Other hepatoprotectants. Silymarin (milk thistle) should also be instituted (Table 2). This nutraceutical alters the composition of hepatocyte membranes and limits the entry of hepatotoxins into cells.31 It also stimulates protein synthesis and hepatic regeneration.31 Silymarin contains flavonoids such as silybin, silydianin, and silychristin, which increase glutathione concentrations and
provide antioxidant effects.31 Inhibition of the inflammatory effects of leukotrienes is also reported.31
S-adenosylmethionine (SAMe) is a precursor to glutathione and has antioxidant effects (Table 2).32 It also enhances DNA repair.32 While studies clearly indicate that milk thistle and SAMe protect hepatocytes from damage, studies have not confirmed that
either is useful in dogs with mucoceles.31,32
Monitoring. Reexamine dogs undergoing medical therapy for mucoceles after four to six weeks. The recheck should include abdominal ultrasonography,
a complete blood count, and a serum chemistry profile. In one report involving two dogs, alanine aminotransferase and alkaline
phosphatase activities and total bilirubin concentrations remained elevated for weeks to months after ultrasonographic resolution
of the mucocele.1 These persistent elevations are most likely associated with the extension of pathological processes from the gallbladder
to the liver or from a concurrent hepatic or endocrine (e.g. hyperadrenocorticism, hypothyroidism, diabetes mellitus) condition.
Prognosis. The prognosis for patients treated medically appears to be variable. In one study, seven of 25 patients with mucoceles were
treated with ursodiol and SAMe. Two died within two weeks, two were lost to follow-up, and three survived without complications
for at least six months.12
In a recent case study, two clinically ill patients with mucoceles were successfully managed with medical therapy.1 One dog was treated with SAMe, omega-3 fatty acids, famotidine, ursodiol, and levothyroxine. The second dog received ursodiol,
fenbendazole, and levothyroxine and was fed a hypoallergenic diet. Levothyroxine was used to treat hypothyroidism, and fenbendazole
was used for prophylactic gastrointestinal parasite therapy. These patients showed complete ultrasonographic resolution of
the mucocele after two and three months.1
Surgical intervention should be recommended in all dogs that fail to improve with medical therapy, including those with unresolved
clinical signs, worsening laboratory findings, and progressing ultrasonographic abnormalities.
Gallbladder mucoceles are being diagnosed with increasing frequency in dogs, but their true incidence remains uncertain. The
underlying cause of this condition is still controversial, but there is a strong association with mucous gland hyperplasia
within the gallbladder epithelium. While surgical management has been the historic treatment of choice, recent case-based
evidence suggests that some patients may respond to medical management.
Rebecca Quinn, DVM
Audrey K. Cook, BVM&S, MRCVS, DACVIM, DECVIM-CA
Department of Small Animal Clinical Sciences
College of Veterinary Medicine and Biomedical Sciences
Texas A&M University
College Station, TX 77843
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