Case History: A four year old female spayed Cavalier King Charles Spaniel presented to the Cornell University Hospital for Animals for a six week history of small bowel diarrhea, decreased appetite, intermittent vomiting, and weight loss. She had a four day history of worsening panhypoproteinemia, hypocholestrolemia, ascites, and pleural effusion. Clinical Findings: The patient presented with ascites, peripheral edema, a left sided II/VI systolic murmur and a body condition score of 3/9. Diagnostic Findings: Initial diagnostics performed at the referring veterinarian showed hypoalbuminemia, hypoglobulinemia, hypocholestrolemia, hypomagnesemia, hypocalcemia, a nonregenerative anemia, a metabolic alkalosis, a normal urinalysis, and an elevated Spec cPL. These tests ruled down protein losing nephropathy as a source for protein loss. Additional blood work was performed upon presentation to Cornell which showed a normal cobalamin, normal fecal analysis ruling down parasitic causes, normal bile acids ruling down hepatic causes, normal PT and APTT clotting times, a metabolic alkalosis, and normal ionized electrolyte values. Radiographs from the referring veterinarian showed abdominal and pleural effusion and an increased bronchointerstitial pattern. An abdominal ultrasound showed a hyperechoic peritoneal mesentery, jejunal lymphadenopathy, slightly thickened small intestines, a questionable diffuse hepatopathy, and no apparent cause for the panhypoproteinemia. Fine needle aspirates of the liver were performed to rule down liver disease and lymphoma and endoscopic biopsies of the stomach and duodenum were performed showing mild lymphocytic plasmacytic gastritis and enteritis. Problem List: The patient’s major problems were panhypoproteinemia, hypocholesterolemia, chronic small bowel diarrhea, vomiting, weight loss, ascites, pleural effusion, peripheral edema, and a II/VI left sided systolic heart murmur. Treatment: The dog was treated for inflammatory bowel disease with an anti-thrombotic medication, steroids, dietary modification, metronidazole, B12 injections, and a gastroprotectant.