Gastroenterology for practitioners: part 2 (Proceedings)

Case 8: 6 year old dog on phenobarbital. ALK PHOS 2000, ALT 120, BILI 0.2.

Phenobarbital induces elevated alkaline phosphatase in many dogs and is not considered a sign of impending liver failure. ALT (and certainly serum bilirubin) elevations are much more concerning and should be followed up with serum bile acids (pre- and post-prandial), serum phenobarbital level, consideration to lowering the dose of phenobarbital with substitution of an alternative anticonvulsant (potassium bromide, levetiracetam, zonisamide, gabapentin) and potentially liver biopsy. Phenobarbital-induced liver disease is dose-related with toxicities occurring when serum phenobarbital levels exceed 30 microg/dl. The prognosis for advanced phenobarbital-induced liver disease is poor; avoidance and/or early detection are important.

Case 9: 6 month old golden retriever is stumbling and dull. ALK PHOS IS 300, ALT IS 300, BILI 0.3.

Portosystemic shunting of blood often causes only mild elevations of liver enzymes. Some cases (more frequently in cats) have completely normal liver enzymes. Diagnostic testing should include complete blood count, biochemical profile, serum bile acids (pre- and post-prandial), urinalysis, and abdominal ultrasound. The mean corpuscular volume is often decreased. If the shunt cannot be confirmed with ultrasound, further diagnostics may include a radiographic contrast or nuclear scintigraphic study. Medical therapy includes dietary protein restriction, metronidazole or neomycin, and lactulose. Prognosis is generally good with surgery.

Case 10: 8 year old obese cat. Owner boards for two weeks while on vacation. When owner returns, cat is not eating. Pe jaundice. ALK PHOS 600, SAP 300, BILI 6.0.

Fatty Liver Syndrome (Idiopathic Hepatic Lipidosis) may either be "primary" (explained by an external event such as boarding, dietary change, or new puppy) or "secondary" (to an underlying illness such as pancreatitis). Primary cases are treated supportively; with secondary cases the underlying cause must also be addressed. Diagnosis is suspected in an icteric cat with elevation of serum alkaline phosphatase (greater than ALT) and normal GGT values. Abdominal ultrasound is helpful to exclude concurrent disease; the value of fine needle aspiration and/or hepatic biopsy is questionable. Treatment is appropriate nutritional support. The use of nasogastric, gastric or preferably esophageal feeding tubes are recommended. Antiemetics are used as needed to allow oral feeding. Recover occurs in most cases but may take weeks. Recovery is often complete.

Case 11: 6 year old obese cocker spaniel. Vomiting acutely after holiday picnic. PE: T103.0, painful abdomen. PCV 45, TS 10.0, lipemic serum. Radiographs unremarkable.

Lipemic serum in a vomiting dog is highly suggestive of pancreatitis. Lipemia falsely elevates total solids as measured by refractometry. Abdominal ultrasound is useful to confirm the diagnosis but not essential for diagnosis or treatment. Mild, moderate, and severe cases exist and the disease can be fatal. Treatment involves fluids, pain medications, antiemetics, and allowing nothing per os. Recovery occurs in most cases although the length of supportive care must be decided on a case-by-case basis.

Case 12: 5 year old cocker spaniel, vague complaint of "not well." ALT 800, alkaline phosphatase 600, BILI 1.1.

Hepatopathies may be acute and severe, chronic and mild, or chronic and progressive. Clues that trigger a more aggressive diagnostic and therapeutic response include age and breed, with young dogs of the cocker spaniel, Doberman, and Labrador retriever breeds having well-recognized syndromes of progressive hepatopathy. Diagnostic testing includes serum bile acids (not needed if bilirubin is elevated), coagulation profile, abdominal ultrasound and liver biopsy. Biopsies should be sent for histopathology and copper quantitation. Treatment includes glucocorticoids and/or other immunosuppressants. Famotidine is prescribed for life. Medications such as S-adenosylmethionine, urosodiol, Vit. C, Vit. E, may be added, however it is difficult to assess the efficacy of each.