Page 1491 - Small Animal Internal Medicine, 6th Edition

CHAPTER 94 Polysystemic Bacterial Diseases 1463

Clinical Findings
Dogs of any age, breed, or gender can develop leptospirosis BOX 94.2
VetBooks.ir if not previously immune. Male, middle-aged, herding dogs; Clinical Findings in Dogs With Leptospirosis
hounds; working dogs; and mixed-breed dogs were at greater
Signalment
risk than companion dogs younger than 1 year in one study
(Ward et al., 2002). But in a more recent study, small breed All ages, breeds, and gender
dogs were over-represented (Lee et al., 2014). Dogs with per- History
acute clinical disease are usually presented for evaluation
of anorexia, depression, generalized muscle hyperesthesia, Exposure to appropriate reservoir host or contaminated
environment
tachypnea, and vomiting (Box 94.2). Fever, pale mucous Urban environment common
membranes, and tachycardia are usually present. Petechiae, Anorexia, depression, lethargy
ecchymoses, melena, and epistaxis occur frequently from
thrombocytopenia and disseminated intravascular coagu- Physical Examination
lation. Peracute infections may rapidly progress to death Fever
before marked renal or hepatic disease is recognized. Anterior uveitis
Fever, depression, and clinical signs or physical exami- Hemorrhagic tendencies, including melena, epistaxis,
nation findings consistent with hemorrhagic syndromes, petechiae, and ecchymoses
hepatic disease, renal disease, or a combination of hepatic Vomiting, diarrhea
and renal disease are common in subacutely infected dogs. Muscle or meningeal pain
Conjunctivitis, panuveitis, rhinitis, tonsillitis, cough, and Renomegaly with or without renal pain
dyspnea occur occasionally. Oliguric or anuric renal failure Hepatomegaly
Polyuria/polydipsia
can develop during the subacute phase. Clinical findings can Icterus
vary on the basis of the infecting serovar (Goldstein et al., Coughing or respiratory distress
2006). The pulmonary hemorrhagic syndrome described
in people is likely to occur in dogs as well, so leptospiro- Clinicopathologic and Imaging Findings
sis should be on the differential list for dogs with dyspnea Thrombocytopenia
(Klopfleisch et al., 2010). Leukopenia (acute)
Some dogs that survive peracute or subacute infection Leukocytosis (subacute)
develop chronic interstitial nephritis or chronic active hepa- Azotemia
titis. Polyuria, polydipsia, weight loss, ascites, and signs of Suboptimal urine concentrating ability
hepatic encephalopathy secondary to hepatic insufficiency Pyuria and hematuria without obvious bacteriuria
are the most common manifestations of chronic leptospirosis. Hyperbilirubinemia and bilirubinuria
Increased activities of alanine transaminase, aspartate
Diagnosis transaminase, alkaline phosphatase, and creatine
kinase
Multiple nonspecific clinicopathologic and imaging abnor- Interstitial to alveolar lung disease
malities occur in dogs with leptospirosis and vary depend- Hepatomegaly or renomegaly
ing on the host, the serovar, and whether the disease was
peracute, subacute, or chronic. Leukopenia (peracute lep- Diagnosis
tospiremic phase), leukocytosis with or without a left shift, Culture of urine, blood, or tissues
thrombocytopenia, regenerative anemia (from blood loss), Demonstration of the organism in urine by darkfield or
or nonregenerative anemia (from chronic renal or hepatic phase-contrast microscopy
disease) are common hematologic abnormalities. Hyponatre- Demonstration of organismal DNA in urine, blood, or
tissues by PCR
mia; hypokalemia; hyperphosphatemia; hypoalbuminemia; Combination of increasing antibody titer with clinical
hypocalcemia; azotemia; hyperbilirubinemia; decreased signs and response to therapy
total carbon dioxide concentrations; and increased activities
of alanine transaminase, alkaline phosphatase, and aspar- PCR, Polymerase chain reaction.
tate transaminase are common serum biochemical abnor-
malities that develop from renal disease, hepatic disease,
gastrointestinal losses, or acidosis. Hyperglobulinemia is abnormalities. Mineralization of the renal pelves and corti-
detected in some dogs with chronic leptospirosis. Dogs ces can occur with chronic leptospirosis. On histopathologic
with myositis may have increased creatine kinase activity. evaluation of renal tissues, mesangial proliferative glomeru-
Urinalysis abnormalities include bilirubinuria, suboptimal lonephritis with or without interstitial nephritis were the
urine specific gravity in the face of azotemia, granular casts, most common lesions in one study (Ortega-Pacheco, 2008).
and increased numbers of granulocytes and erythrocytes. Detection of anti-Leptospira antibodies is commonly
The organism is not seen in the urine sediment by light performed by a microscopic agglutination test (MAT). In
microscopy. Renomegaly, hepatomegaly, and interstitial or some countries, there are also now two commercially avail-
alveolar pulmonary infiltrates are common radiographic able point of care assays (Zoetis Animal Health; IDEXX