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CANINE LEPTOSPIROSIS: A PERSPECTIVE ON RECENT TRENDS | Figure 5. Diffuse small intestinal hemorrhage Figure 6. Diffuse pulmonary hemorrhage Uveitis & Enteritis Uveitis has been recognized as a concurrent finding in some dogs with either acute kidney injury or hepatitis, although it may be subtle and, therefore, undiagnosed in some cases.17 Likewise, intussusceptions as a result of severe enteritis (Figure 5) have been reported as a rare concurrent condition in dogs with acute kidney injury.18 Polyuria & Polydipsia Polyuria and polydipsia (PU/PD) in the absence of any routine laboratory abnormalities (other than hypo- sthenuria) is the second most common syndrome seen at my institution.19 While these dogs appear out- wardly healthy, they exhibit profound PU/PD. Many have a history of brief fever and lethargy that is self- limiting up to 2 weeks prior to onset of PU/PD; an event that can be easily overlooked. Most causes of PU/PD are easily eliminated from the differential list based on: UÊ ÊnoÀm>lÊ Ê>n`ÊÃiÀÕmÊLioVhimiV>lÊ«ÀoviliÊ UÊ/hiÊ>LÃinViÊovÊ>VÌiÛiÊÕÀiniÊÃi`iminÌÊoÀÊni}>ÌiÛiÊ urine culture). Testing for leptospirosis should be performed prior to evaluation for central diabetes insipidus or psycho- genic PD. Pulmonary Hemorrhage Recently, concern has been raised about the emergence of pulmo- nary hemorrhagic syndrome, which is seen in humans.20,21 Reports of pulmonary hemor- rhage in dogs with leptospiro- sis (Figure 6) can be found throughout the literature, but it is unclear whether it is truly emerging as a syndrome of sig- nificant incidence. UÊConcurrent syndromes: Many, although not all, dogs with this syndrome have con- current acute kidney injury. UÊPathogenesis: The al- veolar hemorrhage is believed to be caused by vasculitis (which can affect other organs, see Figure 7), potentially complicated by throm- bocytopenia; however, these are not consis- tently found, suggest- ing an alternate patho- genesis. It is not known whether the hemor- rhage occurs secondary to local release of tox- ins, effect of circulating toxins, or an immune- mediated process. UÊImaging: A diffuse miliary, reticulonodular, or bronchointerstitial pattern is most commonly seen on radiographs. UÊSupportive therapy: Some of these patients may require oxygen support during treatment for leptospirosis. No additional therapies are supported in the literature as being particularly effective in reducing mortality associated with this syndrome. DIAGNOSTICS Confirming a diagnosis of leptospirosis is limited to 2 noninvasive tests, based on high sensitivity and speci- ficity, reasonable cost, and speed of turn-around: UÊ iVÀoÃVo«iVÊ>}}lÕÌin>ÌionÊÌiÃÌÊ UÊ*olÞmiÀ>ÃiÊVh>inÊÀi>VÌionÊ* ,®°Ê /®ÊFigure 8) Microscopic Agglutination Test The MAT has long been the standard for leptospirosis diagnosis and is available through most commercial, state, and veterinary college diagnostic laboratories. UÊDiagnostic titers: Ideally, a 4-fold increase in the serum titer documented over a 2- to 4-week peri- od is preferred to confirm a diagnosis, although Figure 7. Edema and hemorrhage of the urinary bladder Figure 8. Photomicrograph of leptospiral microscopic agglutination test with live anti- gen, using darkfield microscopy technique July/August 2012 Today's Veterinary Practice 29