This study establishes that there is a high prevalence of hyperadrenocorticism in dogs with gallbladder mucoceles and suggests
that a similar association may be present between hypothyroidism and mucocele development. It should be pointed out that in
both groups only those dogs with clinical signs compatible with endocrinopathies were tested for hypothyroidism or hyperadrenocorticism.
Therefore, although significantly different from each other, the precise odds ratios determined by the authors may have differed
if all dogs in either population had been tested, rather than the testing being performed at the clinician's discretion.
Nevertheless, based on these results, it appears reasonable to recommend that dogs with gallbladder mucoceles undergo additional
testing for hyperadrenocorticism and hypothyroidism, particularly those dogs with physical examination results or clinicopathologic
findings suggestive of either of these endocrinopathies. Thyroid hormone deficiency and hypercortisolemia are known to result
in gallbladder hypocontractility, alteration in bile composition (particularly through increased mucin secretion), and increased
contraction or tonicity of the sphincter of Oddi, all of which could result in prolonged bile retention and predispose the
patient to mucocele formation. Hyperlipidemia may also play a role in gallbladder mucocele development because, in addition
to the hypertriglyceridemia and hypercholesterolemia associated with hypothyroidism and hyperadrenocorticism, mucoceles are
commonly reported in breeds with heritable dyslipidemias (Shetland sheepdogs) or dogs that have received glucocorticoids.
In short, even in the absence of obvious physical examination findings consistent with either hypothyroidism or hyperadrenocorticism,
tentative evidence suggests that more systematic testing for one or both of these endocrinopathies may be merited in affected
Conversely, you should perhaps consider the development of a gallbladder mucocele as a more likely differential diagnosis
in dogs previously identified as having hyperadrenocorticism or hypothyroidism that newly present with clinicopathologic findings
consistent with hepatobiliary disease. However, it is unknown if earlier diagnosis and treatment of these endocrinopathies
in affected dogs would have slowed, reversed, or prevented the formation of gallbladder mucoceles.
Finally, in this study, the authors did not find that Shetland sheepdogs were predisposed to gallbladder mucocele formation.
That finding is in contrast to other publications and general anecdotal impressions in the United States and suggests caution,
as these results may not hold true in dog populations in other geographic areas.
Mesich ML, Mayhew PD, Paek M, et al. Gall bladder mucoceles and their association with endocrinopathies in dogs: a retrospective
case-control study. J Small Anim Pract 2009;50(12):630-635.
The information in "Research Updates" was provided by Erika Meler, DVM, MS, and Barrak Pressler, DVM, PhD, DACVIM, Department
of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
1. Aguirre AL, Center SA, Randolph JF, et al. Gallbladder disease in Shetland sheepdogs: 38 cases (1995-2005). J Am Vet Med Assoc 2007;231(1):79-88.
2. Walter R, Dunn M, D'Anjou MA, et al. Nonsurgical resolution of gallbladder mucocele in two dogs. J Am Vet Med Assoc 2008;232(11):1688-1693.