What they did
Given the differences in the diagnostic approach and prognosis for patients with congenital portosystemic shunts (CPSSs) or acquired portosystemic shunts (APSSs), researchers sought to determine whether clinical or clinicopathologic data could be used to differentiate between the two to help guide diagnostic testing. The goal of the study was to determine whether this data could assist veterinarians at first-opinion practices with no access to advanced diagnostics in differentiating between young dogs with CPSSs and young dogs with APPSs. The researchers retrospectively evaluated data from 93 dogs with either CPSSs or APSSs. Normal dogs were not included in this retrospective study.
What they found
Neurologic signs consistent with hepatic encephalopathy were noted more often in dogs with CPSSs compared with dogs with APSSs, while ascites and poor body condition (< 4/9) were strong predictors of a diagnosis of APSSs, regardless of age. The researchers also noted that APSSs were not relegated to older dogs; a 5-month-old dog was found to have an APSS. Elevated alanine transaminase (ALT) activities and low hematocrit and mean corpuscular volume concentrations were also more commonly found in dogs with APSSs than in dogs with CPSSs.
While clinical signs and clinicopathologic abnormalities alone are not sufficient to distinguish between these two groups, specific findings (e.g. ascites, elevated ALT activity) may raise suspicion for one or the other and help veterinarians at first-opinion practices target diagnostics and educate pet owners.
Adam FH, German AJ, McConnell JF, et al. Clinical and clinicopathologic abnormalities in young dogs with acquired and congenital portosystemic shunts: 93 cases (2003-2008). J Am Vet Med Assoc 2012;241(6):760-765.
Link to abstract: http://avmajournals.avma.org/doi/abs/10.2460/javma.241.6.760