Page 1170 - Cote clinical veterinary advisor dogs and cats 4th

584 Leptospirosis

• Other causes of hepatic injury (e.g., bacterial PCR assays: • Intravenous fluid therapy as needed to replace
cholangiohepatitis, toxic hepatopathy, sepsis, • Sensitive and specific; may be positive in initial deficits, guided by quantification of
VetBooks.ir Initial Database • Identifies Leptospira but not serovars large-volume fluid administration, whereas
urine production. Polyuric patients may need
early infection before rise in specific antibody
idiopathic chronic hepatitis [p. 442])
detected by MAT is present.
anuric/oliguric patients must not be fluid
• CBC
overloaded and may need dialysis.
persist in urine. Because the exact timing of
○ White blood cells (WBCs): neutrophilia; • Leptospires appear in blood first and then • Management of kidney and liver injury and
± left shift, lymphopenia, monocytosis appearance is not known, both urine and other consequences of infection (pp. 23, 269,
○ Red blood cells (RBCs): mild to moderate blood testing is recommended. and 442)
nonregenerative anemia • False-negatives are possible and are especially
○ Platelets: thrombocytopenia in > 50% of likely after the start of antibiotic therapy. Recommended Monitoring
patients; may be severe Point-of-care assays: • Renal, hepatic, and electrolyte parameter
• Serum biochemistry profile • Point-of-care and laboratory ELISA tests are monitoring to assess response to treatment
○ Azotemia and hyperphosphatemia are available. and to adjust therapy
common. • Formats that detect IgM (Witness Lepto, • Blood pressure because systemic hypertension
○ Increased alanine aminotransferase (ALT), Zoetis) and IgG (SNAP Lepto, IDEXX) are may occur and require treatment (p. 1065)
alkaline phosphatase (ALP), and bilirubin available. • Urine output monitoring is essential in
are common in azotemic patients; however, • Assays are subject to some of the same patients with AKI (p. 23).
isolated hepatic injury is rare. limitations as MAT testing, with the pos- • Monitor for development of complications
○ Electrolyte disturbances: hyponatremia, sibility of a false-negative early in disease (DIC, respiratory failure) (pp. 27 and 269).
hypochloremia, and hypokalemia occur and false-positive related to vaccination.
in some cases; however, dogs with oliguria • As with other types of testing for lepto- PROGNOSIS & OUTCOME
or anuria develop hyperkalemia. spirosis, these point-of-care assays must be
○ Metabolic acidosis (low pH on blood interpreted in light of history, signs, and • Survival rates for dogs with clinical lepto-
gas analysis, low bicarbonate concentra- often in combination with other types of spirosis: 70%-85%
tion), often accompanied by increased tests. • Patients with AKI may become oliguric
anion gap Other (often unrewarding and not recommended) or anuric. These patients benefit from
○ Hypoalbuminemia due to vasculitis or • Dark-field microscopy: false-negatives dialysis or continuous renal replacement
severe liver dysfunction common therapy (CRRT) and often do well after
• Urinalysis • Organism identification in tissues section: treatment.
○ Isosthenuria/hyposthenuria invasive • Patients may recover clinically but have
○ Signs of tubular damage: glucosuria, • PCR of tissue section: invasive persistent evidence of liver and kidney injury.
proteinuria, granular casts • Urine or blood culture: fastidious organisms; Many continue to improve over the following
○ Polyuria, oliguria, and anuria are all false-negatives common months, whereas others have chronic disease
possible. (p. 167).
• Thoracic radiographs: interstitial to severe TREATMENT
reticulonodular pattern, alveolar infiltrates PEARLS & CONSIDERATIONS
with pulmonary involvement and effusion Treatment Overview
are possible. Treatment goals are to eliminate leptospires, Comments
• Abdominal radiography and ultrasonography: maintain renal perfusion and urine output, • Leptospirosis should be considered as a dif-
± enlargement of liver, spleen, kidneys; prevent disease progression, contain shedding ferential in any case of AKI, fever, vasculitis,
renomegaly, pyelectasia, increased renal in the environment, and treat associated condi- and/or acute or chronic liver disease in a
cortical echogenicity, perinephric effusion, tions (kidney injury, hepatic insufficiency, DIC, dog.
and a medullary rim sign (medullary band uveitis). • Due to zoonotic potential, precautions
of increased echogenicity) should be taken when handling suspected
• Coagulation profile (p. 1325): prolonga- Acute General Treatment leptospirosis patients.
tions of prothrombin time and/or partial • Whenever possible, doxycycline should be • Early identification, isolation, and treatment
thromboplastin time with increased FDP used as the initial antimicrobial because it (e.g., antibiotics) are important for the
are common. treats the leptospiremia and clears the carrier patient’s recovery and to reduce the risk of
state that leads to environmental shedding. transmission.
Advanced or Confirmatory Testing If urine is to be submitted for PCR testing, • Canine leptospirosis is a reportable disease in
Microscopic agglutination test (MAT) and PCR collect sample before or as soon as possible some U.S. states; contact regional authorities.
are the most commonly used diagnostic tests. after antimicrobial treatment is begun. • Hemodialysis and CRRT are widely avail-
MAT titer should not be used to determine ○ Doxycycline 5 mg/kg PO or IV q 12h able and should be considered for AKI
causative serovar: for 2 weeks patients.
• Initial titer with acute illness often negative • Doxycycline concentrates in bile and is
• Suggestive excreted in the feces, and supraphysiologic Prevention
○ Single titer ≥ 1:800 in unvaccinated serum concentrations may occur in patients • At-risk dogs should be vaccinated. Dogs
animals with liver disease. In these patients, beta- at risk include pets living in urban areas if
○ Titer ≥ 1:6400 in vaccinated animal, or lactam antibiotics (e.g., penicillin, ampicillin) their environment could be contaminated
titer > 800 to a nonvaccine serovar and can be initially used to clear the leptospi- by wildlife or rodents.
a concurrent titer < 400 to a vaccine remia. This must be followed with 2 weeks • Currently, bivalent vaccines containing
serovar of doxycycline to clear the carrier state. icterohaemorrhagiae and Canicola serovars
• Diagnostic ○ Ampicillin 20 mg/kg IV q 6h, with dose and vaccines containing icterohaemorrhagiae,
○ Paired titers 2-4 weeks apart with fourfold reduction for azotemic dogs, or Canicola, grippotyphosa, and Pomona serovars
increase from first to second titer or ○ Penicillin sodium 25,000-40,000 U/kg IV are available in North America. These vac-
seroconversion from negative to positive q 12h, with dose reduction for azotemic cines produce serospecific immunity but may
titer dogs offer some immunity to antigenically similar

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