Page 244 - ONLINE PROCEEDING BOOK WSAVA 2017
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An Urban Experience
WSVA7-0383
INTERNAL MEDICINE III
INTERPRETATION OF LABORATORY PARAMETER CHANGES IN PATIENTS WITH GI DISORDERS
S. Unterer1
1Clinic of Small Animal Medicine, Centre for Clinical Veterinary Medicine- Faculty of Veterinary Medicine, Munich, Germany
INTERPRETATION OF LABORATORY PARAMETERS IN PATIENTS WITH GI DISORDERS
Stefan Unterer, DVM, DECVIM
Clinic of Small Animal Medicine, Centre for Clinical Veterinary Medicine, LMU Munich
Email: s.unterer@medizinische-kleintierklinik.de
In patients with gastrointestinal symptoms (GIS), the following laboratory parameters should be determined in order to rule out extraintestinal causes of disease:
• Blood urea nitrogen (BUN), creatinine and urine speci c gravity to rule out renal failure
• Serumbileacidsorammoniatoruleoutportosystemic shunting and liver dysfunction
• Serum basal cortisol concentration to rule out hypoadrenocorticism
• (not always elevated in mild/chronic forms)
A recently performed study showed that 6/151 dogs (4%) presented for chronic GIS were diagnosed with hypoadrenocorticism (HA). Hyperkalemia/ hyponatremia were not observed in those dogs, and HA could not
be separated from other disorders causing chronic GIS based on any information from the history or based on laboratory parameters. Therefore, it has been suggested that basal serum cortisol levels should be measured as a screening test for hypoadrenocorticism in every dog with chronic GIS, followed by an Adrenocorticotropic hormone (ACTH) stimulation test in cases with a basal serum cortisol concentration < 2 μg/dL.
Packed cell volume (PCV) determination can provide important information about the hydration status of a patient and is easy to perform. In some dogs with acute onset of gastrointestinal signs, the degree of dehydration might be underestimated by relying only on clinical parameters. Speci cally, in dogs with blood in feces, PCV helps to distinguish between GI bleeding (PCV is decreased or low normal in a dehydrated patient) and hemorrhagic enteritis. In dogs with acute hemorrhagic diarrhea syndrome, PCV is often signi cantly increased, and in some patients PCV is within the reference interval. In this patient group, a decreased PCV would be an unusual  nding. Additional parameters, which
might be seen in association with GI bleeding, include melena, regenerative microcytic anemia (iron de ciency), thrombocytosis, disproportionally elevated BUN compared to creatinine, low total protein/albumin. To detect the presence of small amounts of blood in the feces, a guaiac fecal occult blood test (hemoccult test) can be performed. Since this test can show false positive results due to different dietary components (e. g. red meat, vegetables, vitamin C in fruits), a speci c feeding regime should be initiated 3 days before testing (e. g. rice and cottage cheese for dogs, Hills k/d chicken for cats).
Neutrophils are frequently elevated due to stress response in patients with GIS. However, if neutrophils are signi cantly elevated (> 25 x 109/l), or if a signi cant left shift is present (band neutrophils > 1.5 x 109/l) in
a GI patient, an in ammatory response is likely. In this case, clinician should check for a possible bacterial infection as well as for translocated bacteria (blood culture, or culture of aspirated material from enlarged abdominal lymph nodes should be performed). Signi cant neutrophilia and a left shift is usually an indication for antibiotic treatment after obtaining samples for culture. Antibiotics are also indicated in GI patients with GIS and signi cant neutropenia. Patients with the combination of neutropenia and destroyed intestinal mucosal barrier, typically seen in dogs with parvovirosis, are especially prone to sepsis. In general, patients with combination of increased intestinal permeability (e.
g. hemorrhagic diarrhea, protein losing enteropathy)
and reduced immune competence (e. g. neutropenia, immunosuppressive treatment, liver dysfunction, portosystemic shunting) have an increased risk for systemic bacterial infection.
Laboratory tools to assess the intestinal function and/ or the severity of intestinal disease include: albumin, cobalamin (vit B12), folate (vit B9), C-reactive protein (CRP) concentrations, and canine pancreatic lipase immunoreactivity (cPLI). Low albumin concentration due to intestinal loss always re ects a severe form
of gastrointestinal disease, termed protein losing enteropathy. In rare cases, hypoadrenocorticism can mimic a primary intestinal disease causing protein
loss into the gastrointestinal tract. After ruling out hypoadrenocorticism, parasites and focal intestinal disorders, intestinal biopsies are usually indicated
for diagnosis. In general, patients with signi cant gastrointestinal protein loss have a guarded prognosis.
Similar to albumin, cobalamin concentration is also a prognostic factor. Cobalamin concentration should be determined in every case of suspected GI or pancreatic disorder. Since cobalamin is absorbed in the ileum, hypocobalaminemia in a patient with intestinal disease can help locate the location from which biopsy samples
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42ND WORLD SMALL ANIMAL VETERINARY ASSOCIATION CONGRESS AND FECAVA 23RD EUROCONGRESS


































































































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