Clinicopathologic Findings in Dogs with Protein-Losing Nephropathy and Anti-Borrelia burgdorferi Antibodies
ACVIM 2008
D.J. Slade; T.J. Nolan; M.P. Littman
University of Pennsylvania School of Veterinary Medicine
Philadelphia, PA, USA

The purpose of this retrospective study was to review findings in clinical cases at a referral teaching hospital which were positive for Borrelia burgdorferi (Bb) antibodies by the SNAP-3Dx or SNAP-4Dx (IDEXX) in-house tests and which demonstrated evidence of protein-losing nephropathy (Lyme+PLN). Medical records were reviewed for variables such as signalment, history, clinical signs, results of CBC, biochemical profile, urinalysis, urine protein/creatinine ratio (UPC), exposure to co-infections, renal histopathologic findings, treatments, and outcome.

From May 2001, the SNAP-3Dx (IDEXX) in-house assay was used to test for heartworm antigen and antibodies against Bb and Ehrlichia canis. After Nov 2006, the SNAP-4Dx assay was used to test for the above and anti-Anaplasma phagocytophilum/platys (Ap) antibodies. Positive Bb antibody test results were found in 215/919 (23%) of healthy blood donor dogs compared with 962/3941 (24%) of hospital clinic cases during the period of May 2001-Dec 2007.

Medical records from the hospital population of Bb-seropositive dogs were studied. Within our referral population, 102/962 (10%) of Lyme-positive dogs showed evidence of protein-losing nephropathy (hypoalbuminemia, proteinuria). A preliminary review of 55 of these cases was undertaken. Breeds most frequently represented included Labrador Retrievers (16/55, 29%), Golden Retrievers (6/55, 10%), and mixed breed (15/55, 27%), with males comprising 47% (26/55). Average patient weight was 26.1 kg and average age at presentation was 6.3 years.

Common presenting complaints in 55 dogs included inappetance (89%), lethargy (89%), vomiting (72%), weight loss (69%), peripheral lymphadenopathy (33%), and polyuria/polydipsia (31%); only 9% had a history of lameness and 11% had previous Lyme vaccination. Common blood test abnormalities on admission included anemia (49/53, 92%), thrombocytopenia (42/53, 79%), azotemia (50/52, 96%), hypoalbuminemia (47/52, 90%), and hypercholesterolemia (15/52, 29%). Urinalysis and UPC in all 55 dogs confirmed proteinuria (100%) with USG <1.022 in 72%, glucosuria (27%), and bilirubinuria (27%). Hypertension during hospitalization was found in 69% (37/54). A small group of patients showed antibodies to Ehrlichia canis (3/55, 5%) or Rickettsia rickettsii (2/38, 5%). Anti-Ap antibodies were found in 14% (2/14) of Lyme+PLN dogs tested.

Patients were treated with doxycycline (42/55, 76%), ACE inhibitors (43/55, 78%), amlodipine (14/55, 25%), low-dose aspirin (18/55, 33%), and famotidine (33/55, 60%). A small group (6/55, 11%) received immunosuppressive doses of prednisone. Follow-up of 30 dogs found 60% (18/30) were euthanized or died with mean survival of 24 days post-admission.

In this preliminary study, dogs seropositive for Bb antibodies and exhibiting signs of protein-losing nephropathy had a high mortality rate in the initial period following diagnosis. Further study is warranted to investigate whether other therapeutic modalities, including immune suppression, may be of benefit to these patients.

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Dennis Slade

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