetrate the mucosa, triggering an immune response.
Cytokine Production: Elevated levels of pro-inflammatory cytokines (e.g., IL-1β, TNF-α) perpetuate inflammation and tissue damage.
Histopathological Changes:
- Infiltration of the lamina propria with lymphocytes and plasma cells.
- Villous atrophy and crypt hyperplasia.
- In severe cases, fibrosis and architectural distortion of the intestinal mucosa.

5. Clinical Signs

Gastrointestinal:
- Chronic vomiting.
- Diarrhea (may be small or large bowel in nature).
- Weight loss.
- Anorexia or hyporexia.
- Tenesmus and hematochezia (if colon is involved).
Systemic:
- Lethargy.
- Dehydration.
- Poor body condition.

6. Diagnostic Methods

Laboratory Tests:
- Complete Blood Count (CBC): May reveal anemia of chronic disease or lymphocytosis.
- Serum Biochemistry: Hypoalbuminemia, hypoglobulinemia, elevated liver enzymes if concurrent hepatic involvement.
- Cobalamin (Vitamin B12) Levels: Often decreased due to malabsorption in the ileum.
Fecal Analysis:
- Rule out parasitic infections (e.g., Giardia, Tritrichomonas foetus).
Imaging:
- Abdominal Ultrasound: May show thickened intestinal walls, loss of layering, and enlarged mesenteric lymph nodes.
Definitive Diagnosis:
- Endoscopic or Full-Thickness Biopsy: Histopathological examination reveals lymphoplasmacytic infiltration of the intestinal mucosa.

7. Treatment Options

Dietary Management:

Novel Protein or Hydrolyzed Diets: Eliminate potential dietary antigens.
High-Fiber Diets: May benefit cats with colonic involvement.

Pharmacologic Therapy:

Glucocorticoids:
- Prednisolone: 2 mg/kg PO once daily; taper based on clinical response.
- Budesonide: 0.5–1 mg/cat PO once daily; preferred in cats with diabetes mellitus due to lower systemic effects.
Immunosuppressive Agents:
- Chlorambucil: 0.1–0.2 mg/kg PO every 24–48 hours; used in combination with glucocorticoids for refractory cases.
Antibiotics:
- Metronidazole: 10–15 mg/kg PO every 12 hours; has immunomodulatory properties.
Cobalamin Supplementation:
- Parenteral: 250 µg SC weekly for 6 weeks, then monthly.

Supportive Care:

Probiotics to restore normal intestinal flora.
Appetite stimulants (e.g., mirtazapine) if anorexia persists.

8. Complications / Prognosis

Complications:

Progression to intestinal lymphoma.
Protein-losing enteropathy leading to severe hypoalbuminemia.
Chronic malnutrition and weight loss.

Prognosis:

Varies based on response to treatment.
Many cats respond well to dietary management and immunosuppressive therapy.
Prognosis is guarded in cases with severe hypoalbuminemia or poor response to therapy.