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Featured Case Study:
Three-year-old male intact Labrador retriever, Jake Douglas
Jane
Robertson, DVM, DACVIM and Richard E. Goldstein, DVM, DACVIM,
DECVIM-CA
Interpretation
Hematology
There is mild normocytic, normochromic nonregenerative anemia. This
anemia is most likely a result of chronic inflammatory disease.
Decreased erythropoeiten production secondary to renal insufficiency
may be contributing to the anemia. The modest leukocytosis composed of
mature neutrophilia and monocytosis with concurrent lymphopenia is
consistent with an established inflammatory condition. The
thrombon/platelets are within normal limits.
Clinical chemistry profile
There is a mild increase in BUN, creatinine and phosphorus in
conjunction with isothenuric urine, indicating that this dog has renal
azotemia. There is a moderate hypoalbuminemia with a concurrent
significant proteinuria, indicating that the dog has a protein-losing
glomerulonephropathy. Confounding the renal azotemia, the severe
hypoalbuminemia will lower colloid oncotic pressure, decreasing
intravascular fluid volume and renal perfusion. This would likely
result in a prerenal contribution to the azotemia.
Increases in ALT suggest mild hepatocellular injury. Increases in
alkaline phospatase indicate cholestasis. In this case, these changes
are most likely secondary to systemic or intrahepatic vasculitis or a
reactive or vacuolar hepatopathy, which can be associated with chronic
inflammation, infection or ischemia. Bile acids would help to rule out
that liver dysfunction was not contributing to the hypoalbuminemia.
Vasculitis and third-space loss may be contributing to the low albumin
in this patient as well.
Urinalysis
The urine is isothenuric, indicating tubular inability to concentrate
the urine. The presence of granular casts supports that there has been
tubular damage, however, the number of casts in the urine cannot
reliably predict the severity, reversibility or duration of this
injury. The degree of proteinuria indicates significant glomerular
disease.
Serology
Given that this dog has clinical signs of lameness and uveitis, and
has laboratory data supporting a protein-losing nephropathy, the
positive Lyme C6 antibody test indicates that this dog most
likely has an active Lyme infection.
Cytology
Arthrocentesis—The
suppurative inflammatory joint fluid with no obvious identifiable
etiologic agent is consistent with immune-mediated polyarthritis or
polyarthritis resulting from a rickettsial infection such as
ehrlichiosis, or in this case, is suspected to be secondary to an
infection with Borrelia burgdorferi.
  
Lyme node FNA—Reactive
lymphoid hyperplasia suggests a systemic inflammatory reaction. In
this case, this is likely secondary to the Lyme infection.
Histopathology
Renal biopsy—The
histopathologic lesions in the kidney are unique and consistent with
glomerulotubular disease seen with a syndrome known as Lyme
nephropathy.
Diagnosis
Given the clinical and laboratory findings, a diagnosis of Lyme
disease resulting in Lyme nephritis, olyarthritis, systemic vasculitis
and uveitis is strongly suspected.
Additional Recommended Diagnositics
- Blood was sent to IDEXX Reference Laboratories for a Lyme Quantitative C6
Antibody Test. This two-tiered approach to diagnosing and
monitoring Lyme disease allows C6 antibody levels to be
followed in this dog. Studies have shown that drops in Lyme C6
antibody levels correlate with effective treatment.
- Co-infections with tick-borne diseases is quite common. Screening
for additional tick-borne diseases would be prudent. The dog was
negative for E. canis on the IDEXX SNAP® 3Dx®
Test, but Anaplasma phagocytophilium (formerly known as
Ehrlichia equi) also uses Ixodes species ticks
(deer ticks) as its vector.
- Blood pressure measurement should be obtained since hypertension
is common with glomerulonephritis.
Treatment/Plan
- Hospitalization and treatment with intravenous fluids is
indicated until the patient’s condition is stabilized (i.e., azotemia
has resolved or plateaued, the fever has resolved, the lameness and
lymphadenopathy has improved, and the dog is eating and drinking).
- At least a one-month course of doxycycline at 10 mg/kg/day should
be initiated immediately.
- Management of the uveitis with topical glucocorticoid containing
ophthalmic drops and atropine is also indicated.
- Long-term management of this patient will require treatment with
an angiotensin-converting enzyme (ACE) inhibitor such as enalapril, a
low-protein renal diet, omega-3 fatty acids and low-dose aspirin.
- The renal panel and UPC Ratio should be monitored at regular intervals
in this patient to aid in follow-up treatment decisions and
assessment of long-term prognosis.
- Hypertension should be monitored and managed appropriately.
Prognosis
Lyme nephritis is a devastating glomular-tubular disease that carries
a guarded long-term prognosis. Early diagnosis is critical. All dogs
in endemic areas should be screened for Lyme with the SNAP 3Dx Test.
Every positive dog should be screened for proteinuria. Additionally,
in endemic areas, every time proteinuria is detected in a dog, it
should be screened for Lyme. This is the key to early recognition of
this disease, which will lead to earlier treatment and a better
prognosis. Close monitoring of the individual patient is critical in
the management of the disease and assessing its progression.
Prevention
Prevention of Lyme disease includes reducing tick exposure, utilizing
tick repellant products and consideration of vaccinating at-risk
patients.
Zoonotic Potential
Since pets share our environment, they may incidentally become our
sentinels; therefore, borreliosis in our canine companions should be a
warning to increase vigilance and re-evaluate tick-prevention
protocols. Lyme disease is not transmissible directly from the canine
patient to the owner. However, the owners should be educated that they
are living in a tick-endemic area and the ticks may be infected with
Lyme disease.
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Introducing the
Archos® Digital Video Recorder*
for easy capture and submission of ultrasound videos and still images.
The digital video recorder, when connected to your ultrasound
machine, records a digital video of your ultrasound that can be
transmitted easily to IDEXX
Telemedicine for consultation with board-certified specialists.
IDEXX Telemedicine provides consultative services in the areas of
cardiology, radiology and internal medicine. With the availability of
the digital video recorder, IDEXX Laboratories continues its
commitment to innovation in veterinary diagnostics.
 Digital
video recorder features:
-
Simple set-up and use
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Easy access to board-certified specialists
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Fast turnaround times
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Case submission to IDEXX Telemedicine independent of current
ultrasound software package
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No membership fees—pay per consultation
To order the digital video recorder, call a representative at 1-800-593-4207.
For a complete list of IDEXX Telemedicine services, visit idexx.com/telemedicine.
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