Gastroenterology for practitioners: part 3 (Proceedings)

Case 13: 12 year old labrador retriever, pre-dental workup reveals ALT 250, alkaline phosphatase 355, BILIRUBIN 0.2.

Elevations of liver enzymes may be divided into "primary" and "secondary" liver diseases. Causes of primary liver disease include infection, inflammation, and infiltration. Secondary liver disease is associated with pancreatic or gastrointestinal disease. With secondary (also known as reactive) hepatopathy inflammatory mediators released into the portal vein cause non-specific irritation to the liver; hepatic biopsy is often unhelpful and direct hepatic therapy unnecessary.

I am unlikely to immunosuppress an older patient with asymptomatic liver disease. Therefore my diagnostics may stop if abdominal ultrasound and bile acids are normal in the patient described above (hepatic biopsy being of little therapeutic benefit). Monitoring of liver values over time is suggested to look for progressive elevations.

Case 14: 9 yr SF labrador retriever, hospitalized x 6 days for vomiting/diarrhea, now TP 3.8 (ALB 1.9, GLOB 1.9). How to biopsy?

The decision of endoscopy vs. celiotomy should be thoroughly discussed prior to biopsy. If endoscopy reveals neoplasia the diagnosis is confirmed, however often inflammation surrounds neoplastic areas of intestine. Pre-biopsy ultrasound is helpful.

Case 15: 8 yr sf doberman. Intermittent diarrhea with blood and mucus; responds to metronidazole but relapses.

Antibiotic-responsive diarrhea is common. Antibiotic-responsive diarrhea may be associated with low-fiber diets and Clostridium perfringens spore formation. Signs are consistent with large bowel diarrhea in an otherwise healthy dog. Stool cytology is useful but the value of stool culture and enterotoxin assays is uncertain. Treatment involves short term administration of an antibiotic (metronidazole, tylosin, amp/amoxillin). Dietary fiber should be increased if relapsing episodes occur. Rare patients require intermittent or chronic antibiotic administration.

Case 16: 14 yr CM DLH presents for anorexia and dyschezia; palpation and radiographs reveal severe constipation.

Rehydration and enemas are performed with deobstipation under general anesthesia if stools are not passed. Pelvic canal narrowing and rectal strictures should be excluded. Nasogastric administration of Go-Lytely® has been described as a method of deobstipation. MiraLax or lactulose may be used as stool softeners and cisapride to increase colonic motility. Some cats improve with a high fiber diet, others with a low-residue diet, and some experimentation must be performed. Colectomy often has a good outcome and is recommended for young and/or refractory patients.

Case 17: 6 yr SF DSH diagnosed with idiopathic hepatic lipidosis. What are the options for nutritional support?

Forced oral feeding involves stress for both the owner and patient and intake cannot be quantitated. Nasogastric feeding may be initially used in patients deemed unable to tolerate anesthesia. These severely ill patients have a guarded prognosis. Nasogastric diets are limited (Clinicare®) due to tube size. Gastric feeding tubes (placed surgically or percutaneously) should not be removed prior to 7 days after placement. Jejunal feeding tubes (placed surgically or endoscopically) are rarely used by the author. Esophageal feeding tubes are recommended in most cases. Esophageal tubes are easy to place, requiring no special instruments, and remarkably well tolerated. Change the wrap daily for the first few days, then weekly. Monitor for cellulitis at the entry site. Feeding schedule for cats: 5 ml water every 4 hours initially, and then 5-10 ml Eukanuba Max Cal® or Hills A/d® every 4-6 hours with gradual escalation up to approximately 200 kcals per day divided into 3 or 4 feedings. Note: calorie requirements equal water requirements.