Therapeutic Management
Both medical and surgical management is available for patients with cholecystitis. Medical management is indicated in cases of non-necrotizing cholecystitis where the GB wall integrity does not appear compromised on abdominal ultrasound.
When embarking on medical treatment it is important that the pet owner be warned of the possible need for surgical intervention in the future either if medical management is unsuccessful in resolving the infection or if biliary rupture/ EHBO subsequently occurs. Medical management typically consists of intravenous fluid therapy, antibiotic and analgesic therapy, anti-emetic and gastro-protectant therapy, if indicated, and the use of choleretics such as ursodiol. The choice of antibiotic therapy should ideally be guided by bacterial cultures of bile samples retrieved via chole- cystocentesis. In one study 62% of patients with cholecystitis had positive cultures, with E. coli, Enteroccoccus spp, Bacteroides spp, Streptococcus spp and Clostridium spp being the most commonly isolated bacteria (Wagner, Hartmann, and Trepanier 2007). Thus without bile samples for culture, empiric antibiotic therapy effective against gram negative bacteria and anaerobic bacteria is advised. Such antibiotics would include cefoxitin, metronidazole, and/or enrofloxa- cin. Antibiotics should be continued for a minimum of 4 weeks and potentially longer to ensure complete resolution of the infection.Regular monitoring of patients during medical therapy (at least 3 weekly) is imperative and should include serial ultrasonographic examination of the GB and serum liver enzyme activity analyses. Frequent communication with pet owners on their perception of the status of their dog's clinical condition is also important. Progression of the disease in any fashion on serial examinations should warrant immediate surgical intervention.
Euthanasia may unfortunately need to be considered in cases where medical management is unsuccessful in resolving the infection and controlling clinical signs and cost constraints prohibit surgery.In patients with necrotizing or emphysematous cholecystitis where there is ultrasonographic evidence of severe GB wall compromise or GB rupture, surgical intervention in the form of cholecystectomy is advised. In some cases, placement of a temporary biliary stent or a cholecystoenteros- tomy may also be required to circumvent a permanently occluded distal common bile duct, but should be carefully considered because of the high rate of complications, especially in cats. During surgery samples of bile, gallbladder wall, choleliths, and liver tissue should also always be submitted for histopathology and aerobic and anaerobic culture.
Preoperative management of cholecystitis should focus on restoration of fluid and electrolyte status (these patients often have severe cardiovascular compromise or sepsis), appropriate analgesia, and treatment with broad-spectrum antibiotics effective against enteric opportunists. Patients with chronic EHBO may also have a coagulopathy due to a relative deficiency of vitamin K from altered hepatobiliary excretion of bile acids required for vitamin K absorption (Richter and Pike 2014). It is, therefore, recommended that coagulation profiles be performed pre-operatively and failing that, prophylactic vitamin K (0.5-1.5 mg/kg IM or SC) or a fresh frozen plasma transfusion be administered.
If only the gallbladder is involved, and in the absence of neoplasia, simple cholecystectomy may be curative with a long-term survival and good quality of life expected. If the common bile, cystic, or hepatic ducts are involved, a more guarded prognosis is warranted, and long-term antibiotic therapy recommended. Patients having undergone biliary tree decompression by placement of a biliary stent or by biliary enteric-anastomoses are also more susceptible to future retrograde septic cholangitis and choledochitis. Owners should be instructed to monitor such patients for pyrexia, inappetance, vomiting, and signs of cyclic illness. A complete blood count and liver enzyme activity levels should be assessed every 3-4 months. Chronic or intermittent antimicrobial administration may be needed to control ascending cholangitis in these patients. Fortunately, illness is usually transient and responsive to antibiotics.